2025-01126 SUPPLEMENTAL MATERIAL - Airport South Industrial Annexation (P21-017) (Noticed on 11072025; Published 11072025; Passed for Publication 10212025; Published 10242025) [Updated 11/18/2025 @4:41 PM] - Part 6 — Sacramento City Council, November 18, 2025 (part 1 of 5)

Natomas Basin Habitat
Conservation Plan Area
Biological Effectiveness
Monitoring Report
2022 ANNUAL SURVEY RESULTS
ICF. 2023. Natomas Basin Habitat Conservation Plan Area Biological Effectiveness Monitoring Report. Final. April. Prepared for the Natomas Basin Conservancy, Sacramento, CA. Prepared by ICF, Sacramento, CA.

FINAL

BIOLOGICAL EFFECTIVENESS MONITORING

FOR THE NATOMAS BASIN

HABITAT CONSERVATION PLAN AREA
2022 ANNUAL SURVEY RESULTS
P R E P A R E D F O R :

The Natomas Basin Conservancy
2150 River Plaza Drive, Suite 460
Sacramento, CA 95833
Contact: John Roberts, Executive Director
916.649.3331
P R E P A R E D B Y :

ICF
980 9th Street, Suite 1200
Sacramento, CA 95814
Contact: Douglas Leslie
916.737.3000
April 2023

ICF. 2023. Biological Effectiveness Monitoring for the Natomas Basin Habitat Conservation Plan Area 2022 Annual Survey Results. April. Final. (ICF 104332.) Sacramento, CA. Prepared for the Natomas Basin Conservancy, Sacramento, CA.

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Contents
List of Tables iv ..........................................................................................................................................

List of Figures vi .........................................................................................................................................

List of Acronyms and Abbreviations ix ......................................................................................................

Chapter 1 Introduction 1-1 ......................................................................................................................

1.1 Background 1-1 ......................................................................................................................

1.1.1 1-2 Location .....................................................................................................................

1.1.2 Setting 1-2 .......................................................................................................................

1.2 The Biological Effectiveness Monitoring Program 1-3 ...........................................................

1.2.1 Goals and Objectives 1-3 .................................................................................................

1.2.2 Covered Species 1-3 ........................................................................................................

1.2.3 Types of Monitoring 1-3 ..................................................................................................

1.3 Summary of the 2022 Biological Effectiveness Monitoring Program Results 1-5 .................

1.4 References 1-6 .......................................................................................................................

Chapter 2 Land Cover Mapping, Botanical Inventory, and Noxious Weed Monitoring 2-1 .......................

2.1 Introduction 2-1 .....................................................................................................................

2.1.1 Background 2-1 ................................................................................................................

2.1.2 Goals and Objectives 2-1 .................................................................................................

2.2 Methods 2-2 ...........................................................................................................................

2.2.1 Land Cover Mapping 2-2 .................................................................................................

2.2.2 Botanical Surveys 2-3 ......................................................................................................

2.2.3 Noxious Weed Mapping 2-3 ............................................................................................

2.3 Results 2-4 ..............................................................................................................................

2.3.1 Land Cover Types Basin-Wide 2-4 ...................................................................................

2.3.2 Land Cover Types on Reserves 2-5 ..................................................................................

2.3.3 Noxious Weed Surveys 2-6 ..............................................................................................

2.3.4 Botanical Surveys 2-6 ......................................................................................................

2.4 Discussion 2-7 ........................................................................................................................

2.4.1 Land Cover Types Basin-Wide 2-7 ...................................................................................

2.4.2 Land Cover Types on Reserves 2-7 ..................................................................................

2.4.3 Botanical Surveys 2-7 ......................................................................................................

2.4.4 Noxious Weeds 2-8 ..........................................................................................................

2.5 Effectiveness 2-8 ....................................................................................................................

2.6 Recommendations 2-8 ...........................................................................................................

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2.7 References 2-9 .......................................................................................................................

Chapter 3 Giant Gartersnake 3-1 .............................................................................................................

3.1 Introduction 3-1 .....................................................................................................................

3.1.1 Background 3-1 ................................................................................................................

3.1.2 Goals and Objectives 3-2 .................................................................................................

3.1.3 Life History 3-3 .................................................................................................................

3.1.4 History of the Natomas Basin 3-5 ....................................................................................

3.2 Methods 3-5 ...........................................................................................................................

3.2.1 Trapping Giant Gartersnake 3-5 ......................................................................................

3.2.2 Analytical Methods 3-7 ....................................................................................................

3.2.3 Habitat Assessment 3-10 .................................................................................................

3.2.4 Radio-Telemetry Translocation Study 3-11 .....................................................................

3.2.5 American Bullfrog Capture-Mark-Recapture Study 3-11 ................................................

3.3 Results 3-12 ............................................................................................................................

3.3.1 Demography 3-13 ............................................................................................................

3.3.2 Distribution of Giant Gartersnake on Reserve Lands 3-15 ..............................................

3.3.3 Habitat Assessment 3-16 .................................................................................................

3.3.4 Radio-Telemetry Translocation Study 3-20 .....................................................................

3.3.5 American Bullfrog Capture-Mark-Recapture Study 3-21 ................................................

3.4 Discussion 3-21 ......................................................................................................................

3.4.1 Demography 3-21 ............................................................................................................

3.4.2 Distribution of Giant Gartersnake on Reserve Lands 3-24 ..............................................

3.5 Effectiveness 3-26 ..................................................................................................................

3.6 Recommendations 3-28 .........................................................................................................

3.7 References 3-29 .....................................................................................................................

Chapter 4 Swainson’s Hawk 4-1 ..............................................................................................................

4.1 Introduction 4-1 .....................................................................................................................

4.1.1 Background 4-1 ................................................................................................................

4.1.2 Goals and Objectives 4-2 .................................................................................................

4.1.3 Life History 4-2 .................................................................................................................

4.2 Methods 4-4 ...........................................................................................................................

4.2.1 Population Assessment 4-4 .............................................................................................

4.2.2 Habitat Assessment 4-4 ...................................................................................................

4.3 Results 4-4 ..............................................................................................................................

4.3.1 Population Assessment 4-4 .............................................................................................

4.3.2 Habitat Assessment ................................................................................................... 4-7

4.4 Discussion ........................................................................................................................ 4-8 Biological Effectiveness Monitoring for the
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4.5 Effectiveness .................................................................................................................. 4-10

4.6 Recommendations ......................................................................................................... 4-11

4.7 References ..................................................................................................................... 4-12 Chapter 5 Other Covered Wildlife Species 5-1 .........................................................................................

5.1 Introduction 5-1 .....................................................................................................................

5.1.1 Background 5-1 ................................................................................................................

5.1.2 Goals and Objectives 5-2 .................................................................................................

5.2 Methods 5-2 ...........................................................................................................................

5.2.1 Surveys on Reserves 5-2 ..................................................................................................

5.2.2 Surveys on SAFCA Reserves 5-3 .......................................................................................

5.2.3 Non-Reserve Land Surveys 5-3 ........................................................................................

5.2.4 Analytical Methods 5-3 ....................................................................................................

5.3 Results 5-4 ..............................................................................................................................

5.3.1 Generalized Avian Surveys 5-4 ........................................................................................

5.3.2 Other Covered Species 5-8 ..............................................................................................

5.4 Discussion 5-13 ......................................................................................................................

5.5 Effectiveness 5-15 ..................................................................................................................

5.6 Recommendations 5-15 .........................................................................................................

5.7 References 5-17 .....................................................................................................................

Appendix A NBHCP Reserve Land Cover Data
Appendix B Botanical Survey Results
Appendix C Avian and Other Covered Species Survey Results

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Tables
Tables appear at the end of the chapter in which they are referenced 1-1 Reserve Lands Acquired under the NBHCP on which Biological Effectiveness Monitoring was Conducted 1-7 .............................................................................................................................. 1-2 Species Covered under the NBHCP 1-8 ............................................................................................... 2-1 Basin-Wide Extent (acres) of Mapped Land Cover Types, 2005–2022 2-11 ....................................... 2-2 Basin-Wide Summary of Major Habitat Types, 2005–2022 2-12 ........................................................ 2-3 On-Reserve Extent (acres) of Mapped Land Cover Types, 2005–2022 2-13 ...................................... 2-4 On-Reserve Summary of Major Habitat Types, 2005–2022 2-14 ....................................................... 2-5a On-Reserve Extent of Major Habitat Types as a Proportion of Each Habitat Type in the Basin, 2005–2014 2-15 ........................................................................................................................ 2-5b On-Reserve Extent of Major Habitat Types as a Proportion of Each Habitat Type in the Basin, 2015–2022 2-15 ........................................................................................................................ 2-6 Noxious Weed Occurrences on TNBC Reserve Lands, 2005–2022 2-16 ............................................. 3-1 Summary of Giant Gartersnake Captures and Sampling Effort at Natomas Basin Conservancy Reserves, 2022 3-31 ....................................................................................................... 3-2 Prior Probabilities for Parameters of Single-Season Occupancy Models for Giant Gartersnake on Natomas Basin Conservancy Reserve Properties, 2022 3-32 ................................... 3-3 Model-Averaged Posterior Distributions for Capture Parameters of Closed Abundance Model of Giant Gartersnake in the Natomas Basin, 2022 3-32 .......................................................... 3-4 Summary of Giant Gartersnake Captures and Abundance Estimates, 2022 3-33 .............................. 3-5 Posterior Summaries for Parameters from the Robust-Design CMR Model, 2018–2022 3-33 .......... 3-6 Posterior Model Probabilities for Probability of Occurrence of Giant Gartersnake Based on Habitat on Natomas Basin Conservancy Reserves, 2022 3-33 ...................................................... 3-7 Posterior Distributions for Parameters of the Final Single-Season Occupancy Habitat Model for Giant Gartersnake on Natomas Basin Conservancy Reserve Properties, 2022 3-34 ......... 3-8 Posterior Model Probabilities for Effects of Habitat on Dynamic Occupancy of Giant Gartersnake on Natomas Basin Conservancy Reserves, 2011–2022 3-34 .......................................... 4-1 Results of 2022 Swainson’s Hawk Surveys, NBHCP Area 4-14 ............................................................ 4-2 Reproductive Data for Active Swainson’s Hawk Territories in the NBHCP Area, 1999– 2022 4-18 ............................................................................................................................................

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4-3 Number of Active Territories on the Sacramento River, 2001–2022 4-19 ......................................... 4-4 Swainson’s Hawk Foraging Habitat in the NBHCP Area (acres), 2004–2022 4-19 .............................. 4-5 Extent and Proportion of Suitable Swainson’s Hawk Foraging Habitat on and off TNBC Reserve Lands, 2022 4-19 ................................................................................................................... 5-1 Summary of Results of Monthly Avian Surveys by Reserve and Tract, 2018–2022 5-17 ................... 5-2 Number of Pairs of Other Covered Species on TNBC Mitigation Lands, 2004–2022 5-18 ................. 5-3 Average Number of Observations per Survey of Other Covered Species Recorded during Monthly Avian Surveys on Reserves, 2005–2022 5-19 ....................................................................... 5-4 Average Number of Observations per Survey of Other Covered Species Recorded during Monthly Basin-Wide Surveys, 2005–2022 5-19 ..................................................................................

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Figures
Figures follow the tables in each chapter
1-1 Project Location
1-2 Natomas Basin Reserves
1-3 Central and Northern Basin Habitats
1-4 Riparian Habitats in the Northern Basin
1-5 Southern and Western Basin Habitats
1-6 Eastern Basin Habitats
2-1 Distribution of Land Cover Types in the Natomas Basin, 2022 2-2 Changes in Acreage of the Major Habitat Types in the Natomas Basin, 2004–2022 2-3 Sankey Canal Giant Gartersnake Tule Bench along the Northwest Edge of the Lucich North Tract in the North Basin Reserve
3-1 Giant Gartersnake
3-2 Areas Sampled for Giant Gartersnake in the Natomas Basin in 2022 3-3 Model Averaged Effect of an Ephemeral Behavioral Response and Water Temperature on Giant Gartersnake Capture Probability in the Natomas Basin in 2022 3-4 Posterior Distribution of Estimated Giant Gartersnake Abundance in the Sampled Area at BKS Based on Closed Population Models in 2022
3-5 Posterior Distribution of Estimated Giant Gartersnake Abundance in the Sampled Area at Sills Based on Closed Population Models in 2022
3-6 Posterior Distribution of Estimated Giant Gartersnake Abundance in the Sampled Area at Lucich North Based on Closed Population Models in 2022 3-7 Posterior Distribution of Estimated Giant Gartersnake Abundance in the Sampled Area at Lucich South Based on Closed Population Models in 2022 3-8 Distribution of Male and Female Snout-Vent Length (A) and Mass (B) in the Natomas Basin, 2022
3-9 Annual Apparent Survival Estimate for Giant Gartersnake in the BKS Tract, 2018-2022 3-10 Annual Apparent Survival Estimate for Giant Gartersnake in the Lucich North Tract, 2018-2022
3-11 Annual Apparent Survival Estimate for Giant Gartersnake in the Sills Tract, 2018-2022

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3-12 Proportion of Reserve Sites Occupied (A) and Number of Occupied Sites (B) Based on Static Occupancy Models for the Natomas Basin, 2022
3-13 Effect of (A) Water Temperature and (B) Date on the Detection Probability of Giant Gartersnake in the Natomas Basin, 2022
3-14 Annual Probability of Occurrence of Giant Gartersnake on Reserves Based on the Dynamic Occupancy Model
3-15 Estimated Number of Sampled Reserve Sites Occupied by Giant Gartersnake 3-16 Annual Intrinsic Rate of Occupancy Growth for Giant Gartersnake in Reserves, 2011- 2022
3-17 Suitability of Habitat in the Canals of the Natomas Basin for Giant Gartersnake in 2022 4-1 Swainson’s Hawk
4-2 Swainson’s Hawk Range
4-3 Swainson’s Hawk Nesting and Foraging Habitat
4-4 General Representation of Swainson’s Hawk Breeding Cycle in the Central Valley 4-5 Swainson’s Hawk in the Nest
4-6 Number of Occupied Swainson’s Hawk Nesting Territories, Successful Nests, and Total Young Fledged in the Natomas Basin, 2001–2022
4-7 Trends in the Number of Occupied Territories in the Natomas Basin Nesting Population, 2001–2022
4-8 Various Measures of Swainson’s Hawk Reproductive Success in the Natomas Basin, 1999–2022
4-9 Trends in the Number of Young Fledged Per Successful Nest in the Breeding Population of Swainson’s Hawk in the Natomas Basin, 1999–2022
4-10 Number of Occupied Swainson's Hawk Nesting Territories along the Sacramento River in the Natomas Basin, 2001–2022
4-11 Changes in the Abundance of Three Categories of Swainson’s Hawk Foraging Habitat in the Natomas Basin, 2004–2022
4-12 Distribution of Suitable Swainson’s Hawk Foraging Habitat, 2022 5-1 Monthly Basin-Wide Survey Routes
5-2 Mean Number of Raptors Detected per Survey on TNBC Reserves in the Natomas Basin, 2005–2022

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5-3 Mean Number of Waterfowl Detected per Survey on TNBC Reserves in the Natomas Basin, 2005–2022
5-4 Mean Number of Neotropical Migrants Detected per Survey on TNBC Reserves in the Natomas Basin, 2005–2022
5-5 Mean Number of Shorebirds Detected per Survey on TNBC Reserves in the Natomas Basin, 2005–2022
5-6 Mean Number of Yellow-Billed Magpies and Canada Geese Detected per Survey on TNBC Reserves in the Natomas Basin, 2005–2022
5-7 Mean Number of Loggerhead Shrikes Detected and the Proportion of Surveys on which Shrikes were Detected on TNBC Reserves in the Natomas Basin, 2005–2022 5-8 Mean Number of White-Faced Ibis Detected and the Proportion of Surveys on which Ibis Were Detected on TNBC Reserves in the Natomas Basin, 2005–2022 5-9 Mean Number of Tricolored Blackbird Detected and the Proportion of Surveys on which Blackbirds Were Detected on TNBC Reserves in the Natomas Basin, 2005–2022 5-10 Mean Number of Burrowing Owls Detected and the Proportion of Surveys on which Owls were Detected on TNBC Reserves in the Natomas Basin, 2005–2022 5-11 Mean Number of Pacific Pond Turtles and Unidentified Turtles and the Proportion of Surveys on which Turtles were Detected on TNBC Reserves in the Natomas Basin, 2005– 2022

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Acronyms and Abbreviations
Basin Natomas Basin
BEMT Biological Effectiveness Monitoring Team
Cal-IPC California Invasive Plant Council
CESA California Endangered Species Act
CMR capture-mark-recapture
Covered Species species covered by the Plan
DFG California Department of Fish and Game
DFW California Department of Fish and Wildlife
ESA Endangered Species Act
g grams
GIS Geographic information system
I- Interstate
ICF ICF International and ICF Jones & Stokes
km2 square kilometers
MAP HCP Metro Air Park Habitat Conservation Plan
mm millimeters
NAIP National Agricultural Imagery Program
NBHCP Natomas Basin Habitat Conservation Plan
NLIP Natomas Levee Improvement Program
PIT passive integrated transponder
Plan Natomas Basin Habitat Conservation Plan
plan area NBHCP Area
SAFCA Sacramento Area Flood Control Agency
SCAS Sacramento County Airport System
SMF Sacramento International Airport
SR State Route
SSMP Site-Specific Management Plan
SUL snout-urostyle-length
SVL snout–vent length
TAC Technical Advisory Committee
TNBC The Natomas Basin Conservancy
TVL tail–vent length
USACE U.S. Army Corps of Engineers
USFWS U.S. Fish and Wildlife Service
UTM Universal Transverse Mercator

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Chapter 1
Introduction

CHAPTER HIGHLIGHTS
• 2022 marked the 19th year of comprehensive biological effectiveness monitoring for the Natomas Basin and Metro Airpark Habitat Conservation Plans. • This annual report fulfills the monitoring and reporting requirements of the federal incidental take permit issued by the U.S. Fish and Wildlife Service and the state permit issued by the California Department of Fish and Wildlife.
• A summary of monitoring results for 2022 is provided at the end of this chapter.

1.1 Background
In November 1997, the Natomas Basin Habitat Conservation Plan (NBHCP) (City of Sacramento 1997) was submitted to the U.S. Fish and Wildlife Service (USFWS) and the California Department of Fish and Game (DFG, now the Department of Fish and Wildlife [DFW]) in support of an application for a federal permit under Section 10(a)(1)(B) of the Endangered Species Act (ESA) and a state permit under Section 2081 of the California Fish and Game Code. USFWS and DFG subsequently approved the NBHCP and issued permits. A modified version of the NBHCP was approved in 2003 (City of Sacramento et al. 2003).

The NBHCP (also referred to as the Plan) was designed to promote biological conservation while allowing economic development and the continuation of agriculture in the Natomas Basin (Basin) (Figure 1-1). The Plan establishes a multispecies conservation program to minimize and mitigate the expected loss of habitat values and the incidental take of species covered by the Plan (hereafter referred to as Covered Species) that could result from urban development and certain actions associated with implementation of the conservation activities that are required as mitigation.

The overall goal of the NBHCP is to minimize incidental take of Covered Species in the NBHCP Area (also referred to as the plan area) and to mitigate the impacts of covered activities on Covered Species and their habitats. Mitigation is accomplished primarily through the acquisition and management of reserve lands for the benefit of Covered Species. The primary biological goal of the NBHCP is to create a system of reserves that contain both wetland and upland components that will support viable populations of Swainson’s hawk (Buteo swainsoni), giant gartersnake (Thamnophis gigas), and other species covered under the Plan.

The Natomas Basin Conservancy (TNBC) is the nonprofit entity responsible for administering and implementing the NBHCP and the Metro Air Park Habitat Conservation Plan (MAP HCP).1 TNBC serves as the Plan Operator on behalf of the City of Sacramento, Sutter County, and the MAP Property Owners Association. TNBC’s actions are governed primarily by the terms of the NBHCP and the commitments set forth in the NBHCP Implementation Agreement. TNBC’s primary function is

1 The MAP HCP covers a 2,015-acre portion of the Basin, adjacent to Sacramento International Airport (SMF), that is part of the 17,500 acres of planned urban development considered in the NBHCP.

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the acquisition and management of reserve lands. To fulfill this function, TNBC develops and implements Site-Specific Management Plans (SSMPs) and Site-Specific Biological Effectiveness Monitoring Plans for its mitigation land holdings within the Basin. A Technical Advisory Committee (TAC) provides technical assistance to TNBC as needed and as described in the NBHCP.

To achieve the goals of the Plan, TNBC retained ICF (formerly ICF International and ICF Jones & Stokes) to conduct the biological effectiveness monitoring required by the NBHCP. ICF has assembled a Biological Effectiveness Monitoring Team (BEMT) to conduct biological effectiveness monitoring to document the progress made toward meeting the biological goals and objectives of the NBHCP and to inform the adaptive management strategy.

By April of 2022, TNBC owned and managed 36 separate tracts totaling approximately 5,104 acres (2,066 hectares) in the Basin on which biological effectiveness monitoring was implemented (Table 1-1). Since 2007, individual tracts of mitigation land have been organized into three main reserves:
the North Basin Reserve, the Central Basin Reserve, and the Fisherman’s Lake Reserve (Figure 1-2).

1.1.1 Location
The Basin is a low-lying area of the Sacramento Valley that encompasses portions of northern Sacramento County and southern Sutter County (Figure 1-1). The 54,206-acre (21,666-hectare) plan area is bounded on the west by the Sacramento River, on the north by the Natomas Cross Canal, on the east by Steelhead Creek (formerly known as the Natomas East Main Drainage Canal), and on the south by Garden Highway (Figure 1-2).

The plan area contains incorporated and unincorporated areas within the jurisdictions of the City of Sacramento, Sacramento County, and Sutter County. The southern portion of the Basin is mostly urbanized, but the rest remains primarily agricultural.

1.1.2 Setting
The Basin is in the historical floodplain of the Sacramento and American Rivers. The historical land cover types in the Basin were wetlands, narrow streams with associated riparian vegetation, shallow lakes, and grasslands on the terraces along the Basin’s eastern edge. During the late 1800s and early 1900s, most of the Basin was converted to agriculture and many native habitats were removed. Channelized water delivery and drainage systems replaced the natural stream corridors.

The lowest areas of the Basin are in the central and northern portions, which are flat, open areas with deep clay soils and which primarily support rice farming (Figure 1-3). Very few trees or native vegetation types are present, except for the mature riparian forest and wetland complex that occur along the length of the Natomas Cross Canal on the Basin’s northern boundary (Figure 1-3).

The southern and western portions of the Basin contain mostly alluvial soils and support a mixture of row, grain, and hay crops. Small remnant stands of valley oak woodland and remnant patches of riparian woodland (e.g., along Fisherman’s Lake), persist throughout this area (Figure 1-4). The Sacramento River, on the Basin’s western edge, supports mature cottonwood-dominated riparian forest. Most of the southern portion of the Basin has been urbanized and consists of residential development (Figure 1-5).

The highest portion of the Basin is the eastern edge, which is on a terrace with gently rolling topography. The eastern edge contains loam and clay-loam soils and supports annual grasslands and The Natomas Basin Conservancy

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both dry and irrigated pastures. Steelhead Creek forms the eastern Basin boundary and is a channelized drainage with an extensive wetland complex and sparse riparian vegetation along its length (Figure 1-6).

1.2 The Biological Effectiveness Monitoring Program

1.2.1 Goals and Objectives
The purpose of the Biological Effectiveness Monitoring Program is to evaluate the effectiveness of the NBHCP with respect to meeting its biological goals and objectives, and to inform the adaptive management strategy. In general, monitoring is designed to establish baseline conditions, track changes over time, and evaluate the effectiveness of management actions. Specific purposes of the Biological Effectiveness Monitoring Program are listed below. • Track population trends of Covered Species within the plan area to evaluate the effectiveness of the NBHCP in sustaining populations of Covered Species in the Basin. • Evaluate the effectiveness of reserve design and management. • Provide information that can be used to improve the design and management of reserves.

Monitoring must be conducted in accordance with the guidelines set forth in the NBHCP to achieve compliance with the provisions of the ESA 10(a)(1)(B) permit.

1.2.2 Covered Species
The NBHCP’s 22 Covered Species are listed in Table 1-2. Two Covered Species—Swainson’s hawk and tricolored blackbird—are currently listed under the California Endangered Species Act (CESA), while a third Covered Species—giant gartersnake—is listed under both CESA and the federal ESA.

Swainson’s hawks and giant gartersnakes are widely distributed in the Basin. Accordingly, most of the monitoring effort is devoted to these two species. These species are addressed individually in Chapter 3, Giant Gartersnake, and Chapter 4, Swainson’s Hawk. The remaining Covered Species are collectively referred to as Other Covered Species and are addressed in Chapter 5, Other Covered Wildlife Species, with the exception of covered plant species, which are addressed in Chapter 2, Land Cover Mapping, Botanical Inventory, and Noxious Weed Monitoring.

1.2.3 Types of Monitoring
The NBHCP and its Implementation Agreement require that monitoring be conducted in accordance with conditions of the ESA 10(a)(1)(B) permit from USFWS and the 2081 permit from DFW.

Therefore, a comprehensive monitoring strategy has been developed to satisfy these conditions.

1.2.3.1 Land Cover Mapping, Botanical Inventory, and Noxious Weed Monitoring
Comprehensive land cover mapping began in 2004 and informs the baseline for all the monitoring efforts. Land cover mapping is conducted both on reserve lands and Basin-wide. The mapping efforts on reserve lands are conducted at a higher resolution than the Basin-wide mapping efforts.

The Natomas Basin Conservancy

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The land cover mapping efforts have built a comprehensive, chronological picture of changes in the distribution and abundance of habitat types in the Basin.

Botanical surveys on reserve lands were initiated in 2004 and are conducted to monitor the vegetative composition, to assess changes in vegetation over time, and to document occurrences of covered plant species.

Noxious weed surveys on reserve lands were also initiated in 2004 to monitor the presence and extent of weed populations that can affect the ability of native habitats to support Covered Species.

The methods and results of these surveys are described in Chapter 2, Land Cover Mapping, Botanical Inventory, and Noxious Weed Monitoring.

1.2.3.2 Giant Gartersnake Monitoring
Monitoring efforts for giant gartersnake have been conducted in the Basin since the late 1990s. A standardized monitoring protocol and survey design was initiated in 2004. The monitoring protocol was modified in 2011 to address issues associated with the low capture probabilities typically encountered with giant gartersnake, and again in 2018 to take advantage of advances in sampling and analytical techniques. Chapter 3, Giant Gartersnake, describes the sampling protocol and methods and presents the results of these surveys.

1.2.3.3 Swainson’s Hawk Monitoring
Systematic Swainson’s hawk monitoring has been conducted under the auspices of the NBHCP since 1999. Because Swainson’s hawks are far-ranging birds, this species is intensively monitored throughout the Basin and on both sides of the drainages that form the periphery of the Basin. The methods and results of the Swainson’s hawk surveys are described in Chapter 4, Swainson’s Hawk.

1.2.3.4 Other Covered Wildlife Species Monitoring
Monitoring of populations of Other Covered Species was initiated in 2004. Surveys on reserve lands are conducted to evaluate the effectiveness of reserve design and management in meeting objectives for Other Covered Species. Surveys on non-reserve lands are conducted to serve as “controls” for comparison to reserve lands to evaluate the success of design and management in increasing the numbers of Other Covered Species. The methods and results of surveys for Other Covered Species are described in Chapter 5, Other Covered Wildlife Species.

1.3 Summary of the 2022 Biological Effectiveness
Monitoring Program Results
This section summarizes the 2022 results of the Biological Effectiveness Monitoring Program. It should be noted that 2017 ended 5 consecutive years of extreme drought in California, with one of the wettest years on record, followed by several more years of extreme drought. These extremes in weather and climate would be expected to negatively affect populations of Covered Species in both predictable and unpredictable ways.

In 2015, construction was completed for the portion of the Natomas Levee Improvement Program (NLIP) setback levee managed by SAFCA along the rural portions of the Sacramento River. Large The Natomas Basin Conservancy

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swaths of grassland, riparian habitat, and managed marsh habitat that were created as mitigation for NLIP have been fully functional for more than 5 years and should contribute significantly to the conservation of Other Covered Species in the Basin.

Changes in land cover types from 2021 to 2022 were significant, with an unprecedented number of acres of rice and upland agricultural lands being fallowed due to extreme drought conditions.

Concomitantly, the rate of development has continued to increase.

The sampling effort for giant gartersnake in 2022 was similar to 2021 and higher than 2020 at the height of the COVID-19 pandemic, but was still lower than other previous years due to issues related to the pandemic. The trapping season and the sampling period have remained consistent since 2021.

The number of snakes caught per unit effort was lower in 2022 than 2021. The size distribution of captured snakes in 2022 was consistent with a healthy population, and estimates of occupancy increased from 2021 to 2022, although the probability that the proportion of occupied sites was stable (i.e., did not change by more than 10%) from 2011 to 2022 was approximately 99%. Apparent survival at the BKS site was higher from 2018 to 2019 than in subsequent years.

The total number of Swainson’s hawk pairs in the Basin declined substantially from 2020 to 2021, but increased in 2022 to the third highest number recorded since monitoring began in 2000, and the total number of pairs continues to exhibit a statistically significant increase over time. Following a substantial decrease in all measures of reproductive success in 2021, reproductive metrics rebounded in 2022 but remained. A statistically significant long-term decline in the number of young produced per successful nest was still evident in 2022, a phenomenon observed across the range of the species in California.

The mean number of loggerhead shrike (Lanius ludovicianus) detections per survey on reserve lands decreased to zero in 2022. Loggerhead shrike detections have been decreasing substantially on reserve lands since 2012, with a more severe decline evident on non-reserve lands. The reasons for the decline are unknown, but are likely related to decreases in insect prey populations.

White-faced ibis (Plegadis chihi) did not nest in the Basin in 2022. Both the mean number of detections per survey and the proportion of surveys with detections decreased in 2022 on both reserve and non-reserve lands. However, white-faced ibis appear to be thriving in the Basin.

Tricolored blackbirds (Agelaius tricolor) did not nest in the Basin in 2022 after nesting successfully for the first time in 9 years in 2020. Both the mean number of detections per survey and the proportion of surveys in which the species was detected on reserve lands decreased slightly from 2021 to 2022. On non-reserve lands, both the mean number of detections per survey and the proportion of surveys on which tricolored blackbirds were detected increased. The species has declined significantly throughout its range, and in 2018 it was listed under CESA as threatened.

Both the mean number of burrowing owls (Athene cunicularia) detected per survey and the proportion of surveys with detections on both reserve and non-reserve lands decreased from 2021 to 2022.

Both the mean number of Pacific pond turtle (Actinemys marmorata) and unknown pond turtle detections per survey and the proportion of surveys with detections increased slightly in 2022. This species now appears to be well established on most (if not all) tracts with managed marsh habitat.

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Biological Effectiveness Monitoring for the
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1.4 References
City of Sacramento. 1997. Natomas Basin Habitat Conservation Plan, Sacramento and Sutter Counties, California. November. Sacramento, CA.

City of Sacramento, Sutter County, and the Natomas Basin Conservancy. 2003. Natomas Basin Habitat Conservation Plan; Sacramento and Sutter Counties, California. Sacramento, CA.

Natomas Basin Conservancy. 2022. Current Base Map. Available: https://www.natomasbasin.org/ helpful-documents/preserve-maps/. Accessed: February 9, 2022.

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Table 1-1. Reserve Lands Acquired under the NBHCP on which Biological Effectiveness Monitoring was Conducted a, b
Reserve/Tract Date Acquired Acres
North Basin Reserve
Atkinson 6/12/03 199
Bennett North 5/17/99 227
Bennett South 5/17/99 132
Bolen North 4/29/05 114
Bolen South 4/29/05 102
Bolen West 9/01/06 155
Frazer 7/31/00 93
Huffman East 9/30/03 136
Huffman West 9/30/03 158
Lauppe North 1/5/22 185
Lauppe South 6/30/20 172
Lucich North 5/18/99 268
Lucich South 5/18/99 352
Nestor 9/1/06 233
Ruby Ranch 6/23/03 91
Verona 7/02/20 116
Vestal 9/12/05 95
Willey 10/19/20 108
Central Basin Reserve
Betts 4/5/99 139
Bianchi West 11/7/06 110
Elsie 11/7/06 158
Elverta 7/13/21 288
Frazer South 11/7/06 110
Kismat 4/16/99 40
Paulsen South 9/28/20 52
Richter 1/03/20 81
Sills 7/15/02 436
Silva 1/7/99 159
Silva South 1 9/28/12 29
Tufts 9/29/04 148
Fisherman’s Lake Reserve
Alleghany 11/7/02 50
Cummings 11/7/02 67
Natomas Farms 7/9/01 55
Rosa Central 3/23/05 100
Rosa East 3/23/05 106
Souza 7/2/01 40
Total 5,104
Source: The Natomas Basin Conservancy 2021.
a Includes only properties owned by TNBC in fee title. Does not include 27.08 acres under easement.

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b Acreage totals gathered through land cover mapping and GIS analysis may vary slightly.

Table 1-2. Species Covered under the NBHCP
Common Name Scientific Name
White-faced ibis Plegadis chihi
Aleutian cackling goosea Branta hutchinsii leucopareiaa Swainson’s hawk Buteo swainsoni
Burrowing owl Athene cunicularia
Loggerhead shrike Lanius ludovicianus
Bank swallow Riparia riparia
Tricolored blackbird Agelaius tricolor
Giant gartersnake Thamnophis gigas
Pacific pond turtle Actinemys marmorata
California tiger salamander Ambystoma californiense
Western spadefoot Spea hammondii
Valley elderberry longhorn beetle Desmocerus californicus dimorphus Vernal pool fairy shrimp Branchinecta lynchi
Midvalley fairy shrimp Branchinecta mesovallensis
Vernal pool tadpole shrimp Lepidurus packardi
Delta tule pea Lathyrus jepsonii ssp. jepsonii
Sanford’s arrowhead Sagittaria sanfordii
Colusa grass Neostapfia colusana
Boggs Lake hedge-hyssop Gratiola heterosepala
Sacramento Orcutt grass Orcuttia viscida
Slender Orcutt grass Orcuttia tenuis
Legenere Legenere limosa
a Formerly Aleutian Canada goose (Branta canadensis leucopareia).

Graphics … 890.10 NBC 3-11-2021) TAG
FIGURE 1-1
Project Location
Sankey Rd.

Riego Rd.

Elverta Rd.

Elkhorn Blvd.

Powerline Rd.

Sacramento
Int'l.

Airport
Northgate Blvd.

Natomas Blvd.

El Centro Rd.

Del Paso Rd.

San Juan Rd.

El Camino Ave.

Steelhead Creek
(Natomas East Main
Drainage Canal)
70 99
5 5
80 15
16 17
18 North Basin Reserve
1 Atkinson
2 Bennett North
3 Bennett South
4 Bolen North
5 Bolen South
6 Bolen West
7 Frazer North
8 Huffman East
9 Huffman West
10 Lucich North
11 Lucich South
12 Nestor
13 Ruby Ranch
14 Vestal
15 Lauppe South
16 Verona
17 Willey
18 Lauppe North

Central Basin Reserve
19 Betts-Kismat-Silva
20 Bianchi West
21 Elsie
22 Frazer South
23 Sills
24 Silva South 1
25 Paulson South
26 Tufts
27 Richter
28 Elverta
Fisherman’s Lake Reserve
29 Alleghany
30 Cummings
31 Natomas Farms
32 Rosa Central
33 Rosa East
34 Souza
20 21
22 23
24 26
25 27
29 30
31 32
33 34
28 19
NBC 104332 (4-20-2023) TG
FIGURE 1-2
Natomas Basin Reserves
Typical habitat of the central and northern Natomas Basin Natomas Cross Canal
Graphics … 890.10 (3-11-2021) TAG
FIGURE 1-3
Central and Northern Basin Habitats
Fisherman’s Lake
Mature riparian forest along the Sacramento River
Graphics … 890.10 (3-11-2021) TAG
FIGURE 1-4
Riparian Habitats in the Northern Basin
Typical habitat of the west and south Natomas Basin
Residential development in the south basin
FIGURE 1-5
Southern and Western Basin Habitats
Graphics … 890.10 (3-11-2021) TAG
Typical habitat of the east basin
Steelhead Creek (formerly the Natomas East Main Drain Canal) FIGURE 1-6
Eastern Basin Habitats
Graphics … 890.10 (3-11-2021) TAG

Biological Effectiveness Monitoring for the
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2022 Annual Survey Results
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Chapter 2
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring

CHAPTER HIGHLIGHTS
• Across the plan area, active rice fields decreased by more than 7,000 acres between 2021 and 2022, while fallow lands increased by over 6,300 acres. • Large developments in the north and west of the plan area have been steadily increasing the acreage of developed land in the plan area.
• There was a spike in noxious weed observations between 2021 and 2022. Large patches of yellow-star thistle, milk thistle, mustard, and Harding grass were identified. Additionally, water primrose was found in all marshes within the reserves.
• No covered plant species were detected, and vernal pools did not pond long enough in 2022 for any Covered Species—if they were present—to be detected.

2.1 Introduction

2.1.1 Background
Biological effectiveness monitoring is designed to measure the progress of the NBHCP toward meeting the Plan’s goals and objectives for Covered Species and their habitats [emphasis added]. The land cover and habitat mapping component of the biological effectiveness monitoring program applies to all Covered Species and tracks changes in land cover and habitats over time. The two types of land cover and habitat monitoring being implemented to meet the NBHCP goals and objectives are (1) monitoring on reserve lands and (2) monitoring off reserves to identify changes Basin-wide.

Land cover and habitat monitoring on reserves follows comprehensive, systematic procedures in accordance with the Protocols for Surveying and Evaluating Impacts to Special Status Native Plant Populations and Natural Communities (California Department of Fish and Wildlife 2018). Botanical surveys are conducted to identify sensitive plant species and noxious weeds.

Basin-wide land cover and habitat monitoring entails annual field verification of each land cover polygon originally mapped in 2004 (i.e., when the comprehensive monitoring program was established) and documenting any changes that have occurred since the previous year.

2.1.2 Goals and Objectives
Effective resource monitoring requires baseline information on the distribution and abundance of the resources of interest. The land cover and habitat mapping component of the biological The Natomas Basin Conservancy
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effectiveness monitoring effort establishes the baseline for the entire biological effectiveness monitoring effort. The objectives of the Basin-wide land cover and habitat monitoring component are listed below.
• Quantify the distribution and abundance of land cover and habitat types throughout the Basin. • Provide spatially explicit information on the distribution and abundance of land cover and habitat types throughout the Basin to guide future acquisitions of mitigation lands, to provide information on potential dispersal corridors between reserves, and to assess changes in the distribution and abundance of suitable habitats for Covered Species over time.

Botanical surveys on reserves are conducted annually. The objectives of these surveys are listed below.
• Document changes in the distribution and condition of land cover and habitat types. • Document the location, numbers, and/or cover of covered plant species and invasive/noxious plant populations where they occur.

2.2 Methods

2.2.1 Land Cover Mapping
The baseline conditions for land cover in the plan area were first documented in 2004 using aerial imagery. Geographic information system (GIS) specialists generated a base map of the permit area using true-color digital ortho-rectified aerial imagery of Sacramento and Sutter Counties purchased from AirPhotoUSA. The original aerial imagery from Sacramento County was taken in April 2004 at a resolution of 1 foot (i.e., each cell represents an area on the ground of approximately 1 square foot); the original aerial imagery from Sutter County was taken in spring 2004 at a resolution of 2 feet (i.e., each cell represents an area of 4 square feet). The aerial imagery was updated in 2008 and 2012 to achieve a resolution of 1 foot for both counties. National Agricultural Imagery Program (NAIP) imagery at a resolution of 1 meter has been used subsequently.

Botanists experienced with aerial imagery interpretation and vegetation signatures of the southern Sacramento Valley mapped land cover types on screen using Environmental Systems Research Institute’s ArcGIS 10.3.1 software. Lines were drawn to delineate polygons following visible differences in color tone and texture on the photographs. Polygons were delineated at a scale of 1:2,500–1:5,000 (approximately 1 inch = 200–400 feet). Riparian areas and wetlands were in some cases digitized at larger scales. Minimum polygon size (i.e., the minimum mapping unit) was generally 5 acres (2 hectares) for agricultural habitat types and developed areas, 0.25 acre (0.1 hectare) for seasonal wetlands, and 0.5 acre (0.2 hectare) for other sensitive habitat types. Polygons were then field-checked to ensure accuracy of the digitizing and photo-interpretation effort. Ditches were mapped as line features, and no attempt has been made to calculate their area.

Field verification of land cover polygons Basin-wide is conducted annually, primarily while conducting surveys for other purposes. All polygons are checked before the fall harvest begins, with the exception of a few off-reserve, privately owned polygons that cannot be checked because access is not available. In these areas, the most current aerial imagery from Google Earth is used to verify land cover types.

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Surveys were conducted in late spring and summer, at times appropriate for mapping habitat polygons. In addition, the surveys were conducted at optimal times for observing and documenting potential invasive/noxious weed species and sensitive plant populations.

Appendix A lists the acreages of each mapped land cover type by reserve and tract.

2.2.2 Botanical Surveys
Botanical surveys were completed from June through August 2022 on reserve lands. Surveys were conducted to record any changes in vegetation, habitat, or crop type; detect any changes in the distribution and abundance of suitable habitat for Covered Species; and document any potential noxious weeds and sensitive plants. Plant species encountered for the first time were added to the cumulative list of species observed on each tract (Appendix B). In addition, the following data were collected for each polygon on reserve lands.
• All plant taxa (identified to genera level or level appropriate to determine if the plant is sensitive or a noxious weed)
• Any changes in land cover or crop type, or in the distribution of suitable habitat for covered plant species
Nomenclature follows the second edition of The Jepson Manual: Vascular Plants of California (Baldwin et al. 2012) and updates published online by the Jepson Flora Project (Jepson Flora Project 2022). The plant list in Appendix B has been updated to reflect any nomenclature changes from the first edition of The Jepson Manual (Hickman 1993).

2.2.3 Noxious Weed Mapping
A complete list of noxious weeds known to occur in Sutter and Sacramento Counties was initially compiled from information in CalFlora (CalFlora n.d.) and ICF file data. This list has been annually updated to reflect the current status of noxious weeds with the potential to occur on the reserves.

The noxious weeds tracked during botanical surveys are those rated High or Moderate or designated a Red Alert species by the California Invasive Plant Council (Cal-IPC). These lists identify plants considered invasive to wildlands and natural vegetation, rather than weeds of agricultural importance that are found primarily in disturbed habitats.

The list of weeds tracked on TNBC reserves is reviewed and updated annually on the basis of Cal-IPC updates and input from local land managers. Also included are plants that are potentially invasive in wetlands and may be of management concern to TNBC.

Each noxious weed occurrence observed during the botanical surveys on reserves was hand- mapped on aerial imagery or mapped with an iPad and then added to the cumulative list of weed occurrences. The level of infestation (i.e., population size) was recorded in five cover/distribution categories:
• T = Trace (rare): less than 1% cover.
• L = Low (occasional plants): 1–5% cover.
• M = Moderate (scattered plants): 5–25% cover.
• H = High (fairly dense): 25–75% cover.

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• D = Dense (dominant): more than 75% cover.

Whenever highly invasive species requiring immediate management action are detected, a KMZ file is created and immediately sent to TNBC that identifies the weed type and location.

2.3 Results

2.3.1 Land Cover Types Basin-Wide
Table 2-1 lists the acreages of each land cover type mapped in the Basin from 2005 to 2022. The distribution of these types is shown on Figure 2-1 (note that several land cover types have been combined in the figure for clearer representation). The major land cover types that provide habitat for Covered Species in the Basin are rice, wetlands, upland agricultural lands, fallow agricultural fields, and grasslands. Upland agricultural fields, fallow agricultural fields, and grasslands constitute the majority of foraging habitat for Swainson’s hawk, one of the three Covered Species that are listed under either the California or federal ESAs. Active rice fields and the irrigation and drainage ditches that supply them are important habitats supporting giant gartersnake (federally listed as endangered), while created wetlands provide critical habitats for giant gartersnake and several other Covered Species. The acreages of these land cover categories are shown in Table 2-2, along with the proportion of the Basin comprising each type. Figure 2-2 shows changes in the acreage of major land cover types since 2005; these changes are summarized below. • Although active rice fields continue to dominate the landscape, they decreased substantially from 2021 to 2022 by approximately 7,866 acres dropping from 36.4% of the Basin in 2021 and

21.9% of the Basin in 2022.
• Fallow lands increased by 6,399 acres between 2021 and 2022, covering 6.3% of the Basin in 2021 and 18.1% of the Basin in 2022.
• Upland agricultural lands decreased by approximately 1,032 acres, covering 16.2% of the Basin in 2021 and 14.3% in 2022.
• Grassland cover increased by 1,377 acres, but most of this is probably due to fallow lands being classified as ruderal habitat in 2022.
• Developed land cover increased by approximately 840 acres.

The most significant long-term changes in land and habitat values over the last 10 years continues to be driven by construction of the NLIP. Mitigation for impacts from the NLIP setback levee construction project have included the creation of fresh emergent marsh habitats from soil borrow sites and the creation and preservation of large swaths of grassland and riparian habitats adjacent to the new setback levee.

The other significant change over the last few years has been the rapid increase in development resulting from the lifting in 2017 of the moratorium on development issued in December 2008 out of concern for flood protection in the Basin. In 2021, developed—low density decreased by 499 acres and developed—high density increased by 611 acres; approximately 164 acres of developed— low density was converted into developed—high density. In 2022, developed—low density The Natomas Basin Conservancy
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decreased by 324 acres as it was converted to high density use. Developed—high density increased by 511 acres. The rate of development is expected to increase in the coming years.

Natural vegetation, composed of tree- and shrub-dominated natural communities such as valley oak woodland, riparian woodland, and riparian scrub, constitutes an extremely small proportion of the Basin (i.e., 2.6% of the land area), but provides high-quality habitat for a large number of species, including the Swainson’s hawk and loggerhead shrike, both Covered Species under the NBHCP. As noted above, the Basin-wide acreage comprising these habitat types has been increasing due to mitigation from the NLIP. The maturation of tree plantings at freeway off-ramps resulted in those areas being mapped as woodland land cover types (e.g., mixed oak woodland, live oak woodland) in 2022. The small area of terrace grassland on the eastern edge of the Basin was not differentiated from the nonnative annual grassland category, although this area includes some remnant valley floor grassland.

2.3.2 Land Cover Types on Reserves
The total acreage of each land cover type mapped on reserves from 2005 to 2022 is shown in Table 2-3; the major categories of land cover types providing habitat for Covered Species on reserves (rice, wetlands, upland agricultural lands, fallow agricultural fields, and grasslands) are shown in Table 2- 4, along with the proportion of reserve lands comprising each type.

With the acquisition of the Elverta, Richter, Paulsen South, Lauppe North, Lauppe South, Verona, and Willey Reserves, the acreage of reserve lands increased by approximately 1,000 acres from 2021 to 2022. This resulted in an increase in both rice and upland agricultural habitats on reserve lands, although these changes are not reflected in the tables due to the severe drought that resulted in drastic increases in both fallow rice and fallow upland agriculture.

Table 2-5 summarizes the major habitat types on reserves as a proportion of those habitats in the entire Natomas Basin. In 2022, reserve lands accounted for 43% of the managed marsh/wetlands in the Basin, but only 12.8% of the rice lands and 11.3% of upland agricultural habitats. Reserve lands now account for a smaller proportion of wetlands in the Basin due to the creation of the managed marsh complex by the Greenbriar development.

The area of plantings that was added on the Souza Tract in 2016 is continuing to thrive and mature.

2.3.3 Noxious Weed Surveys
Noxious weed occurrences recorded from 2005 to 2022 are summarized in Table 2-6.

A total of 224 new weed occurrences were documented in 2022: 8 tree of heaven (Ailanthus altissima), 10 black mustard (Brassica nigra ), 7 Italian thistle (Carduus pycnocephalus), 5 bull thistle (Cirsium vulgare), 40 yellow star-thistle (Centaurea solstitialis), 7 stinkwort (Dittrichia graveolens), 1 water hyacinth (Eichhornia crassipes), 4 medusahead (Elymus caput-medusae), 2 edible fig (Ficus carica), 22 short pod mustard (Hirschfeldia incana), 22 water primrose (Ludwigia peploides), 2 pennyroyal (Mentha pulegium), 12 Harding grass (Phalaris aquatica), 71 milk thistle (Silybum marianum), 8 Himalayan blackberry (Rubus armeniacus), and 3 puncture vine (Tribulus terrestris).

Conversely, a total of 106 weed occurrences documented in 2021 were not found in 2022: 18 bull thistle, 3 edible fig, 6 Harding grass, 9 Himalayan blackberry, 4 Italian thistle, 2 milk thistle, 8 The Natomas Basin Conservancy
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pennyroyal, 5 perennial pepper weed, 37 stinkwort, 3 fennel (Foeniculum vulgare), and 11 yellow star-thistle.

Historically, these populations have been controlled by active management practices. Due to regeneration from seedbanks or root segments, invasive species eradication on reserve lands may require multiple removal efforts over several growing seasons.

Active management has targeted plant species that are known to be or are very likely to become invasive and that are locally considered to be particularly invasive and/or difficult to control.

Specific examples of highly invasive species with the potential to compromise habitat values include perennial pepperweed, and water primrose species (Ludwigia sp.). Construction activities are a major cause of noxious weed dispersal. Given the projected increase in development activities in the coming years, careful monitoring and active management should continue.

Vegetation management to prevent the spread of water primrose, perennial pepperweed, cattail (Typha sp.), and other invasive and undesirable species using mechanical means (e.g., pulling, mowing, managing water levels) and chemical means (e.g., herbicide applications) has been very effective historically. Water primrose, mosquito fern (Azolla filiculoides), and cattail can never be completely eradicated, but management efforts to date indicate that they can be controlled and contained using aggressive management.

2.3.4 Botanical Surveys
No covered plant species were recorded on TNBC reserves in 2022. Freshwater marsh and banks adjacent to open water canals provide suitable habitat for Delta tule pea and Sanford’s arrowhead.

Potential vernal pool habitat for the remaining covered plants is extremely rare in the Basin.

However, due to a lack of rainfall, created vernal pools on the BKS tract—which could potentially provide habitat for covered plant species—have not ponded for a sufficient duration over the last 4 years to allow for vernal pool-dependent plants to germinate. The cumulative list of plant species recorded on each tract through the 2022 field season is presented by reserve in Appendix B.

2.4 Discussion

2.4.1 Land Cover Types Basin-Wide
Significant changes in the distribution and abundance of land cover and habitat types across the Basin have been primarily due to: (1) the fallowing of rice lands in 2006 and subsequent return to rice over the last decade; (2) the implementation of the NLIP, which resulted in a substantial increase in grasslands and managed marsh/wetland habitats; (3) the rapid resumption of development after the lifting of the moratorium on development in 2017; and (4) the fallowing of rice land in 2022 due to extreme drought.

The resumption of rice agriculture in areas fallowed in 2006 and the increase in managed marsh habitats in the Basin resulting from the creation of marshes in areas soil-mined for the NLIP have resulted in a significant increase in habitats available for use by giant gartersnake.

Variation in the amount of rice, fallow lands, and upland agricultural lands has been significant over the last 4 years and may be due in part to variation in weather patterns that result in some lands The Natomas Basin Conservancy
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being left fallow. Rainfall that occurs late in the season has also likely resulted in some rice lands being fallowed, particularly in 2017 and 2019. Severe drought resulted in the fallowing of a substantial portion of rice and upland agricultural fields in 2022.

2.4.2 Land Cover Types on Reserves
Habitats on reserve lands are important components of the habitat landscape throughout the Basin.

Managed marsh on TNBC reserves provides important habitats for a number of Covered Species.

Because these marshes constitute almost half the wetlands in the entire Basin, they are an extremely important component of the mosaic of Basin-wide habitats.

Rice and upland agriculture are the other two important agricultural habitat types for Covered Species in the Basin. In 2022, active rice fields on reserve lands constituted 12.8% of the Basin-wide total, up from 11.3% in 2021. Upland agriculture on reserve lands accounted for approximately

11.3% of the upland agriculture in the Basin in 2022, up from 7.5% in 2021.

2.4.3 Botanical Surveys
A cumulative total (2005–2022) of 386 plant species from 66 families has been recorded on reserve lands. Nonnative species account for more than half (55%) of this total. Approximately two-thirds of these species were dicotyledons and one-third were monocotyledons; the two groups included similar proportions of nonnative species. The four most common families have remained unchanged from 2006; in descending order these are the grass family (Poaceae) with 51 species (13% of the total), the sunflower family (Asteraceae) with 38 species (10%), the bean family (Fabaceae) with 21 species (5%), and the mustard family (Brassicaceae) with 13 species (3%). The sedge family (Cyperaceae), and the dock family (Polygonaceae) are represented by more than 10 species each.

Species richness of the flora of each tract was correlated with the size of the reserve and the diversity of habitat types. Large tracts with aquatic habitats (e.g., BKS and Lucich North) had the highest number of plant species, while smaller tracts with a high proportion of upland agriculture (e.g., Souza and Alleghany) generally had the lowest number of plant species.

2.4.4 Noxious Weeds
The majority of noxious weed species on reserves are common and widespread in the Central Valley’s agricultural habitats. Occurrences typically composed small patches with low to moderate levels of infestation. Annual weed control is highly recommended to keep noxious weed populations and their seed banks small and manageable.

Noxious weed monitoring detected an expansion of nonnative species not tracked in monitoring efforts prior to 2022, consisting of black mustard, shortpod mustard, and medusahead. These species occurrences are now being tracked annually as a part of the noxious weed monitoring.

Should their coverage become problematic and reduce habitat value for Covered Species, manual removal and control of the species would be warranted.

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2.5 Effectiveness
Biological effectiveness as it pertains to habitat management is measured on the basis of successful implementation of habitat management recommendations outlined in the NBHCP and those developed by TNBC in consultation with species and vegetation management experts to maintain and enhance habitat values for Covered Species. Given that reserve lands are surrounded by a mosaic of urban, agricultural, and disturbed areas, management of noxious weed occurrences is necessary to sustain habitat values.

Improved communication and coordination among TNBC, the BEMT, and Triangle Properties, the land management and weed control contractor hired by TNBC several years ago, have been effective in ensuring that management actions are implemented in a timely fashion. Control of perennial pepperweed has historically been successful in preventing its spread on reserve lands. Mechanical removal of some noxious weed occurrences (e.g., giant reed) has also been highly effective. The program of early detection and removal of water primrose has proven effective in past years since marsh maintenance and enhancement activities had resulted in its near complete removal. However, a surge in noxious weeds that began in 2018 as a result of record drought being followed by record high rainfall resulted in a resurgence of aquatic weed species, particularly water primrose. However, water primrose can provide habitat for giant gartersnake when kept to moderate levels, so eradication as a goal may not be warranted at some sites.

2.6 Recommendations
Continue to monitor the distribution and abundance of noxious weeds on reserves, with a particular focus on aquatic plants (e.g., water primrose, mosquito fern, perennial pepperweed, and small smutgrass) that may compromise habitat values for Covered Species.

Continue to ensure that all TNBC personnel, consultants, and contractors can identify and immediately report the highest priority noxious weeds to ensure that management action can be taken before the species becomes established. Where possible, removal should occur before the summer when many species disperse their seeds.

Monitor results of the created wetland maintenance and enhancement activities to measure the effectiveness of new designs for maintaining open water habitats by preventing sedimentation and invasion by cattails and other aquatic vegetation that could potentially threaten the functionality and habitat values of created managed marsh, while maintaining and increasing emergent tule habitats.

Document the methods used to treat noxious weed infestation on all reserves and monitor their effectiveness over time to further refine weed management protocols specific to TNBC reserves.

Amend Site-Specific Management Plans to include successful management strategies.

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2.7 References
Baldwin, B. G., D. H. Goldman, D. J. Keil, R. Patterson, T. J. Rosatti, and D. H. Wilken (eds). 2012. The Jepson Manual: Vascular Plants of California, second edition, revised. Berkeley, CA: University of California Press.

CalFlora. No date. Information on Wild California Plants. Available: https://calflora.org//. Accessed:

June–August 2022.

California Department of Fish and Wildlife. 2018. Protocols for Surveying and Evaluating Impacts to Special Status Native Plant Populations and Natural Communities. California Natural Resources Agency. Sacramento, CA.

Hickman, J. C. (ed.). 1993. The Jepson Manual. Berkeley, CA: University of California Press.

Jepson Flora Project (eds.) 2022. Jepson eFlora. University of Berkeley, Berkeley, California.

Available: http://ucjeps.berkeley.edu/IJM.html. Accessed June–August 2022.

The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
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April 2023

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The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
2-11
April 2023

Table 2-1. Basin-Wide Extent (acres) of Mapped Land Cover Types, 2005–2022 Land Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Rice 22,321 14,792 14,590 14,224 15,014 15,023 15,287a 16,956 19,001 20,104 20,796 20,482 16,329 19,092 17,442 20,256 19,758 11,892 Fallow 1,625 10,101 10,033 10,076 5,869 2,912 2,323 2,282 2,160 1,555 1,366 1,712 6,442 3,307 4,667 3,234 3,414 8,951 Alfalfa 931 1,401 1,189 1,519 2,194 1,302 2,417 2,023 1,303 1,179 1,200 1,386 877 470 352 555 794 695 Irrigated grassland 452 374 451 373 378 345 746 750 757 757 352 326 326 311 311 310 314 295 Grass hay 178 153 2,212 2,367 2,769 6,724 5,423 6,504 6,250 6,850 7,582 7,043 7,211 f 7,570 7,571 6,220 5,271 4,265 Wheat 1,824 2,375 1,104 804 3,919 695 585 413 440 978 650 1,192 383 172 792 705 321 552 Milo 0 328 211 161 0 0 0 0 155 94 0 0 0 303 104 111 289 14 Tomatoes 50 145 112 113 8 10 0 0 0 108 63 40 0 51 261 175 389 528 Sunflower 709 572 0 251 166 804 714 362 821 903 388 519 355 464 181 55 443 690 Safflower 886 532 244 426 162 214 278 322 0 29 448 426 345 511 196 262 193 404 Other row and grain crops 2,537 582 2,396 2,279 2,096 3,770 4,937 3,645 2,370 906 1,151 958 1586 1445 719 445 770 308 Orchard 184 184 184 99 99 94 53 50b 50 307d 406d 406 406 480 480 482 463 626 Fresh emergent marsh (created) 575 575 676 897 897 897 897 897 897 1,042 1,042 1,042 1,042 1,042 1042 1,042 1,199 1,199 Fresh emergent marsh 138 154 154 155 155 155 154 154 154 154 154 154 154 154 154 154 154 154 Seasonal wetland 105 105 108 105 105 110 103 103 115 115 115 115 115 115 115 116 116 103 Grassland (created) 49 71 68 74 74 80 74 75 469c 511 511 511 506 506 506 506 506 506 Nonnative annual grassland 7,389 6,786 5,192 4,988 5,016 4,032 3,670 3,652 3,609 3,594 2,887 2,723 3,035 2,939 2,887 2,877 2,896 3,537 Ruderal 329 406 409 399 704 747 864 766 754 856 946 924 824 814 801 661 639 1,375 Valley oak woodland 191 195 192 192 194 209 240 242 257 248 261 322e 322 322 322 340 i 341 328 Live oak woodland – – – – – – – – – – – – – – 38 h 34 h 28 28 Mixed oak woodland – – – – – – – – – – – – – – – 11 i 11 11 Riparian woodland 348 346 357 357 354 359 357 398 398 393 389 390 393 393 393 393 407 407 Riparian scrub 117 117 114 133 133 133 133 133 133 134 134 138 138 138 137 g 137 137 137 Non-riparian woodland 52 50 51 51 51 29 28 43 43 43 28 28 26 26 26 43 i 43 51 Open water 352 340 340 337 337 360 381 387 490 459 459 462 462 462 462 462 462 456 Developed—low density 1,565 1,639 1,706 1,949 1,961 1,977 2,114 2,202 2,307 2,296 2,310 2,306 2,115 2,194 3,000 3,072 2,573 2,249 Developed—high density 9,859 10,764 11,533 11,304 11,260 10,910 10,770 a 10,604 10,529 10,533 10,505 10,539 10,753 10,868 11,191 11,470 12,081 12,592 Disturbed/bare 1,440 1,127 578 573 291 2,321 1,659 1,243 744 58 63 62 62 58 55 81j 177 830 Vineyard – – – – – – – – – – – – – – – – 19 2
Total 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 54,206 a In 2011, 586 acres of rice were erroneously mapped as developed—low density; acreages for both land cover types have been corrected in this report. b Decrease in orchard acreage due to availability of new aerial imagery that allowed visibility of private pr operty. This 3-acre crop is now irrigated grassland. c Increase in grassland (created) due to conversion of disturbed/bare by SAFCA. d Increase in orchard due to conversion of land west of the airport from row crops to orchard in 2014 and 2015. e Increase in valley oak woodland due to establishment of woodland planted during the SAFCA revegetation of the setback levee. f In 2017, 10 acres of grass hay were erroneously mapped as grassland (created), and 15 acres of grassland (created) were mapped a s grass hay. Acreages for both land cover types have been corrected in this report. g Small swath of riparian scrub along a canal was developed for housing. h Maturation of live oak woodland plantings along freeway off-ramps; acreage was refined in 2020 I Maturation of woodlands along off-ramps.
j Disturbed/bare land cover was incorrectly labeled as fallow in 2019 and 2020; in 2021 the parcel’s restoration was finished and it is now a fresh emergent marsh (created).

The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
2-12
April 2023

Table 2-2. Basin-Wide Summary of Major Habitat Types, 2005–2022 Habitat Typea
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin Acres % of
Basin
Rice 22,321 41.2 14,782 27.3 14,590 26.9 14,224 26.2 15,017 27.7 15,023 27.7 15,287b 28.2b 16,956 31.3 19,001 35.1 20,104 37.0 20,796 38.4 20,482 37.8 16,329 30.1 19,092 35.2 17,442 32.2 20,256 37.4 19,758 36.4 11,892 21.9 Managed
marsh/
wetlands
818 1.5 834 1.5 938 1.7 1,157 2.1 1,157 2.1 1,162 2.1 1,153 2.1 1,153 2.1 1,165 2.1 1,311 2.4 1,311 2.4 1,311 2.4 1,311 2.4 1,311 2.4 1,311 2.4 1,311 2.4 1,468 2.7 1,455 2.7
Upland
agriculture 7,567 14.0 6,462 11.9 7,919 14.6 8,293 15.5 11,692 21.6 13,863 25.6 15,100 27.9 14,019 25.9 12,096 22.3 11,601 21.4 11,771 21.7 11,890 21.9 11,084 d 20.4 11,777 21.7 10,488e 19.3 8,837 16.3 8,784 16.2 7,752 14.3 Grassland 7,767 14.3 7,263 13.4 5,669 10.5 5,461 10.1 5,794 10.7 4,853 9.0 4,608 8.5 4,493 8.3 4,832 8.9c 4,961 9.2 4,344 8.0 4,157 7.7 4,364 d 8.0 4,257 7.8 4,193 7.7 4,043 7.5 4,041 7.4 5,418 10.0 Fallow 1,625 3.0 10,101 18.6 10,033 18.5 10,076 18.5 5,869 10.8 2,912 5.4 2,323 4.3 2,282 4.2 2,160 4.0 1,555 2.9 1,366 2.5 1,712 3.2 6,442 11.9 3,307 6.1 4,667 8.6 3,234 6.0 3,414 6.3 9,813 18.1 Developed 12,864 23.7 13,531 25.0 13,817 25.5 13,826 25.5 13,512 24.9 15,208 28.1 14,543b 26.8b 14,049 25.9 13,581 25.1 12,887 23.8 12,878 23.8 12,907 23.8 12,929 23.9 13,120 24.1 14,246 26.3 14,623 27.0 14,831 27.3 15,671 28.9 Other 1,245 2.3 1,233 2.3 1,239 2.3 1,169 2.2 1,168 2.2 1,184 2.2 1,192 2.2 1,254 2.3 1,371 2.5 1,787 3.3 1,740 3.2 1,746 3.3 1,204 2.2 1,342 2.5 1,860 3.4 1,902 3.5 1,909 3.5 2,205 4.1 Total 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 54,206 100 a The managed marsh/wetlands habitat category includes the following land cover types: fresh emergent marsh, fresh emergent mar sh (created), and seasonal wetland. The upland agriculture habitat category includes the following land cover types: alfalfa, grass hay, irrigated grassland, tomatoes, milo, safflower, sunflower, wheat, and other row and grain crops. The grassland habitat category includes the following land cover types: gras sland (created), nonnative annual grassland, and ruderal. The fallow habitat category includes the following land cover types: fallow, fallow rice, and fallow row and grain crops. The developed habitat category includes the following land cover types: developed—low density, developed—high density, and disturbed/bare. b In 2011, 586 acres of rice were erroneously mapped as developed—low density; acreages for both land cover types have been corrected in this report. c Increase in grassland (created) due to conversion of disturbed/bare by SAFCA. d In 2017, 10 acres of grass hay were erroneously mapped as grassland (created), and 15 acres of grassland (created) were mapped as grass hay. Ac reages for both land cover types have been corrected in this report. e In the 2019 annual report, orchard was erroneously included in this category; it has been corrected here.

The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
2-13
April 2023

Table 2-3. On-Reserve Extent (acres) of Mapped Land Cover Types, 2005–2022 Land Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Rice 1,671 1,529 1,715 1,849 2,136 2,059 1,930 2,200 2,273 2,205 2,442 2,344 1,820 2,262 2,000 2,344 2,606 1,526 Fallow 820 593 727 373 375 450 668 348 177 206 64 214 643 58 558 144 213 1,655 Alfalfa 106 106 150 150 204 127 126 259 204 348 348 348 143 143 88 161 335 437 Irrigated grassland 0 96 0 0 4 5 0 0 0 0 0 0 0 0 0 0 0 0 Grass hay 19 19 81 160 157 144 57 84 147 135 158 57 295 f 356 145 241 136 196 Wheat 207 497 77 79 132 187 58 58 58 58 47 74 11 23 299 204 71 0 Milo 0 0 49 0 0 0 0 0 155 94 0 0 0 0 0 0 0 0
Tomatoes 0 0 55 55 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Sunflower 0 0 0 0 0 104 116 84 56 50 0 0 29 104 0 0 204 226 Safflower 0 0 0 0 104 0 68 11 0 0 0 23 41 0 0 0 0 0
Other row crops 10 157 279 472 26 32 27 6 27 0 37 59 132 127 28 23 58 0 Fresh emergent marsh (created)a 561 561 627 627 627 627 627 627 627 627 627 627 627 627 627 627 627 626 Fresh emergent marsh 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Seasonal wetland 6 6 4 4 4 4 3 3 4 4 4 4 4 4 4 4 3 3
Grassland (created) 47 76 76 72 72 72 71 72 72 73 73 73 67f 67 67 67 52 52 Nonnative annual grassland 318 225 254 254 254 254 254 228 226 226 226 203 203 203 203 203 204 204 Ruderal 38 33 29 29 29 28 25 25 25 36 36 36 47 47 42 44 34 34 Valley oak woodland 6 7 7 7 7 7 7 7 7 7 7 7 7 7 7 5g 6 6 Riparian woodland 13 13 12 12 12 12 12 12 12 12 12 12 12 12 12 12 9 9 Riparian scrub 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5
Nonriparian woodland 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Open water 0 0 0 0 0 0 0 0 20c 20 20 20 20 20 20 20 22 22 Developed—low density 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 Developed—high density 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 Disturbed/bare 0 0 0 0 0 0 63b 47 11 0 0 0 0 0 0 0 0 10 Totald 3,835 3,931 4,154 4,154 4,154 4,124b 4,124 4,082b 4,112e 4,112 4,112 4,112 4,112 4,112 4,112 4,112 4,593 5,052 a The fresh emergent marsh (created) land cover type includes some, but not all, of the associated uplands for most, but not all, t racts with wetlands. When patches of associated uplands are smaller than the minimum mapping unit, they are included in the f resh emergent marsh (created) land cover type; when they are larger than the minimum mapping unit, they are mapped as the land cover type that characterizes the m. b Acreage change from previous years is due to the SAFCA NLIP. c Completion of improvements to linear water conveyance features in the North Basin Reserve resulted in the change of 20 acres of disturbed/bare to open water habitat in 2013. d Discrepancies between this total and the surveyed acreages are due to inclusion here of a 12-acre easement of the Sills tract and minor GIS rounding errors. e Acreage increase is due to the acquisition of the Silva South 1 tract. f In 2017 on the Atkinson tract, 10 acres of grass hay were erroneously mapped as grassland (created), and 15 acres of grasslan d (created) were mapped as grass hay. Acreages for both land cover types have been corrected in this report. g Valley oaks were removed as a part of levee improvements and maintenance.

The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
2-14
April 2023

Table 2-4. On-Reserve Summary of Major Habitat Types, 2005–2022 Habitat
Type
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres
% of Reserve Lands
Acres

% of Reserve Lands
Rice 1,671 43.6 1,529 38.9 1,715 41.3 1,849 44.5 2,136 51.5 2,059 49.93 1,930 46.8 2,200 53.9 2,273 55.3 2,205 53.6 2,442 59.4 2,344.4 57.0 1,819.7 44.3 2,262.2 55.0 2,000.1 48.6 2,343.9 57.0 2,231 54.9 1,526 30.2 Managed
marsh/
wetlands
569 14.8 569 14.4 631 15.2 631 15.2 631 15.2 631 15.2 630 15.3 631 15.4 631 15.3 630 15.3 630 15.3 630.1 15.3 630.1 15.3 630.1 15.3 630.1 15.3 630.1 15.3 626 15.4 626 12.4 Upland
agriculture
342 8.9 875 22.3 691 16.7 916 22.1 627 15.1 594 14.4 452 11 502 12.3 647 15.7 591 14.4 591 14.4 560 13.6 651 e 15.8 794 19.3 560.2 13.6 629.6 15.3 655 16.1 873 17.3 Grassland 403 10.5 334 8.5 359 8.6 355 8.5 355 8.5 331 8.02 350 8.5 325 8.0 323 7.8 334 8.1 334 8.1 312 7.6 317 e 7.7 317 7.7 312 7.5 314.0 7.6 289 7.1 290 5.7 Fallow 820 21.4 593 15.1 727 17.5 373 9.0 375 9.0 450 10.9 668 16.2 348 8.5 177 4.3 206 5.0 64 1.5 214 5.2 643 15.6 58 1.4 558.0 13.6 144.0 3.5 213 5.2 1,674 33.1 Developed 5 0.1 5 0.1 5 0.1 5 0.1 5 0.1 5 0.1 68b 1.6 51 1.2 16 0.4 5 0.1 5 0.1 5 0.1 5 0.1 5 0.1 5 0.1 5 0.1 5 0.1 16 0.3 Other 25 0.7 26 0.7 25 0.6 25 0.6 25 0.6 54 0.8 26 0.6 25 0.6 45 1.1 140 3.4 46 1.1 46 1.1 46 1.1 46 f 1.1 46 1.1 44.9 1.1 44 1.1 47 0.9 Totalc 3,835 100 3,931 100 4,154 100 4,154 100 4,154 100 4,124b 100 4,124 100 4,082b 100 4,112d 100 4,112 100 4,112 100 4,112 100 4,112 100 4,112 100 4,112 100 4,112 100 4,063 100 5,052 100 a The fresh emergent marsh (created) land cover type includes some, but not all, of the associated uplands for most, but not all, t racts with wetlands. When patches of associated uplands are smaller than the minimum mapping unit, they are included in the f resh emergent marsh (created) land cover type; when they are larger than the minimum mapping unit, they are mapped as the land cover type that characterizes the m. b Acreage change from previous years is due to the SAFCA NLIP. c Discrepancies between this total and the surveyed acreages are due to inclusion here of a 12-acre easement of the Sills tract and minor GIS rounding errors. d Acreage increase is due to the acquisition of the Silva South 1 tract. e “Other” acreage reported incorrectly as 0 acres in 2018; acreage fixed in this report. f In 2017 on the Atkinson tract, 10 acres of grass hay were erroneously mapped as grassland (created) and 15 acres of grassland (created) were mapped as grass hay. Acreages for both land cover types have been corrected in this report.

The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
2-15
April 2023

Table 2-5a. On-Reserve Extent of Major Habitat Types as a Proportion of Each Habitat Type in the Basin, 2005–2014 Habitat Type
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Rice 14,782 10.3 1,715 14,745 11.6 1,849 14,224 12.9 7.5 1,529 14,782 10.3 1,715 14,745 11.6 1,849 14,224 12.9 1,820 16,329 11.1 2,262 19,092 11.8 2,204.1 17,442 11.5 2,205 20,104 11.0 Managed
marsh/
wetlands
834 68.2 631 936 67.3 631 1,157 54.5 69.6 569 834 68.2 631 936 67.3 631 1,157 54.5 630 1,311 48.1 630 1,311 48.1 630 1,311 48.1 630.1 48.1 Upland
agriculture
6,462 13.5 691 7,919 8.7 916 8,293 11.0 4.5 875 6,462 13.5 691 7,919 8.7 916 8,293 11.0 651 11,089 5.9 794 11,782 6.7 560.2 10,488 5.3 629.6 6.8 Grassland 7,263 4.6 359 5,669 6.3 355 5,461 6.5 5.2 334 7,263 4.6 359 5,669 6.3 355 5,461 6.5 319 4,902 6.5 319 4252 7.5 312 4,193 7.4 314.0 7.8 Fallow 10,101 5.9 727 10,035 7.2 373 10,076 3.7 50.5 593 10,101 5.9 727 10,035 7.2 373 10,076 3.7 643 6,442 10.0 58 3,307 1.8 558 4,667 12.0 144.0 4.5 Developed 13,531 0 5 13,817 0 5 13,826 0 0 5 13,531 0 5 13,817 0 5 13,826 0 5 12,929 0.0 5 13,062 0.0 5 14,246 0.0 5 0.0 Other 1,233 2.1 25 1,239 2 25 1,169 2.1 2 26 1,233 2.1 25 1,239 2 25 1,169 2.1 46 1,204 3.8 46 1,399 0 46 1,860 2.5 44.9 3.2 Total 54,206 7.3 4,154 54,206 7.6 4,154 54,206 7.7 7.1 3,931 54,206 7.3 4,154 54,206 7.6 4,154 54,206 7.7 4,112 54,206 7.6 4,112 54,206 7.6 4,112 54,206 7.6 4,112 54,206 7.6 Table 2-5b. On-Reserve Extent of Major Habitat Types as a Proportion of Each Habitat Type in the Basin, 2015–2022 Habitat Type
2015 2016 2017 2018 2019 2020 2021 2022
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres
Basin Acres
% of Habitat on Reserves
Reserve Acres

Basin Acres
% of Habitat on Reserves
Rice 2,442 20,796 11.70% 2,344.40 20,482 11.4 1,820 2,606 2606 2,262 19,092 11.8 2,000.1 17,442 11.5 2,343.9 20,256 11.6 2,231 19,758 11.3 1,526 11,891 12.8 Managed marsh/wetlands 630 1,311 48.10% 630.1 1,311 48.1 630 630 630 630 1,311 48.1 630 1,311 48.1 630.1 1,311 48.1 626 1,468 42.6 626 1,455 43.0 Upland agriculture 591 11,771 5.00% 560 11,850 4.7 651 g 805 805 794 11,782 6.7 560.2 10,488 5.3 629.6 9,319 6.8 655 8,784 7.5 873 7,752 11.3 Grassland 334 4,344 7.70% 312 4,157 7.5 319 g 290 290 319 4252 7.5 312 4,193 7.4 314 4,043 7.8 289 4,041 7.2 290 5,418 5.4 Fallow 64 1,366 4.70% 214 1,712 12.5 643 213 213 58 3,307 1.8 558 4,667 12 144 3,234 4.5 213 3,414 6.2 1,674 9,813 17.1 Developed 5 12,878 0.00% 5 12,907 0 5 6 6 5 13,062 0 5 14,246 0 5 14,623 0 5 14,831 0 16 15,671 0.1 Other 46 1,740 2.60% 46 1,787 2.6 46 43 43 46 1,399 0 46 1,860 2.5 44.9 1,420.20 3.2 44 1,909 2.3 47 2,205 2.1 Total 4,112 54,206 7.60% 4,112 54,206 7.6 4,112 4,593 4593 4,112 54,206 7.6 4,112 54,206 7.6 4,112 54,206 7.6 4,063 54,206 7.5 5,052 54,206 9.3 The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results—Administrative Draft
2-16
April 2023

Table 2-6. Noxious Weed Occurrences on TNBC Reserve Lands, 2005–2022 Reserve Noxious Weed Species
Number and Degree of Occurrences
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 North Basin Reserve
Atkinson
Edible fig 1, T 1, T 1, T 1, T 1, T 1, T 1, T 1, T 1, T 1, T 1, T 1, T – – – – 1, T – Perennial pepperweed 3, M-H 3, M-H 1, M 1, M 1, M – – – – – – – – – – 2, L-M 2, T, H – Himalayan blackberry 1, H 1, H 3, M-H 3, M 3, M-H 3, M 3, M 2, M 2, M 1, M 1, M 2, M 1, T 2, M 3, L-D 8, T-D 7, L-D 2, H-D Stinkwort – – – – – – – – – – – – – 1, L 1, M – – –
Bull thistle – – – – – – – – – – – – – 5, T-L 1, T 4, T-M 1, L – Yellow star-thistle – – – – 2, L-M 2, L 1, L 2, L 3, L 1, L 3, L 4, L 2, T 2, T-H 3, T-M – – 2, L-M Harding grass – – – – – – – – – – – – – – – – 1, T 2, L-H Milk thistle – – – – – – – – – – – – – – – – – 6, M-D
Bennett
North
Yellow star-thistle 1, L 1, L 1, L – – 1, L 2, M 1, L 1, T – 1, T 1, L – 1, T 5, T-M – – 3, M-H Bull thistle – – – – – 1, L – 1, L 2, T 3, T 2, T 1, T 1, T – – – – – Harding grass – – – – – – – – – – – – – – – – 1, T –
Water primrose – – – – – – – – – – – – – – – – – 10, L_H Himalayan blackberry – – – – – – – – – – – – – – – – – 1, L Milk thistle – – – – – – – – – – – – – – – – – 3, L_M
Black mustard – – – – – – – – – – – – – – – – – 5, L-M
Shortpod mustard – – – – – – – – – – – – – – – – – 8, L-H Edible fig – – – – – – – – – – – – – – – – – 1, M
Bennett
South
Bull thistle – – – – – – – 2, L – – 1, L – 1, T 2, T – – 1, T 1, L Edible Fig – – – – – 3, M – – – – – – – 2, T – – – –
Perennial pepperweed – – – – – – – – – – – – – 1, L – – – – Yellow star-thistle 2, L-M 2, L-M 2, M 1, M 3, L 2, L-M 1, L-M 1, L – – 2, L 1, L-M – – – 1, T – 1, L Italian thistle – – – – – – – – – – – – – – – – 1, H 1, M Water primrose – – – – – – – – – – – – – – – – – 5, L-D Milk thistle – – – – – – – – – – – – – – – – – 4, L-M
Bolen
North
Perennial pepperweed 1, M 1,L – – – – – – – – – – – – – – – – Himalayan blackberry 1, T 1,T – – – – – – – – – – – – – 1, D 1, L 1, L Yellow star-thistle – – – – – – – – – – – – – 1-L 6, T-M 3, T-L – 3, M-H Bull thistle – – – – – 3, L 2, L 2, L 1, T 2, T 1, T 3, T – 3, T-L – – 5, T-M – Italian thistle – – – – – – – – – – – – – – – – 1, M –
Milk thistle – – – – – – – – – – – – – – – – 1, T –
Black mustard – – – – – – – – – – – – – – – – – 3, L-M
Shortpod mustard – – – – – – – – – – – – – – – – – 8, L-H Edible fig – – – – – – – – – – – – – – – – – 1, M
Water primrose – – – – – – – – – – – – – – – – – 10, L-H Bolen
South
Himalayan blackberry 5, L-H 5, L – – – 2, M 2, M – – – – – 3, T-L 1, M – – 1, D 2, D Perennial pepperweed – – – – – – – – – – – – – 1, M – – – – Bull thistle – – 2, L 2,L 2, L – – 1, L 2, L – 1, L 1, L – – – – 4, T-L – Harding grass – – – – – – – – – – – – – – – – 1, M –
Bolen
West
Bull thistle – – – – – 1, M – 1, L – 1, T 2, T – – – 6, T-M – 4, L-M – Yellow star thistle – – – – – – – – – – – – – – – 2, T – 4, L-M Milk thistle – – – – – – – – – – – – – – – 2, T – 9, L-H Italian thistle – – – – – – – – – – – – – – – – 2, L-M 1, L Stinkwort – – – – – – – – – – – – – – – – – 1, L
Himalayan blackberry – – – – – – – – – – – – – – – – – 1, M Russian thistle – – – – – – – – – – – – – – – – – 1, M
Shortpod mustard – – – – – – – – – – – – – – – – – 1, M Frazer
Bull thistle – – – – – – – – – – – – – – 1, T 1, T 2, T 2, T-L Stinkwort – – – – – – – – – – – – – – 1, T 3, L-T 4, T 4, T-M Yellow star-thistle 1, H 2, L-H 4, M-L 4, M-L 5, M-L 4, M 1, L 3, L 2, T 3, M 3, L 2, L-M 2, L-M – 1, T – – 2, M Shortpod mustard – – – – – – – – – – – – – – – – – 12, T-M Milk thistle – – – – – – – – – – – – – – – 1, M 6, T-M 4, L-M Harding grass – – – – – – – – – – – – – – – – 2, L-M –
Huffman
East
Yellow star-thistle 7, L-H 7, L-M – – 3, L 2, M-L 3, M-L 1, L 1, L – 1, T 1, L – 1, M 2, T-M 2, T 6, T-M 2, M-H Himalayan blackberry 1, M 1, M – – – – 1, M – – – – – 2, T – – – – - Bull thistle – – 2, T 3, T 3, T – – 1,L – 2, T – 1, L – – – – – – Water primrose – – – – – – – – – – – – – – – – – 2, M-D Shortpod mustard – – – – – – – – – – – – – – – – – 2, L-M Milk thistle – – – – – – – – – – – – – – – 1, T – 6, L-H Huffman
West
Yellow star-thistle – – – – – 1, L 1, L 2, L 3, T - 2, L 4, T – – – 2, T 1, T – Sweet fennel 2, T 2, T – – 1, T – – – – – – – – – – – – – Himalayan blackberry – – 1, H 1, H 1, M 2, M – – – – – – 1, T – – – – – Milk thistle – – – – – – – – – – – – – – – 1, T – –
The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring
Table 2-6. Continued
Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
2-17
April 2023

Reserve Noxious Weed Species
Number and Degree of Occurrences
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Lucich
North
Yellow star-thistle 10, L-H 10, L-H 5, L-M 2, L 4, L-M 3, L – 1, L 4, L 3, L 2, L 5, L 3, L-M – 1, M – 1, H – Perennial pepperweed 3, H 3, H 1, T 1, T 1, T 1, T – – – – – – – 3, L-D 3, L-M – 2, L, H – Bull thistle – – 4, T-H 4, T-H 3, T-H 2, T – 1, T 1, T 4, T 3, L-M 2, T – 49, T-D 25-T-M 12, T-L 12, T-H 10, T-H Edible fig – – – – – – – – – – – – – 1, T 1, T 1, L 2, T – Pennyroyal – – – – – – 1, M 1, M 1, M 1, M 1, M 1, M 2, T-L – – – – 2, T-M Italian thistle – – – – – – – – – – – – – – 1, T – 1, L – Stinkwort – – – – – – – – – – – – – – 10, T-M 1, T 5, T-L 1, M Milk thistle – – – – – – – – – – – – – – – 6, T-D 17, T-M 21, L-H Water primrose – – – – – – – – – – – – – – – – – 3, M-H Shortpod mustard – – – – – – – – – – – – – – – – – 2, M-H Harding grass – – – – – – – – – – – – – – – – 1, H –
Lucich
South
Yellow star-thistle 3, M 3, M 9, T-H 4, T-H 4, T-M 3, L 1, L 1, T 2, T 3, T 2, M 4, T-M – 8, M-D 9, T-D 6, T-D 11, T-M 10, L-H Bull thistle 1, T – 1, H 2, L-M 2, L-M 2, L-M 3, L-M 2, L 1, T – 2, L 3, L-M – 1, T – – – - Italian thistle – – 1, L 1, L 1, L 1, L 1, L – – – 1, L 2, L – – – – – 1, M Water primrose – – – – – – – – – – – – – – – – – 1, M
Milk thistle – – – – – – – – – – – – – – – – – 8, L-H
Shortpod mustard – – – – – – – – – – – – – – – – – 1, M Nestor
Bull thistle – – – – – – 1, L – – – – 1, T – – – – – – Yellow star-thistle – – – – – – – – – – – – – 1, L – – – 5, L-M Himalayan blackberry – – – – – – – – – – – – – – – 1, M – – Milk thistle – – – – – – – – – – – – – – – – – 3, L-M
Shortpod mustard – – – – – – – – – – – – – – – – – 6, L-H Stinkwort – – – – – – – – – – – – – – – – – 1, M
Ruby
Ranch
Yellow star-thistle 1, T 1, T – – 1, L – 1, L – 1, T – 1, L 2, T – – – – – 3, L-M Italian thistle – – 1, H 1, H 1, M – – – – – 1, T – – – – – – 1, M Milk thistle – – – – – – – – – – – – – – – – – 3, L-M
Stinkwort – – – – – – – – – – – – – – – – – 1, M
Medusahead – – – – – – – – – – – – – – – – – 1, M
Verona Yellow star-thistle – – – – – – – – – – – – – – – – 1, T – Milk thistle – – – – – – – – – – – – – – – – – 4, M-H
Bull thistle – – – – – – – – – – – – – – – – – 2, L-H
Italian thistle – – – – – – – – – – – – – – – – – 1, L
Puncture vine – – – – – – – – – – – – – – – – – 1, M
Black mustard – – – – – – – – – – – – – – – – – 2, M-H
Wild radish – – – – – – – – – – – – – – – – – 1, H
Vestal
Yellow star-thistle – 3, T – – – 3, L-M 2, L-M 2, L 3, T 2, T 1, L 3, T 1, T 1, L 2, T-M 2, T – 4, L-M Himalayan blackberry – – 1, M 1, M 1, M – – – – – – – 1, T – – – – 1, H Bull thistle – – – – – 2, L 3, L 1, L 2, T – 1, L 2, L – – – – – – Edible fig – – 1, L 1, L 1, L 1, L 1, L 1, L 1, L 1, L 1, L 1, L 1, L – – – – 1, H Water primrose – – – – – – – – – – – – – – – – – 1, D
Tree of Heaven – – – – – – – – – – – – – – – – – 1, L
Stinkwort – – – – – – – – – – – – – – – – – 2, M
Willey Bull thistle – – – – – – – – – – – – – – – – 1, M – Central Basin Reserve
Betts-
Kismat-
Silva
Bull thistle – – – – 2, T 1, T – – 1, T 2, T 1, T 2, T 1, T 6, T-D 2, T 8, T-L 4, T-L – Yellow star-thistle L-H L-H 7, T-H 5, T-L 5, T-L – – – – – 2, T 1, T – – – – – – Perennial pepperweed T T 1, H 1, L 2, T-L – – 5, T-M – – – – – 1, M – – 1 – Giant reed L L L – – – – – – – – – – – – – – –
Italian thistle 1, T – – – – – – – – – – – – 2, T-L 1, T – 1, T 2, M Pennyroyal L-M L-M – – – 2, M 2, M 1, M 1, M 2, M 1, M 1, M 1, T 7, T-L 6, T-M 11, T-L 8, T-M – Catalpa One tree One tree One tree One tree One tree One tree One tree One tree One tree One tree One tree One tree One tree One tree One tree One tree – – Tree-of-heaven 1, M 1, M – 1, H 1, H – – – – – – – – – – – – – Himalayan blackberry D D 3, M-H 3, M-H 3, M-H 2, M 2, M – – – – – – – – – – 1, L Edible fig – – 1, M 2, M 2, M 2, M 2, M 1, M 1, M 1, M 1, M 1, M – – – – – – Small smutgrass – – – – – 1,T – – – – – – – – – – – –
Stinkwort – – – – – – – – – – – – 9, L-M 10, L-M 7, T-D 31, T-M 35, T-H 8, L-M Licorice – – – – – – – – – – – – – – – 1, M 2, L, H –
Harding grass – – – – – – – – – – – – – – – – 1, L 1, H Shortpod mustard – – – – – – – – – – – – – – – – – 4, L-M Water primrose – – – – – – – – – – – – – – – – – 11, M-H Medusahead – – – – – – – – – – – – – – – – – 5, H-D
Milk thistle – – – – – – – – – – – – – – – – – 2, M
The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring
Table 2-6. Continued
Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
2-18
April 2023

Reserve Noxious Weed Species
Number and Degree of Occurrences
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Bianchi
Westb
Harding grassb – – – – – 3, L 2, L 2, L 1, L 2,L – – – – – – – – Yellow star-thistle – – – – – 1, M 2, L 1, L 1, T – 1, T 2, T – 3, T-L – 4, L-H – 2, M-H Elsie Yellow star-thistle – – – – – – 2, T 1, M 2, T – 2, T 1, T – – – – – 1, M Stinkwort – – – – – – – – – – – – – – – 1, T – 1, H
Frazer
South
Stinkwort – – – – – – – – – – – – – – 2, T-L 1, T – 1, M Milk thistle – – – – – – – – – – – – – – – – – 2, M
Shortpod mustard – – – – – – – – – – – – – – – – – 1, M Italian thistle – – – – – – – – – – – – – – – – – 1, M
Sills Yellow star-thistle – – 1, M 1, M 2, L 1, L 2, L 1, M 2, T – 1, T 2, T – 4, L-T 6, T-D 2, L-H – 16, T-H Bull thistle – – – – – – – – – – – – – – – 1, T – 1, L
Water primrose – – – – – – – – – – – – – – – – – 2, H
Italian thistle – – – – – – – – – – – – – – – – – 1, H
Milk thistle – – – – – – – – – – – – – – – – – 5, L-H
Black mustard – – – – – – – – – – – – – – – – – 1, H
Purple top vervain – – – – – – – – – – – – – – – – – 1, H Stinkwort – – – – – – – – – – – – – – – – – 1, M
Tufts Yellow star-thistle 1, M 1, M – – – – – – – – 1, M – – – – – – 2, L-H Fisherman’s Lake Reserve
Alleghany
Sweet fennel 1, T 1, T – – – – – – – – – – – – – – – –
Edible fig 1, T 1, T – – – – – – – – – – – – – – – –
Himalayan
blackberry 1, D 1, D 2, M-H 2, L-M 2, L-M 3, L-M 2, M 2, M 1, M 2, T 2, M 1, M 2, M-H 1, L 1, L – – – Harding grassb – – 1, L 1, L 1, L – – – – – – – – – – – – 3, M-H Bull thistle – – 1, L 1, L 1, L 2, L 1, L 2, L 1, T 2, T – – – – – – – – Italian thistle – – 2, L 2, T-L 1, L – – – 1, T – – 1, L – – – – 1, L – Yellow star-thistle – – – – – 1, L 1, L 2, L 2, T – 3, L 2, T – – – – – – Tree of Heaven – – – – – – – – – – – – – – – 2, M – –
Black mustard – – – – – – – – – – – – – – – – – 1, H
Shortpod mustard – – – – – – – – – – – – – – – – – 1, H Milk thistle – – – – – – – – – – – – – – – – – 1, H
Cummings
Himalayan blackberry 1, M 1, M 1, M 1, M 1, M 1, M 1, M – – 1, T 1, M 1, L 2, T – – – – – Sweet fennel 1, T 1, T – – 1, T – – – – – – – – – – – – – Perennial
pepperweed 1, L-M 1, L – – – – – 1, M – – – – – 1, T 1, T – – – Pampas grass – – 1, L 1, L 1, L – – 1, M 1, M – – – – – – – – – Italian thistle – – – – – – – – – – – – – 1, L – – – 1, L Bull thistle – – – – – – – – 1, T 2, M 3, L 1, T – – 5, L-T 1, T – 3, M-H Stinkwort – – – – – – – – – – – – – – 1, T – – –
Harding grass – – – – – – – – – – – – – – – 3, L-M I, L 4, L-H Milk thistle – – – – – – – – – – – – – – – – – 1, H
Tree of Heaven – – – – – – – – – – – – – – – 3, M – –
Natomas
Farms
Sweet fennel 1, L 1, L – 1, T 1, T 1, T – – – – – – – – – – – – Himalayan blackberry 1, M 1, L 1, L 1, L 1, L 1, L – 2, L 1, L 1, T 2, L 1, T 1, L – – – 1, D – Edible fig – – – – – – – – – – – – – 1, L – – – –
Bull thistle – – – – – – – – – – – – 1, T 3, L-D 3, T-D 6, T-D 2, M 3, T-M Italian thistle – – – – – – – – – – – – – – – – – 1, L Milk thistle – – – – – – – – – – – – – – – – – 1, M
Harding grass – – – – – – – – – – – – – – – 10, L-M 9, T-M 13, M-H Rosa
Himalayan blackberry 5, L-D 5, L-M 5, M-D 4, M-D 4, M 6, L-M 4, L-M 7, L-M 5, L-M 6, L-M 4, L-M 5, L-M 2, T-M 2, L 1, M 2, T-M 2, H-D 3, L-H Perennial
pepperweed 3, T-M 3, T-L 4, T-H 4, T-H 4, T-M 3, L-M 2, L-M 6, T-M 2, T 1, T 2, T 1, T 1, M 1, H – – – – Sweet fennel 1, L 1, L 3, T 3, T 3, T 1, M 1, M – – – – – – – – – – – Poison hemlock 1, H 1, M – – – – – 1, T 1, T – – – – – – – – – Bull thistle – – 3, L-M 4, T-L 3, T-L 5, L-M 4, L 1, M 2, M 3, T 4, T 3, L – 1, T – 1, T – – Stinkwort – – – – – – – – – – – – – – – 1, T – –
Harding grass – – – – – – – – – – – – – – – – 1, L 4, L-H Tree of Heaven – – – – – – – – – – – – – – – – 1, L 8, L-H Water primrose – – – – – – – – – – – – – – – – – 1, D
Milk thistle – – – – – – – – – – – – – – – – – 14, L-H
Italian thistle – – – – – – – – – – – – – – – – – 3, M-H The Natomas Basin Conservancy
Land Cover Mapping, Botanical Inventory, and
Noxious Weed Monitoring
Table 2-6. Continued
Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
2-19
April 2023

Reserve Noxious Weed Species
Number and Degree of Occurrences
2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Souza
English ivy 1, D 1, M – – – – – – – – – – – – – – – –
Himalayan blackberry – – 1, L 1, L 1, L – – – – – – – 1, H 2, L-M – – – 3, M-H Bull thistle – – 1, L 1, L 1, L 1, L – 1, L 2, L 3, T – 2, T – – – – – – Harding grass – – – – – – – – – – – – – – – 1, L – 3, M-H Milk thistle – – – – – – – – – – – – – – – – – 5, L-H
Stinkwort – – – – – – – – – – – – – – – – – 1, L
a Occurrences reflect the number of occurrences on each tract followed by the level of infestation, as shown below:
• T = Trace (rare): less than 1% cover.
• L = Low (occasional plants): 1–5% cover.
• M = Moderate (scattered plants): 5–25% cover.
• H = High (fairly dense): 25–75% cover.
• D = Dense (dominant): more than 75% cover.
b Harding grass was not tracked in 2018 and 2019 because the species did not demonstrate an invasive distribution in the reserv es. After several more occurrences were detected in 2020, vegetation monitoring efforts resumed tracking Harding grass.

SACRAMENTO CO

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SACRAMENTO CO

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YOLO CO.

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Feather River
Sacramento River
American River
Sankey Rd
Powerline Rd
Riego Rd
Elverta Rd
Elkhorn Blvd
Del Paso Rd
Truxel Rd
Airport Blvd
San Juan Rd
Northgate Blvd
El Camino Ave
El Centro Rd
Sills
T ufts
Lucich
South
Atkinson
Lucich North
Silva
Bennett North
Frazer
Rosa East
Rosa Central
Bolen South
Bennett South
Bolen North
Huffman West
Ruby Ranch
Souza
Cummings
Natomas
Farms
Huffman East
Alleghany
Vestal
Nestor
Bolen
West
Elsie Bianchi West
Kismat
Betts
Frazer South
Silva South 1
Lauppe South
Paulson South Richter
Verona
Willey
Figure 2-1
Distribution of Land Cover Types in the Natomas Basin, 2022 Legend
Reserve Lands
NBHCP Area Boundary
Rivers
County Boundaries
Major Roads
Roads
Land Cover
Alfalfa
Developed
Disturbed / Bare
Fallow
Fresh Emergent Marsh
Grass Hay
Grassland
Irrigated Grassland
Oak Woodland
Open Water
Orchard
Rice
Riparian Scrub
Riparian Woodland
Row Crops
Seasonal Wetland
Valley Oak Woodland
Vineyard 1 0 1
Miles
³
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\figure2_1_basemap_habA.mxd 19393 Date: 06 Mar 2023/ Graphics … 662.17 NBC (3-9-2023) TG
FIGURE 2-1
Distribution of Land Cover Types in the Natomas Basin, 2022 0 5,000
10,000
15,000
20,000
25,000
2022202120202019 2018 2017 2016 2015 2014 2013 2012 2011 2010200920082007200620052004 Rice
Upland Agriculture
Grasslands
Managed Marsh/Wetlands
Acres
Fallow Lands
NBC 104332 2022 AR (2-24-2023)
FIGURE 2-2
Changes in Acreage of the Major Habitat Types in the Natomas Basin, 2004–2022 This Page Intentionally Left Blank
Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
3-1
April 2023

Chapter 3
Giant Gartersnake

CHAPTER HIGHLIGHTS
• Sampling effort in 2022 was comparable to 2021 and higher than in 2020, but was reduced overall compared to 2011–2019.
• The trapping season (May–August) and sampling period (21 days) has been consistent since 2021.

The number of sites sampled was comparable, from 40 in 2020, 45 in 2021, and 41 in 2022. • Catch-per-unit of effort decreased from 2021 to 2022. The size distribution of captured snakes in 2022 was consistent with a healthy population. Estimates of occupancy increased between 2021 and 2022, although the probability that the proportion of occupied sites was stable (i.e., did not change by more than 10%) from 2011 to 2022 was approximately 99%. • Apparent survival of giant gartersnakes at BKS was higher from 2018–2019 than in subsequent years.
• Giant gartersnake populations throughout the Basin and on reserve lands would likely benefit from: (1) creating more managed marsh; (2) increasing the amount of emergent tule vegetation in existing marshes (e.g., Cummings, Natomas Farms, and Lucich South); (3) flooding up existing marshes earlier in the season (early spring); (4) maintaining rice agriculture; and (5) continued research into conservation actions such as translocation and habitat and water management, that target giant gartersnake.

3.1 Introduction

3.1.1 Background
The NBHCP (City of Sacramento et al. 2003) and its Implementing Agreement require an annual assessment of giant gartersnake populations within the Natomas Basin (Chapter VI, Section E [2][a][2] of the 2003 NBHCP). The NBHCP also requires an assessment of habitat connectivity for giant gartersnake within and between reserves. This chapter addresses these requirements.

Studies from 2001 through 2003 focused on the distribution of giant gartersnake in the Natomas Basin (Wylie et al. 2003:21). Subsequent surveys attempted to assess population trends across a broad array of habitats and geographic areas, but detection probabilities were too low and the range of environmental conditions too variable to allow for estimation of abundance that accounted for variable detection probabilities. In 2011, the study was redesigned to increase sample sizes and account for the detection and capture process in a more statistically rigorous and defensible manner. In 2018, the study design was further revised to take advantage of advances in analytical methods for wildlife populations and knowledge gained about giant gartersnake since 2011. The 2018 revision allows for estimation of giant gartersnake occupancy, abundance, and demographic parameters from a larger sample of sites throughout the Natomas Basin and increases the efficiency of sampling and the ability to estimate the effects of management actions on giant gartersnake.

The Natomas Basin Conservancy

Giant Gartersnake

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
3-2
April 2023

3.1.2 Goals and Objectives
Monitoring protocol revisions implemented in 2011 were designed to assess progress toward achieving the goals of the NBHCP. In particular, the revised protocol was designed to meet the following objectives.
• Examine the demography of giant gartersnake populations at a larger sample of locations within the Natomas Basin, with an emphasis on measuring abundance and estimating survival, recruitment, and population growth rate.
• Quantify the effects of management practices on giant gartersnake demography to promote positive population growth.
• Examine the distribution of giant gartersnake on TNBC reserves, with an emphasis on evaluating evidence for trends in the proportion of reserves occupied, and quantify environmental variables associated with the occurrence of giant gartersnake.

The 2018 revisions to the study design were designed to better meet the objectives outlined above.

Changes included removing the “demography” traplines and implementing an occupancy and abundance sampling approach throughout the Basin. The sampling period at each sampling site was also extended to 21–29 days (this was modified in 2020 due to the COVID-19 pandemic but was resumed in 2021, as described further in Section 3.2.1, Trapping Giant Gartersnake), allowing for enough recaptures in many cases to estimate abundance and demographic rates at more sites throughout the Basin. In cases where adjacent or nearly adjacent wetland units or rice canals are sampled, the information from those traplines can be combined, resulting in more precise estimates of abundance and demographic rates and increasing the probability of recapture because a larger area is being sampled. By increasing sample sizes, the new design also allows for better inferences about the effect of habitat on giant gartersnake and the effects of management actions.

However, the change in sampling design precludes comparison of results from previous years under the old sampling design. Accordingly, it is not possible to track changes in abundance or demographic rates from years prior to 2019.

The purpose of monitoring giant gartersnake demography is to determine the abundance, apparent survival (the probability of surviving and remaining in the sampled area from 1 year to the next), recruitment (the rate at which individuals are born in the sampled area [and survive their first year] or migrate to the sampled area), and population growth rate of giant gartersnake at occupied sites in the Natomas Basin. The management goal with respect to demography is to maintain stable or positive population growth.

The purposes of monitoring the distribution of giant gartersnake on TNBC reserve lands are to determine what proportion of sites within reserve lands are occupied, to determine what variables correlate with the probability that a site is occupied, and ultimately to calculate trends in occurrence probability. The management goal with respect to occupancy is to maintain a stable or increasing trend in the probability of occurrence throughout the reserve system.

3.1.3 Life History
Giant gartersnake (Figure 3-1) is a large aquatic gartersnake endemic to wetlands in California’s Central Valley. It was first described in the southern San Joaquin Valley by Fitch (1940) as a subspecies of the aquatic gartersnake (at that time, Thamnophis ordinoides). Further taxonomic The Natomas Basin Conservancy

Giant Gartersnake

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
3-3
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revisions resulted in the consideration of giant gartersnake as a subspecies of Sierra gartersnake (Thamnophis couchii). Because giant gartersnake is morphologically distinguishable from and allopatric with its most closely related species, aquatic gartersnake (Thamnophis atratus) and Sierra gartersnake, it was recognized as a full species in 1987 (Rossman and Stewart 1987).

Giant gartersnake is highly aquatic and historically occurred in marshes, sloughs, and other habitats with slow-moving, relatively warm water and emergent vegetation, especially tules. Although conversion of wetlands to agriculture has nearly extirpated giant gartersnake from the San Joaquin Valley, this species persists in rice fields and nearby agricultural canals in the Sacramento Valley (Halstead et al. 2010). Canals associated with rice agriculture can provide marsh-like habitat conditions throughout the giant gartersnake active season—late March through early October (Wylie et al. 2009)—and rice fields themselves are emergent wetlands for a portion of the giant gartersnake active season. The quality of rice habitats relative to natural or restored marshes is an area of active research. Recent work has shown that although giant gartersnake does not spend much time in rice fields compared to irrigation canals, snakes have higher survival when inhabiting areas with more active rice fields surrounding them (Halstead et al. 2019).

Giant gartersnake feeds primarily on small fish, frogs, and tadpoles (Rossman et al. 1996). Specific prey items may include tadpoles and small adults of American bullfrog (Lithobates catesbeianus) and tadpoles and adults of Sierran treefrog (Pseudacris Sierra). Fish prey items include mosquitofish (Gambusia affinis) and small cyprinid and centrarchid fishes. Little is known about the diet of juvenile giant gartersnake, but neonates preferred tadpoles to fish in laboratory feeding trials (Ersan et al. 2020a, b).

Giant gartersnake is the longest gartersnake (Rossman et al. 1996), and like many snakes within its genus, it is sexually dimorphic for size, with females as the larger sex (Wylie et al. 2010). Smaller giant gartersnakes grow more rapidly than larger giant gartersnakes (Coates et al. 2009; Rose et al. 2018d). Males and females exhibit differing patterns of seasonal growth, with males forgoing foraging (and growth) for reproductive opportunities in the early spring (Coates et al. 2009).

Similarly, male body condition is much lower than female body condition during the spring mating season, but males and females enter hibernation in similar condition (Coates et al. 2009). Body condition might be related to the thermal ecology of giant gartersnake. Female giant gartersnakes exhibit elevated body temperatures during June, July, and August (Wylie et al. 2009), which is the period during which they are gravid. In contrast, males elevate body temperature in the winter and early spring (Wylie et al. 2009), likely to prepare for the spring mating season. The elevated body temperature of male snakes might be metabolically costly, causing decreased body condition for them in spring.

Although some aspects of giant gartersnake demography remain elusive, detailed study of populations in the Sacramento Valley has yielded some insight into the population ecology of giant gartersnake. Giant gartersnakes in the Sacramento Valley tend to produce smaller litters than those historically observed in the San Joaquin Valley. In the San Joaquin Valley, mean litter size was 23 (Hansen and Hansen 1990). In the Sacramento Valley, mean litter size was 17 (95% credible interval1 = 13–21) based on females captured from 1995 to 1997 (Halstead et al. 2011a) and 16 (range = 5–35) based on females examined from 2013 to 2016 (Rose et al. 2018a). Mean parturition date in the Sacramento Valley was August 13, although parturition can occur from early July through

1 Credible intervals are the Bayesian equivalent of confidence intervals in traditional frequentist statistics. All ranges reported in this chapter represent 95% credible intervals.

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early October (Halstead et al. 2011a). Neonates in the Sacramento Valley are born at approximately 209 millimeters (mm) snout–vent length (SVL) with a mass of 4.9 grams (g) (Halstead et al. 2011a).

Litter size varies temporally, potentially with resources, and larger females produce more, rather than larger, offspring (Halstead et al. 2011a; Rose et al. 2018a).

Survival of adult female giant gartersnakes in the Sacramento Valley varies among sites, years, and conditions. The annual survival probability of adult females greater than 180 g was 0.61 (0.41–0.79) at an average site in an average year (Halstead et al. 2012). Individuals are at 2.6 (1.1–11.1) times greater daily risk of mortality when in aquatic habitats than in terrestrial habitats (Halstead et al. 2012), likely because most terrestrial locations consist of subterranean refuges. The effect of linear habitats on daily risk of mortality varied with context: in rice agricultural systems, daily risk of mortality was lower in canals than away from canals, but in systems with natural or restored marshes, risk of mortality was lower in these two-dimensional habitats than in simple linear canals (Halstead et al. 2012). Overall survival was greatest in a site with a relatively large network of restored marshes (Halstead et al. 2012). A recent capture-mark-recapture (CMR) study found survival of giant gartersnake is also positively related to SVL up to peak, after which survival likely plateaus for the largest individuals (Rose et al. 2018b). This study also found a positive relationship between snake survival and the cover of emergent vegetation at a site (up to approximately 40% emergent vegetation cover; Rose et al. 2018b). Giant gartersnake population growth is highly dependent on the survival rate of adult females (Rose et al. 2019); therefore, fostering wetland characteristics that support high adult female survival is important for population persistence.

Abundance, density, and body condition of giant gartersnake vary by site, presumably as a result of site differences in habitat. Abundances and densities were greatest at a natural wetland, lower in a natural wetland modified for agricultural uses, lower still in rice agriculture, and lowest in seasonal marshes managed for waterfowl (moist soil management in summer, flooded in winter; Wylie et al. 2010). Body condition of females followed a similar pattern (Wylie et al. 2010). Habitats that most closely approximate natural marshes are therefore most likely to support dense populations of healthy giant gartersnakes.

The historical range of giant gartersnake extended from Butte County in the north to Kern County in the south (Fitch 1940; Hansen and Brode 1980). The draining of wetlands and subsequent urban and agricultural development have contributed to the loss of over 95% of giant gartersnake’s original habitat (Frayer et al. 1989). The few remaining natural wetlands are fragmented, the natural cycle of seasonal valley flooding by high Sierra Nevada snowmelt has been limited, and the waters have been diverted by a network of dams and levees. As a result, giant gartersnake populations have become fragmented with only small, isolated populations remaining in the San Joaquin Valley. These factors precipitated the listing of giant gartersnake by the State of California (California Department of Fish and Game Commission 1971) and later by the U.S. Fish and Wildlife Service as a threatened species with a recovery priority designation of 2C: full species, high degree of threat, and high recovery potential (U.S. Fish and Wildlife Service 1993, 1999). The recovery of giant gartersnake will require the restoration and protection of marsh habitats, a reliable supply of water to these habitats throughout the year, and further research into the most effective conservation practices for this species.

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3.1.4 History of the Natomas Basin
The lands of the Natomas Basin were historically subject to frequent flooding events because of the Basin’s proximity to the American and Sacramento Rivers. Situated just north of the confluence of these major river systems, the Natomas Basin was characterized by abundant marshlands, small streams, and a mixture of riparian, oak woodland, and grassland vegetation. The presently available information about the historical range of giant gartersnake indicates that the Natomas Basin would have been within the distribution of giant gartersnake and was likely home to an abundant population.

3.2 Methods

3.2.1 Trapping Giant Gartersnake
All aspects of the giant gartersnake monitoring effort involve using trap transects composed of floating galvanized minnow traps (Casazza et al. 2000) for capture. Beginning in 2012, traps were modified to contain one-way valves constructed from cable ties placed in the small opening of the funnels. Beginning in 2013, traps were also modified to include two pieces of hardware cloth attached to each end of the funnel using zip ties (Halstead et al. 2013a). These modifications help to direct snakes moving along the edge of a habitat into the trap and keep the snake within the trap, thus increasing capture probability.

Giant gartersnake occurrence and demography were monitored at 60 sites in 2018 and 2019, 40 sites in 2020, 45 sites in 2021, and 41 sites in 2022. Between 2020 and 2022, we dealt with substantial challenges caused by the COVID-19 pandemic. In 2022, we faced additional obstacles such as heat waves and drought that caused low water levels and high water temperatures. The start date of our field season was delayed to train all technicians on a rigorous safety protocol that prioritized the health of our technicians and the public. Although our season was safe and successful, the protocols added time constraints to our already delayed season. Like the previous year, in 2022 we were able to continue the 21-day sampling periods as opposed to the 14-day period in 2020, but some traplines had to be pulled early due to low water level or high water temperature. Despite these caveats, our total number of sampled sites 2022 was higher than in 2020, although still lower than the number sampled in 2018, 2019, and 2021. We selected which sites to sample using a Generalized Random Tessellation Stratified approach to ensure a random, spatially dispersed sample (Table 3-1; Figure 3-2). Random selection of sites allows inference to TNBC reserves as a whole. Sampled sites consisted of individual wetland units (defined as being contained within water control structures) and canals adjacent to rice, and the selection of sampled sites was stratified by reserve area (22 sites in the North Basin Reserve, 11 sites in the Central Basin Reserve, and eight sites in the Fisherman’s Lake Reserve) to ensure adequate representation of each reserve. At each site, one transect of 50 traps was deployed, with traps spaced approximately 10–20 meters apart. In 2022, trap transects were deployed for approximately 14–21 days each, from as early as possible in the active season, after we determined field work could proceed safely (beginning May 2, 2022), until August 31, 2022. Sampling did not take place on Memorial Day, Juneteenth Independence Day, and Independence Day.

For sites that were sampled as “occupancy traplines” in previous years, transects were generally placed in the same location in 2022; this approach maintains the same extent of sampling to provide The Natomas Basin Conservancy

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inference about giant gartersnake occurrence to the same areas. However, at the five “demography sites” on the BKS, Lucich North, Lucich South, Natomas Farms, and Sills tracts, sampling from 2018 to 2022 differed from the areas sampled from 2011 to 2017. From 2011 to 2017, three transects were sampled at each demography site each year. In 2018 and 2019 at the BKS tract, all three “old” demography traplines were sampled, along with an additional five traplines placed in other wetland units, while beginning in 2020 only two “old” demography traplines (BKS 2 and 3) were sampled, along with three of the additional traplines sampled in 2018 and 2019. These same five traplines sampled at BKS in 2020 were also sampled in 2021 and 2022, with the exception of one of the additional traplines, which was not sampled in 2021 (only four BKS traplines were sampled in 2021). At Lucich North, only one of the three “old” demography traplines (Lucich North 4) has been sampled during the past five years, however seven additional traplines were added to wetlands at this tract in 2018. Lucich North 4 was sampled in 2018, 2019, 2020, and 2022, but was not sampled in 2021. The seven additional traplines added at Lucich North in 2018 were all sampled in 2018 and 2019, six were sampled in 2020 and 2022, and four were sampled in 2021. Within Lucich South, one of the three “old” demography traplines (Lucich South 3) was sampled each year from 2018–2022, and two additional traplines were added to canals in 2018. Of these two additional canal traplines, both were sampled in 2018, 2019, and 2022, while only one was sampled in 2020 and 2021. At the Natomas Farms tract, one “old” demography trapline (Natomas Farms 1) was sampled each year from 2018–2020, three “old” demography traplines (Natomas Farms 1, 2, and 3) were sampled in 2021, and two “old” demography traplines (Natomas Farms 1 and 2) were sampled in 2022. In addition to these “old” demography traplines, one additional wetland trapline was sampled at Natomas Farms in 2018, 2019, 2021, and 2022. At the Sills tract, two “old” demography traplines (Sills 2 and 3) were sampled in 2018 and 2019 while no “old” demography traplines were sampled from 2020–2022. However, three additional traplines were added to canals at Sills in 2018 and all three were sampled each year from 2018–2022. These changes made to our study’s sampling methods allowed us to survey a broader area at most of the “old” demography sites (except in 2020 when the entire study was truncated); however, they also meant that some areas that were sampled from 2011–2017 were not covered by trap arrays from 2018–2020. As noted above, these changes present ramifications for modeling giant gartersnake demography and interpreting changes in abundance estimates, as described below in Section 3.2.2, Analytical Methods.

Trap transects were positioned along the banks, at the edges of emergent vegetation in wetlands, or along the edges of canals because giant gartersnake forages along habitat edges. Habitat edges also act as natural drift fences that direct snake movement to traps. While deployed, traps were checked daily.

Environmental conditions relevant to giant gartersnake behavior were monitored daily at each trap transect including water temperatures, air temperatures, and fluctuations in water level. To obtain a measure of the relative abundance and diversity of potential local aquatic prey, contents of every fifth trap were recorded and then all contents were removed. All other traps were monitored, but prey items such as fish, tadpoles, and small frogs were left in the traps so that they became naturally “baited” over time. In some instances, large fluctuations in water level (draining of wetlands, canals, or ditches) necessitated opening traps temporarily or relocating transects to a suitable nearby location within the selected site.

Universal Transverse Mercator (UTM) coordinates of all trap locations were recorded and vegetation and habitat surveys conducted at points within and adjacent to each trap transect.

Percent cover of habitat types (water, submerged aquatic vegetation, floating aquatic vegetation, The Natomas Basin Conservancy

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emergent vegetation, terrestrial vegetation, rock, or bare ground) and vegetative composition (species or higher taxonomic category) was estimated within a 0.5-meter radius of every fifth trap.

Associated with each habitat and vegetation survey along the transect, a point to the left (odd- numbered traps) or right (even-numbered traps) of the transect was selected at a random perpendicular distance of 2–5 meters, and percent cover of habitats and vegetative composition was estimated within a 1-meter radius of this point to better characterize habitat surrounding the traps.

Each captured giant gartersnake was measured, sexed, and uniquely marked. Scale measurements in Rossman et al. (1996) were used to verify the species of each captured gartersnake. The SVL and tail-vent length (TVL) of each individual were measured to the nearest millimeter, and each individual was weighed to the nearest gram. The sex of each individual was determined by probing the cloaca to detect the presence or absence of hemipenes. After examination, each individual that showed no sign of previous capture was given a unique brand on its ventral scutes (Winne et al. 2006) and, if large enough (>35 grams), implanted with a passive integrated transponder (PIT) tag.

PIT tags were implanted using syringe injector needles swabbed with alcohol before each use, and the injection site on the snake was swabbed with alcohol prior to tag insertion. The tag was injected subcutaneously, approximately one-third of the SVL anterior to the cloaca. After insertion of the tag, cyanoacrylate glue was applied to the insertion site to seal the dermis and prevent tag loss. Most individuals were processed in the field within a few minutes of their capture. If snakes were held for more than a few minutes, they were kept in the shade in cooled and insulated containers to prevent overheating until they could be examined and released. Each individual was released at its location of capture immediately after processing.

3.2.2 Analytical Methods
Most analyses were conducted in a Bayesian analytical framework. In Bayesian analyses, the probabilities are interpreted slightly differently from traditional frequentist statistical analyses. The posterior probability is the probability of a random event or uncertain proposition given the data at hand and is most analogous to the probabilities used in frequentist statistics. The posterior probability is how most people intuitively think about probability (e.g., how people interpret a weather forecast). Bayesian analyses also require specification of a prior probability distribution, which allows for the inclusion of information obtained through other sources into the analysis. The prior can be an informative prior (i.e., a distribution based on previously collected data or a hypothesis about the probability distribution of interest) or an uninformative prior (i.e., a probability distribution that will have no effect on the outcome of the analysis). All parameter estimates are accompanied by 95% credible intervals. Unless otherwise noted, for all parameter estimates posterior medians are reported with equal-tailed 95% credible intervals in parentheses.

3.2.2.1 Demography
Abundance of giant gartersnake was estimated at each site where the species was detected using Bayesian analysis of CMR data, closed population models, and data augmentation (Royle and Dorazio 2008; Kéry and Royle 2016).2 In contrast to occurrence, where site was defined as the area between two water control structures, for the purposes of this analysis, site refers to clusters of

2 Data augmentation is an approach to CMR analysis in which a large number of all-zero capture histories is appended to the observed capture histories. This approach is much more flexible than other approaches to estimation of demographic rates and allows a unified framework for analysis of detection-nondetection and CMR data (Royle and Dorazio 2008).

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transects that snakes could likely move between (see below). Closed population models are those that assume no migration in or out of the population of interest over the sampling period (in this case, the 14–21 days during which a site was sampled). These models are used to estimate abundance using simplifying assumptions. A single model was used to estimate abundance for each site, and information on capture probability was shared among sites which resulted in more precise estimates of abundance at each site.3 The effects of water temperature, snake SVL, snake sex, and a behavioral response on capture probabilities were tested. Models also included temporal variation in capture probability (i.e., variation in capture probability among days of sampling) and individual heterogeneity in capture probability (i.e., variation in capture probability among individual snakes).

Because some traplines were proximate to one another, four snakes were caught in multiple traplines, and it is likely that other individuals moved between traplines as well. To account for demographic linkage between nearby traplines, captures of snakes were grouped into eight “demographic clusters,” and abundance was estimated for each cluster. Clustering traplines avoided duplicate counting of snakes captured at more than one trapline and provided abundance estimates relevant to larger reserve areas rather than a single section of a canal or wetland. Because larger areas were sampled at BKS, Lucich North, and Sills in 2018 and 2019 compared to 2011–2017, less area was sampled overall in 2020 due to the COVID-19 pandemic, and because not all of the old demography traplines were sampled from 2018 to 2022, abundance estimates for these tracts from 2018 to 2022 are not directly comparable to previous years.

In addition to abundance estimates from closed population models, we estimated the density of giant gartersnake (in snakes per [hectare] ha of habitat) at four sites in 2022 using spatially-explicit capture-recapture (SECR) models. SECR models use the spatial locations where animals are captured or observed to estimate their “activity centers” as a measure of their use of space.

Importantly, SECR account for both the location of traps and the period during which each trap was active and therefore able to capture an animal. Fitting SECR models requires sufficient recaptures of individuals within a single active season to estimate how capture probability decreases with the distance from the detector (in this case, a funnel trap). Therefore, we pooled data from nearby sites to ensure we had a dataset rich enough in recaptures to estimate the necessary parameters. The four sites for which we estimated density were BKS (BKS + Frazer South traplines), Sills (Sills + Tufts + Elsie traplines), Lucich South (Lucich South + Bennett South traplines) and Lucich North (Lucich North, Frazer North, and Bennett North traplines). We defined giant gartersnake habitat by creating polygons corresponding to wetland reserve habitat from satellite imagery in ArcMap version 10.8

3 To estimate abundance accurately, the probability of capturing a giant gartersnake must also be estimated.

Investigators fit a single “multinomial N-mixture model” (Kéry & Royle 2016) using capture data from all eight demographic cluster sites, with random effects of site, date, and individual on capture probability. This type of joint model has the advantage of sharing information on capture probability among sites, which allows for more precise estimates of capture probability and abundance at each site. This model has proven effective at estimating abundance of giant gartersnake (Rose et al. 2018c). The capture histories of trapped individuals were augmented with enough all-zero capture histories to give a total pool of 1,200 individual snakes. The number of pseudo- individuals was deemed adequate because the posterior density for abundance fell far below the number of augmented individuals. Uninformative priors were used for all parameters of all models: Uniform(0,1) for probabilities, N(0,1.648) for regression coefficients, and half-Cauchy (0,1) for standard deviations. The closed population model was run on five independent chains of 100,000 iterations after a burn-in of 5,000; each chain was thinned by a factor of 10 to give a final output of 50,000 samples for inference. The model was analyzed by calling JAGS 4.3.0 (Plummer 2003) from R 4.1.2 (R Core Team 2021) using the package “runjags” (Denwood 2016).

Posterior distributions were summarized with the posterior median and 95% credible interval (2.5% and 97.5% quantiles of the posterior distribution).

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(ESRI). For habitat in canals, we created a line feature representing the center of the canal and buffered this line by 10 m on either side to create a 2-dimensional approximation of the habitat area.

We fit SECR models using the “secr” R package (Efford 2022) and report the mean, standard error, and 95% credible interval of the density of snakes.

Since the revision of our study design implemented in 2018, we have collected four annual intervals of mark-recapture data. This allowed us to start estimating apparent survival using open-population models. Although there is overlap between the areas sampled from 2011 to 2017 and the areas sampled from 2018 to 2022, the change in spatial coverage could lead to biased estimates of these vital rates. For example, individual giant gartersnakes with home ranges overlapping trapping arrays in 2016 and 2017 that were not captured in 2018, 2019, or 2020 could be treated as mortalities by the open-population CMR model, when in reality they survived this time interval but were unlikely to be caught in traps based on the new trapping locations from 2018 to 2022.

Therefore, our estimates of apparent survival, annual recapture probability, and availability for capture (i.e., presence “on site”) are only based on capture data from 2018 to 2022.

We calculated estimates of apparent survival using CMR data each year from 2018 to 2022 at three tracts (BKS, Lucich North, and Sills) that had greater than 15 individual giant gartersnakes captured over this period and more than one giant gartersnake recaptured subsequent to its first year of capture. All other tracts had fewer than 15 individuals captured over the period from 2018 to 2022.

We estimated apparent survival (ϕ) using a robust-design CMR model designed to give unbiased estimates of survival by accounting for availability of individuals for capture (γ, i.e., temporary emigration) in addition to recapture probability (Riecke et al. 2018). We estimated separate survival rates for female and male giant gartersnake, and the apparent survival estimate also varied by site and year according to random effects of each. We estimated a single shared recapture probability parameter (p) for the two sexes, because preliminary model runs indicated no difference in recapture probability between female and male giant gartersnake.4 Sex ratios and size distributions were calculated using data from all captured individuals, regardless of method of capture or date of capture. Bayesian analytical methods were used to estimate sex ratios with binomial tests of proportions for all sampling locations within the Basin.5 Bayesian methods were also used to describe the mean SVL and mass of giant gartersnakes of each sex from all sampling locations within the Basin.6 Sexual size dimorphism in SVL and mass was examined throughout the Basin using separate means and variances for males and females. These tests are

4 The robust-design model used uninformative Beta(1,1) prior distributions for the probabilities of apparent survival (ϕ), recapture (p), and availability on site during sampling (γ). All random effects parameters were drawn from normal distributions centered on zero with a standard deviation estimated from the data. Standard deviation parameters had Exponential(1) priors to shrink values toward zero if variation among sites and years was minimal but allow for larger values if warranted by the data. The model included random effects of year and site on ϕ, p, and γ. The robust-design model was fit using JAGS 4.3.0 (Plummer 2003) from R 4.1.2 (R Core Team 2021) using the R package runjags (Denwood 2016). The model was fit using five independent chains of 80,000 iterations each after a burn-in of 10,000 iterations. Each chain was thinned by a factor of 10, resulting in a final posterior sample of 40,000 iterations.
5 The binomial model assumes sampling with replacement (Skalski et al. 2005); accordingly, counts of captures rather than individuals were used for analysis.
6 Normal models were fit for each size measurement (mass and SVL), and the goodness of fit of each model was examined with a Bayesian p-value. Normal models fit well to the mass and SVL data, with Bayesian p-values of 0.51 and 0.52 for mass and SVL, respectively.

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equivalent to t-tests with unequal variances (Kéry 2010).7 Sexual size dimorphism, sex ratios, and mean SVL and mass were not examined at individual sites because of the great uncertainty in estimating means with small sample sizes.

3.2.2.2 Distribution of Giant Gartersnake on Reserve Lands The probability of occurrence of giant gartersnake on TNBC reserves in 2022 was estimated using Bayesian analysis of single-season occupancy models (Royle and Dorazio 2008; Kéry 2010). The probability of occurrence was modeled as a linear function of selected habitat variables, and the probability of occurrence was allowed to vary among reserve areas (North Basin, Central Basin, and Fisherman’s Lake). We initially modeled habitat effects only to identify supported habitat variables, then added a fixed effect of reserve area to a model containing only supported habitat variables. The habitat variables included effects of wetland or rice habitat and the percent cover of emergent vegetation, floating aquatic vegetation, open water, and terrestrial vegetation on the probability of occurrence of giant gartersnake. Priors for the occupancy component of each model were chosen to be uninformative (Table 3-2).8
In addition to the single-season occupancy models evaluated above, a Bayesian state-space dynamic occupancy model (MacKenzie et al. 2006; Royle and Kéry 2007; Kéry and Schaub 2011) was evaluated to identify any evidence for changes in the probability of occurrence of giant gartersnake on TNBC reserves over time from 2011 to 2022. Occurrence of giant gartersnake among various wetland units can change between years due to colonization of sites that were previously unoccupied and extinction at sites that were previously occupied. Accordingly, the dynamic occupancy models account for these changes and are used to estimate the rates at which these changes occur and the annually varying colonization and extirpation probabilities.9 The effects of the same habitat variables that were evaluated using static occupancy models were evaluated to determine if they were related to extinction and colonization probabilities, and we used uninformative priors for the parameters related to occurrence, site-survival, site-colonization, and detection components of the model.

7 Each model was run on five independent chains of 20,000 iterations after a burn-in of 2,000; each chain was thinned by a factor of five. Each model was analyzed by calling JAGS 4.3.0 (Plummer 2003) from R 3.6.2 (R Core Team 2019) using the R package jagsUI (Kellner 2016). Posterior distributions were summarized with the posterior median and 95% credible interval.
8 All continuous variables were standardized to improve behavior of the Markov Chain Monte Carlo (MCMC) algorithm and to allow direct comparison of model coefficients. The posterior probability of each subset of the full model was calculated using indicator variables on model parameters (Kuo and Mallick 1998; Royle and Dorazio 2008). Each model was run on five independent chains of 110,000 iterations each after a burn-in of 2,000; each chain was thinned by a factor of 5, resulting in a final total of 110,000 samples for inference after pooling chains.

Each model was analyzed by calling JAGS 4.3.0 (Plummer 2003) from R 3.6.2 (R Core Team 2019) using the package runjags (Denwood 2016). Posterior distributions were summarized with the posterior median and 95% symmetrical credible interval.
9 All probabilities were given U(0,1) priors. The dynamic occupancy model was run on five independent chains of 200,000 iterations each after a burn-in of 20,000; each chain was thinned by a factor of 100, resulting in 10,000 samples for inference. Each model was analyzed by calling JAGS 4.3.0 (Plummer 2003) from R 3.6.2 (R Core Team 2019) using the package R2jags (Su and Yajima 2015). Posterior distributions were summarized with the posterior median and 95% symmetrical credible interval (2.5% and 97.5% quantiles of the posterior distribution).

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3.2.3 Habitat Assessment

3.2.3.1 Habitat Distribution and Abundance
The distribution and abundance of land cover/crop types throughout the Natomas Basin, both on and off reserve lands, are documented annually (see Chapter 2, Land Cover Mapping, Botanical Inventory, and Noxious Weed Monitoring). These data are used to document large-scale changes in the distribution and abundance of suitable habitat for giant gartersnake on reserve lands and throughout the Basin.

3.2.3.2 Habitat Connectivity
Connectivity among and between tracts and reserves was assessed by examining habitat variables along the major linear water conveyance features based on assessment in the field and using aerial imagery available from Google Earth. All culverts crossing major roadways were examined during field checks.

3.3 Results
Overall, 130 individual giant gartersnake were captured 159 times by hand or trap at 41 sites on TNBC reserve tracts over the course of 42,997 trap days in 2022 (Table 3-1; Figure 3-2). The 2022 monitoring year had a similar number of trap days to 2021 but was still lower than any year from 2011 to 2019, likely contributing to low numbers of both unique giant gartersnake individuals captured, and total captures compared to the years before the pandemic. The catch-per-unit effort (snakes captured per trap-night) across the Natomas Basin was 0.0037 in 2022. For comparison, catch-per-unit effort was 0.0049 in 2021 when 153 individuals were captured 226 times over 46,567 trap days; 0.0068 in 2020 when 147 individuals were captured 185 times over 27,398 trap days; 0.0062 in 2019 when 274 individuals were captured 394 times over 63,297 trap days; and

0.0054 in 2018 when 265 individuals were captured 374 times over 67,022 trap days. Catch-per- unit effort was 0.0047 in 2017, 0.0037 in 2016, 0.0017 in 2015, 0.0033 in 2014, 0.0035 in 2013,

0.0028 in 2012, and 0.0031 in 2011.

3.3.1 Demography

3.3.1.1 Estimates of Abundance Using Closed Population Models Capture probability, which is the variable with the greatest influence on estimates of all demographic parameters, averaged over all sites was 0.0017 (0.0005–0.0056). The standard deviation of capture probability among sites (0.0008 [0.0001–0.0047]) was slightly lower than the standard deviation of capture probability among days (0.0009 [0.0002–0.0030]). There was more variation in capture probability among individuals (0.0012 [0.0004–0.0028]). There was evidence for a positive ephemeral behavioral response to capture, and for a positive effect of water temperature on capture probability (Figure 3-3; Table 3-3).

Four instances of giant gartersnakes moving between traplines were detected in 2022. Three snakes were captured in multiple traplines within the Sills tract, and one snake was detected moving between traplines in the Bennett North tract. Traplines in close enough proximity that giant The Natomas Basin Conservancy

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gartersnakes did or would be expected to move between traplines were grouped together and treated as a single site for this analysis (e.g., all traplines in the Natomas Farms wetland complex; one trapline in the Frazer South tract was grouped with traplines in the BKS tract), resulting in seven demographic “clusters.” Estimates of abundance at each of the seven demographic clusters where giant gartersnakes were captured are summarized in Table 3-4.

At the six traplines within the BKS cluster (including one trapline from Frazer South), 79 individuals were captured 87 times over 6,300 trap days in 2022 (Table 3-4). Of 88 individuals that were captured in 2021, 11 were recaptured in 2022. Five snakes captured at BKS in 2020 were recaptured in 2022, six snakes captured in 2019 were recaptured in 2022, and four individuals first captured in 2018 were recaptured in 2022. The estimated abundance in sampled areas at BKS in 2022 was 385 (211–681) individuals (Figure 3-4, Table 3-4). The estimated abundance at BKS was 200 (147–352) individuals in 2021, 566 (256–1,303) individuals in 2020, and 559 (374–944) individuals in 2019.

At five traplines within the Sills cluster (including one trapline in the Elsie tract and one trapline in the Tufts tract), 31 individuals were captured 48 times over 4,752 trap days in 2022 (Table 3-4). For comparison, 36 individuals were captured 73 times over 4,178 trap days in 2021. Of the 36 individuals captured at Sills in 2021, 8 were recaptured in 2022. Of the 39 individuals captured at Sills in 2020, 2 were recaptured in 2022, and a single snake caught in 2018 was recaptured in 2022.

The estimated abundance at Sills in 2022 was 148 (76–267) snakes (Figure 3-5, Table 3-4). In 2021, the estimated was 74 (51–137). The estimated abundance at Sills in 2020 was higher, with an estimate of 258 (117–590) individuals.

At 10 traplines within the Lucich North cluster (including two traplines in the Frazer North tract and one in the Nestor tract), eight individuals were captured nine times in 2022 over 10,241 trap days (Table 3-4). The estimated abundance at Lucich North in 2022 was 46 (23–83) individuals (Figure 3-6, Table 3-4). For comparison, the estimated abundance in 2021 was 31 (19–55) individuals. In 2021, 10 individuals were captured 14 times at Lucich North over 5,241 trap days. The estimated abundance of giant gartersnake at Lucich North in 2021 was 31 (19–55) individuals at five traplines.

None of the eight snakes captured at Lucich North in 2022 had been captured in previous years.

At three traplines within the Lucich South demographic cluster, nine individuals were captured 15 times over 2,788 trap days in 2022. At two traplines within the Lucich South demographic cluster, one individual was captured once over 1,550 trap days in 2021. In 2020, two individuals were captured three times at two traplines. The estimated abundance at Lucich South in 2022 was 46 (22–84) individuals (Figure 3-7, Table 3-4). For comparison, the estimated abundance at Lucich South in 2021 was lower, at 23 (12–43) individuals. None of the nine snakes captured at Lucich South in 2022 had been captured in previous years.

In the Fisherman’s Lake Reserve area, no giant gartersnakes were captured at eight traplines in the Cummings, Natomas Farms, and Rosa tracts over 8,293 trap days in 2022. Likewise, in 2021 and 2020, no giant gartersnakes were captured at the three tracts (Cummings, Natomas Farms, and Rosa) over 8,335 trap days (2021) and over 2,798 trap days (2020). In 2019, one giant gartersnake was captured at two traplines, while in 2018, no giant gartersnakes were captured at either trapline in the Fisherman’s Lake Reserve area.

The other traplines at which snakes were captured were in the Bennett North, Bennett South, and Huffman West tracts. At Bennett North, two individuals were captured a total of three times, and the median estimated abundance was 42 (19–77) snakes (Table 3-4). At Bennett South and Huffman The Natomas Basin Conservancy

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West, one individual was captured a single time at each site. The median estimated abundance at Huffman West was 42 (20–77) individuals and the median estimated abundance at Bennett South was 42 (20–77).

3.3.1.2 Estimates of Density Using SECR Models
The highest density of giant gartersnake in the Natomas Basin in 2022 was at BKS, with a mean estimate of 10.5 snakes/ha of habitat (5.1–21.7 snakes/ha). The lowest density of giant gartersnake in 2022 was at Lucich North + Bennett North, with a mean estimate of 0.16 snakes/ha (0.05–0.59 snakes/ha). Snake density estimates at the Sills tract (mean = 1.11 snakes/ha; 0.63–1.97 snakes/ha) and Lucich South + Bennett South (mean = 1.53 snakes/ha; 0.70–3.34 snakes/ha) were comparable and intermediate to BKS and Lucich North.

3.3.1.3 Size Distribution and Sex Ratio
The overall sex ratio of captured snakes in the Natomas Basin was slightly female-biased. The sex ratio was 0.74 (0.51–1.02) males per female for all sites in the Basin combined. Basin-wide mean SVL was 612 mm (585–639 mm), and Basin-wide mean mass was 109.13 g (94.88–125.66 g). Mean female SVL (674 mm [637–712 mm]) was 148 mm (102–194 mm) greater than mean male SVL (526 mm [499–553 mm]), and mean female mass (150.9 g [125.16–182.29 g]) was 81.74 g (52.53–114.16 g) greater than mean male mass (69.16 g [58.53–81.74 g]; Figure 3-8).

3.3.1.4 Survival Estimates from 2018–2022
Average annual recapture probabilities, given 21 days of sampling at a site, were 0.14 (0.07–0.35).

There was no support for a difference in apparent survival rate between female and male giant gartersnake. Apparent survival varied among years and sites. At BKS, apparent survival was highest from 2018 to 2019 and lower from 2019 to 2020, 2020 to 2021, and 2021 to 2022 (Figure 3-9). At Lucich North, apparent survival was similar over each of the year-long intervals (Figure 3-10). At the Sills tract, apparent survival estimates were highest for the interval from 2019 to 2020 (Figure 3-11). The probability a snake was available on site for capture (γ) was slightly higher for female than male giant gartersnake (Table 3-5). As for the closed CMR model, there was a positive relationship between capture probability and water temperature (Table 3-5).

3.3.2 Distribution of Giant Gartersnake on Reserve Lands Giant gartersnakes were detected at 20 of 41 sites sampled in 2022 (Figure 3-2). Of the 35 sites surveyed in both 2021 and 2022, giant gartersnakes were detected at four sites in 2021 where no giant gartersnakes were detected in 2022. There were six sites where giant gartersnakes were detected in 2022 but had not been detected in 2021. Of the sites monitored in 2022, 30 (22–37) were estimated to be occupied (Figure 3-12).

The effects of habitat variables on the probability of occurrence were not supported in 2022 (Table 3-6). Water temperature had a positive effect on daily detection probability, but the effect of date of sampling on daily detection probability was not supported (Table 3-7; Figure 3-13). Daily detection probabilities for giant gartersnake in 2022 at an occupied site on a day with average conditions (e.g., average water temperature) were 0.07 (0.03–0.23). Over 21 days of trapping, this corresponded to a cumulative probability of detecting giant gartersnake at least once, given they occurred at a site in 2022, of 0.94 (0.43 – >0.99).

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The probability of occurrence of giant gartersnake varied by reserve (i.e., North Basin, Central Basin, and Fisherman’s Lake). The probability of occurrence in wetlands in the North Basin Reserve was

0.91 (0.42–0.99), the probability of occurrence in wetlands in the Central Basin Reserve was 0.95 (0.50–0.99), and the probability of occurrence in wetlands in the Fisherman’s Lake Reserve was 0.09 (0.01–0.82). Most sites in the Fisherman’s Lake Reserve were wetland sites (six of eight), whereas most sites in the Central Basin Reserve were rice sites (10 of 14), and sites were nearly evenly divided between the two types in the North Basin Reserve (13 of 22 sites were wetlands).

The dynamic occupancy model indicated evidence for a slight decrease in the probability that sites on TNBC reserves were occupied by giant gartersnakes from 2011 to 2013, followed by a period of stability from 2013 to 2018, an increase from 2018 to 2019, a decrease from 2019 to 2021, and an increase in 2022. Large uncertainty in occupancy in 2011 encompassed the modal estimates from all later years (Figure 3-14). The number of occupied sampled sites followed a similar pattern, with a decrease from 2019 to 2021 and an increase in 2022 (Figure 3-15). Both occupancy parameters were estimated with much greater precision in 2018 and 2019, when the number of sites increased to 60 as part of the revised sampling design, than in previous years. Conversely, precision of these parameters was much lower between 2020 and 2022 compared to the two previous years, due to decreasing the number of sites to 40 (2020), 45 (2021), and 41 (2022) because of the COVID-19 pandemic. The annual probability that occupied sites would become unoccupied (site extirpation) was generally low and stable between 2011 and 2019; while it was higher from 2020 to 2022 compared to previous years, site-extirpation probability consistently declined since 2020 (Figure 3- 14). The annual probability that unoccupied sites were colonized exhibited no trend from 2011 to 2018; increased from 2018 to 2020; decreased from 2020 to 2021; and increased from 2021 to 2022 (Figure 3-14). The mean intrinsic growth rate of occupancy from 2011 through 2022 was -0.042 (-0.072 to -0.006; Figure 3-16). Overall, although mean estimates of occupancy growth were slightly negative, credible intervals were close to zero, indicating occupancy was relatively stable from 2011 to 2022. Notably, there was clear evidence of positive occupancy growth from 2018 to 2019 and from 2021 to 2022. Occupancy growth was most negative between 2019 and 2020, potentially because of the reduction in the number of sampled sites, but it rebounded since the 2020–2021 period (Figure 3-16). The probability that the number of occupied sites was stable from 2011 through 2022 (less than 10% change; >0.99) was higher than the probability that the number of occupied sites decreased by more than 10% from 2011 through 2022 (<0.01), or that occupancy increased by more than 10% annually (<0.01). Beginning in 2017 three additional trap transects were surveyed (“NACONN” 1–3 in 2017 and NACONN 1, 3, and 5 from 2018–2021) in the Giant Gartersnake Drainage Canal that connects the North Drainage Canal to the West Drainage Canal along the southwestern edge of the Natomas Basin. No giant gartersnakes were detected at any of these trap transects between 2017 and 2021, and their addition could have caused the estimated occupancy for 2017, 2018, 2020, and 2021 to be slightly lower. However, occupancy increased in 2019 despite surveying these newly created, and as-yet unoccupied, sites. No giant gartersnakes were detected at Natomas Farms 2 and Natomas Farms 3, which had been “old” demography sites prior to our study design change in 2018. Addition of these sites to the occupancy analyses likely contributed to the lowest estimate of occupied sites in 2021; however, occupancy increased in 2022 despite including these sites to the analyses.

There was no support for effects of habitat on site-survival probabilities nor strong evidence for effects of habitat variables on occupancy dynamics (Table 3-8).

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3.3.3 Habitat Assessment

3.3.3.1 Habitat Distribution and Abundance
TNBC reserve lands provide better giant gartersnake habitat than that present in the Natomas Basin as a whole. Created marsh, seasonal wetlands, and other emergent wetlands are the highest quality giant gartersnake habitat and constituted 12.9%10 (667 acres) of the area of reserve properties but just 1.6% (789 acres) of non-reserve lands. TNBC reserves provided 46% of the wetland habitat within the Natomas Basin. Rice agriculture, which along with its supporting infrastructure of canals provides the only remaining suitable giant gartersnake habitat in the Basin, comprised 30.5% (1,573.3 acres) of the area of reserve properties compared to 21.0% (10,319.2 acres) of the non- reserve lands. The reduction of active rice habitat compared to 2021 (56.7% [2,606.4 acres]) is likely transient due to fallowing of rice fields; for example, of the 23 reserves in 2021 with active rice agriculture, 17 were fallowed in 2022.

Overall, 2,281.3 acres (44.3%) of the total acres of TNBC reserve lands was potential giant gartersnake habitat, while only 37.4% (18,323.1 acres) of the total acres of non-reserve area in the Basin was potential giant gartersnake habitat. It should be noted, however, that only marsh and a fraction of the linear water conveyance features that make up a very small proportion of the total acreage in rice provide suitable giant gartersnake habitat in all seasons, and that even these land cover types are only suitable if they contain adequate water to provide usable giant gartersnake habitat (i.e., a non-negligible amount of surface water immediately adjacent to emergent vegetation or steep canal banks). Giant gartersnakes require enough water to submerge themselves for foraging and predator escape, and they require this water to be immediately adjacent to basking and hiding sites, like emergent vegetation and steep canal banks. If water is not properly managed to ensure that all components of giant gartersnake habitat are present, marshes and canals no longer function as giant gartersnake habitat. Rice fields and their associated linear water conveyance features provide almost no giant gartersnake habitat for much of the year (i.e., September through June), so the amount of created marsh with adequate water is a better measure of giant gartersnake habitat for comparison than the sum of created marsh and rice. As noted above however, even the total acreage of created marsh may overestimate giant gartersnake habitat if it does not contain enough water.

Tracts in the Fisherman’s Lake Reserve cover approximately 388 acres. A total of 72.1 of these acres (18.6%) were created marsh in 2022. No rice existed in the Fisherman’s Lake Reserve tracts in 2022. Recently constructed wetlands (SAFCA wetlands) constitute much of the landscape immediately southeast of the Natomas Farms tract and between the Natomas Farms and Cummings tracts, and these wetlands have developed into suitable giant gartersnake habitat. Of the six tracts in the Fisherman’s Lake Reserve, one (Alleghany) contained no habitat for giant gartersnake in 2022, while the other five contained habitat suitable for giant gartersnake.

Tracts in the Central Basin Reserve cover approximately 1,423 acres. A total of 140 of these acres (9.8%) were created marsh and 551 acres (38.7%) were active rice in 2022. This represents a decrease of 507 acres (48%) compared to the 1,058 acres (74.3%) of rice that existed in the Central Basin Reserve in 2021. A total of 546.7 acres of Central Basin were fallowed rice fields in 2022.

10 The fresh emergent marsh (created) land cover type includes some, but not all, of the associated uplands for most, but not all, tracts with created marshes. Therefore, this number is not representative of the percentage of reserve lands in created marsh for purposes of assessing compliance with the terms of the NBHCP.

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Overall, 1,199.1 acres (84.3%) of the total acreage of the Central Basin Reserve was potential giant gartersnake habitat in 2022, although—as noted above—only created marsh and some canals associated with rice agriculture provide suitable habitat in all seasons. Of the 12 tracts in the Central Basin Reserve, one (Paulsen South) contained no canal habitat for giant gartersnake in 2022, while the other 11 contained habitat suitable for giant gartersnake.

In 2022, tracts in the North Basin Reserve covered approximately 2,332 acres. A total of 414 of these acres (17.8%) were created marsh and 637 acres (27.3%) were in active rice cultivation. A total of 764.1 acres of the North Basin were fallowed rice fields in 2022. This represents an increase of 616.3 acres from the 147.8 acres that were classified as fallowed rice in 2021. Overall, 1,818.0 acres (78.0%) of the total acreage of the North Basin Reserve was potential giant gartersnake habitat in 2022. Of the 18 tracts in the North Basin Reserve, 16 contained suitable habitat for giant gartersnakes and two (Vestal and Ruby Ranch) contained only marginal habitat, based on the canals, for giant gartersnakes in 2022.

3.3.3.2 Habitat Connectivity
An assessment of habitat connectivity is incomplete without addressing the different means by which animal populations are connected. Connectivity generally occurs via the dispersal of individuals across the landscape. Little is known about reptile dispersal, but radio-telemetry studies suggest that most giant gartersnakes have small home ranges (Valcarcel 2011), although individuals can move several kilometers through appropriate habitat if necessary (Reyes et al. 2017). Two distinct forms of connectivity must also be considered. Demographic connectivity refers to the movement of individuals among (sub) populations to the extent that migration plays a role in population dynamics, potentially rescuing local populations from extirpation through migration into them from a source population (Mills 2007). Genetic connectivity is the dispersal of enough individuals among populations to prevent genetic differentiation among them. A one-migrant-per- generation rule is often considered an adequate amount of connectivity to avoid the negative effects of inbreeding (Mills 2007). In general, demographic connectivity requires the exchange of far more individuals than genetic connectivity. Both forms of connectivity are addressed in the following discussion.

Although portions of TNBC’s reserve system are well-connected, some notable exceptions exist (Figure 3-17). In particular, although surface water connects the Fisherman’s Lake Reserve with other reserve areas, the northernmost suitable Fisherman’s Lake Reserve tract (Rosa Central), is approximately 14 kilometers (by canal) south of the nearest suitable Central Basin Reserve tract known to be occupied by giant gartersnake (Elsie). Giant gartersnakes have small home ranges and typically move relatively short distances (Valcarcel 2011; Reyes et al. 2017) but nonetheless can exhibit movements up to 5 kilometers over multiple days (U.S. Geological Survey unpublished data).

Given the stretches of marginal habitat in canals that connect tracts, the surrounding land uses inhospitable to giant gartersnakes, potential fragmentation caused by I-5, and the distance between tracts of the Central Basin Reserve and the Fisherman’s Lake Reserve, it is unlikely that the Fisherman’s Lake Reserve is currently demographically connected to the other reserves.

Connectivity between the Fisherman’s Lake Reserve and other habitats north of I-5 may have improved with the completion of the Giant Gartersnake Drainage Canal, constructed as mitigation for the NLIP project that connects the North Drainage Canal just south of the Sacramento/Sutter County line with the West Drainage Canal just north of I-5. The majority of this new canal was categorized as suitable habitat for giant gartersnake in 2020–2022. Additionally, the canal connects The Natomas Basin Conservancy

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to the Fisherman’s Lake Reserve through the West Drainage Canal, which was categorized as suitable habitat in 2020–2022 (Figure 3-17). Within the Fisherman’s Lake Reserve, four of the suitable tracts (Rosa East, Rosa Central, Natomas Farms, and Cummings) are connected by approximately 3.5 kilometers of canal habitats that compose Fisherman’s Lake, and by the intervening SAFCA wetlands. The eastern boundary of the fifth suitable tract, Souza, is adjacent to the northernmost wetlands of the Natomas Farms and SAFCA tracts. The creation of the SAFCA wetlands provide much greater continuity of habitat within the Fisherman’s Lake area than was previously present. Movement data from radio-tagged snakes translocated to the SAFCA wetlands between 2019 and 2021 showed individual snakes moved between the Natomas Farms, SAFCA, and Cummings wetlands, but did not show signs of migration out of the Fisherman’s Lake Reserve.

In contrast to the tracts of the Fisherman’s Lake Reserve, the tracts of the Central Basin Reserve are near those of the North Basin Reserve, and these two areas are linked by a dense network of canals.

The eastern edge of Ruby Ranch tract in the North Basin Reserve is only approximately 3 kilometers (by canal) from the Sills and Tufts tracts of the Central Basin Reserve. Within the Central Basin Reserve, tracts are nearly contiguous, with the exception of a 0.8-kilometer gap between Bianchi West and Frazer South tracts. The intervening tract consists of rice agriculture and a canal with marginal habitat, so demographic connectivity among these tracts is likely and genetic connectivity is nearly certain. Perhaps a greater barrier to connectivity among Central Basin tracts is SR 99, which lies between the Bianchi West and Sills tracts. Although this highway is a formidable barrier, it is possible for giant gartersnakes to cross it. A female giant gartersnake initially marked in 2010 at Bianchi West (east of SR 99) was captured at Sills (west of SR 99) three times in 2011. This individual almost certainly crossed through the 132-meter-long single box culvert under SR 99, providing strong evidence for genetic (and possibly even demographic) connectivity across SR 99 in the Natomas Basin (Halstead et al. 2013b). No such movements were detected in 2022. We did not sample at Bianchi West in 2022 but no movement between the Sills tracts and any of the next closest tracts west of SR 99 (BKS3 and Frazer South N) were detected. Given that the Sills tract and BKS tract contain the two most abundant populations of giant gartersnake in the Central Basin Reserve, connectivity across SR 99 could increase the probability of persistence of giant gartersnake in this region as a whole.

Like the tracts of the Central Basin Reserve, the tracts of the North Basin Reserve are well- connected. No major highways fragment North Basin tracts, and the only discontinuity between tracts containing suitable habitat is 1 kilometer between the Lucich North and Nestor tracts. This gap occurs along the North Drain, which has improved from marginal giant gartersnake habitat in 2020 to suitable habitat in 2021 and remains suitable in 2022; this improvement of habitat suitability will likely contribute to improved connectivity between the two areas. We captured a snake in the Nestor tract in 2018 that was originally marked in the Lucich North tract in 2012, demonstrating the connectivity between these two areas. It is highly likely that all tracts in the North Basin Reserve are genetically connected, and nearly all tracts are demographically connected with at least one other tract as well. Resumption of rice agriculture on the Nestor tract likely enhances the connectivity of the North Basin Reserve tracts.

Overall, it is very likely that all North Basin and Central Basin Reserve tracts are genetically connected and that these tracts are also demographically connected to at least one other tract. These conditions help to promote genetic diversity, limit the effects of genetic drift and inbreeding depression, and may rescue small populations on some reserves by the migration of individual giant gartersnake from neighboring reserves. In the future, maintaining this connectivity and its benefits The Natomas Basin Conservancy

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to giant gartersnake will require the continued availability of suitable habitat in canals that link wetland reserves. In contrast to the North and Central Basin Reserves, connectivity between the Fisherman’s Lake Reserve and the other reserves is far more tenuous. Although Natomas Farms and Cummings are almost certainly genetically connected and possibly demographically connected, the very small population in this area and isolation of these reserves from demographic rescue and genetic input from other, more abundant giant gartersnake populations to the north leaves them at risk for founder effects, inbreeding depression, and fixation of deleterious alleles through genetic drift, and it renders them very sensitive to both demographic and environmental stochasticity (e.g., random variation in birth/death rates or climatic conditions). It is hoped that the establishment of these reserves and the additional marsh habitat created by SAFCA can provide the conditions that will allow this population to recover, but detailed demographic study of this population will ascertain whether more intensive management strategies (such as augmentation of the population with genetically distinct individuals to increase genetic diversity [Madsen et al. 1996, 2004]) are warranted in the Fisherman’s Lake area. The radio-telemetry study that began in 2018 is an important first step to determine the potential effectiveness of translocation of individuals from more abundant and presumably more genetically diverse populations, as a means to “rescue” sparse populations in the Fisherman’s Lake Reserve. Individuals from the Central Basin Reserve were translocated to the SAFCA wetlands in the Fisherman’s Lake Reserve in 2019, and current analysis and publication of data collected from these individuals will provide information about the suitability of these recently created marshes for giant gartersnake.

Although some sections of canal in each reserve were downgraded from suitable to marginal habitat from 2021 to 2022, many canals in each reserve were upgraded from marginal to suitable habitat in 2022; overall, the continuity of suitable habitat for giant gartersnakes improved in 2022. The most notable downgrade in habitat suitability in the North Basin occurred in canals between the Nestor and Bennett North tracts, where two larger sections of canals were downgraded from suitable to marginal. However, there was great improvement in habitat (marginal to suitable) in the rest of the tracts in the North Basin and even two sections of canals in the Frazer North tract that were classified as unsuitable in 2021 improved to marginal and suitable in 2022. In the Fisherman’s Lake and the Central Basin tracts, no canal sections were downgraded to unsuitable habitat, except for a small section of canal near the Sills tract. Most of this canal was already classified as unsuitable in 2021 but the small portion that was still considered marginal was downgraded to unsuitable. One section of canal along the Elsie and Paulsen South tracts that was classified as no longer a canal in 2021 returned to marginal habitat in 2022. As for the rest of the Central Basin there was about an equal split between habitat that switched from marginal to suitable and habitat that was downgraded from suitable to marginal between 2021 and 2022. These changes occurred throughout the Central Basin and did not appear to be concentrated to a certain area or set of tracts, which could be indicative of natural habitat fluctuations between years. In the Fisherman’s Lake tract, six sections of the canals were upgraded from marginal to suitable, one was downgraded from suitable to marginal and no canal sections were downgraded to unsuitable habitat. As seen in previous years the habitat dynamics of canals with respect to giant gartersnake can both improve or degrade from year to year based on annual fluctuations in water availability and growth of emergent vegetation.

Monitoring these changes over time will be important to determine if any long-term trends exist and whether those trends are positive or negative for giant gartersnake persistence.

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3.4 Discussion

3.4.1 Demography

3.4.1.1 Abundance and Density
Abundance varied substantially among sites. For three of the seven demography clusters, three or fewer snakes were captured, and abundance was estimated to be 19–77 individuals. Similar abundance estimates were obtained for Lucich North and Lucich South, at which only eight and nine individuals were captured in 2022, respectively. For two sites with more than 30 individuals captured, abundance was estimated to be much greater, with more than 75 individuals (Sills), or over 210 individuals (BKS). The daily capture probability of marked giant gartersnake in 2022 was lower than in 2021 and the abundance estimates had larger credible intervals in 2022 compared to 2021. The average number of captures per individual in 2022 (1.25) was lower than in 2021 (1.57 captures per individual), and more comparable to 2020 (1.26 captures per individual). The number of captures per individual was intermediate in 2019 (1.44) and 2018 (1.41). Capture probabilities varied substantially, with similar variance attributable to temporal variation (fluctuations from day to day) and variation among sites. The random variation in capture probability among days likely reflects day-to-day changes in the weather that influence the behavior of giant gartersnake. On cool, cloudy days, snakes are less likely to go foraging in the water and thus are less likely to be captured in traps than on hot days when they spend more time foraging. Capture probability might differ among sites due to differences in habitat that influence the effectiveness of traps—for example, how well traps are able to fit flush to the canal or wetland bank to funnel foraging snakes into the trap.

The ability to share information on capture probabilities among sites is valuable because it allows for more precise estimates of abundance, as well as the effect of habitat covariates on capture probability. Heterogeneity in capture probability among individual giant gartersnakes could result from differences in behavior, with some individuals foraging along habitat edges more frequently or learning to forage in traps because they contain concentrations of prey. Heterogeneity can also result from spatial overlap between individual home ranges and traplines. Snakes with home ranges centered in the middle of a trapline would be expected to be captured more frequently than snakes with a home range that only partially overlaps one end of a trapline. This variation in individual home ranges is addressed explicitly in the SECR models used to estimate snake density.

SECR models explicitly account for the spatial locations of traps and where snakes are captured, which enables them to estimate the density of snakes within a defined area. Density estimates from SECR models are more suitable for comparisons among sites, because they account for differences in the area sampled at each site. BKS had both the greatest estimated abundance of giant gartersnake and the highest density, or number of snakes per ha of habitat. A comparison of Sills and Lucich South is instructive of the value of SECR models. The estimated abundance of snakes at Sills was higher than at Lucich South (median value of 148 compared to 46), but the estimated densities of snakes at the two sites were similar. In contrast, despite Lucich North having a similar number of individuals captured and a similar abundance estimate to Lucich South, the density of snakes at Lucich North was estimated to be much lower in 2022. The lower estimated density at Lucich North from the SECR model results from the much greater area sampled compared to Lucich South. In the future, comparisons of snake density among sites, and inclusion of habitat covariates on snake density could help inform what habitat management actions are most likely to support dense, healthy giant gartersnake populations.

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In contrast to 2018–2021, there was support for an effect of water temperature on capture probabilities in 2022. The effect of water temperature on snake behavior is likely more important in the spring, when cooler weather may prevent snakes from reaching a high enough body temperature to forage in cool water. In 2022, trapping began a week earlier in May than in 2021, which could partially explain the greater importance of water temperature to snake capture probability in 2022. As in each year from 2018 to 2021, there was evidence of a positive ephemeral behavioral response to capture (“trap-happiness”) in 2022. This pattern is likely observed simply because the individuals were in the vicinity of the trap array immediately after release and happened to enter another trap, or because individual snakes might forage for several consecutive days within a relatively small area, then shelter in burrows to digest their meals or shed. The behavioral response could also be caused by individuals that entered traps being rewarded with an easy meal; these individuals were therefore more likely to search for prey within traps the following day—and be trapped—than individuals that had not been trapped the previous day. This effect of behavioral response is a common theme across all years of monitoring. In 2022, there was little support for an effect of giant gartersnake sex or SVL on capture probability. This is in contrast to 2021, when there appeared to be some support for effects of sex and SVL on capture probability.

3.4.1.2 Size Distribution and Sex Ratio
The sex ratio of giant gartersnake in the Natomas Basin in 2022 was slightly lower than one male per female and lower than in 2021. Although the credible interval overlapped 1 in 2022, which may indicate a more equal sex ratio, it was with low precision likely due to the lower sample of captures in this year. This female-biased sex ratio should not limit the reproductive potential of the species, given the mating system in gartersnakes, where both females and males can mate with multiple partners (Schwartz et al. 1989; Shine et al. 2001). The biased sex ratio is largely a result of a low proportion of males among the snakes captured at three sites: BKS (42 females and 29 males), Lucich North (no males and four females), and Lucich South (one male and eight females). Trapping within Lucich North in which moderately more female giant gartersnakes were captured in 2022 occurred during late summer (i.e., mid-July to late August). During this time of year, females are likely to be foraging after giving birth (parturition) to improve their body condition. The likelihood that large adult females foraging after reproduction in part drove the sex-bias in captures is further supported because the average SVL and mass of captured females were higher in 2022 (674 mm SVL, 150.9 g mass), 2021 (611 mm SVL, 131.76 g mass), 2020 (616 mm SVL, 117.45 g mass), 2019 (630 mm SVL, 164.5 g mass), and 2018 (665 mm SVL, 161.9 g mass) than in 2017 (586 mm SVL, 115.5 g mass), and the size distribution of females was shifted toward longer and heavier individuals between 2018 and 2022 (with the revised sampling design) than in 2017, when greater trapping effort occurred earlier in the active season. Continued monitoring of giant gartersnake sex ratios is warranted, but differences in seasonal activity patterns between the sexes must be considered when interpreting the sex ratio of captured individuals. Although managing unharvested populations for sex ratio is not generally feasible, continued monitoring of sex ratios on TNBC reserves could warn of sex-biased mortality factors (assuming an equal sex ratio at birth [Halstead et al. 2011a; Rose et al. 2018a]).

Size distributions of giant gartersnake on TNBC reserves indicated the presence of a mixed-age population. Size distributions indicated the presence of both younger, smaller snakes and larger, older individuals in the population. Small yearling snakes were caught in spring 2022 that were likely born in summer 2021, and neonate snakes likely born in summer 2022 were captured in August 2022. The evidence of recruitment of young individuals provided by size distributions is The Natomas Basin Conservancy

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important supplemental information to determine if recruitment is occurring (at least in part) through in-situ reproduction. It should be noted, however, that inferring the health of a population (i.e., population growth rate) from size (or age) distributions alone is a risky proposition (Caughley 1974).

3.4.1.3 Survival Rate of Giant Gartersnake
With the additional year of sampling in 2022, we were able to obtain more precise estimates of apparent survival (the probability of surviving and remaining available on site for capture) for giant gartersnake in 2022. The only clear trend in the survival estimates was that apparent survival was much higher at BKS from 2018–2019 than in the subsequent years. This decrease in apparent survival could be driven by the decrease in sampling effort in BKS in 2020 (six traplines for approximately 14 days each), 2021 (five traplines), and 2022 (six traplines) compared to 2018 and 2019 (nine traplines). The higher sampling effort in 2018 and 2019 led to a higher recapture rate of snakes in 2019 compared to subsequent years. Therefore, it is possible that some of the snakes that were first captured and marked in 2018 and 2019 survived until 2020 and 2021 but either (1) were not available for capture in the more limited area sampled from 2020–2022 or (2) evaded capture during the shorter sampling period in 2020. Trapping effort was more consistent in the Sills tract, and survival was higher from 2019–2020 than in other years. Despite a drop in trapping effort (fewer traplines and fewer trap days) at Lucich North in 2020 and 2021 compared to 2018 and 2019, apparent survival was similar among years. There was no support for a difference in survival among male and female giant gartersnake. There was weak support for a higher availability for capture for female giant gartersnake than male giant gartersnake, however. One potential explanation for higher availability for capture for female giant gartersnake is that male giant gartersnake disperse farther and are more likely to emigrate from trapped areas.

3.4.2 Distribution of Giant Gartersnake on Reserve Lands The occupancy analysis for 2022 indicated that giant gartersnake is expected to occur in nearly 60% of wetland and rice units on reserve lands, with occupancy highest in the Central Basin Reserve. It is notable that there was great uncertainty on the effects of whether sites classified as “rice” (i.e., canals next to rice) were more or less likely to be occupied than wetland sites, after accounting for variation in occupancy rates among the three reserves. The results suggest that the presence of rice likely did not affect the occurrence of giant gartersnakes in 2022. This, however, does not minimize the importance of rice agriculture as an alternative wetland habitat for this conservation-reliant species (Halstead et al. 2019). It also should be noted that the Central Basin has historically had the highest proportion of sites occupied and the highest proportion of sites that are considered rice agriculture; these patterns remained evident in 2022. Because the Central Basin is dominated by rice and the Fisherman’s Lake Reserve is dominated by wetlands, it is difficult to fully disentangle the effects of rice from geographic variation in probability of occurrence.

The lack of a strong effect of emergent vegetation on occurrence was notable in 2022. In 2021, emergent vegetation was not found to be an important variable for explaining occurrence probability. In 2020, a negative effect of emergent vegetation on occurrence was seen, but this habitat covariate was found to have an important positive effect in 2017, 2016, and in years prior to 2014. However, this likely does not demote the importance of emergent vegetation; rather, given the model selection results, there could be additional benefits of rice agriculture, not measured in the current analysis, that influence giant garter snake occurrence.

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It is suspected that emergent vegetation still provides the best habitat for giant gartersnake cover from predators and higher prey concentrations. Radio-telemetry study of giant gartersnake movement and habitat selection has shown that giant gartersnake preferentially select tule over other vegetation types (Halstead et al. 2016). Because tule marsh is historical habitat for giant gartersnake, management for emergent vegetation, particularly tule, is important. It is notable that there was great uncertainty on the effects of whether sites classified as “rice” (i.e., canals next to rice) were more or less likely to be occupied than wetland sites, after accounting for variation in occupancy rates among the three reserves.

The probability of occupancy was greatest in the Central Basin Reserve, moderate in the North Basin Reserve, and lowest in the Fisherman’s Lake Reserve. Both the North Basin Reserve and Central Basin Reserve have a mix of rice and wetland habitat, whereas the Fisherman’s Lake Reserve is primarily composed of recently created freshwater marsh. Notably, giant gartersnakes were captured at six sites in the North Basin (Bennett, Frazer, and Lucich sites) in 2022, where no snakes were detected in 2021. In 2023 and beyond, occupancy trapping will track changes in occupancy that follow giant gartersnake translocation efforts into the Fisherman’s Lake Reserve. Additional data collection over the coming years, with the greater precision afforded by the larger sample size of the revised study design, will improve inference into the strength of the effects of emergent vegetation, floating aquatic vegetation, open water, and rice on the probability of occurrence, site- colonization, and site-extirpation of giant gartersnake and the mechanisms by which these components of the habitat affect giant gartersnake occupancy.

Based on the dynamic occupancy model, the proportion of occupied wetland units on reserve lands was stable (changing by less than 10% annually) from 2011 through 2022 with over 99% probability, with a near-zero probability (<0.1%) that occupancy decreased by more than 10% during that period. This stability is different from the trend of decreasing giant gartersnake occupancy seen in 2015, 2016, 2020, and 2021 but it matches the findings of the dynamic occupancy model in 2017, 2018, 2019, and 2022. The apparent declines in occupancy, particularly in 2020 and 2021, could be an artifact of reduction in sampled sites and survey effort in 2020 and 2021 compared to prior years. The larger sample of sites surveyed in 2018 and 2019, and the longer survey period used in the revised study design, resulted in more precise estimates of occupancy for 2018 and 2019 than for previous years. However, the shorter survey period used in 2020 resulted in less precise estimates for 2020 than in the 2 previous years. Resuming the 21-day period sampling in 2021 and 2022 likely improved detection and contributed to the slightly higher precision of the parameter estimates from the dynamic occupancy model compared to 2020. Relative to previous years, the probability that occupied sites became unoccupied (site extirpation) declined from 2021 to 2022, but was higher than in 2019. The probability that unoccupied sites became occupied (site colonization) in 2022 was slightly higher than in 2021 and comparable to 2019, but overlapping credible intervals suggest it would be wrong to conclude a large difference. Although there was overwhelming support that giant gartersnake occupancy did not change by more than 10% from 2011 through 2022, there does appear to be a decline in the number occupied sites over this period, with most of that decline appearing to occur from 2011 to 2013, as well as from 2019 to 2021.

One potential mechanism leading to a decrease in the proportion of sites occupied is the extreme drought conditions from 2012 to 2015 and from 2021 to 2022. According to the California Department of Water Resources, California experienced the second driest water year (October 2020–September 2021) in 2021. Although water remained on TNBC reserves during the drought, it is unknown to what extent the source of water (surface water vs. groundwater) affects giant The Natomas Basin Conservancy

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gartersnake occupancy or demography, and precipitation may influence the productivity of lower trophic levels including giant gartersnake prey. Thus far, occupancy does not appear to have completely rebounded to earlier levels (e.g., 2011), but 2022 showed a clear increase after 2 years of decline in 2020 and 2021. This was comparable to 2019, which showed a clear increase after 4 years of stability from 2015 to 2018. The rebound in occupancy in 2019 follows 3 out of 4 years of normal to above-average rainfall (2016, 2017, and 2019). Three years of favorable rainfall in a 4-year period might not be long enough for giant gartersnake to recolonize every site from which it was extirpated during the drought, but 2019 showed some positive signs of recolonization.

Despite the dry water year in 2021, site-extirpation rate decreased, and occupancy growth rate continued to increase (although <0) between the 2021–2022 period and 2020–2021 period, compared to the 2019–2020 period. These may be explained by resuming the longer sampling period in 2021 and the slight increase in sampled sites compared to 2020. It is also possible that the improvement of habitat suitability across the TNBC reserves has protected the giant gartersnake population from adverse effects of the drought; alternatively, the full effects of the drought might not be realized until future years because snakes might have concentrated in the areas we could trap (i.e., that contained water) even as giant gartersnake habitat on non-reserve lands contracted and our sampling likely occurred before the worst effects of drought were realized. Occupancy dynamics on TNBC reserves were not strongly related to any habitat variables at the surveyed sites. Continued monitoring in 2023 and beyond could help understand how habitat improvement in the TNBC reserves might buffer against environmental stress factors on giant gartersnakes.

3.5 Effectiveness
The effectiveness of the NBHCP for conserving giant gartersnake is assessed based upon the acquisition of reserve lands; changes in the abundance or, preferably, demographic rates of giant gartersnake; and land management activities to increase the distribution and health of giant gartersnake in the Natomas Basin.

The primary issue affecting giant gartersnake throughout its range is habitat, and the Natomas Basin is no different in this regard. Marshes that most nearly approximate natural tule marshes provide the best habitat for giant gartersnake, promoting both higher densities and greater body condition than other habitats (Wylie et al. 2010). For example, a recent, long-term study of giant gartersnake throughout the Sacramento Valley found that survival was positively related to the percent cover of emergent vegetation at a site (Rose et al. 2018b). The point estimate of density of giant gartersnake was 946% greater in created marsh habitats in the BKS tract compared to the highest estimates for rice and associated canals on the Sills tract, which had the third highest density (and second highest in abundance) estimate on the Sills tract. Although giant gartersnake has persisted in a rice agricultural landscape in the Sacramento Valley, the limited duration of rice fields as appropriate habitat (mid-May through August), the restriction of giant gartersnake to structurally simple linear canals during the other 4 months of the active season, as well as the rice fallowing in response to drought or late spring rains in recent years likely reduce the carrying capacity of agricultural habitats relative to natural or well-managed created marshes. Nevertheless, rice agricultural habitats are the only agricultural habitats in which giant gartersnake can persist (Halstead et al. 2010), and they provide connectivity between other patches of suitable habitat. Also, the survival rate of radio-tracked giant gartersnake has been found to be positively related to the area of active rice growing surrounding their home range (Halstead et al. 2019). The Lucich South, Sills, and The Natomas Basin Conservancy

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Lucich North tracts had the second, third, and fourth highest density estimates, respectively, of giant gartersnake in 2022, illustrating the importance of rice agricultural habitats in the Natomas Basin, particularly in the Central Basin Reserve. Nonetheless, giant gartersnake density in the Lucich North cluster of sites, which is dominated, by created marsh, was lower than many rice sites and almost two orders of magnitude less than the giant gartersnake density at BKS. The low water levels at this location, with extensive areas of mudflat or shallow, hot water between emergent vegetation and deeper water, likely contributed to lower giant gartersnake densities at this cluster. TNBC has been effective in creating managed marsh habitats and providing for the continuation of rice agriculture in the Natomas Basin. Maintaining additional water in created marsh habitats would further benefit giant gartersnake.

Managing habitat for giant gartersnake is only effective insofar as adequate water is supplied to these habitats. The persistence of water adjacent to cover on the landscape throughout the active season is important for giant gartersnake, and increased water availability has been shown to be related to higher rates of survival for adult female giant gartersnake (Reyes et al. 2017; Halstead et al. 2019). Drying of marshes, fallowing of rice fields for more than a year, cultivation of alternative crops (especially if accompanied by lack of water in canals), and low or fluctuating water levels in marshes reduce the availability and quality of habitat for giant gartersnake. Reducing the amount of rice grown in an area has the potential to negatively affect the survival of adult giant gartersnake (Halstead et al. 2019). TNBC has created suitable managed marsh habitats that can provide relatively persistent aquatic habitat throughout the year if water levels are maintained to provide aquatic foraging and escape habitat next to, and ideally below, basking sites.

Another important component of giant gartersnake habitat is refuge from predators and, perhaps as important, environmental extremes. Mammal burrows and lodges and crayfish burrows offer important refuge for giant gartersnakes and should be maintained in association with marshes and canals to the maximum extent practical. Unless burrows threaten the integrity of the berms and levees required to maintain water in marshes or canals, or they present a major hazard to humans or livestock, they should be maintained in abundance. Muskrats (Ondatra zibethicus), California ground squirrels (Otospermophilus beecheyi), and crayfish likely improve habitat quality for giant gartersnakes by providing refugia in the form of burrows; muskrats further enhance habitat suitability by constructing lodges and reducing the density of cattails (thereby promoting the emergent vegetation/open water interface) through their foraging activity. Similar to muskrat lodges, tule thatch that accumulates naturally in mature tule marshes (like BKS) may also serve as important refuge from predators and temperature extremes and should be maintained in abundance. Giant gartersnakes have been found to actively select tule over other microhabitats available in their environment (Halstead et al. 2016).

Overall, management actions in the Natomas Basin are consistent with healthy giant gartersnake populations. Conversion of additional habitats to created marshes and maintaining proper water levels in the marshes would undoubtedly benefit giant gartersnake in the long term, and maintenance of rice agriculture will help achieve connectivity, prey production, high adult survival in canals adjacent to rice fields, and other conservation goals. Continuing to minimize ground disturbance, ensuring aquatic habitat is available in the spring for foraging upon emergence from winter refuges (Halstead et al. 2019) and maintaining stable, high water levels throughout the active season will also enhance the quality of existing habitats for giant gartersnake. Lowering water levels in the early fall may also help to concentrate prey prior to hibernation; the effectiveness of this practice as a management strategy warrants further investigation.

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3.6 Recommendations
• Maintain and encourage emergent vegetation (primarily tule) in wetlands and canals. • Maximize the open water/emergent vegetation interface that increases the probability of occurrence of giant gartersnake and has been shown in other studies (Valcarcel 2011) to be positively selected by individual giant gartersnakes. Maintaining emergent vegetation at wetland edges, clumps of vegetation in open water, and pockets of open water in stands of emergent vegetation would likely benefit giant gartersnake. Importantly, managing for maximization of the open water/emergent vegetation interface includes ensuring that water levels are high enough that snakes can forage and escape predators immediately below and adjacent to the emergent vegetation.
• Vegetation should be managed to promote tules in preference to other emergent aquatic vegetation. Giant gartersnake selection for tules is stronger than its selection of other aquatic vegetation (Halstead et al. 2016).
• Continue to encourage rice agriculture as important alternative habitat for tule marshes. • Continue to control mosquito fern and other floating aquatic vegetation where possible. Giant gartersnake tends to avoid mosquito fern and other floating aquatic vegetation when it occurs at high densities (U.S. Geological Survey unpublished data), despite apparent positive selection at low densities (Halstead et al. 2016). Apparent selection of floating aquatic vegetation at low densities is likely an artifact of these vegetation types accumulating along the edges of water, where giant gartersnakes forage (Halstead et al. 2016). Floating aquatic vegetation likely alters vegetative and prey communities and water characteristics. • Maintain herbaceous terrestrial bankside vegetation to provide cover for giant gartersnake when in terrestrial habitats (Halstead et al. 2016). Minimize mowing during the active season near the edge of marshes to the extent practicable, providing tall grasses for snake to hide in when moving between aquatic and terrestrial habitats.
• To the extent possible, avoid rapid changes in water levels during giant gartersnake’s inactive season (October through March) to avoid disturbance to hibernating individuals, and restrict changes in water levels to the minimum number of fluctuations possible. • Maintain as many muskrat burrows, crayfish burrows, and burrows of California ground squirrel and other small mammal burrows as feasible to provide giant gartersnakes abundant summer refuges and winter hibernacula (Halstead et al. 2015). Muskrat lodges also provide potential hibernation, basking, and shelter sites.
• Ensure aquatic habitat is available in wetlands and canals by flooding marsh complexes early in spring when giant gartersnakes emerge from burrows and begin foraging. Snake body condition (body mass relative to length) is low at this critical point in the year (Coates et al. 2009), when individuals’ energy reserves are depleted from a long period of overwintering. Likely as a result of poor body condition, risk of mortality is high for giant gartersnake during this time of year (Halstead et al. 2019). Having aquatic habitat available for giant gartersnake to forage in during the early spring would likely lead to higher survival rates. • Continue to minimize management activities in marsh habitats to the extent practicable to minimize disturbance. When wetlands must be drained during the giant gartersnake active season, do so slowly in the late summer (August or September) to more nearly approximate the The Natomas Basin Conservancy

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historical drying cycle of natural wetlands in the Central Valley. Doing so may provide giant gartersnake with an abundance of stranded prey and an important source of energy reserves for hibernation. Try to reflood wetlands as soon as possible and maintain stable water levels throughout the hibernation period.
• Attempt to maintain substantial aquatic habitat adjacent to marsh units drained for maintenance to ensure adequate habitat is available to giant gartersnake that might be affected by marsh maintenance activities.
• When excavating marshes during maintenance activities, ensure that slopes are not too steep for snakes that become entrapped in excavated channels to free themselves. If slopes must be steep, provide periodic (every 50 meters) shallower slopes that allow entrapped snakes to exit the channel.
• Minimize channel clearing activities to the extent practicable. Clearing water conveyance channels temporarily degrades giant gartersnake foraging habitat.

3.7 References
California Department of Fish and Game Commission. 1971. California Code of Regulations: Animals of California Declared to be Endangered or Threatened. Sacramento, CA.

Casazza, M. L., G. D. Wylie, and C. J. Gregory. 2000. A Funnel Trap Modification for Surface Collection of Aquatic Amphibians and Reptiles. Herpetological Review 31:91–92.

Caughley, G. 1974. Interpretation of Age Ratios. The Journal of Wildlife Management 38:557–562. doi: 10.2307/3800890.

City of Sacramento, Sutter County, and Natomas Basin Conservancy. 2003. Natomas Basin Habitat Conservation Plan; Sacramento and Sutter Counties, California. Sacramento, CA.

Coates, P. S., G. D. Wylie, B. J. Halstead, and M. L. Casazza. 2009. Using Time-Dependent Models to Investigate Body Condition and Growth Rate of the Giant Gartersnake. Journal of Zoology 279:285–293.

Denwood, M. J. 2016. runjags: An R package providing interface utilities, model templates, parallel computing methods and additional distributions for MCMC models in JAGS. Journal of Statistical Software 71, 1–25.

Ersan, J. S. M., B. J. Halstead, E. L. Wildy, M. L. Casazza, and G. D. Wylie. 2020a. Giant gartersnakes (Thamnophis gigas) exploit abundant nonnative prey while maintaining their appetite for native anurans. Herpetologica 76:290–296.

Ersan, J., B. J. Halstead, E. Wildy, M. L. Casazza, and G. D. Wylie. 2020b. Intrinsic prey preference of the giant gartersnake: A threatened predator in a nonnative prey-dominated community.

Journal of Fish and Wildlife Management 11:164–173.

Fitch, H. S. 1940. A Biogeographical Study of the Ordinoides Artenkreis of Garter Snakes (Genus Thamnophis). University of California Publications in Zoology 44:1–150.

Frayer, W. E., D. D. Peters, and H. R. Pywell. 1989. Wetlands of the California Central Valley: Status and Trends: 1939-mid-1980’s. U. S. Fish and Wildlife Service, Region 1, Portland, OR.

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Govindarajulu, P., R. Altwegg, and B. R. Anholt. 2005. Matrix model investigation of invasive species control: bullfrogs on Vancouver Island. Ecological Applications 15:2161–2170.

Halstead, B. J., G. D. Wylie, and M. L. Casazza. 2010. Habitat Suitability and Conservation of the Giant Gartersnake (Thamnophis gigas) in the Sacramento Valley of California. Copeia 2010:591–599.

Halstead, B. J., G. D. Wylie, M. L. Casazza, and P. S. Coates. 2011a. Temporal and Maternal Effects on Reproductive Ecology of the Giant Gartersnake (Thamnophis gigas). The Southwestern Naturalist 56:29–34.

Halstead, B. J., G. D. Wylie, P. S. Coates, and M. L. Casazza. 2011b. Bayesian Adaptive Survey Protocols for Resource Management. The Journal of Wildlife Management 75:450–457.

Halstead, B. J., G. D. Wylie, P. S. Coates, P. Valcarcel, and M. L. Casazza. 2012. Bayesian Shared Frailty Models for Regional Inference about Wildlife Survival. Animal Conservation 15:117–124.

Halstead, B. J., G. D. Wylie, and M. L. Casazza. 2013a. Efficacy of Trap Modifications for Increasing Capture Rates of Aquatic Snakes in Floating Aquatic Funnel Traps. Herpetological Conservation and Biology 8:65–74.

Halstead, B. J., G. D. Wylie, M. L. Casazza, E. C. Hansen, and J. R. Roberts III. 2013b. Thamnophis gigas (Giant Gartersnake) Movement. Herpetological Review 44:159–160.

Halstead, B. J., S. M. Skalos, G. D. Wylie, and M. L. Casazza. 2015. Terrestrial Ecology of Semi-Aquatic Giant Gartersnakes (Thamnophis gigas). Herpetological Conservation and Biology 10:633‒644.

Halstead, B. J., P. Valcarcel, G. D. Wylie, P. S. Coates, M. L. Casazza, and D. K. Rosenberg. 2016. Active Season Microhabitat and Vegetation Selection by Giant Gartersnakes Associated with a Restored Marsh in California. Journal of Fish and Wildlife Management 7:397‒407.

Halstead, B. J., J. P. Rose, G. A. Reyes, G. D. Wylie, and M. L. Casazza. 2019. Conservation reliance of a threatened snake on rice agriculture. Global Ecology and Conservation 19:e00681.

Hansen, G. E., and J. M. Brode. 1980. Status of the Giant Garter Snake Thamnophis couchii gigas (Fitch). California Department of Fish and Game, Sacramento, CA.

Hansen, R. W., and G. E. Hansen. 1990. Thamnophis gigas (Giant Garter Snake) Reproduction.

Herpetological Review 21:93–94.

Kellner, K. 2016. jagsUI: A Wrapper Around “rjags” to Streamline ’JAGS" Analyses. https://cran.r- project.org/web/packages/jagsUI/index.html
Kéry, M. 2010. Introduction to Winbugs for Ecologists: Bayesian Approach to Regression, ANOVA, Mixed Models and Related Analyses. Academic Press: Burlington, MA.

Kéry, M., and J. A. Royle. 2016. Applied Hierarchical Modeling in Ecology. Academic Press: San Diego, CA.

Kéry, M., and M. Schaub. 2011. Bayesian Population Analysis using WinBUGS: A hierarchical perspective. Academic Press: Waltham, MA.

Kuo, L., and B. Mallick. 1998. Variable Selection for Regression Models. Indian Journal of Statistics 60:65–81.

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Lowe, S., M. Browne, S. Boudjelas, and M. De Poorter. 2004. 100 of the World’s Worst Invasive Alien Species. [A selection from the global invasive species database.] Invasive Species Specialist Group, Species Survival Commission, World Conservation Union. Auckland, New Zealand.

MacKenzie, D. I., J. D. Nichols, J. A. Royle, K. H. Pollock, L. L. Bailey, and J. E. Hines. 2006. Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence. Academic Press:

Amsterdam, The Netherlands.

Madsen, T., B. Stille, and R. Shine. 1996. Inbreeding Depression in an Isolated Population of Adders Vipera berus. Biological Conservation 75:113–118.

Madsen, T., B. Ujvari, and M. Olsson. 2004. Novel Genes Continue to Enhance Population Growth in Adders (Vipera berus). Biological Conservation 120:145–147.

Mills, L. S. 2007. Conservation of Wildlife Populations: Demography, Genetics, and Management.

Blackwell Publishing: Malden, Massachusetts.

Plummer, M. 2003. JAGS: A Program for Analysis of Bayesian Graphical Models using Gibbs Sampling. In Proceedings of the 3rd International Workshop on Distributed Statistical Computing 124:125.

R Core Team. 2019. R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing. Vienna, Austria. Version 3.6.2. Retrieved from http://www.R-project.org.

Reinert, H. K., and D. Cundall. 1982. An improved surgical implantation method for radio-tracking snakes. Copeia, 1982(3):702-705.

Reyes, G. A., B. J. Halstead, J. P. Rose, J. S. M. Ersan, A. C. Jordan, A. M. Essert, K. J. Fouts, A. M. Fulton, K.

B. Gustafson, R. F. Wack, G. D. Wylie, and M. L. Casazza. 2017. Behavioral Response of Giant Gartersnakes (Thamnophis gigas) to the Relative Availability of Aquatic Habitat on the Landscape.

U.S. Geological Survey Open-File Report 2017-1141. doi:10.3133/ofr20171141.

Riecke, T. V., A. G. Leach, D. Gibson, and J. S. Sedinger. 2018. Parameterizing the robust design in the BUGS language: Lifetime carry-over effects of environmental conditions during growth on a long-lived bird. Methods in Ecology and Evolution 9:2294–2305. doi:10.1111/2041-210X.13065 Rose, J. P., J. S. M. Ersan, G. D. Wylie, M. L. Casazza, and B. J. Halstead. 2018a. Reproductive Frequency and Size-Dependence of Fecundity in the Giant Gartersnake (Thamnophis gigas). Herpetological Conservation and Biology 13:80–90.

Rose, J. P., G. D. Wylie, M. L. Casazza, and B. J. Halstead. 2018b. Integrating Growth and Capture- Mark-Recapture Models Reveals Size-Dependent Survival in an Elusive Species. Ecosphere 9:e02384.

Rose, J. P., J. S. M. Ersan, G. A. Reyes, K. B. Gustafson, A. M. Fulton, K. J. Fouts, R. F. Wack, G. D. Wylie, M. L. Casazza, and B. J. Halstead. 2018c. Findings from a Preliminary Investigation of the Effects of Aquatic Habitat (Water) Availability on Giant Gartersnake (Thamnophis gigas) Demography and Reproduction in the Sacramento Valley, California, 2014–17. U.S. Geological Survey Open-File Report 2018-1114. doi:10.3133/ofr20181114
Rose, J. P., B. J. Halstead, G. D. Wylie, and M. L. Casazza. 2018d. Spatial and Temporal Variability in Growth of Giant Gartersnakes: Plasticity, Precipitation, and Prey. Journal of Herpetology 52:40–

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Rose, J. P., J. S. M. Ersan, G. D. Wylie, M. L. Casazza, and B. J. Halstead. 2019. Demographic factors affecting population growth in giant gartersnakes. Journal of Wildlife Management 83:1540– 1551.

Rossman, D. A., and G. R. Stewart. 1987. Taxonomic Reevaluation of Thamnophis couchii (Serpentes:
colubridae). Louisiana State University.

Rossman, D. A., N. B. Ford, and R. A. Seigel. 1996. The Garter Snakes: Evolution and Ecology.

University of Oklahoma Press: Norman, OK.

Royle, J. A., and R. M. Dorazio. 2008. Hierarchical Modeling and Inference in Ecology: The Analysis of Data from Populations, Metapopulations and Communities. 1st edition. Academic Press: London.

Royle, J. A., and M. Kéry. 2007. A Bayesian State-Space Formulation of Dynamic Occupancy Models.

Ecology 88:1813–1823.

Schwartz, J. M., G. F. McCracken, and G. M. Burghardt. 1989. Multiple Paternity in Wild Populations of the Garter Snake, Thamnophis sirtalis. Behavioral Ecology and Sociobiology 25:269–273.

Shine, R., D. O’Connor, M.P. Lemaster, and R.T. Mason. 2001. Pick on Someone Your Own Size:

Ontogenetic Shifts in Mate Choice by Male Garter Snakes Result in Size-Assortative Mating.

Animal Behaviour 61:1133–1141.

Skalski, J. R., K. E. Ryding, and J. J. Millspaugh. 2005. Wildlife Demography: Analysis of Sex, Age, and Count Data. Academic Press: Burlington, MA.

Su, Y. S., and M. Yajima. 2015. R2jags: A Package for Running jags from R. R package version 0.05-01.

U.S. Geological Survey. 2019. Unpublished data on the movement of radio-tracked giant gartersnakes (Thamnophis gigas) in the Sacramento Valley from 2009–2017. Western Ecological Research Center, Dixon, CA.

U.S. Fish and Wildlife Service. 1993. Determination of Threatened Status for the Giant Garter Snake.

Federal Register 58:54053–54066.

U.S. Fish and Wildlife Service. 1999. Draft Recovery Plan for the Giant Garter Snake (Thamnophis gigas). U.S. Fish and Wildlife Service, Sacramento, CA.

Valcarcel, P. 2011. Giant Gartersnake Spatial Ecology in Agricultural and Constructed Wetlands. M.S.

Thesis, Oregon State University, Corvallis, OR.

Winne, C. T., J. D. Willson, K. M. Andrews, and R. N. Reed. 2006. Efficacy of Marking Snakes with Disposable Medical Cautery Units. Herpetological Review 37:52–54.

Wylie, G. D., M. L. Casazza, and L. L. Martin. 2003. Giant Garter Snake Surveys in the Natomas Basin:
2000–2002. U.S. Geological Survey, Sacramento, CA.

Wylie, G. D., M. L. Casazza, B. J. Halstead, and C. J. Gregory. 2009. Sex, Season, and Time of Day Interact to Affect Body Temperatures of the Giant Gartersnake. Journal of Thermal Biology 34:183–189.

Wylie, G. D., M. L. Casazza, C. J. Gregory, and B. J. Halstead. 2010. Abundance and Sexual Size Dimorphism of the Giant Gartersnake (Thamnophis gigas) in the Sacramento Valley of California.

Journal of Herpetology 44:94–103.

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Zipkin, E. F., C. E. Kraft, E. G. Cooch, and P. J. Sullivan. 2009. When can efforts to control nuisance and invasive species backfire? Ecological Applications 19:1585–1595.

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Table 3-1. Summary of Giant Gartersnake Captures and Sampling Effort at Natomas Basin Conservancy Reserves, 2022
Reserve Area and Reserve
Number of Giant Gartersnakes Dates Trapped
(2022)
Total Trap
Days Individuals Captures
North Basin
Bennett North Central West (wetland) 0 0 22 Jun – 15 Jul 1050 Bennett North Central (wetland) 2 2 28 May – 22 Jun 1050 Bennett North Central East (wetland) 1 1 15 Jul – 5 Aug 1050 Bennett South East (canal) 1 1 24 May – 16 Jun 1050
Bolen North 0 0 2 Aug – 23 Aug 1047
Frazer North Wetland North 1 1 10 Jun – 3 Jul 1047
Frazer North Wetland Central 0 0 15 Jun – 10 Jul 1017
Huffman West 1 1 2 Aug – 23 Aug 1049
Lucich North Central 0 0 8 Aug – 29 Aug 1050
Lucich North South 1 1 1 12 Jul – 2 Aug 1050
Lucich North South2 0 0 12 Jul – 2 Aug 1050
Lucich North East 2 2 21 Jul – 13 Aug 1049
Lucich North Northeast 0 0 16 Aug – 31 Aug 748
Lucich North Northeast 2 0 0 28 Jun – 21 Jul 1048
Lucich North 4 1 2 4 Aug – 25 Aug 905
Lucich South North (rice) 2 4 16 Aug – 31 Aug 750
Lucich South South (rice) 0 0 6 May – 28 May 938
Lucich South 3 7 11 25 Jul – 15 Aug 1050
Nestor East 3 3 22 Jul – 12 Aug 1049
Ruby Ranch 0 0 15 Aug – 31 Aug 786
TNBC5 0 0 15 Aug – 31 Aug 798
TNBC6 0 0 6 Jun – 29 Jun 1050
Central Basin
BKS North Central 5 6 3 May – 24 May 1050
BKS South Central 1 27 27 10 Aug – 31 Aug 1050
BKS Southwest Central 18 20 5 Jul – 26 Jul 1050
BKS2 11 12 2 May – 23 May 1050
BKS3 4 5 6 Aug – 27 Aug 1050
Elsie 0 0 3 Aug – 15 Aug 572
Frazer South North 9 12 7 Aug – 28 Aug 1050
Sills4 19 27 1 Jun – 24 Jun 1033
Sills5 13 17 9 May – 1 Jun 1034
Sills6 2 4 16 Jun – 11 Jul 1050
Tufts3 0 0 10 Jul – 31 Jul 1050
Fisherman’s Lake
Cummings East 0 0 13 Jul – 3 Aug 1050
Cummings East Central 0 0 1 Aug – 22 Aug 1050
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Table 3-1. Continued

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Reserve Area and Reserve
Number of Giant Gartersnakes Dates Trapped
(2022)
Total Trap
Days Individuals Captures
Cummings West 0 0 11 Jul – 1 Aug 1047
Natomas Farms North 0 0 27 Jul – 17 Aug 1049
Natomas Farms 1 0 0 13 Jun – 8 Jul 1050
Natomas Farms 2 0 0 9 Aug – 30 Aug 1049
Rosa Central 0 0 23 May – 15 Jun 1050
Rosa Central South 0 0 12 Aug – 31 Aug 948
Total 130 159 42,997
Table 3-2. Prior Probabilities for Parameters of Single-Season Occupancy Models for Giant Gartersnake on Natomas Basin Conservancy Reserve Properties, 2022 Component Model Parameter Uninformative priors
Detection All β0 N(0,1.648)
All βtemp N(0,1.648)
All βdate N(0,1.648)
All σsite U(0,10)
Occupancy

ψhabitat and ψbasin β0 N(0,1.648)
ψhabitat βrice N(0,1.648)
βem.vegergent N(0,1.648)
βfl.veg N(0,1.648)
βopen.water N(0,1.648)
βterr.veg N(0,1.648)
ψbasin βnorth N(0,1.648)
βcentral N(0,1.648)
βsouth N(0,1.648)

Table 3-3. Posterior Distributions for Capture Parameters of Closed Abundance Model of Giant Gartersnake in the Natomas Basin, 2022
Model Component Parameter Median (95% CI)
Capture p0 0.0017 (0.0005–0.0056)
αtemp 0.1959 (0.0025–0.3928)
αSVL 0.2212 (-0.2764–0.7037)
αsex 0.2800 (-0.6028–1.1758)
αbehav 1.9797 (1.0637–2.7824)
σsite 0.0008 (0.0001–0.0005)
σind 0.0012 (0.0004–0.0028)
σday 0.0009 (0.0002–0.0030)

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Table 3-4. Summary of Giant Gartersnake Captures and Abundance Estimates, 2022 Site Indiv Cap N Trap Days Shoreline Sampled (kilometers) Bennett North 2 3 42 (19–77) 3,150 2.67
Bennett South 1 1 42 (20–77) 1,050 0.86
BKS 79 87 385 (211–681) 6,300 4.01
Huffman West 1 1 42 (20–77) 1,049 0.82
Lucich North 8 9 46 (23–83) 10,116 8.13
Lucich South 9 15 46 (22–84) 2,788 2.40
Sills 31 48 148 (76–267) 4,752 3.71
Total 131 164 751 (402–1342)

Table 3-5. Posterior Summaries for Parameters from the Robust-Design CMR Model, 2018–2022 Model component Parameter Median (95% CI)
Recapture p 0.007 (0.003–0.020)
βwt 0.205 (0.095–0.319)
σsite 0.572 (0.092–1.909)
σyear 0.388 (0.148–0.777)
Survival φfemale 0.493 (0.338–0.678)
φmale 0.501 (0.340–0.705)
σφ 0.759 (0.229–1.804)
Availability γfemale 0.585 (0.365–0.833)
γmale 0.405 (0.139–0.886)
σγ 0.500 (0.024–1.954)
Table 3-6. Posterior Model Probabilities for Probability of Occurrence of Giant Gartersnake Based on Habitat on Natomas Basin Conservancy Reserves, 2022
Explanatory Variable
Posterior
Probability Rice
Emergent
Vegetation
Floating Aquatic
Vegetation Open Water
Terrestrial
Vegetation
0 0 0 0 0 0.097
0 1 0 0 0 0.069
1 0 0 0 0 0.062
0 0 1 0 0 0.057
1 1 0 0 0 0.050
0 0 0 0 1 0.047
Notes: “1” indicates that the variable was included in the model. “0” indicates that the variable was left out of the model.

Only those models with posterior probability >0.05 and the null model are presented in the table.

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Table 3-7. Posterior Distributions for Parameters of the Final Single-Season Occupancy Habitat Model for Giant Gartersnake on Natomas Basin Conservancy Reserve Properties, 2022 Model Component Parameter Posterior Probability
Detection μp 0.07 (0.03 to 0.23)
α0 -2.34 (-3.53 to -1.13)
αtemp 0.31 (0.01 to 0.61)
αdate -0.32 (-1.07 to 0.43)
σsite 2.14 (1.24 to 3.3)
Occurrence ψNorth 0.91 (0.42 to 0.99)
ψCentral 0.95 (0.50 to 0.99)
ψFisherman’s_Lake 0.09 (0.01 to 0.82)
βNorth 0.96 (-1.30 to 3.40)
βCentral 1.58 (-0.80 to 4.07)
βFisherman’s_Lake -2.06 (-4.59 to 0.53)
βrice 0.13 (-2.74 to 3.28)
Nocc 30 (22 to 37)
Note: Posterior distributions are represented by the posterior median and symmetric 95% credible interval.

Table 3-8. Posterior Model Probabilities for Effects of Habitat on Dynamic Occupancy of Giant Gartersnake on Natomas Basin Conservancy Reserves, 2011–2022 Explanatory Variable
Posterior Probability
Emergent
Vegetation
Terrestrial
Vegetation
Floating
Aquatic
Vegetation
Submerged
Aquatic
Vegetation Rice
0 0 0 0 0 0.3423
0 0 0 0 1 0.1197
0 1 0 0 1 0.1104
Notes: “1” indicates that the variable was included in the model. “0” indicates that the variable was left out of the model.

Only those models with posterior probability >0.05 are presented in the table.

NBC 104332 (2-9-2023) TG
FIGURE 3-1
Giant Gartersnake (Thamnophis gigas
)
xar, GeoEye, Earthstar Geographics, CNES/Airbus
S, AeroGRID, IGN, and the GIS User Community
Source: Esri, Ma

DS, USDA, USG
0 1.5 3 4.5 60.75
Kilometers
!(
! (
! (! (! (
! (
! (
! (! (
! (! (
! (
! (
! (
! (
! (! (! (
! (! (
! (
! (! (
! (
! (! (
! (
! (! (! (! (! (
! (
! (
! (
! (
! (! (
! (!(
!(
!(
!(!(
Giant Gartersnakes
Captured in 2022
!( Yes
!( No
±
Sources: Esri, Maxar, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA, USGS,
AeroGRID, IGN, and the GIS User Community
Legend
Trap location
NBC 104332 (2-9-2023) TG
FIGURE 3-2
Areas Sampled for Giant Gartersnake
in the Natomas Basin in 2022
Water Temperature (˚C)
Solid red lines represent a snake that was not
captured the previous day; dashed blue lines
represent a snake that was captured the
previous day.

Thick lines represent mean relationships; thin
lines represent 95% credible intervals.

0.00 0.02 0.04 0.06 0.08 0.10
Daily Capture Probability (p)
NBC 104332 (2-9-2023) TG
FIGURE 3-3
Model Averaged Effect of an Ephemeral Behavioral Response and Water Temperature on Giant Gartersnake Capture Probability in the Natomas Basin in 2022 Abundance (N)

Density
200 400 600 800
NBC 104332 (2-9-2023) TG
FIGURE 3-4
Posterior Distribution of Estimated Giant Gartersnake Abundance in the Sampled Area at BKS Based on Closed Population Models in 2022 Abundance (N)
Density
0 50 100 150 200 250 300
FIGURE 3-5
Posterior Distribution of Estimated Giant Gartersnake Abundance in the Sampled Area at Sills Based on Closed Population Models in 2022 NBC 104332 (2-9-2023) TG
Abundance (N)
Density
0 20 40 60 80 100
NBC 104332 (2-9-2023) TG
FIGURE 3-6
Posterior Distribution of Estimated Giant Gartersnake Abundance in the Sampled Area at Lucich North Based on Closed Population Models in 2022 Abundance (N)
Density
0 20 40 60 80 100
NBC 104332 (2-9-2023) TG
FIGURE 3-7
Posterior Distribution of Estimated Giant Gartersnake Abundance in the Sampled Area at Lucich South Based on Closed Population Models in 2022 Snout−vent length (mm)
A. Snout–Vent Length
Mass (g)
B. Mass
Density
Female
Male
0 300 700 1,100 0 200 400 600
Vertical and horizontal lines near the
x-axis indicate the median and 95%
credible interval of the mean snout-vent
length and mass for each sex.

Male
Male
Female
Female
NBC 104332 (2-9-2023) TG
FIGURE 3-8
Distribution of Male and Female
Snout-Vent L
ength (A) and Mass (B) in the Natomas Basin, 2022
Median—female
Median—male
Thin lines represent the 95% credible interval of
the mean; thick lines represent the 50% credible
intervals.

MaleFemale
MaleFemale MaleFemale
MaleFemale

0.0 0.2 0.4 0.6 0.8 1.0
Apparent Survival
2018–2019 2019–2020 2020–2021 2021–2022
NBC 104332 (4-26-2023) TG
FIGURE 3-9
Annual Apparent Survival Estimate for Giant Gartersnake in the BKS Tract, 2018–2022
Median—female
Median—male
Thin lines represent the 95% credible interval of
the mean; thick lines represent the 50% credible
intervals.

MaleFemale
MaleFemale
MaleFemale
MaleFemale

0.0 0.2 0.4 0.6 0.8 1.0
Apparent Survival
2018–2019 2019–2020 2020–2021 2021–2022
NBC 104332 (4-26-2023) TG
FIGURE 3-10
Annual Apparent Survival Estimate for Giant Gartersnake in the Lucich North Tract, 2018–2022
Median—female
Median—male
Thin lines represent the 95% credible interval of
the mean; thick lines represent the 50% credible
intervals.

MaleFemale
MaleFemale
MaleFemale
MaleFemale

0.0 0.2 0.4 0.6 0.8 1.0
Apparent Survival
2018–2019 2019–2020 2020–2021 2021–2022
NBC 104332 (4-26-2023) TG
FIGURE 3-11
Annual Apparent Survival Estimate for Giant Gartersnake in the Sills Tract, 2018–2022
Probability of occurrence (ψ)
Density

0.0 0.2 0.4 0.6 0.8 1.0

0.0 0.5

1.0 1.5

2.0 2.5

3.0 3.5
A. Reserve Sites
20 23 26 29 32 35 38 41 44
Number of occupied sampled sites
Frequency

0.00 0.02

0.04 0.06

0.08 0.10

0.12 0.14
B. Occupied Sites
NBC 104332 (2-8-2023) TG
FIGURE 3-12
Proportion of Reserve Sites Occupied (A) and Number of Occupied Sites (B) Based on Static Occupancy Models for the Natomas Basin, 2022 Temperature (°C)
Detection probability
15 20 25 30 35

0.0 0.1

0.2 0.3

0.4 0.5

0.6 0.7

0.8 0.9

1.0 A. Water Temperature
Date
May June July Aug
B. Date
Thick lines represent the median detection probability; thin lines represent 95% credible intervals.

NBC 104332 (2-8-2023) TG
FIGURE 3-13
Effects of (A) Water Temperature and (B) Date on the Detection Probability of Giant Gartersnake in the Natomas Basin, 2022
2012 2014 2016 2018 2020 2022

0.0 0.2

0.4 0.6

0.8 1.0
Year
Probability
2011 2013 2015 2017 2019 2021
Points represent posterior modes (occurrence) or
posterior medians (colonization and extirpation);
error bars represent 95% credible intervals.

Probability of occurrence
Colonization of unoccupied sites
Extirpation of occupied sites
NBC 104332 (3-9-2022) TG
FIGURE 3-14
Annual Probability of Occurrence of Giant Gartersnake on Reserves Based on the Dynamic Occupancy Model
2012 2014 2016 2018 2020 2022
20 30
40 50
60 70
80 Year
Number of occupied monitored sites
2011 2013 2015 2017 2019 2021
Points represent posterior modes; error bars represent 95% credible intervals.

Note that 41 sites were sampled in 2022, and a total of 83 unique sites were sampled for giant gartersnake occurrence in at least 1 year from 2011 to 2022.

NBC 104332 (3-9-2022) TG
FIGURE 3-15
Estimated Number of Sampled Reserve Sites Occupied by Giant Gartersnake Year
Occupancy growth rate (r)
2011–12 2013–14 2015–16 2017–18 2019–20 2021–22
–0.5
–0.4
–0.3
–0.2
–0.1

0.0 0.1

0.2 0.3

0.4 0.5
Points represent posterior modes; error bars represent 95% credible intervals.

The red dotted line at 0 indicates no change in occupancy. The mean annual occupancy growth rate from 2011 to 2022 is indicated by the thick dashed line (mode) and thin dashed lines (95% credible interval).

NBC 104332 (3-9-2022) TG
FIGURE 3-16
Annual Intrinsic Rate of Occupancy Growth for Giant Gartersnake in Reserves, 2011–2022 Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community
Habitat Suitability 2022
Suitable
Marginal
Not Suitable
J
0 2.5 5 7.5 101.25
Miles
Sources: Esri, Maxar, GeoEye, Earthstar
Geographics, CNES/Airbus DS, USDA,
USGS, AeroGRID, IGN, and the GIS
User Community
Legend
Suitable habitat
Marginal habitat
Unsuitable habitat
NBC 104332 (4-25-2023) TG
FIGURE 3-17
Suitability of Habitat in the Canals of the
Natomas Basin for Giant Gartersnake in 2022
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Chapter 4
Swainson’s Hawk

CHAPTER HIGHLIGHTS
• Following a decrease in the number of occupied territories to slightly above the monitoring period average in 2021, the number of occupied territories in 2022 increased to the third highest observed during the monitoring period.
• Following a substantial decrease in all measures of reproductive success in 2021, reproductive metrics rebounded somewhat but remained relatively low in 2022. A statistically significant long- term decline in the number of young produced per successful nest was still evident in 2022, a phenomenon observed across the range of the species in California. • Management of habitats on reserve lands continues to be better than on similar lands in the Basin outside of reserves. However, the proportion of suitable foraging habitat in the Basin composed of reserve lands is too small to determine if management of reserve lands is contributing significantly to the success of the Swainson’s hawk population in the Basin. • Provision of future nest trees, planting suitable crops (e.g., alfalfa or winter wheat followed by another row crop), and maintenance of vegetative cover on fallow rice fields are management actions most likely to contribute to the effectiveness of reserve lands in supporting the Swainson’s hawk population in the Basin.

4.1 Introduction

4.1.1 Background
The NBHCP and its Implementing Agreement (City of Sacramento et al. 2003) require that an annual survey of nesting Swainson’s hawks be conducted throughout the Basin (Chapter VI, Section E [2][a][1] of the 2003 NBHCP). In compliance with the conditions described in the NBHCP, this chapter describes the methods, results, and implications of the results of surveys for Swainson’s hawk in the Natomas Basin from 1999 through 2022.

It should be noted that the study area for this species differs slightly from the study area used in all other monitoring efforts. For the purposes of conducting Swainson’s hawk population monitoring, the study area was expanded in 2001 to include the far side of the peripheral water bodies (i.e., the Sacramento River, the Natomas Cross Canal, and Steelhead Creek) because these areas support nesting habitat for Swainson’s hawks that forage within the Basin. Moreover, individual pairs may use alternate nest sites within given territories that span these water bodies. This expanded study area is referred to as the Basin in this chapter.

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4.1.2 Goals and Objectives
Monitoring efforts for Swainson’s hawk are designed to assess the progress of the NBHCP toward meeting the Plan’s goals and objectives for Swainson’s hawk populations and the habitats they use.

The Swainson’s hawk monitoring surveys are designed to achieve the following specific objectives. • Document the numbers, distribution, density, and reproductive success of the Swainson’s hawk population in the Basin.
• Conduct surveys in a systematic and repeatable manner that will ensure detection of all active Swainson’s hawk nests in the Basin from year to year.
• Document changes in land use and availability of foraging habitats throughout the Basin over time.

4.1.3 Life History

4.1.3.1 Status and Range
Swainson’s hawk (Figure 4-1) inhabits grassland plains and agricultural regions of western North America during the breeding season and grassland and agricultural regions from Central Mexico to southern South America during the non-breeding season (Bechard et al. 2010; Airola et al. 2019).

Early accounts described Swainson’s hawk as one of the most common raptors in the state, occurring throughout much of lowland California (Sharp 1902). Since the mid-1800s, the native habitats that supported the species have undergone a gradual conversion to agricultural uses.

Today, native grassland habitats are virtually nonexistent in the state, and only remnants of the once-vast riparian forests and oak woodlands still exist (Katibah 1983). This habitat loss contributed to a substantial reduction in the breeding range and has reduced the estimated size of the breeding population by more than 90% in California (Bloom 1980; Bechard et al. 2010).

More recent surveys indicate a larger and possibly expanding breeding population in the Central Valley, which supports approximately 94% of the statewide population (Anderson et al. 2007). The results of the 2005–2006 statewide survey conducted by DFW and the Swainson’s Hawk Technical Advisory Committee indicated the Central Valley supported an estimated 3,218 (± 947) breeding pairs (Battistone et al. 2019), or between 19% and 80% of the historical population (Bloom 1980).

The most recent effort to estimate the statewide population was conducted in 2018 (Furnas et al. 2022) with results suggesting a more substantial recovery of the species in California and an estimated population of 18,810 (95% CI: 11,353–37,228) exceeding the range of the estimated historical population. However, the results are inconsistent with the continuing reduction of suitable foraging habitat in the Central Valley and the results of regional surveys and monitoring efforts, issues which are acknowledged in the Furnas et al. (2022) report. This report also identified potential survey and modeling issues that may have resulted in an overestimation of the size of the population, which led the authors to recommend changes to the protocol for subsequent survey efforts and to caution readers regarding the use of the results to address management implications.

The Central Valley population extends from Tehama County south to Kern County. Yolo, Sacramento, and San Joaquin Counties support the bulk of this Central Valley population (Estep 1989; Battistone et al. 2019) (Figure 4-2). The Central Valley population is geographically isolated from the rest of the breeding population, which extends northward into western and central Canada and eastward to northwestern Illinois (England et al. 1997). Unpublished data from banding studies conducted by R.

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Anderson, P. Bloom, J. Estep, and B. Woodbridge suggest that no movement occurs between the Central Valley breeding population and other populations. However, results of satellite radio telemetry studies of migratory patterns indicate that birds outside of the Central Valley may occasionally travel through portions of the Central Valley during migration (Kochert et al. 2011).

Despite the loss of native habitats in the Central Valley, Swainson’s hawks appear to have adapted relatively well to certain types of agricultural patterns in areas where suitable nesting habitat remains. However, nesting and foraging habitat for Swainson’s hawks continues to decline in the Central Valley primarily due to agricultural practices and urban expansion.

4.1.3.2 Habitat Use
Swainson’s hawks usually nest in large native trees, such as valley oak (Quercus lobata), cottonwood (Populus fremontii), walnut (Juglans spp.), and willow (Salix spp.), and with increasing frequency in nonnative trees, such as eucalyptus (Eucalyptus spp.). Nests occur in riparian woodlands, roadside trees, trees along field borders, isolated trees, small groves, and on the edges of remnant oak woodlands. Stringers of remnant riparian forest along drainages contain the majority of known nests in the Central Valley (Estep 1984; Schlorff and Bloom 1984; Kochert et al. 2011). Nests are usually constructed as high as possible in the tree, providing protection to the nest as well as visibility from it (Figure 4-3).

Nesting pairs are highly traditional in their use of nesting territories and nesting trees. Many nest territories in the Central Valley have been occupied annually since 1979, and banding studies conducted since 1986 confirm a high degree of nest site and mate fidelity (Estep unpublished data).

In the Central Valley, Swainson’s hawks feed primarily on small rodents, usually in large fields that support low vegetative cover (providing access to the ground) and high densities of prey (Bechard 1982; Estep 1989, 2009). These habitats are usually hay fields, grain crops, certain row crops, and lightly grazed pasturelands. Fields lacking adequate prey populations (e.g., flooded rice fields) or those that are inaccessible to foraging birds (e.g., vineyards, orchards) are rarely used (Estep 1989, 2009; Babcock 1995; Nur et al. 2019). Urban expansion and conversion of agricultural lands to unsuitable crop types are responsible for a continuing reduction of available Swainson’s hawk foraging habitat in the Central Valley.

4.1.3.3 Breeding Season Phenology
Swainson’s hawks arrive at the breeding grounds from mid-March to early April (Figure 4-4).

Breeding pairs immediately begin constructing new nests or repairing old ones. Eggs are usually laid in mid- to late April, and incubation continues until mid-May when young begin to hatch. The brooding period typically continues through early to mid-July when young begin to fledge (Bechard et al. 2010). Studies conducted in the Sacramento Valley indicate that one or two—and occasionally three—young typically fledge from successful nests (Estep 2007; Estep and Dinsdale 2012; ICF 2019) (Figure 4-5). After fledging, young remain near the nest and are dependent on the adults for about 4 weeks, after which they permanently leave the breeding territory (Anderson and Estep unpublished telemetry data). By mid-August, breeding territories are no longer defended, and Swainson’s hawks begin to form communal groups. These groups begin their fall migration from late August to mid-September. Unlike most other Swainson’s hawk populations, which migrate to southern Argentina for the winter, the Central Valley population winters from Central Mexico to central South America (Airola et al. 2019).

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4.2 Methods

4.2.1 Population Assessment
Surveys were conducted by systematically driving all available roads within the Basin, including both sides of all peripheral drainages. Where roads could not be used, surveys were conducted on foot. All potential nesting trees were searched with binoculars and/or a spotting scope for nests and adult Swainson’s hawks.

Surveys were conducted in three phases. Phase 1 surveys were conducted early in the breeding season (late March to mid-April) to (1) detect Swainson’s hawk activity at previously known nest sites as well as in all other suitable nesting habitats and (2) to detect early nest failures that might otherwise be missed. All suitable nesting habitats were checked for the presence of adult Swainson’s hawks and to note nesting activity and behavior (e.g., nest construction, courtship flights, defensive behavior). Activity was noted and mapped; locations of nests were documented using a global positioning system receiver.

Phase 2 surveys were conducted in mid-May through June to (1) determine whether potentially breeding pairs detected during Phase 1 surveys were nesting and (2) resurvey all previously unoccupied potential nesting habitat for late-nesting pairs and for active nests that may have been missed during Phase 1 surveys.

Phase 3 surveys were conducted during July to determine nest success and record the number of young fledged per nest. Incidental observations, such as foraging, roosting, and other sightings of adult Swainson’s hawks, were also noted.

An occupied territory is defined as a nest site that was occupied by a pair of Swainson’s hawks, regardless of the reproductive outcome. An active nest is defined as a nest in which eggs were laid. A successful nest is defined as a nest in which young were fledged. A failed nest is defined as a nest in which eggs were laid but from which no young were fledged.

4.2.2 Habitat Assessment
The distribution and abundance of land cover/crop types throughout the Basin, both on and off reserve lands, are documented annually (see Chapter 2, Land Cover Mapping, Botanical Inventory, and Noxious Weed Monitoring). These data are used to document any changes in the distribution and abundance of suitable Swainson’s hawk foraging habitat throughout the Basin.

4.3 Results

4.3.1 Population Assessment
Swainson’s hawks continued to nest primarily in the southern portion and along the far western and northern edges of the Basin during 2022. The nest sites are predominantly along the Sacramento River and within approximately 1 mile of the river. These areas support suitable habitat for both nesting and foraging: potential nesting trees are distributed along roadsides, in remnant riparian and oak woodlands, and as isolated trees; foraging habitat is present in the upland row crops that The Natomas Basin Conservancy

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dominate this part of the Basin. Conversely, most of the Basin north of Elkhorn Boulevard and east of Powerline Road is less suitable for nesting or foraging by Swainson’s hawks because it is dominated by rice production, which provides limited foraging value, and because there are relatively few potential nest trees in this area.

A total of 149 current and historical Swainson’s hawk nesting territories were monitored during 2022 (Table 4-1). However, many of these territories are assumed to represent alternative nesting locations for the same breeding pairs. In instances where individual birds are marked (i.e., color banded) and can be identified, or where a new nest site occurs in proximity to a known and unoccupied nest with no other known territories in the immediate vicinity, the site is considered an alternate nest of a known territory. In the absence of either of these conditions, the site is considered a new territory. Therefore, although the number of territories may increase each year, this increase does not necessarily reflect new breeding pairs within the study area.

Changes in the number of occupied Swainson’s hawk nesting territories, the number of successful nests, and the total number of young fledged from 2001 through 2022 are depicted on Figure 4-6.

Although annual variation in the total number of occupied territories is large, the trend is a general increase over time (R2 = 0.620, P < 0.001, Figure 4-7). The total number of occupied territories increased by 10 from 2021, which was the second largest increase in the number of occupied territories from year to year since comprehensive monitoring began in 2001. In total, 69 territories were occupied during 2022, well above the average of 57 occupied territories and the third highest over the 21-year monitoring period.

Measures of reproductive success continue to exhibit high annual variation. Since 2009 there have been five precipitous drops in most measures of reproductive success, including the total number of successful nests, total number of young fledged, the number of young per occupied territory and the number of young per active nest. In all cases, reproductive metrics have rebounded the following year, often dramatically (Figures 4-6 and 4-8).

All measures of reproductive success rebounded slightly in 2022 but remained below the monitoring period average. The number of young per occupied territory, which is essentially the reproductive rate of the breeding population, rebounded significantly, but remains well below 1, the approximate value of a stable population. The reproductive rate is significantly negatively correlated with the number of pairs (i.e., occupied territories) that fail to nest at all (R2 = 0.656, P < 0.001). The relatively low reproductive rate observed in 2022 is consistent with results from other areas of the Central Valley (Estep 2020, Estep pers obs.) and not unique to—or based on conditions within—the Natomas Basin.

The number of young per successful nest (a measure of brood size) also increased substantially.

However, the long-term decrease in the number of young produced per successful nest (measured since 1999) continues to be statistically significant as measured by simple linear regression (R2 =

0.594, P < 0.001, Figure 4-9). The cause(s) and relevance of the decline in this particular parameter of reproductive success is unknown. The number of young fledged per successful nest is negatively correlated with the total number of occupied territories each year (R2 = 0.352, P = 0.004).

Forty-nine (71%) of the 69 pairs that occupied territories nested. Thirty-five of these were successful while 14 nest attempts failed, and eight pairs did not nest at all. The reproductive outcome of 12 occupied territories was undetermined. A total of 40 fledglings were fledged within the study area in 2022, or just over one young per successful nest (Table 4-2). Five of the 35 successful nests had more than one young in 2022 (Table 4-1).

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In 2022, there were 35 active nesting territories along the Sacramento River, an increase of eight from 2021, and the highest number observed since 2004 (Table 4-3, Figure 4-10). Although the total number of nesting pairs along the Sacramento River fluctuates substantially from year to year (𝑥̅ =

28.9; SD = 3.9), there is no discernible trend over time. This relative constancy in the mean number of pairs has persisted despite continuing home construction, ongoing tree removal, and increasing human disturbances, including disturbance associated with implementation of the SAFCA NLIP along the east side of the river. Many pairs have alternate nest sites on both sides of the river, allowing for changes in nest site location in response to local disturbances.

Swainson’s hawks often use alternate nest sites within the breeding territory. Of the 69 active territories in 2022, 49 (71%) have one or more alternate nest sites. Of the 61 pairs that nested in 2022, seven pairs selected alternate nest trees that had no previously documented use, and 15 pairs selected known alternate nest trees that were different from the previous year. All the alternate nest trees were in the immediate vicinity of previously used nest trees.

Historical activity within the 69 active territories is variable but indicates the extent of territory fidelity and the tendency toward long-term occupancy. Twenty-six (38%) of the territories were first reported active during or before the first year of monitoring under the current protocols in 2001 and, although some have been inactive in some of the intervening years, most have been fairly consistently active throughout the entire 22-year monitoring period. Forty-nine (71%) of the 69 active territories were first reported active prior to 2010.

Two Swainson’s hawk nest trees were removed in 2022. Although not used since 2004, the large cottonwood tree that supported the nest for NB-10 was removed; and the row of eucalyptus trees that supported the nest for NB-97, last active in 2019, was also removed. However, there are potential alternative nesting sites in the immediate vicinity of both sites. Although many potential nest trees were removed during levee construction activities associated with the SAFCA NLIP, restoration actions have established new potential replacement trees near the toe of the new levee.

These trees are expected to provide new potential nesting habitat when they reach maturity.

Although no Swainson’s hawk nest trees were removed within the NLIP in 2022, a total of nine have been removed since implementation of the NBHCP, seven of which resulted in the apparent abandonment of the nesting territory (Table 4-1). Levee construction activities on the next phase of the NLIP began in 2019 and continued through the 2022 breeding season. Numerous mature valley oak and other native trees were removed from the land side of the existing levee south of Powerline Road. Additional tree removal is planned as the project moves southward. There are no reported nests within the project right-of-way; however, substantial suitable nesting habitat is present and will be removed to expand the levee. Construction disturbance from levee construction activities is also likely to affect nesting activity and reproductive output of active nests that occur on the water side of the levee.

Competition with other nesting raptors also influences the distribution and abundance of nesting Swainson’s hawks. In 2022, 16 previously documented Swainson’s hawk territories were occupied by nesting red-tailed hawks and great-horned owls.

Sources of adult or nestling mortality are usually difficult to confirm but presumably include predation by great-horned owls and direct disturbances to nests from construction or recreational activities that result in nest abandonment. Collisions with airplanes have also been documented but are difficult to quantify. In 2014, Sacramento County Airport System (SCAS) reported four adult Swainson’s hawk fatalities resulting from collisions with aircraft, including the banded (i.e., The Natomas Basin Conservancy

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identifiable) adult female from territory NB-107, immediately west of the airport perimeter fence.

SCAS staff reported two Swainson’s hawk fatalities from collision with aircraft in 2017, two in 2018, one in 2020, and one in 2021.

4.3.2 Habitat Assessment
Changes from 2004 through 2022 in the total acreages of three general habitat categories (upland agriculture, fallow lands, and grasslands) that provide suitable Swainson’s hawk foraging habitat are listed in Table 4-4 and depicted on Figure 4-11. The distribution of suitable Swainson’s hawk foraging habitat in 2022 is shown on Figure 4-12. Basin-wide foraging habitat increased over 46% (7,530 acres) from 2021 to 2022 (Table 4-4), primarily due to the substantial increase in fallow lands, particularly fallow rice lands, that occurred due to the ongoing drought in California.

Similarly, suitable habitats on reserve lands also increased substantially, also due to an increase in fallow lands caused by the drought, but also by the addition of several new tracts to the reserve system.

Total Swainson’s hawk foraging habitat in the Basin declined from 2006 through 2015, but has been highly variable since that time frame. There has been no significant increase or decrease over the monitoring period in upland agriculture, fallow lands, or total Swainson’s hawk foraging habitat, although there has been a significant decline in grasslands (R 2 = 0.616, P < 0.001) and alfalfa
throughout the Basin (R2 = 0.336, P = 0.012). Annual fluctuations in total available acres of suitable Swainson’s hawk foraging habitat have been driven primarily by rice farming practices in the Basin, because fallow rice fields are considered to be suitable—although low quality—foraging habitat for Swainson’s hawks, and the number of acres of rice in production has varied substantially over the monitoring period.

There is no correlation between the number of occupied territories each year and the total acreage of suitable forging habitat in the Basin (R
2 = 0.076, P = 0.254), the acreage of upland row and field crops (R2 = 0.121, P = 0.145), or the total acreage of alfalfa each year (R2 = 0.079, P = 0.258).

However, the total number of occupied territories is negatively correlated with the total acres of grassland habitat in the Basin (R
2 = 0.337, P = 0.009). No measures of reproductive success were significantly correlated with the total acreage for any of the categories of Swainson’s hawk suitable foraging habitat in the Basin, including alfalfa.

Table 4-5 lists the extent and proportion of four categories of suitable Swainson’s hawk foraging habitat on both reserve and non-reserve lands in 2022. These categories include both cultivated and uncultivated lands. Suitable cultivated habitats consist of alfalfa; row, grain, and other hay crops; and fallow lands. Suitable uncultivated habitats consist of irrigated pasture and grasslands (created native grasslands, nonnative annual grasslands, and ruderal habitats). The relative foraging value of the different types depends on prey density and availability, but all have foraging value; collectively, these habitat types provide an important diversity of foraging habitats in the Basin. Although other habitat types are occasionally used for foraging, their value is generally considered to be less than that of the habitat types listed above.

Alfalfa is considered one of the highest habitat-value crop types for Swainson’s hawk. Alfalfa decreased Basin-wide from 2020 to 2021, but increased on reserve lands. This was due in part to the acquisition of alfalfa growing lands by TNBC from 2021 to 2022. Nevertheless, the proportion of suitable foraging habitat comprising alfalfa remains substantially higher on reserve than on non- reserve lands (Table 4-5), as it has been for several years. As a result of the establishment of a The Natomas Basin Conservancy

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substantial number of acres of grasslands on non-reserve lands by the SAFCA NLIP, the proportion of grasslands is now substantially higher on non-reserve lands than reserve lands.

The reserve system currently accounts for approximately 15% of the suitable Swainson’s hawk foraging habitat in the Basin. Consequently, the extent to which TNBC-managed land will be able to influence the trajectory of the Swainson’s hawk population in the Basin is currently limited.

4.4 Discussion
Trends over time in the number of occupied territories are indicative of a stable but slightly increasing breeding population of Swainson’s hawks in the Natomas Basin. Interestingly, in 2019 the lowest reproductive metrics and number of active nests occurred concurrently with the highest number of occupied breeding territories since monitoring began. In 2020, the number of active and successful nests fully recovered, and although the reproductive rate also recovered slightly, it remained low compared with past years. Occupancy declined again in 2021 along with another sharp decline in reproductive output, and increased in 2022, with only slightly increased reproductive output. However, the extreme decline in reproductive metrics in 2019 and continuing low rate from 2020 to 2022 was part of a broader condition throughout the Central Valley in these years. Similar phenomena were observed in 2011 and 2013, which may indicate that reproductive success is likely to rebound in subsequent years.

Although it remains speculative, in any given year the likely causes for this widespread lack of production among Swainson’s hawks and other nesting raptor species in the Central Valley include drought, late-spring storms, changes in agricultural patterns or practices, or more subtle climate- change phenomena—which may affect prey (i.e., rodent) populations—or possibly a natural cyclical decline in microtine rodents, or a combination of both. The arrival dates of Swainson’s hawks on the breeding grounds and the pattern of territory establishment was typical from 2019 to 2022, and territory occupancy was relatively high, which may indicate that the decline in reproductive performance is related to food resources.

The significant decline over the monitoring period in the number of young per successful nest, a reproductive metric influenced by clutch size and brood size, is unusual because of the intrinsic invariability in the metric (i.e., it is derived from a series of mostly 1s and 2s) but not unprecedented. The breeding population of Swainson’s hawk in Saskatchewan experienced a similar long-term decline in the number of young fledged per successful nest that coincided with a decline in the principal prey species, Richardson’s ground squirrel (Urocitellus richardsonii) (Houston and Schmutz 1995). Annual variation in clutch or brood size is common among some raptor species (including Swainson’s hawk) that rely to a large extent on a single prey species, particularly if that species is subject to its own reproductive cycles, such as the California vole (Microtus californicus).

However, a gradual and long-term decrease in average clutch or brood size may suggest a change in habitat conditions, such as the continuing conversion of row and field crop habitats to orchards or other crop types that could influence the availability of Swainson’s hawk food resources. The increase in the number of occupied territories in conjunction with a decrease in the number of young per successful nest is also consistent with a density-dependent response in the reproductive rate to an increase in the size of the breeding population. Other possible but less likely factors include pesticides or disease.

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The generally increasing trend in the number of occupied Swainson’s hawk nesting territories is not positively correlated with the total acreage of upland agricultural crops in the Basin or any other habitat metric. This may indicate that the Basin provides only a portion of the foraging habitat required for this population, which is consistent with recent telemetry studies that demonstrated substantial use of out-of-Basin foraging habitats by Swainson’s hawks nesting in the Basin (Fleishman et al. 2016).

The 2022 distribution of nest sites remained similar to past years, with the bulk of the nests occurring in trees along the perimeter drainages, primarily the Sacramento River and the Natomas Cross Canal. Most of the remaining sites are in the south Basin (i.e., south of Elkhorn Boulevard) and along the western edge of the Basin.

Nest tree removal and conversion of agricultural foraging habitat, mostly because of urbanization, have historically resulted in the removal of some nesting territories in the south Basin. The 2008 moratorium on planned and proposed urbanization because of levee-related restrictions was lifted in 2015, and development has resumed, primarily in the south Basin. As a result, suitable nesting and foraging habitat is expected to decline more rapidly within the Basin in the near future, which could result in nesting pairs being displaced. Recent urbanization in the Basin south of Elkhorn Boulevard and east of Powerline Road has and continues to cause the removal of suitable foraging habitats. Nesting territories in this area, such as NB-27 and NB-140, that are becoming increasingly surrounded by urbanization, are expected to eventually be abandoned. Others, such as NB-98 and NB-63, are subject to increasing risk due to recent urbanization within the territory. However, despite this loss, which was anticipated in the NBHCP, the management of preserves and other suitable nesting and foraging habitats in the Basin have contributed to maintaining a stable and even increasing Swainson’s hawk nesting population.

The ongoing loss of trees could limit future nesting opportunities and the ability of the Swainson’s hawk population to respond to habitat changes throughout the Basin. The County of Sacramento continues to allow residential development on the waterside of the Sacramento River levee, which accelerates tree loss as riparian vegetation is cleared for home sites. These projects, along with tree and brush clearing for vegetation management and a fire on the east side of the river just north of Powerline Road in 2010, have cumulatively contributed to additional tree loss along the river. This loss of potential nesting trees and the increase in human disturbance along the river could potentially result in territory abandonment and limit opportunities for relocation of displaced nesting pairs and the establishment of new nesting sites.

In addition, SCAS, citing Federal Aviation Administration regulations, has removed trees on airport lands that are considered potential hazard trees due to bird use (County of Sacramento 2006).

Although these actions may have been warranted to meet federal safety regulations, they have resulted in the removal of a substantial number of mature trees, including sites known to be used by Swainson’s hawks as nest sites. No active nest trees were removed by SCAS in 2022.

SCAS also implements a wildlife hazard management plan to minimize the potential for bird strikes with planes on airport lands (Sacramento County Airport System 2007). This program involves the removal of a variety of bird species, including raptors. The loss of individual Swainson’s hawks through this program is inconsistent with the goals of the NBHCP with respect to the maintenance of existing Swainson’s hawk population levels in the Basin. Despite implementation of the wildlife hazard management plan, airplane collision with birds at Sacramento International Airport (SMF) is a cause of mortality that could potentially affect the Natomas Basin Swainson’s hawk population.

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Much of the land within the SMF perimeter fence is managed as a short grassland, which is attractive to foraging Swainson’s hawks and other raptors, putting them at risk of collision with planes landing or taking off. Collision mortality during the breeding season can result in the abandonment of active nests and loss of productivity and increase adult turnover in the breeding population.

Implementation of the SAFCA NLIP has resulted in impacts on the Swainson’s hawk population, but effects have generally been short term and appear to be mitigated. Despite the changes in habitat value resulting from levee and canal construction activities, tree removal, restoration activities, and related disturbances that may have been responsible for some nest failures in the last several years, the distribution of nesting pairs within the area affected by levee construction remains relatively stable. In addition, the restored grassland habitats in the area of the SAFCA NLIP provide moderate- to high-value foraging habitat and may also provide potential refugia for voles and other prey populations on adjacent agricultural lands, while the restored woodland habitats are expected to provide future nesting opportunities.

The majority of major levee construction activities from the Natomas Cross Canal to Powerline Road—coordinated by SAFCA—have been completed; however, the next phase of the project, from Powerline Road southward, which began in 2019, has been ongoing through 2022 and has largely been completed south to San Juan Road. Levee work will continue through at least 2023 south of San Juan Road. The landside levee construction is coordinated by USACE, including the removal of trees along the remaining portion of the Sacramento River and along Steelhead Creek, could affect nesting activity in those areas.

4.5 Effectiveness
Biological effectiveness as it pertains to Swainson’s hawk is measured on the basis of acquisition of reserve lands and management activities that meet the goals for Swainson’s hawk habitat, as well as the population’s response to these actions. Effectiveness is also measured through successful implementation of management recommendations designed to further benefit Swainson’s hawk through targeted land acquisition or specific land management activities.

As discussed above, the status of the Swainson’s hawk population in the Basin remains stable to slightly increasing. Evidence to date thus indicates that implementation of the NBHCP and Metro Airpark HCP has been effective in conserving the nesting population of Swainson’s hawks in the Natomas Basin. However, additional population effects could become evident as urbanization of the Basin continues following the lifting of the building moratorium and actions unforeseen by the NBHCP continue, such as the continuation of the SAFCA NLIP south of Powerline Road, bird control actions by SCAS, bird–aircraft collision mortality, continued disturbance and habitat removal along the east side of the Sacramento River, future urbanization of county lands, or possibly factors affecting hawks outside the breeding season (i.e., on wintering habitats).

Swainson’s hawk habitat goals continue to be met through establishment and management of suitable upland habitat, including the planting of potential future nesting trees, on reserve lands.

The first documented active nest on an NBHCP Reserve tract was a nest on the BKS tract in 2005. 2019 marked the second year Swainson’s hawks occupied a nest on an NBHCP Reserve tract. A nesting pair established a new nest within a small group of trees planted in 2007 between the Huffman East and Huffman West tracts in the North Basin Reserve. In 2020, a third Swainson’s hawk The Natomas Basin Conservancy

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nest site was found on the Atkinson tract of the North Basin Reserve. The nest was near the southern end of the cottonwood grove, where the nesting pair successfully fledged two young.

As discussed in Section 4.3, Results, reserve lands managed for Swainson’s hawk foraging habitat continue to provide a higher proportion of high-value cover types (i.e., alfalfa) than other comparable lands in the Basin. Swainson’s hawk habitat has been a key consideration in reserve land acquisition. Acquisitions have generally been consistent with recommendations in the Biological Effectiveness Monitoring Report for the last several years. In 2022, a significant portion of fallow rice on reserve lands was managed to provide higher quality foraging habitat for Swainson’s hawk, in keeping with past recommendations. This effort is expected to continue in 2023.

4.6 Recommendations
• Although TNBC is currently ahead of NBHCP requirements for acquiring lands within 1 mile of the Sacramento River, it should continue to focus on those areas, where the majority of nesting pairs occur and where soils are more conducive to long-term sustainability of suitable upland foraging habitats, and on lands that consolidate ownership into larger contiguous habitat reserves.
• Continue efforts to create new nesting and foraging habitat in protected areas. • Continue to coordinate with SAFCA, USACE, or other responsible agencies to minimize the effects of the remaining segments of the NLIP on TNBC reserves and other lands in the Basin. To the extent feasible, coordinate with agencies regarding mitigation and compensation for impacts that may be compatible with TNBC goals such as tree replacement activities, restoration activities, and other management opportunities.
• Continue efforts to inform, educate, and share information with Sacramento County to raise awareness of the importance of native trees along the Sacramento River to provide current and future nesting habitat for Swainson’s hawks.
• Continue to meet habitat goals for Swainson’s hawk through acquisition and restoration of upland habitats as necessary. Non-rice agricultural fields, grasslands, and pastures provide the highest value foraging habitat.
• Continue to experiment with Swainson’s hawk-friendly crops and crop rotations on marginal soils to improve foraging opportunities.
• Manage fallow lands with cover crops or other techniques to increase prey production for Swainson’s hawk.
• Give preference to utilizing simple management techniques and existing farm resources for the Swainson’s hawk components of the reserve lands. Efforts should be made to integrate surrounding farmlands with reserve lands.
• Consideration of installation of uncultivated field borders composed of native grasses (and forbs used by pollinator species) to provide refugia for prey populations has been a long-standing recommendation. However, with the development and maturation of SAFCA NLIP mitigation lands along the Sacramento River levee that currently appear to provide this refugia, this recommendation may be dropped in the future if these habitats continue to function adequately.

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4.7 References
Airola, D. A., J. A. Estep, D. Krolick, D. Anderson, and J. Peters. 2019. Wintering Areas and Migration Characteristics of Swainson’s Hawks that Breed in the Central Valley of California. Journal of Raptor Research 53(3):237–252.

Anderson, D. A., J. L. Dinsdale, R. Schlorff, K. Fien, S. Torres, C. Chun, and J. Estep. In preparation.

Foraging Habitat Use Patterns of Swainson’s Hawks in Agricultural Landscapes of the Central Valley, CA. U.C. Davis Wildlife Health Center and the California Department of Fish and Game.

Babcock, K. W. 1995. Home Range and Habitat Use of Breeding Swainson’s Hawks in the Sacramento Valley of California. Journal of Raptor Research 29:193–197.

Battistone, C. L., B. J. Furnas, R. L. Anderson, J. L. Dinsdale, K. M. Cripe, J. A. Estep, C. Chun, and S. G.

Torres. 2019. Population and Distribution of Swainson’s Hawk (Buteo Swainsoni) in California’s Great Valley: A Framework for Long-Term Monitoring. Journal of Raptor Research 53(3):253– 265.

Bechard, M. J. 1982. Effect of Vegetative Cover on Foraging Site Selection by Swainson’s Hawk.

Condor 84:153–159.

Bechard, M. J., C. S. Houston, J. H. Sarasola, and A. S. England. 2010. Swainson’s Hawk (Buteo swainsoni). In A. Pool, (ed.), The Birds of North America online. Ithaca, NY: Cornell Lab of Ornithology. Available: http://bna.birds.cornell.edu/bna/species/265.

Bloom, P. H. 1980. The Status of the Swainson’s Hawk in California. California Department of Fish and Game, Nongame Wildlife Investigations. Project Report W-54-R-12, Sacramento, CA.

City of Sacramento, Sutter County, and the Natomas Basin Conservancy. 2003. Natomas Basin Habitat Conservation Plan; Sacramento and Sutter Counties, California. Sacramento, CA.

County of Sacramento. 2006. Final Environmental Report for the Yuki Pear Orchard Removal.

Sacramento, CA: Department of Environmental Review and Assessment.

England, A. S., M. J. Bechard, and C. S. Houston. 1997. Swainson’s Hawk (Buteo swainsoni). In A. Poole and F. Gill (eds.), The Birds of North America, No. 265. Philadelphia, PA: The Academy of Natural Sciences and Washington, DC: The American Ornithologists’ Union.

Estep, J. A., and J. Dinsdale. 2012. Distribution, Abundance, and Habitat Associations of Nesting Swainson’s Hawks in the Central San Joaquin Valley. Central Valley Bird Club Bulletin 15:84–106.

Estep, J. A. unpublished data.

Estep, J. A. 1984. Diurnal Raptor Eyrie Monitoring Program. California Department of Fish and Game, Nongame Wildlife Investigations. Project Report W-65-R-1, Job No. II-2.0. Sacramento, CA. ———. 1989. Biology, Movements, and Habitat Relationships of the Swainson’s Hawk in the Central Valley of California, 1986–1987. California Department of Fish and Game, Nongame Bird and Mammal Section, Sacramento, CA.
———. 2007. The Distribution, Abundance, and Habitat Associations of Swainson’s Hawk (Buteo swainsoni) in South Sacramento County. Prepared for the City of Elk Grove, CA.

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———. 2009. The Influence of Vegetation Structure on Swainson’s Hawk (Buteo Swainsoni) Foraging Habitat Suitability in Yolo County, CA. Prepared for the Yolo Natural Heritage Program, Woodland, CA.
———. 2020. The 2020 Distribution, Abundance, and Habitat Associations of the Swainson’s Hawk (Buteo Swainsoni) in Yolo County, CA. Prepared for the Yolo Habitat Conservancy, Woodland, CA. ———. In preparation. Ecology of the Swainson’s Hawk in the Central Valley of California.

Fleishman, E., J. Anderson, B. G. Dickson, D. R. Krolick, J. A. Estep, R. L. Anderson, C. Elphick, D. S.

Dobkin, and D. A. Bell. 2016. Space Use by Swainson’s Hawks (Buteo swainsoni) in the Natomas Basin, California. Collabra 2:1–12.

Furnas, B. J., D. H. Wright, E. N. Tennant, R. M. O’Leary, M. J. Kuehn, P. H. Bloom, and C. L. Battistone. 2022. Rapid growth of the Swainson’s Hawk population in California since 2005. Ornithological Applications, Volume 124, Issue 2, 5 May 2022, https://doi.org/10.1093/ornithapp/duac006 Houston, C. S. and J. K. Schmutz. 1995. Declining reproduction among Swainson's Hawks in prairie Canada. J. Raptor Res. 29:198–201.

ICF. 2019. Biological Effectiveness Monitoring for the Natomas Basin Habitat Conservation Plan Area 2018 Annual Survey Results. Agency Final. April. (ICF 00890.10.) Sacramento, CA. Prepared for The Natomas Basin Conservancy, Sacramento, CA.

Katibah, E. F. 1983. A Brief History of Riparian Forests in the Central Valley of California. Pages 23– 29 in R. E. Warner, and K. M. Hendrix (eds.), California Riparian Systems: Ecology, Conservation, and Productive Management. Berkeley, CA: University of California Press.

Kochert, M. N., M. R. Fuller, L. S. Schueck, L. Bond, M. J. Bechard, B. Woodbridge, G. L. Holroyd, M. S.

Martell, and U. Banasch. 2011. Migration Patterns, Use of Stopover Areas, and Austral Summer Movements of Swainson’s Hawks. The Condor 113(1):89–106.

Nur, N., D. Jongsomjit, and S. Veloz. 2019. Swainson’s Hawk Foraging Study: Analysis of Foraging in Relation to Crop Characteristics in the Central Valley, California. Technical Report to Swainson’s Hawk Technical Advisory Committee. Point Blue Conservation Science, Petaluma, CA.

Sacramento County Airport System. 2007. Wildlife Hazard Management Plan. Sacramento County Airport System, Sacramento, CA.

Schlorff, R., and P. H. Bloom. 1984. Importance of Riparian Systems to Nesting Swainson’s Hawks in the Central Valley of California. Pages 612–618 in R. E. Warner, and K. M. Hendrix (eds.), California Riparian Systems: Ecology, Conservation, and Productive Management. Berkeley, CA:

University of California Press.

Sharp, C. S. 1902. Nesting of Swainson’s Hawk. The Condor 4:116–118.

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Table 4-1. Results of 2022 Swainson’s Hawk Surveys, NBHCP Area Territory Number Statusa Number of Young Nesting Habitat Nest Tree Speciesb NB-1 I Urban Valley oak
NB-2 I Urban Cottonwood
NB-3 NLE Isolated tree—removed in 2003 Valley oak
NB-4 I Riparian Cottonwood
NB-5 I Riparian Willow
NB-6 I Ornamental grove Eucalyptus
NB-7 NLE Isolated trees—removed in 2002 Willow
NB-8 I Roadside tree row—ornamental Cottonwood
NB-9 I Channelized riparian Cottonwood
NB-10 I Isolated tree – removed in 2021 Cottonwood
NB-11 I Riparian Valley oak
NB-12 A-S 1 Riparian Cottonwood
NB-13 A-S 1 Riparian Oregon ash
NB-14 A-S 1 Tree row—ornamental Eucalyptus
NB-15 NLE Isolated tree—removed in 2002 Valley oak
NB-16 A-S 1 Oak grove Cottonwood
NB-17 NLE Isolated tree—removed in 1998 Valley oak
NB-18 I Isolated tree Cottonwood
NB-19 A-F 0 Tree along irrigation canal Cottonwood
NB-20 NLE Isolated tree—removed in 2002 Cottonwood
NB-21 A-F 0 Riparian Cottonwood
NB-22 A-F 0 Isolated tree Willow
NB-23 I Riparian Willow
NB-24 A-U Riparian Valley oak
NB-25 I Riparian Walnut
NB-26 NLE Roadside tree—removed in 2002 Valley oak
NB-27 I Riparian Cottonwood
NB-28 I Riparian Cottonwood
NB-29 A-X 0 Riparian Willow
NB-30 A-X 0 Riparian Cottonwood
NB-31 I Riparian Willow
NB-32 A-S 1 Riparian Cottonwood
NB-33 I Riparian Cottonwood
NB-34 I Riparian Cottonwood
NB-35 I Riparian Cottonwood
NB-36 A-S 1 Riparian Cottonwood
NB-37 A-X 0 Riparian Cottonwood
NB-38 A-F 0 Riparian Cottonwood
NB-39 A-F 0 Riparian Willow
NB-40 A-S 1 Riparian Cottonwood
NB-41 I Riparian Willow
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Table 4-1 Continued

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Territory Number Statusa Number of Young Nesting Habitat Nest Tree Speciesb NB-42 I Riparian Cottonwood
NB-43 A-S 2 Riparian Cottonwood
NB-44 A-S 1 Riparian Cottonwood
NB-45 I Riparian Cottonwood
NB-46 I Riparian Cottonwood
NB-47 A-S 2 Riparian Cottonwood
NB-48 I Riparian Cottonwood
NB-49 I Riparian Cottonwood
NB-50 I Riparian Sycamore
NB-51 I Riparian Cottonwood
NB-52 A-S 1 Riparian Cottonwood
NB-53 A-X 0 Riparian Cottonwood
NB-54 I Riparian Cottonwood
NB-55 A-X 0 Riparian Cottonwood
NB-56 I Riparian Cottonwood
NB-57 A-U Riparian Cottonwood
NB-58 I Riparian Cottonwood
NB-59 A-U Riparian Cottonwood
NB-60 A-S 1 Riparian Cottonwood
NB-61 I Riparian Cottonwood
NB-62 A-F 0 Riparian Cottonwood
NB-63 I Isolated tree Willow
NB-64 A-S 2 Riparian Valley oak
NB-65 A-S 1 Cottonwood grove Cottonwood
NB-66 A-S 1 Riparian Cottonwood
NB-67 I Riparian Cottonwood
NB-68 A-S 1 Riparian Sycamore
NB-69 I Urban ornamental Willow
NB-70 A-U Riparian Valley oak
NB-71 A-S 1 Riparian Willow
NB-72 I Riparian Cottonwood
NB-73 NLE Tree row – removed in 2019 Ornamental conifer NB-74 A-F 0 Roadside tree Willow
NB-75 A-U Riparian Cottonwood
NB-76 NLE Tree row—removed in 2004 Cottonwood
NB-77 A-S 1 Riparian Cottonwood
NB-78 I Riparian Cottonwood
NB-79 I Riparian Sycamore
NB-80 I Riparian Cottonwood
NB-81 I Isolated tree Cottonwood
NB-82 I Riparian Willow
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Table 4-1 Continued

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Territory Number Statusa Number of Young Nesting Habitat Nest Tree Speciesb NB-83 I Riparian Willow
NB-84 I Riparian Cottonwood
NB-85 A-U Riparian Cottonwood
NB-86 A-U Riparian Cottonwood
NB-87 A-S 1 Riparian Cottonwood
NB-88 A-S 1 Riparian Cottonwood
NB-89 A-S 1 Riparian Valley oak
NB-90 I Riparian Willow
NB-91 A-S 1 Riparian Cottonwood
NB-92 I Riparian Cottonwood
NB-93 I Riparian Cottonwood
NB-94 A-S 1 Riparian Cottonwood
NB-95 A-U Riparian Valley oak
NB-96 A-S 1 Riparian Cottonwood
NB-97 I Tree row Eucalyptus
NB-98 A-S 1 Tree row Eucalyptus
NB-99 I Urban Ornamental pine
NB-100 I Riparian Walnut
NB-101 A-U Riparian Cottonwood
NB-102 I Riparian Cottonwood
NB-103 I Riparian Cottonwood
NB-104 A-S 1 Riparian Black locust
NB-105 A-F 0 Riparian Cottonwood
NB-106 I Roadside Cottonwood
NB-107 I Riparian Cottonwood
NB-108 A-F 0 Ornamental (freeway rest stop) Cottonwood
NB-109 A-X 0 Tree row Valley oak
NB-110 I Riparian Cottonwood
NB-111 I Tree Row Cottonwood
NB-112 I Riparian Valley oak
NB-113 I Riparian Cottonwood
NB-114 A-F 0 Channelized riparian/tree row Valley oak
NB-115 I Riparian Willow
NB-116 A-U Cottonwood grove Cottonwood
NB-117 I Riparian Cottonwood
NB-118 A-F 0 Tree row Valley oak
NB-119 A-U Channelized riparian/tree row Cottonwood
NB-120 A-F 0 Channelized riparian/tree row Valley oak
NB-121 A-S 1 Rural residential Walnut
NB-122 I Tree row Valley oak
NB-123 I Isolated tree Cottonwood
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Table 4-1 Continued

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April 2023

Territory Number Statusa Number of Young Nesting Habitat Nest Tree Speciesb NB-124 A-S 2 Riparian Valley oak
NB-125 A-S 1 Riparian Cottonwood
NB-126 I Riparian Cottonwood
NB-127 A-S 1 Riparian Oregon ash
NB-128 I Riparian Alder
NB-129 A-S 1 Roadside tree row Willow
NB-130 I Isolated tree Locust
NB-131 I Riparian Cottonwood
NB-132 A-S 2 Cottonwood grove Cottonwood
NB-133 I Isolated roadside tree Valley oak
NB-134 I Channelized riparian/tree row Valley oak
NB-135 A-F 0 Isolated roadside tree Sycamore
NB-136 A-U Cottonwood grove Cottonwood
NB-137 I Riparian Valley oak
NB-138 A-S 1 Tree row Valley oak
NB-139 A-X 0 Isolated roadside tree Eucalyptus
NB-140 A-X 0 Roadside tree row Redwood
NB-141 A-S 1 Riparian Cottonwood
NB-142 I Riparian Valley oak
NB-143 I Tree row Willow
NB-144 I Tree row Ornamental conifer
NB-145 A-S 1 Grove Cottonwood
NB-146 I Rural residential Eucalyptus
NB-147 I Riparian Willow
NB-148 A-F 0 Isolated roadside tree Willow
NB-149 A-S 1 Riparian Oregon ash
a A = active; I = inactive; NLE = no longer extant; S = successful; F = failed; X = did not nest; U = undetermined. b For territories designated as I or X, tree species shown reflects last active nest tree.

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Table 4-2. Reproductive Data for Active Swainson’s Hawk Territories in the NBHCP Area, 1999–2022 Year
Occupied
Territoriesb
Successful
Nests
Unsuccessful
Nests
Occupied
but Not
Nesting
Un-
confirmed
Nesting
Status
Number
Young
Reared to
Fledging
Number
Young per
Occupied
Territoryc
Number
Young per
Active
Nestc, d
Number
Young per
Successful
Nestc
1999a 15 14 1 0 0 25 1.67 1.67 1.79
2000a 18 10 4 4 0 20 1.11 1.43 2.00
2001 46 24 15 7 0 40 0.87 1.03 1.67
2002 43 24 11 7 1 38 0.90 1.09 1.58
2003 54 34 15 4 1 53 1.00 1.08 1.56
2004 59 39 12 4 4 54 0.98 1.06 1.38
2005 45 31 11 1 2 48 1.12 1.14 1.55
2006 45 32 9 4 0 48 1.07 1.17 1.50
2007 44 34 9 1 0 48 1.09 1.12 1.41
2008 51 42 8 1 0 64 1.25 1.28 1.52
2009 59 51 2 1 5 83 1.54 1.57 1.63
2010 52 42 4 3 3 70 1.43 1.52 1.67
2011 62 23 27 6 6 30 0.54 0.60 1.30
2012 65 42 14 3 6 59 1.00 1.05 1.40
2013 56 11 26 16 3 12 0.23 0.32 1.09
2014 59 34 11 7 7 39 0.75 0.87 1.15
2015 61 44 6 4 7 69 1.28 1.38 1.57
2016 56 43 3 6 4 63 1.21 1.37 1.47
2017 58 49 4 3 2 68 1.21 1.28 1.39
2018 69 48 9 5 7 70 1.13 1.23 1.46
2019 71 5 33 26 7 5 0.08 0.13 1.00
2020 70 50 8 3 9 54 0.89 0.93 1.08
2021 59 24 25 7 3 24 0.43 0.49 1.00
2022 69 35 14 8 12 40 0.70 0.81 1.14
a Years 1999 and 2000 do not include the Sacramento River territories. b An occupied territory is a nesting area that was occupied by a breeding pair of raptors throughout all or a significant portion of the breeding season. Includes successful nests, unsuccessful nests, pairs with unconfirmed nesting status, and pairs not nesting.
c Does not include pairs with unconfirmed nesting status. d Active nest = number of successful nests + number of unsuccessful nests.

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Table 4-3. Number of Active Territories on the Sacramento River, 2001–2022 River Side 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 West 14 12 12 20 11 14 8 8 8 12 11 11 11 10 12 13 15 20 19 18 11 16 East 13 12 20 18 13 15 12 21 23 15 17 20 14 19 17 13 14 13 13 13 16 19 Total 27 24 32 38 24 29 20 29 31 27 28 31 25 29 29 26 29 33 32 31 27 35

Table 4-4. Swainson’s Hawk Foraging Habitat in the NBHCP Area (acres), 2004–2022 Habitat Type 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Upland agriculture 8,251 7,566 6,462 7,919 8,293 11,692 13,863 15,100 14,019 12,096 11,601 11,771 11,890 11,089 11,782 10,488 8,837 8,784 8,396 Fallow lands 823 1,625 10,101 10,033 10,076 5,869 2,912 2,323 2,282 2,160 1,604 1,893 1,712 6,442 3,307 4,667 3,234 3,414 9,955 Grasslandsa 7,847 7,766 7,263 5,669 5,461 5,794 4,853 4,608 4,491 4,832 4,961 4,344 4,157 4,359 4,252 4,193 4,043 4,041 5,418 Total 16,921 16,957 23,826 23,621 23,830 23,355 21,628 22,031 20,792 19,088 18,166 18,007 17,759 21,890 19,341 19,348 16,114 16,239 23,769 a Grasslands include the grasslands (created), nonnative annual grassland, and ruderal land cover types.

Table 4-5. Extent and Proportion of Suitable Swainson’s Hawk Foraging Habitat on and off TNBC Reserve Lands, 2022 Alfalfa
Row, Grain, and Other
Hay Cropsa Grasslandsb Fallow Total
On-reserve acreage (acres) 437 873 290 1,674 3,532
On-reserve percentage of cover type (%) 12% 25% 8% 47%
Off-reserve acreage (acres) 695 8,396 5,418 9,955 23,769 Off-reserve percentage of cover type (%) 3% 35% 23% 42% Total
a Row, grain, and other hay crops includes the grass hay and irrigated grassland land cover type. b Grasslands include the grasslands (created), nonnative annual grassland, and ruderal land cover types.

Graphics … 662.17 NBC (3-9-2021) TG
FIGURE 4-1
Swainson’s Hawk
Central Valley Range
Swainson’s Hawk Territory
NBC 104332 (2-27-2023)
FIGURE 4-2
Swainson’s Hawk Range
Typical Swainson’s hawk nesting and foraging habitat
in the Central Valley
Typical Swainson’s hawk nest
NBC 104332 (2-27-2023)
FIGURE 4-3
Swainson’s Hawk Nesting and Foraging Habitat

MARCH APRIL MAY JUNE JUL Y AUGUST SEPTEMBER
Arrival,
courtship, nest
construction
Arrival,
courtship, nest
construction
Incubation
phase
Nesting phase
Fledging and
post-ﬂedging
dependency
Formation of
pre-migratory
groups
Departure
NBC 104332 (2-27-2023)
FIGURE 4-4
General Representation of Swainson’s Hawk
Breeding Cycle in the Central Valley
Swainson’s hawk nest with eggs
Nestling Swainson’s hawks
Nearly ﬂedged Swainson’s hawks
NBC 104332 (2-27-2023)
FIGURE 4-5
Swainson’s Hawk in the Nest
0 10
20 30
40 50
60 70
80 90
202221201918171615141312111009080706050403022001
Number Total Young Fledged
Successful Nests
Occupied Nesting Territories Occupied Nesting Territories NBC 104332 (2-28-2023)
FIGURE 4-6
Number of Occupied Swainson's Hawk Nesting Territories, Successful Nests, and Total Y oung Fledged in the Natomas Basin, 2001–2022
Number of Occupied Nesting Territories
y = 1.0655x - 2086.3
R2 = 0.6202
202221201918171615141312111009080706050403022001
0 10
20 30
40 50
60 70
80 NBC 104332 (2-28-2023)
FIGURE 4-7
Trends in the Number of Occupied Territories in the
Natomas Basin Nesting Population, 2001–2022

0.0 0.5

1.0 1.5

2.0 2.5
2022212019181716151413121110090807060504030201001999
Number
Young per Active Nest
Young per Occupied Territory
Young per Successful Nest Young per Successful Nest
NBC 104332 (2-28-2023)
FIGURE 4-8
Various Measures of Swainson's Hawk Reproductive
Success in the Natomas Basin, 1999–2022
y = -0.0277x + 57.092
R2 = 0.5943
2022212019181716151413121110090807060504030201001999

0.00 0.50

1.00 1.50

2.00 2.50
Number of Young Fledged per Successful Nest
NBC 104332 (2-28-2023)
FIGURE 4-9
Trends in the Number of Y oung Fledged per Successful Nest in the Breeding Population of Swainson's Hawk in the Natomas Basin, 1999–2022
0 5
10 15
20 25
30 35
40 202221201918171615141312111009080706050403022001
Number of Occupied Nesting Territories
East Side
West Side
Sacramento River Total Sacramento River Total
NBC 104332 (2-28-2023)
FIGURE 4-10
Number of Occupied Swainson's Hawk Nesting Territories
along the Sacramento River in the Natomas Basin, 2001–2022 0 5,000
10,000
15,000
20,000
25,000
202221201918171615141312111009080706052004
Acres
Upland Agriculture
Fallow Lands
Grasslands
Total Total
NBC 104332 (2-28-2023)
FIGURE 4-11
Changes in the Abundance of Three Categories of Swainson's Hawk Foraging Habitat in the Natomas Basin, 2004–2022

SACRAMENTO CO

SUTTER CO

PLACER CO SUTTER CO

SACRAMENTO CO

PLACER CO
YOLO CO.

SACRAMENTO CO.

SUTTER CO.

Biological Effectiveness Monitoring for the
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Chapter 5
Other Covered Wildlife Species

CHAPTER HIGHLIGHTS
⚫ Burrowing owls continue to use reserve lands in the winter, but nesting on reserve lands has not been documented since 2014. Maintenance and enhancement of California ground squirrel populations on reserve lands and provision of an experimental berm to provide nesting habitat on the Sills tract grassland are management actions most likely to contribute to the effectiveness of reserve lands in supporting the burrowing owl population in the Basin. ⚫ Loggerhead shrikes have declined throughout the Basin and now rarely occur, despite significant increases in potential habitat. Providing potential nesting habitat in areas with little to no disturbance and implementing management actions that could increase insect prey are likely to contribute to the effectiveness of reserve lands in supporting loggerhead shrikes in the Basin. ⚫ White-faced ibises continue to use reserve lands and non-reserve lands in the Basin extensively.

No additional management actions are warranted.
⚫ Pacific pond turtles now occur on most if not all reserve lands with a wetland component.

Population trends are challenging to determine due to the ubiquity of nonnative turtle species that also inhabit the Basin but are difficult to distinguish in the field. Investigating the proportion of native to nonnative turtles and the associated trends over time is recommended. ⚫ Reserve lands continue to provide critical habitats for a wide variety of species, including shorebirds, neotropical migrants, raptors, and waterfowl.

5.1 Introduction

5.1.1 Background
Other Covered Species are those species other than giant gartersnake and Swainson’s hawk that are addressed in the NBHCP and covered by its associated permits (Table 1-2). Monitoring efforts for Other Covered Species, like those for Swainson’s hawk and giant gartersnake, are designed to evaluate the progress of the NBHCP toward meeting the Plan’s goals and objectives for Covered Species and their habitats. Monitoring populations of Other Covered Species is accomplished using a variety of techniques, including a generalized avian survey on reserves. Two general types of monitoring were conducted to meet the NBHCP goals and objectives: monitoring on reserve lands and Basin-wide monitoring on non-reserve lands.

5.1.2 Goals and Objectives
The objectives of monitoring efforts on reserves are listed below. • Document the presence/absence and use of reserves by all wildlife species in general and Other Covered Species in particular.

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• Compare the relative success of Other Covered Species on and off reserves. • Evaluate the extent to which the NBHCP is meeting its objectives to provide open space to benefit all native wildlife species.

Secondary objectives of monitoring on reserve lands include providing information on the effects of management actions and monitoring populations of indicator species that may be useful in assessing the health of managed habitats.

Monitoring on non-reserve lands is limited to surveys for Other Covered Species. The objectives of this monitoring effort are listed below.
• Document the presence/absence of Other Covered Species within the Basin. • Compare the relative success of Other Covered Species on and off TNBC reserve lands.

5.2 Methods

5.2.1 Surveys on Reserves
Surveys for Other Covered Species include surveys for covered avian species and Pacific pond turtles. These surveys are conducted using a generalized avian monitoring protocol that is a modified area search (Ralph et al. 1993). The survey technique consists of slowly driving roads or walking trails and recording the numbers of each species (both Covered and non-Covered Species) seen or heard on each reserve tract. Areas of dense vegetation, linear tree rows, and areas inaccessible by vehicle are surveyed on foot using the area search technique to ensure complete coverage. The exact route and the time allotted for the survey is specific to each tract and is constrained to ensure consistency in effort and technique through time. The numbers of each bird species seen or heard during the search are recorded. Species observed outside each tract are not counted unless they are clearly associated with the tract in some way (e.g., swallows flying overhead hawking insects, or a raptor perched outside the tract and scanning the ground inside the tract, would be counted). The specific routes taken and time allotted for each tract are described in the Natomas Basin Habitat Conservation Plan Area Biological Effectiveness Monitoring Program (ICF Jones & Stokes 2009).

From 2005 through 2017, surveys were conducted once on each tract monthly. Beginning in 2018, the frequency of surveys was changed from one survey per month to two surveys per month from April through June and one survey per month in July and August. Surveys in September through November were dropped. Surveys from December through February were limited to reserves composed of rice fields and emergent wetland habitats (ICF 2017).

The tracts acquired in 2021 included the Willey, Verona, and Lauppe South tracts in the North Basin Reserve, and the Paulsen South, Elverta, and Richter tracts in the Central Basin Reserve. Surveys on the Willey, Paulsen South, and Richter tracts began in January 2021. Surveys on the Verona and Lauppe South tracts began in May 2021. Surveys on the Elverta tract began in January 2022. Surveys on the Lauppe North tract, which was acquired in January 2022, also began in January. Observations of Covered Species on non-reserve lands or outside of formal survey periods were recorded separately as incidental observations. Pacific pond turtle detections were recorded during avian The Natomas Basin Conservancy

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surveys, in particular along marsh shorelines with suitable basking habitat and other areas where turtles congregate to bask.

5.2.2 Non-Reserve Land Surveys
Surveys for Other Covered Species throughout the Basin on non-reserve lands are specifically designed to obtain maximum geographic coverage of the Basin and to ensure repeatability and consistency. These surveys were conducted monthly from 2005–2017. Since 2018, the survey effort has consisted of one survey per month from April through July.

The Basin is divided into three regions for the purposes of these surveys (Figure 5-1). The North Basin is the area between the Natomas Cross Canal and Elverta Road, the Central Basin is the area between Elverta Road and Del Paso Road, and the South Basin is the area between Del Paso Road and Garden Highway. A road transect has been established in each region. Each road transect covers 48–51 kilometers (30–32 miles) and is surveyed in approximately 1.5 hours. Survey times were assigned to road segments in each transect to minimize variation in effort. A single observer drives slowly (when possible) and scans the area for Other Covered Species, occasionally stopping at pullouts or backtracking where appropriate. Stops occur frequently to scan large fields for Other Covered Species, but the duration and number of stops are constrained by the time allotted for each segment and transect. Each survey route is depicted in Figure 5-1. Surveys in the South Basin reserve were discontinued at the end of 2017.

5.2.3 Analytical Methods
The average number of detections per survey (i.e., total number of individuals counted divided by the number of surveys) and the proportion of surveys in which at least one individual was counted are the two metrics or indices used to assess relative abundance between years, seasons, and reserves. Trends over time in the relative abundance were evaluated using simple linear regression.

5.3 Results
A complete list of all wildlife species detected on reserves since comprehensive monitoring began is provided in Appendix C-1. The numbers of each bird species detected by tract and reserve during surveys for Other Covered Species in 2022 are provided in Appendix C-2.

5.3.1 Generalized Avian Surveys
In 2022, 116 avian species were detected on reserves, compared to 123 in 2021, and 118 in 2020.

The number of species observed each monitoring year has ranged from a low of 114 in 2019 to a high of 139 in 2009. Two new species were detected on reserves in 2022. Two mountain plovers (Charadrius montanus) were detected in January on the Lucich South tract. One Phainopepla (Phainopepla nitens) was detected in January and two were detected in February on the Atkinson tract. Table 5-1 summarizes the total number of individuals and number of avian species recorded from 2020 through 2022 on each tract (by reserve) for selected taxonomic groups (raptors, waterfowl, neotropical migrants, and shorebirds) and all birds.

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5.3.1.1 Raptors
The raptor group consists of hawks and owls, a category of predatory birds that predominantly occupy the top of the food web and are generally less abundant than other groups, making them good indicators of ecosystem health. Although Swainson’s hawk and burrowing owl are the only two Covered Species that are raptors, 17 other raptor species have been recorded during avian surveys in the Basin since 2004.

Many raptors are migratory, changing the composition of the raptor community across seasons. For example, Swainson’s hawks occur in the Basin only during the breeding season, spending the winter in Central and South America, while large numbers of red-tailed hawks and other species move into the Basin from other areas during the winter.

Across all years and all seasons, red-tailed hawk continues to be the most abundant raptor on reserve lands, followed by northern harrier, American kestrel, red-shouldered hawk, and white- tailed kite. The annual average number of raptors detected per survey on reserve lands fluctuated from a high of 1.44 in 2009 to a low of 0.063 in 2019 and 2020 (Figure 5-2). The modest overall decline in raptor detections over the course of the monitoring period is no longer evident due to the increase in raptor detections in 2022 (R2=0.204, P=0.060). However, declines in the number of detections of northern harrier (R2=0.609, P<0.001) and American kestrel (R2=0.637, P<0.001) are still evident and statistically significant.

The largest mean numbers of raptors detected per survey across all years were observed on the BKS (0.335 raptor per survey) and Atkinson tracts (0.223 raptor per survey), followed by Lucich South (0.133 raptor per survey) and Lucich North (0.127 raptor per survey). Raptors are most abundant on reserves from October through February when large numbers of them come into the Central Valley to spend the winter.

5.3.1.2 Waterfowl
The waterfowl group—comprising geese, swans, and ducks—is an important aesthetic and sporting resource in the Basin. About 60% of the ducks and geese that migrate along the Pacific Flyway use the wetlands, flooded agricultural fields, and wildlife refuges in the Central Valley during winter. The waterfowl population wintering in the Central Valley comprises 20% of all waterfowl in North America (Heitmeyer et al. 1989). Because less than 10% of the wetlands that historically covered the Central Valley still exist today, this group is of high management concern in the region. Drought and the fallowing of rice fields in 2022 have enhanced that concern.

Across all years, greater white-fronted goose continues to be the most abundant species of waterfowl on reserve lands, followed by snow goose, mallard, northern shoveler, and pintail. The average number of waterfowl detected per survey on reserve lands exhibits a great deal of variation over the monitoring period, as would be expected for migratory species that occur in very large flocks (Figure 5-3). However, there is no evidence of a significant increase or decrease in waterfowl numbers as a group over the monitoring period (R2=0.112, P=0.175). Of the four most abundant species, only the mallard has exhibited a significant decline over the monitoring period (R2=0.702, P=0.001) (Figure 5-3).

The largest numbers of waterfowl averaged over the course of the monitoring period were found on the BKS tract, followed by Lucich South, Lucich North, and Bennett North. BKS and Lucich North are composed almost entirely of wetlands; the other tracts with high numbers of waterfowl are The Natomas Basin Conservancy

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composed of rice fields. Waterfowl numbers are highest from December through February when large numbers of geese and other waterfowl begin to arrive in the Central Valley to spend the winter.

5.3.1.3 Neotropical Migrants
Neotropical migrants are defined here as passerine (perching) birds (e.g., flycatchers, swallows, warblers) that breed in North America in the summer and migrate in fall to the Neotropics (southern United States, Mexico, Central America, and South America) to spend the winter.

Populations of neotropical migrants are generally declining, due in part to loss of habitats such as riparian woodlands in both their breeding and wintering ranges, as well as habitat loss along migration routes. The riparian woodlands on the western and northern edges of the Natomas Basin are an important resource for breeding and migrating neotropical migrants. This habitat type has recently increased substantially in the Basin as a result of mitigation associated with the NLIP. Many species such as kingbirds and swallows also make extensive use of the wetlands, grasslands, and agricultural habitats on reserve lands for foraging.

Across all years, cliff swallows continue to be the most abundant neotropical migrant on reserve lands, followed by barn swallows, tree swallows, and western kingbirds (Figure 5-4). As of 2022, there has been no significant increase or decrease in the numbers of neotropical migrant detections over the monitoring period (R2=0.014, P=0.645). Detections of neotropical migrants have been driven primarily by cliff swallows, which began nesting in large numbers under the carport on the BKS tracts in the Central Basin Reserve in 2012. In 2015, cliff swallows arrived on the BKS tract in April and May, but the colony collapsed and no young were fledged. The cliff swallow nesting colony did not return in 2016 or 2017, although large numbers of birds continue to congregate on the BKS tracts, possibly nesting in smaller groups throughout the tracts. In 2018, cliff swallows nested on both the BKS tracts and under the drainage canal between the AKT and Sharma SAFCA tracts. A similar pattern was repeated in 2019. In 2020, cliff swallows again nested in the culvert draining the SAFCA marshes into Fisherman’s Lake, but in small numbers, and were not detected nesting anywhere else on reserve lands. No nesting colonies of cliff swallows were detected in 2021 or 2022.

Although there has been no significant decrease in neotropical migrants as a whole, there have been significant declines in the numbers of detections of barn swallows and tree swallows over the monitoring period (R2=0.395, P<0.005 and R2=0.254, P=0.033, respectively), No significant declines are evident for either cliff swallows (R2=0.004, P=0.799) or western kingbirds (R2=0.071, P=0.286) (Figure 5-4).

5.3.1.4 Shorebirds
Shorebirds are a diverse taxonomic group that includes sandpipers, plovers, stilts, avocets, snipes, and phalaropes. They are closely associated with wetland areas; the majority of species migrate long distances between breeding and wintering areas. The shallow wetlands and flooded agricultural fields of the Central Valley constitute one of the most important foraging areas in western North America for migrating and wintering shorebirds (Shuford et al. 1998). The post-harvest rice fields and marsh complexes of TNBC’s reserve system provide important habitats for shorebirds during spring and fall migration. Management of these habitats can have a strong influence on the number of shorebirds stopping over in the Basin. Like waterfowl, shorebirds are a group of high management concern in the region.

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Some shorebird species have been documented breeding on reserve lands, including American avocet, black-necked stilt, and killdeer. These species tend to be most abundant during June through August, the period after young have fledged. Conversely, the non-resident shorebirds tend to be most abundant in winter.

Long-billed dowitcher, killdeer, dunlin, and least sandpipers are the most abundant shorebirds on reserve lands. Shorebird detections have decreased significantly over the monitoring period (R2=0.432, P=0.003). Long-billed dowitcher, killdeer, and dunlin all exhibit significant declines in the number of detections over the monitoring period (R2=0.269, P=0.027, R2=0.770, P<0.001, and R2=0.253, P=0.033, respectively), while least and western sandpiper numbers show no evidence of an increase or decrease over the monitoring period (R2=0.006, P=0.758) (Figure 5-5).

The largest numbers of shorebirds averaged over the course of the monitoring period are found on the BKS tract, followed by the Lucich South, Lucich North, and Nestor tracts.

5.3.1.5 Other Species and Observations of Interest
Yellow-billed magpie is endemic to California, and its range is restricted to the Central Valley, southern Coast Ranges, and Sierra Nevada foothills. Numbers of this species have declined rapidly in the Central Valley in association with the introduction and spread of West Nile virus, first detected in this species in 2004 (Ernest et al. 2010). Yellow-billed magpie appears to be more susceptible to West Nile virus than most species (Wheeler et al. 2009), and the impacts of West Nile virus on avian populations is of increasing concern because populations of many species have not recovered after initial contact with the disease, contrary to predictions (George et al. 2015).

The mean number of detections per survey has declined drastically and significantly over the monitoring period (R2=0.809, P<0.001). With the exception of a slight increase in 2021, the number of detections has continued to decline to values significantly below the levels detected prior to the West Nile virus epidemic (Figure 5-6). Although yellow-billed magpies have been detected on most reserve tracts over the monitoring period, they began to disappear from tracts that did not contain nesting habitat after 2008. Not surprisingly, this species is most common on tracts with significant woodlands such as Alleghany 50, Atkinson, BKS, and Huffman West. However, even on these tracts, there has been a significant decline in the number of detections per survey over the monitoring period (R2=0.562, P<0.001).

The distribution and abundance of the Canada geese has been increasing in the United States for several decades. Populations in some areas have grown substantially, so much so that they are considered pests for their droppings, bacteria in their droppings, noise, and damage they do to some grasslands.

Although California is outside the historical breeding range of Canada geese, numerous resident populations have become established. Because they are herbivorous, they can present management problems in natural landscapes where the management goal is establishment of native grasses.

There has been a significant increase in the numbers of Canada geese detected on reserves during the monitoring period (R2=0.824, P<0.001), although the numbers appear to have stabilized since 2018 (Figure 5-6). Canada geese now regularly nest on several reserve tracts, including the BKS, Lucich North, Lucich South, Frazer, Bennett North, and Bennet South tracts.

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5.3.2 Other Covered Species
Of the 20 Other Covered Species, five have been detected in the Basin: white-faced ibis, loggerhead shrike, tricolored blackbird, burrowing owl, and Pacific pond turtle. Although suitable foraging habitat for Aleutian cackling goose (formerly Aleutian Canada goose) is present, this species has not been detected in the Basin since comprehensive monitoring began in 2004. Suitable nesting habitat for bank swallow is not present in the Basin. Suitable habitat for the vernal pool species—vernal pool fairy shrimp, mid-valley fairy shrimp, vernal pool tadpole shrimp, California tiger salamander, and western spadefoot—has not been reported in the Basin except for the 11 vernal pools (1 acre) created on the BKS tract and a few potentially suitable wetlands on private property along the extreme eastern edge of the Basin. To date, no evidence of occupancy of the 11 pools at BKS by any Covered Species has been observed. Several blue elderberry shrubs, the host plant for valley elderberry longhorn beetle, have been documented in the Basin, but the beetle itself has not been found there and no surveys have been conducted. None of the covered plant species have been detected in the Basin (see Chapter 2, Land Cover Mapping, Botanical Inventory, and Noxious Weed Monitoring). Several Sanford’s arrowhead (Sagittaria sanfordii) plants were transplanted to the BKS tract in 2021 but did not survive.

All five Other Covered Species known to occur in the Basin have been documented on reserves, and all have been documented or are suspected of breeding on reserves at some point since comprehensive monitoring began (Tables 5-2 and 5-3). Pacific pond turtles of varying size are now routinely documented on reserves, and thus breeding on reserves is almost certain.

The average number of individuals detected per survey of avian Other Covered Species recorded during surveys on reserves is summarized in Table 5-3. The average numbers of avian Other Covered Species detected per survey during non-reserve land surveys are summarized in Table 5-4.

5.3.2.1 Loggerhead Shrike
Loggerhead shrike has been a year-round resident in the Natomas Basin and has been detected throughout the year (Figure 5-7). The mean number of detections per survey on reserve lands has been cyclic over the course of the monitoring period, peaking in 2009 and 2012, followed by a substantial decline after 2013 (Table 5-3, Figure 5-7). Shrike detections have remained low since 2014 and declined to zero in 2022. The decline in shrike detections on reserve lands over the monitoring period have been significant (R2=0.272, P=0.032).

In 2020, a single shrike was detected twice on the Atkinson tract of the Central Basin Reserve on the south side adjacent to the buffer lands surrounding SMF. A single shrike was also identified once on the adjacent Ruby Ranch tract in 2021. No shrikes were detected on reserve lands in 2022, and none have been detected during Basin-wide surveys in since 2017.

The decline in the shrike population in the Basin is more pronounced on non-reserve lands. Both the mean number of loggerhead shrikes detected per survey on non-reserve lands and the proportion of surveys with shrike detections have declined significantly over the course of the monitoring period (R2=0.831, P<0.001 and R2=0.907, P<0.001, respectively; Table 5-4; Figure 5-7).

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5.3.2.2 White-Faced Ibis
White-faced ibis was regularly detected in small numbers on reserve lands from June through September when comprehensive monitoring began in 2005. However, from 2007 through 2010 white-faced ibis established a large nesting colony on the BKS tract in the Central Basin Reserve (Table 5-2). In 2011, the BKS nesting colony was abandoned and ibis did not nest in the Basin. In 2012, a new nesting colony was established on the Willey Wetlands Preserve, a wetland constructed and owned by SCAS as mitigation for the loss of wetlands associated with airport expansion. The Willey Wetlands Preserve nesting colony was active again in 2013, and ibis from this colony foraged extensively in the rice fields of the adjacent Lucich South and Bennett South tracts. This nesting colony was active again in 2021, with 400 to 600 nesting pairs. White-faced ibis did not nest in the Basin in 2022.

Over the monitoring period, white-faced ibis typically occur in very low numbers outside the breeding season and move into the Basin in large numbers from May through September (Figure 5- 8).

Neither the mean number of ibis detected per survey or the proportion of surveys on which ibis were detected on reserve lands exhibits a significant increase or decrease over the monitoring period. The mean number of ibis detected per survey has remained relatively volatile over the monitoring period, and 2022 was no exception, with detections dropping significantly after a substantial increase in 2021. Conversely, the proportion of surveys in which white-faced ibis are detected has remained relatively constant (Table 5-3, Figure 5-8).

There appears to be a slight increase in the mean number of white-faced ibis detected per survey on non-reserve lands, although it is not statistically significant (R2=0.198, P=0.064), and the proportion of surveys on which ibis was detected exhibits a significant increase over the monitoring period (R2=0.503, P<0.001) (Figure 5-8).

5.3.2.3 Tricolored Blackbird
Tricolored blackbirds are detected in the Basin throughout the year (Figure 5-9), although numbers are impossible to estimate outside the breeding season when they primarily occur in large, mixed- species flocks. During the breeding season, tricolored blackbirds occur in single-species flocks that are more detectable, even when they are not breeding.

Nesting tricolored blackbirds were first documented nesting in the Basin in 2005 on the BKS tract in a small patch of Himalayan blackberry. The species nested in this same spot in 2007, and a second colony was documented in 2007 in a large patch of Himalayan blackberry along the north edge of the Basin on private property. In 2008, the BKS colony moved to the marshes, while the colony along the north edge of the Basin moved to the marshes on the Frazer tract. Tricolored blackbirds continued nesting on the BKS tract through 2010 (Table 5-2). In 2011, a new colony was established on the Willey Wetlands Preserve. In 2012, no tricolored blackbirds nested in the Basin for the first time since 2006. In 2013, tricolored blackbirds began to establish a nesting colony on the Willey Wetlands Preserve but subsequently abandoned the nesting attempt. In 2020, tricolored blackbirds again nested on the Willey Wetlands Preserve adjacent to the Lucich South tract in the North Basin Preserve. Tricolored blackbirds have not nested in the Basin since 2020.

Tricolored blackbirds have historically occurred in the Basin throughout the year, although the numbers detected show a marked increase in May through August (Figure 5-9). However, in the last The Natomas Basin Conservancy

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several years, there have been fewer detections of tricolored blackbirds outside the breeding season.

The mean number of tricolored blackbirds detected per survey on reserve lands exhibits a significant decrease over the monitoring period, primarily due to the presence of nesting colonies on the BKS and Frazer tracts in 2005, 2007, 2008, and 2009 (R2=0.308, P=0.017), while the proportion of surveys on which tricolored blackbirds were detected on reserve lands does not exhibit any significant increase or decrease over time (R2=0.001, P=0.948) (Figure 5-9).

Conversely, the mean number of tricolored blackbirds detected per survey on non-reserve lands exhibits no significant increase or decrease over time (Figure 5-9), while the proportion of surveys on which tricolored blackbirds were detected on non-reserve lands has increased significantly over the monitoring period (R2=0.424, P=0.005) (Figure 5-9), primarily due to the establishment of a new nesting colony on the airport mitigation lands.

5.3.2.4 Western Burrowing Owl
Burrowing owls are known to breed and winter in low densities in the Basin, and are regularly detected throughout the year (Figure 5-10). A single pair resided at the BKS tract in 2004 and 2005 but disappeared after one member of the pair was found dead in 2006, apparently killed by a great horned owl. No burrowing owls have subsequently been detected on the BKS tract (Table 5-2).

In 2008, a pair of owls nested in a ground squirrel burrow in the northeastern corner of the Elsie tract along the Highline Canal that separates the Elsie and Tufts tracts in the Central Basin Reserve.

In 2009, three pairs of owls nested in this area. In 2010, a nesting pair was documented on both the Elsie and Tufts tracts, and each produced at least three young. A single owl was observed during the breeding season on the Sills tract and on one survey was observed to be paired, although no evidence of nesting was subsequently observed. In 2011, there were three pairs documented on the Elsie and Tufts tracts, but no evidence of breeding was observed. In 2012, the pair on the Elsie tract produced a single fledgling, and the Tufts tract contained a single owl. Single owls were observed once in November on the Bolen West tract and the Sills tract. Breeding owls were absent from reserve lands in 2013. The pairs from the Elsie and Tufts tracts abandoned the site after October 2012. Owls returned to the Elsie and Tufts tracts in August 2013, although they subsequently moved to new locations on these tracts. In 2014, a pair was observed on the Tufts tract in a new location during March and April but subsequently disappeared and was not observed again until October. In 2015, a single owl was detected once on the Tufts tract in January. In 2016, a single owl was detected once on the Tufts tract in February. Owls were not detected again until November, when a single owl was detected on the Elsie and Tufts tracts, and again in December on the Elsie tract. No breeding owls were detected on reserve lands in 2016. In 2017, a single owl was detected on the Tufts tract in May but was not detected again until October. No other owls were detected on reserve lands in 2017. In 2018, a pair was detected in February on the Tufts tract, but no owls were detected again until December, when three owls were detected on the Elsie and Tufts tracts. A similar pattern was observed in 2019, when owls were detected on the Elsie, Tufts, and Sills tracts in January, February, and December, with only a single siting in May on the Tufts tract. In 2020, burrowing owls were detected on the Elsie, Tufts, and Nestor tracts in January. Owls were detected on the Elsie tract in February and March as well, but no owls were detected after May on reserve lands in 2020.

In 2021, owls were detected on the Tufts tract in January and February but were not detected again on reserve lands until December, when a single owl was detected on the Elsie tract. In 2022, a single The Natomas Basin Conservancy

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owl was detected once in December on the Elsie tract. Nesting does not appear to be occurring on reserve tracts any longer, although wintering birds still use the area regularly.

Three burrowing owl colonies have been documented in the Basin on non-reserve lands. The largest occupied the tree planters in the parking lot of Sleep Train Arena (formerly Arco Arena). Six pairs were observed in this colony in April 2012. At least three of these pairs produced two, three, and five fledglings by June. In 2013, four pairs were present from May through July with at least one pair producing young. However, in August a large recreational vehicle show created a great deal of disturbance near the nesting colony, and only a single pair was observed until December, when five individuals were detected. In 2014, there was one pair and a single bird. The pair eventually fledged two young. In September, a large number of recreational vehicles were parked in the part of the parking lot where the burrowing owls reside, creating a large disturbance that lasted for at least a month. A single owl was observed each month for the remainder of the year. In 2015, a single bird was detected in February, July, August, November, and December. In 2016, the colony at Sleep Train Arena consisted of a single owl that was detected in nine of the 12 surveys throughout the year. In 2017, a single bird was detected in January, but no owls were subsequently detected. Use of the area once occupied by the owls for parking large recreational and commercial trucking vehicles has resulted in a level of disturbance that is apparently too great for the owls to tolerate. No owls were detected at this colony in 2018 and monitoring in the southern part of the Basin was abandoned in 2019. The demolition of Sleep Train Arena was initiated in August 2022 and completed in October of that year.

The second colony occurs near the eastern edge of the Basin just north of Del Paso Boulevard near Aimwell Road along a dirt road bordering an agricultural field. Two pairs produced four young in this colony in 2010. In 2011, three pairs were observed in April. However, by June there were only two pairs remaining and a maximum of three juveniles were observed at any one time. In 2012, three pairs occupied the site that fledged a minimum of one, two, and four juveniles. In 2013, four pairs occupied the site but only two fledged young were confirmed. In 2014, up to 11 birds were observed on the site, constituting at least three pairs. The maximum number of fledglings detected at one time was three, although the actual number is probably much higher. In October, the field on the north side of the berm was plowed and the berm itself was “fixed,” resulting in the collapse of most of the burrows that had been occupied by the burrowing owls in the colony. A single bird was observed on the site through the rest of 2014. That number increased to two pairs by April 2015. A maximum of 11 individuals were observed in May 2015, probably representing two breeding pairs and seven fledged juveniles. For the remainder of the year, the number of individuals detected ranged from one to three. In 2016, no more than two adults were observed throughout most of the year, with the exception of the September survey, when six birds were observed, indicating a single pair that successfully fledged four young. In 2017, three owls were detected in this colony in January. Subsequently, the area around the dirt road where the owl colony occurred was allowed to become completely overgrown with 3-foot-tall grasses and 6-foot-tall thistle (Cirsium spp.), rendering the habitat largely unsuitable for occupation by burrowing owls. As a result, only a single owl was detected in this colony through the remainder of the year. No owls were detected at this site in 2018 and monitoring of the southern part of the Basin was abandoned in 2019.

The third colony occurs just north of Elkhorn Boulevard near the eastern edge of the Basin in an elevated area between two agricultural fields that historically contained several buildings that have since been removed. Two pairs occupied this site in 2011 and fledged at least six young. In 2012, at least four pairs occupied the site and produced at least eight fledglings. In 2013, at least four pairs The Natomas Basin Conservancy

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occupied the site and produced a minimum of five young. However, by the end of the year only a single owl occupied the site. In 2014, at least three pairs occupied the site and produced a minimum of three young. By the end of June, the site had become so overgrown that it was no longer suitable burrowing owl habitat. However, owls continued to occupy the site through August, after which owls were no longer detected. In 2015, a single pair occupied the site and fledged two young. In 2016, a single pair was observed in June, and a single fledgling was observed in August. Similarly, in 2017 a single pair fledged two young. In 2018, there was a single pair that probably fledged one young. No owls were observed at this site in 2019 or 2020.

Four owls were observed on private property on the north side of Elkhorn Boulevard directly across the street from the old Elkhorn Boulevard colony in 2018. A single owl was detected in June 2019, and one adult and three fledglings were observed in 2020. In 2021, a single pair was detected that fledged at least one young, and in 2022, a single owl was detected in May and again in July.

Burrowing owl use of other locations in the Basin has been documented over the years. A nesting pair was discovered in 2012 nesting at the base of the Steelhead Creek levee just north of the BKS tract. This pair successfully fledged at least two young but have not returned to the site over the last 4 years. Burrowing owls were also detected in a Natomas development just south of Del Paso Road in 2015, and on the east side of the Elverta Road overpass during construction in 2012. A single bird occupied the storm drain in the northeast corner of Del Paso and El Centro Road for a few months, and a breeding pair occupied the SR 99 off-ramp at Elkhorn Boulevard in 2011.

Neither the mean number of burrowing owls detected per survey nor the proportion of surveys on which owls were detected on reserve lands exhibit a statistically significant increase or decrease over the monitoring period (R2=0.170, P=0.089 and R2=0.183, P=0.077, respectively) (Table 5-3, Figure 5-10).

Similarly, neither the mean number of burrowing owls detected per survey nor the proportion of surveys on which owls were detected exhibits a statistically significant increase or decrease over the monitoring period (R2=0.043, P=0.407 and R2=0.005, P=0.788, respectively) (Table 5-4, Figure 5- 10).

It is clear that burrowing owls are occupying fewer places in the Basin and are no longer resident in some areas where they historically have been, both on and off reserve lands.

5.3.2.5 Pacific Pond Turtle
Pacific pond turtles were known to occur in several areas of the Basin prior to the onset of comprehensive monitoring in 2005, including Fisherman’s Lake and near the Prichard Lake and Elkhorn pumping stations. Red-eared sliders, a naturalized but nonnative species that superficially resembles Pacific pond turtle, can be difficult to distinguish from Pacific pond turtles before they slip into the water and disappear. Since 2013, large adult Pacific pond turtles have been observed regularly in Fisherman’s Lake adjacent to the Rosa and Natomas Farms tracts during the summer months. Pacific pond turtles have also been documented on the Cummings, Natomas Farms, and Rosa Central tracts of the Fisherman’s Lake Reserve, the BKS and Sills tracts of the Central Basin Reserve, and the Lucich North, Lucich South, Bennet North, Bennet South, and Frazer tracts of the North Basin Reserve.

Both the mean number of pond turtles and unidentified turtles detected per survey and the proportion of surveys on which pond turtles were detected on reserve lands exhibit a significant The Natomas Basin Conservancy

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increase over the monitoring period (R2=0.766, P<0.001 and R2=0.865, P<0.001), respectively) (Table 5-3, Figure 5-11). It should be noted that small events can strongly influence these results, such as when a tree fell across one of the marshes on the BKS tract and was subsequently used extensively for basking by turtles, which greatly increased the probability of detecting them. In most years during the monitoring period, pond turtles have rarely been detected on non-reserve land surveys, with detections confined to the Del Paso Road crossing of Fisherman’s Lake and sighting of a large female on Metro Air Parkway.

The number of unidentified turtles detected on surveys is increasing. Due to the difficulty in determining species when turtles of all species dive at the first sign of disturbance, it is impossible to tell if the increase is due to an increasing number of Pacific pond turtles or if the increase is due to increased numbers of nonnative turtles.

5.4 Discussion
TNBC reserves provide important wildlife habitats in the Central Valley. On average, 125 species of birds are recorded on reserves each year—most of which are typical of the Central Valley and are associated with open agricultural habitats, aquatic habitats, and oak woodlands. Diversity is lowest on small tracts dedicated to rice or upland agriculture and slightly higher on tracts with row crops where remnant patches of riparian scrub or valley oak woodland occur. Higher diversity is found on tracts with a managed marsh component and on tracts with a diversity of habitat types. Diversity is highest on the BKS tract, where managed marsh, annual grassland, and riparian scrub occur in close association over a large area. Monitoring results to date clearly indicate that TNBC reserves meet the objective outlined in the NBHCP to provide open space to benefit wildlife species.

The number of loggerhead shrike detections has been declining on reserves since 2012, and the situation on non-reserve lands is worse, with the number of detections on Basin-wide surveys remaining at zero for the sixth year in row. The seasonal pattern in loggerhead shrike detections indicates that little reproduction has occurred in the Basin over the past several years.

Despite trends in the numbers of shrike detections, habitat for shrikes has been expanding. The creation of extensive grasslands adjacent to the stands of oak woodland along the western side of the Basin as mitigation for the NLIP, along with the establishment of additional riparian and wetland habitats in this area should prove beneficial to shrike populations in the Basin. However, the effects of the extended and severe drought may be adversely affecting shrike populations and delaying colonization of these new habitats. Another hypothesis concerns declines in insect prey upon which shrikes depend, which has been bolstered recently by studies in Europe showing dramatic declines in insect abundance even in wilderness areas (Hallmann et al. 2017).

The white-faced ibis population has been generally increasing in the Basin since comprehensive monitoring began in 2005. Prior to establishment of the nesting colony on the BKS tract in 2007, ibis were known to nest in only a few scattered locations in the Central Valley (Ryder and Manry 1994).

Ibis now appear to nest in the Basin intermittently, and the pattern of detections indicates that they continue to make greater use of the habitats in the Basin than they did in the period prior to the establishment of a nesting colony. In fact, ibis are now regularly using the rice fields and marshes for foraging.

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Assessment of the health and trends in the tricolored blackbird population in the Basin is difficult because these birds are itinerant breeders that often change nesting locations and frequently fail to breed (Beedy and Hamilton 1999). Tricolored blackbirds occur in mixed-species flocks in the Basin throughout the winter, so it is unknown if new birds come into the Basin during the breeding season or if the existing birds simply flock together and become more detectable beginning in late May.

Tricolored blackbird populations have experienced significant declines throughout their range and were listed as threatened under the CESA and are currently being considered for listing under the federal ESA. Despite the volatility in detections of tricolored blackbirds in the Basin, the created marsh habitats on TNBC reserves and elsewhere have undoubtedly contributed to the conservation of the species.

Prior to the establishment of TNBC’s reserve system, nesting habitat for tricolored blackbirds was extremely limited in the Basin. Although there has been an expansion of nesting habitat as a result of establishment of the TNBC reserve system, it is possible that nesting habitat is not the limiting factor for this species in the Basin, but rather a lack of appropriate foraging habitat and/or insect prey.

Tricolored blackbirds continue to use habitats on both reserve and non-reserve lands each year, even when breeding does not occur.

The mean number of burrowing owls detected per survey on reserve lands has remained at the same low level that began in 2015 after birds occupying the Elsie and Tufts tracts abandoned their nesting burrows (but continued to occupy these burrows in the winter time). The number of available burrows in this area is limited, and it might be expected that abandonment of some of these burrows—at least temporarily—would be necessary after so many years of use. The Highline Canal, where burrows occupied by the owls occur, is both higher and wider than other levees in the Basin with less extensive vegetation, perhaps due to higher compaction. Although these conditions are relatively rare in the Basin, the limited number of observations of owls in rice growing portions of the Basin suggest that raising and widening berms along the larger drainage canals may provide additional burrowing owl habitat.

The mean number of burrowing owls detected per survey at the three breeding colonies on non- reserve lands have all been declining over the last few years, and all three have now been completely abandoned, although a single nesting pair occurs across the street from the Elkhorn colony. Habitat suitability at Sleep Train Arena colony site declined drastically due to increased disturbance in the area where owls were historically most abundant. Habitat values at the Elkhorn Boulevard colony has probably also declined due to excessive vegetation growth and accumulation of tumbleweeds. Although the tumbleweeds were partially removed in 2017, owl numbers have not rebounded. Finally, the owl colony at the end of Aimwell Road also suffered from a major disturbance when the road separating two fields underwent maintenance that resulted in the collapse of nearly all the burrows, followed by a lack of maintenance the following year that allowed the road to become overgrown with vegetation.

Pacific pond turtle detections on reserve lands have continued to increase and it is now clear that they occupy and breed within most, if not all, of the TNBC marsh complexes. The creation and management of marsh habitats by TNBC have provided substantial benefits for Pacific pond turtle populations.

No valley elderberry longhorn beetles or evidence of occupancy of shrubs in the Basin were observed, nor were any new shrubs found. Suitable riparian habitats are generally limited to the north, west, and south Basin margins along the Sacramento River and the Natomas Cross Canal.

The Natomas Basin Conservancy

Other Covered Wildlife Species

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
5-14
April 2023

Habitats for Other Covered Species associated with vernal pools (e.g., vernal pool invertebrates, western spadefoot, and California tiger salamander) are generally lacking in the Basin. There have been no detections of vernal pool Covered Species in the vernal pools created on the BKS tract. No vernal pool associated species have been detected and little habitat capable of supporting them has been reported since implementation of the NBHCP began.

5.5 Effectiveness
Biological effectiveness as it pertains to Other Covered Species is measured primarily on the basis of land management activities that promote the development and enhancement of habitats for these species and the response of populations to these management actions.

White-faced ibis, tricolored blackbird, western burrowing owl, Pacific pond turtle, and loggerhead shrike have all been documented using reserve lands within the Basin. The first nesting of ibis and tricolored blackbirds in the Basin occurred on reserve lands. The persistence of burrowing owls along the Highline Canal between the Elsie and Tufts tracts of the Central Basin Reserve has resulted from careful avoidance of significant disturbance to these sites by maintenance crews maintaining the canal levee. It is clear that the establishment and management of habitats by TNBC have provided substantial conservation benefits to these species. However, declines in populations of these species, all of which are dependent to some extent on the abundance of larger insect prey, indicate that additional management actions are warranted.

5.6 Recommendations
Burrowing owl populations in the Basin have likely always been small. Efforts to protect crops and levee roads in agricultural areas have typically included intensive ground squirrel control, further reducing potential habitat for this species. TNBC should consider the following actions to augment burrowing owl populations on reserves.
• Limit the use of insecticides to the maximum extent practicable on all reserve lands to allow insect prey populations to recover.
• Allow natural colonization of new habitats by California ground squirrels in suitable upland habitats, or consider translocation of ground squirrels to suitable sites. • Look for opportunities to create burrowing owl nesting habitat by creating raised earthen berms in grassland habitat away from trees and power poles where California ground squirrels can occur without substantially interfering with crop production or levee safety. • Consider maintaining an unplowed/unfarmed (but mowed or grazed as necessary) strip of land on upland agricultural fields away from trees and power poles, above grade where possible, to provide potential burrowing owl nesting habitat.
• Allow development projects where burrowing owls occur to actively relocate their burrowing owls onto TNBC reserves, using nest boxes where appropriate.

Tricolored blackbird nesting colonies have become established in managed marsh habitats at the BKS and Frazer tracts, and these habitats constitute an extremely rare and important resource for this species. However, it is possible that foraging habitat and adequate prey resources at the right The Natomas Basin Conservancy

Other Covered Wildlife Species

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
5-15
April 2023

time of year—rather than nesting habitat—is the limiting factor for this species in the Basin. TNBC should consider the following actions to provide additional resources for the nesting tricolored blackbird population in the Basin. Many of these recommendations would also improve conditions for loggerhead shrike.
• Continue to manage some created marsh habitats to further promote the development of dense tule stands. This action will also benefit white-faced ibis. • To the extent possible, conduct necessary management activities (i.e., grazing, mowing, weed spraying, etc.) outside the breeding season (May through August) to minimize disturbance and human presence and the potential for nest disturbance, destruction, or abandonment. • Conduct channel clearing and marsh maintenance activities in a way that maintains the vegetation and vegetation structure used by nesting white-faced ibis and tricolored blackbird to the maximum extent possible.
• Attempt to create and maintain, where appropriate, irrigated pasture, open grasslands, and alfalfa for foraging tricolored blackbirds that minimizes the use of insecticides that would reduce insect prey populations.
• Limit the use of insecticides to the maximum extent practicable on all reserve lands to allow insect prey populations to recover.

The Natomas Basin Conservancy

Other Covered Wildlife Species

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
5-16
April 2023

5.7 References
Beedy, E. C., and W. J. Hamilton III. 1999. Tricolored Blackbird. In The Birds of North America, No. 423 (A. Poole and F. Gill, editors). Philadelphia, PA: The Academy of Natural Sciences and Washington, DC: The American Ornithologists’ Union.

Ernest, H. B., L. W. Woods, and B. R. Hoar. 2010. Pathology Associated with West Nile Virus Infections in the Yellow-Billed Magpie (Pica Nutalli): A California endemic bird. Journal of Wildlife Diseases 46(2):401–408.

George, T. L., R. J. Harrigan, J. A. LaManna, D. F. DeSante, J. F. Saracco, and T. Smith. 2015. Persistent Impacts of West Nile virus on North American bird populations. Proceedings of the National Academy of Sciences of the United States of America 112(46):14290–14294.

Hallmann C. A., M. Sorg, J. E. Ongejans, H. Siepel, N. Hofland, and H. Schwan. 2017. More than 75 Percent Decline over 27 Years in Total Flying Insect Biomass in Protected Areas. PLoS ONE 12(10): e0185809. https://doi.org/10.1371/journal.pone.0185809 Heitmeyer, M. E., D. P. Connelly, and R. L. Pederson. 1989. The Central, Imperial, and Coachella Valleys of California. Pages 475–505 in Habitat Management for Migrating and Wintering Waterfowl in North America (L. M. Smith, R. L. Pederson, and R. M. Kiminski, editors). Lubbock, TX: Texas Technical University Press.

ICF. 2017. Natomas Basin Habitat Conservation Plan Biological Effectiveness Monitoring Program.

Draft. July. (ICF 00486.15.) Sacramento, CA. Prepared for The Natomas Basin Conservancy, Sacramento, CA.

ICF Jones & Stokes. 2009. Natomas Basin Habitat Conservation Plan Area Biological Effectiveness Monitoring Program. October. (ICF J&S 00164.07.). Sacramento, CA. Prepared for the Natomas Basin Conservancy, Sacramento, CA.

Ralph, C. J., G. R. Geupel, P. Pyle, T. E. Martin, and D. F. DeSante. 1993. Handbook of Field Methods for Monitoring Landbirds. General Technical Report PSW-GTR-144. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture.

Ryder, R. A., and D. E. Manry. 1994. White-faced Ibis. In The Birds of North America, No. 130 (A. Poole and F. Gill, editors). Philadelphia, PA: The Academy of Natural Sciences and Washington, DC: The American Ornithologists’ Union.

Shuford, D. W., G. W. Page, and J. E. Kelmyr. 1998. Patterns and Dynamics of Shorebird Use of California’s Central Valley. Condor 100:227–244.

Wheeler, S., C. M. Barker, Y. Fang, M. V. Armijos, B. D. Carroll, S. Husted, W. O. Johnson, and W. K.

Reisen. 2009. Differential Impact of West Nile Virus on California Birds. Condor 111 (1):1–20.

The Natomas Basin Conservancy

Other Covered Wildlife Species

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
5-17
April 2023

Table 5-1. Summary of Results of Monthly Avian Surveys by Reserve and Tract,a 2020–2022 Reserve
Waterfowl Raptors Neotropical Migrants Shorebirds All Bird Species 2020 2021 2022 2020 2021 2022 2020 2021 2022 2020 2021 2022 2020 2021 2022 North Basin Reserve
Atkinson - (-) 179 (4) 73 (3) 52 (9) 41 (8) 42 (6) 158 (9) 116 (9) 136 (9) 2 (1) 6 (2) 8 (2) 1,881 (56) 2,405 (65) 1,609 (59) Bennett North 2,601 (17) 3,414 (12) 748 (11) 17 (5) 29 (6) 8 (4) 23 (4) 15 (3) 47 (3) 103 (2) 8 (2) 20 (1) 4,284 (50) 5,087 (41) 1,550 (38) Bennett South 133 (6) 627 (4) 33 (8) 17 (6) 28 (7) 14 (6) 18 (3) 16 (5) 20 (4) 177 (6) 34 (4) 4 (1) 5,302 (42) 3,702 (42) 4,846 (35) Bolen North 390 (3) 2,483 (3) 12 (1) 6 (2) 5 (2) 8 (3) 1 (1) 2 (1) 1 (1) 111 (4) 48 (3) 9 (2) 1,118 (22) 3,793 (24) 744 (23) Bolen Southb - (-) - (-) - (-) 6 (3) 5 (2) 6 (2) 49 (3) 55 (4) 45 (5) - (-) - (-) - (-) 323 (25) 1,911 (26) 408 (29) Bolen West 21 (2) 676 (5) - (-) 11 (3) 7 (4) 8 (4) 11 (3) 11 (3) 16 (2) 8 (3) 413 (4) - (-) 732 (24) 5,092 (37) 348 (15) Frazer 1,720 (11) 1,078 (9) 548 (11) 8 (4) 9 (4) 9 (3) 64 (4) 8 (1) 22 (3) 22 (2) 15 (1) 20 (2) 3,145 (44) 2,669 (38) 1,865 (40) Huffman East 43 (2) 173 (3) 16 (1) 12 (5) 13 (4) 5 (4) 4 (2) 4 (2) 3 (2) 516 (6) 8 (2) 14 (1) 1,893 (31) 2,341 (24) 1,737 (28) Huffman Westb - (-) - (-) - (-) 35 (3) 25 (5) 12 (4) 20 (3) 32 (4) 25 (5) 22 (2) 13 (2) 8 (1) 897 (24) 1,163 (28) 590 (24) Lauppe North n/a n/a - (-) n/a n/a 15 (5) n/a n/a 15 (2) n/a n/a 44 (3) n/a n/a 1,842 (29) Lauppe South n/a 2 (1) 128 (3) n/a 1 (1) 3 (3) n/a 12 (4) 17 (4) n/a 61 (2) 156 (4) n/a 399 (25) 1,195 (28) Lucich North 5,948 (15) 2,608 (17) 1,338 (19) 21 (6) 26 (5) 15 (5) 51 (3) 32 (3) 46 (4) 159 (4) 429 (4) 180 (5) 12,645 (56) 6,010 (55) 2,542 (52) Lucich South 1,401 (9) 5,630 (13) 265 (6) 30 (5) 32 (7) 22 (4) 4 (3) 2 (1) 12 (2) 370 (7) 99 (7) 158 (4) 6,413 (48) 8,055 (49) 11,463 (41) Nestor 20 (4) 30 (3) 2 (1) 20 (6) 9 (2) 13 (4) 10 (4) 3 (2) - (-) 19 (2) 43 (5) 4 (1) 764 (29) 1,452 (28) 440 (19) Ruby Ranch 25 (1) 28 (2) 60 (1) 4 (3) 7 (3) 10 (2) 100 (3) 18 (4) 14 (2) 18 (2) 20 (3) 9 (2) 1,108 (31) 3,525 (34) 413 (18) Verona n/a 2,507 (3) - (-) n/a 1 (1) 4 (4) n/a 19 (4) 6 (2) n/a 5 (1) 3 (1) n/a 2,780 (26) 276 (19) Vestal 9 (1) 20 (2) 270 (1) 5 (4) 6 (5) 12 (3) 23 (5) 19 (4) 15 (3) 4 (1) 15 (1) 4 (1) 936 (35) 887 (32) 1,106 (28) Willey n/a 756 (5) 3 (1) n/a 5 (3) 4 (2) n/a 3 (2) 2 (2) n/a - (-) 81 (2) n/a 1,088 (21) 1,411(19) Central Basin Reserve
BKS 8.913 (18) 8,342 (19) 2,386 (21) 56 (8) 58 (8) 70 (8) 339 (5) 143 (5) 283 (5) 150 (5) 105 (5) 78 (4) 17,517 (72) 15,771 (72) 7,632 (74) Bianchi West 6 (1) 676 (5) 363 (5) 5 (3) 4 (2) 6 (1) - (-) 3 (1) 2 (1) 79 (5) 57 (4) 65 (6) 732 (24) 1,167 (26) 1,084 (25) Elsie 8 (2) 108 (3) 90 (1) 15 (5) 25 (4) 9 (4) 13 (1) 2 (1) 7 (1) 11 (2) 18 (2) 9 (1) 335 (20) 1,932 (26) 1,813 (19) Elverta/Silva S. n/a n/a 979 (2) n/a n/a 20 (4) n/a n/a 20 (2) n/a n/a 5 (1) n/a n/a 1,693 (27) Frazer South 1,949 (9) 603 (10) 122 (3) 7 (2) 8 (3) 14 (3) 3 (2) 6 (3) 13 (2) 214 (5) 102 (4) 48 (4) 1,819 (37) 1,308 (37) 666 (26) Paulsen South n/a 196 (6) 196 (5) n/a 1 (1) 1 (1) n/a 6 (1) - (-) n/a 9 (2) 26 (4) n/a 374 (20) 454 (21) Richter n/a 2 (1) 15 (1) n/a 7 (3) 4 (2) n/a 1 (1) 2 (2) n/a 10 (2) - (-) n/a 236 (15) 85 (12) Sills 324 (4) 54 (5) 356 (4) 23 (4) 29 (4) 18 (3) 23 (2) 8 (2) 29 (4) 100 (4) 76 (5) 10 (2) 2,727 (29) 2,048 (33) 1,615 (31) Tufts 18 (1) 20 (3) 79 (2) 3 (3) 18 (3) 8 (2) 12 (3) 2 (1) 4 (1) 119 (3) 14 (2) 2 (1) 701 (20) 759 (22) 667 (20) Fisherman’s Lake Reserve
Alleghenyb - (-) - (-) - (-) 2 (2) - (-) 3 (1) 43 (5) 9 (2) 5 (2) 1 (1) - (-) 1 (1) 226 (27) 107 (11) 101 (15) Cummings 111 (6) 162 (5) 56 (7) 18 (6) 11 (4) 4 (3) 76 (5) 33 (4) 26 (3) 2 (1) 5 (1) 3 (1) 999 (50) 626 (34) 593 (35) Natomas Farms 322 (8) 323 (5) 201 (11) 14 (6) 17 (8) 6 (2) 47 (4) 8 (3) 54 (3) - (-) 7 (1) 5 (1) 825 (43) 1,038 (43) 636 (45) The Natomas Basin Conservancy

Other Covered Wildlife Species
Table 5-1 Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
5-18
April 2023

Reserve
Waterfowl Raptors Neotropical Migrants Shorebirds All Bird Species 2020 2021 2022 2020 2021 2022 2020 2021 2022 2020 2021 2022 2020 2021 2022 Rosasb 11 (3) 24 (4) 6 (1) 7 (3) 11 (2) 8 (3) 37 (5) 32 (4) 41 (5) 2 (1) 2 (1) 9 (1) 924 (35) 405 (31) 280 (29) Souzab 6 (1) 5 (1) 79 (2) 5 (2) 6 (3) 1 (1) 13 (3) 29 (2) 3 (1) - (-) 1 (1) 1 (1) 164 (19) 164 (20) 185 (19) a Numbers in this table reflect the total number of individuals of each group observed followed by the number of species observed (in parentheses). b These reserves were surveyed only from May through August and therefore would be expected to have a lower number of observations and species.

Table 5-2. Number of Pairs of Other Covered Species on TNBC Mitigation Lands, 2004–2022 Species 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Burrowing
owl
1 (BKS)
1 (BKS)
1 (BKS,
pair failed)
0 1
(Elsie)
3 (2 Tufts,
1 Elsie)
4 (1 Tufts,
1 Elsie,
1 Sills,
1 BKS)
3 (2 Elsie,
1 Tufts)
1 (Elsie)
2 (Elsie)
1 (Tufts)
0 0 0 0 0 0 0 0
Loggerhead
shrike
4 (3 BKS, 1
Brennan)
3 (2 BKS, 1
Brennan)
3 (1 BKS, 1
Alleghany,
1 Brennan)
3 (1 BKS, 1
Alleghany,
1 Huffman
West)
1 (Alleghany) 1
(Atkinson)
1 (Atkinson)
1 (Atkinson)
3a 3a
(1 Lucich
North,
1 Rosa,
1 Souza)
4a
(Lucich
North,
Bennett
North,
Atkinson,
Rosa)
1a
(Rosa)
0 1
(Rosa)
1 (Rosa)
0 0 0 0
Tricolored
blackbird
0 ~900
(BKS)
0 ~1,200
(BKS)
~4,900
(~900 BKS,
~4,000
Frazer)
~1,500
(BKS)
~700
(BKS)
0 0 0 0 0 0 0 0 0 0 0 0
White-faced
ibis
0 0 0 ~750
(BKS)
~1,500
(BKS)
~2,500
(BKS)
~2,500
(BKS)
0 0 0 0 0 0 0 0 0 0 0 0
a Presumed nesting on/or immediately adjacent to reserve lands.

The Natomas Basin Conservancy

Other Covered Wildlife Species

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
5-19
April 2023

Table 5-3. Average Number of Observations per Survey of Other Covered Species Recorded during Monthly Avian Surveys on Reserves, 2005–2022 Species 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 White-faced
ibisa

0.268 0.989 14.791 48.812 79.329 53.486 4.424 8.093 6.809 4.464 5.271 7.333 1.049 4.949 9.410 4.404 16.051 4.471 Burrowing
owl

0.028 0.039 0.000 0.098 0.196 0.175 0.138 0.058 0.022 0.036 0.004 0.009 0.004 0.020 0.043 0.029 0.018 0.006 Loggerhead
shrike

0.085 0.033 0.067 0.223 0.253 0.047 0.116 0.164 0.164 0.054 0.044 0.036 0.013 0.051 0.020 0.007 0.003 0.000 Tricolored
blackbird

24.169 2.039 26.836 50.031 15.760 2.401 3.763 1.604 6.236 5.000 4.071 0.982 0.391 3.336 0.602 5.211 3.405 3.006 Pacific pond
turtle and
Unidentified
Turtle

0.000 0.000 0.000 0.004 0.000 0.000 0.004 0.027 0.033 0.065 0.047 0.044 0.018 0.099 0.082 0.082 0.071 0.142 a To account for variation in effort in documenting total numbers during Basin-wide surveys and to account for numbers inflated by large counts at nesting colonies, this metric is the proportion of surveys on which the species was detected.

Table 5-4. Average Number of Observations per Survey of Other Covered Species Recorded during Monthly Basin-Wide Surveys, 2005–2022 Species 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 White-faced ibisa 5.385 36.269 33.077 867.348 84.778 7.389 9.444 37.333 104.77 34.273 43.577 114.59 2.773 32.667 105.62 24.286 472.62 124.40 Burrowing owl 0.385 0.385 0.038 1.826 3.519 4.000 4.852 7.292 5.682 4.364 1.855 1.471 1.136 1.222 0.125 0.857 0.625 0.200 Loggerhead shrike 3.269 2.769 2.346 1.565 3.519 2.167 2.111 2.042 1.273 0.545 0.500 0.059 0.045 0.000 0.000 0.000 0.000 0.000 Tricolored
blackbird

6.385 1.154 1.885 261.739 287.222 0.000 18.519 5.000 7.364 37.773 56.154 5.294 12.364 28.333 25.625 53.857 13.75 80.000 a To account for variation in effort in documenting total numbers during Basin-wide surveys and to account for numbers inflated by large counts at nesting colonies, this metric is the proportion of surveys on which the species was detected.

E
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SACRAMENTO CO

SUTTER CO

PLACER COSUTTER CO

SACRAMENTO CO

PLACER CO
YOLO CO.

SACRAMENTO CO.

SUTTER CO.

YOLO CO.
§¨ ¦80
§¨ ¦
5 £¤
99 Sankey Rd
Powerline Rd
Riego Rd
Elverta Rd
Elkhorn Blvd
Del Paso Rd
T ruxel Rd
Airport Blvd
San Juan Rd
Northgate Blvd
El Camino Ave
El Centro Rd
Sills
T ufts
Lucich
South
Atkinson
Lucich North
Silva
Bennett North
Frazer
Rosa East
Rosa Central
Bolen South
Bennett South
Bolen North
Huffman West
Ruby Ranch
Souza
Cummings
Natomas
Farms
Huffman East
Alleghany
Vestal
Nestor
Bolen
West
Elsie Bianchi West
Kismat
Betts
Frazer South
Silva South 1
Figure 5-1
Monthly Basin-Wide Survey Routes
NBC Monitoring Program data sources: ICF International (2010) ³
0 2.5 5
Miles
Legend
Roads
Major Roads
County Boundaries
NBHCP Area Boundary
Reserve Lands
Survey Areas
North
Central
South
Survey Routes
North
Central
South
Survey Start and End Points
E Start
" End
Q: \ PROJECTS \ NBC \ 04002_04 \ ARCMAP \ REPORT_2009 \ CHAPTER5_SPECIES \ FIGURE5_1_SURVEY_ROUTES.MXD (04-12-10) Graphics … 662.17 NBC (3-9-2021) TG
FIGURE 5-1
Monthly Basin-Wide Survey Routes
NBC 104332 (2-27-2023)
FIGURE 5-2
Mean Number of Raptors Detected per Survey on
TNBC Reserves in the Natomas Basin, 2005–2022

0.00 0.25

0.50 22 2120191817161514131211100908070605
White-Tailed Kite

0.0 0.5

1.0 22 2120191817161514131211100908070605
American Kestrel

0.0 0.5

1.0 22 2120191817161514131211100908070605
Northern Harrier

0.0 0.5

1.0 1.5
22 2120191817161514131211100908070605
Red-Tailed Hawk
Mean number per surveyMean number per survey

0.00 0.05

0.10 0.15

0.20 2022 20212020201920182017201620152014201320122011201020092008200720062005 All Raptors
Mean number per survey
NBC 104332 (2-27-2023)
FIGURE 5-3
Mean Number of Waterfowl Detected per Survey on
TNBC Reserves in the Natomas Basin, 2005–2022
0 5
10 15
20 25
30 22 2120191817161514131211100908070605
Mallard
0 5
10 15
20 25
30 22 2120191817161514131211100908070605
Northern Shoveler
0 25
50 75
100
125
150
22 2120191817161514131211100908070605
Snow Goose
0 25
50 75
100
125
150
22 2120191817161514131211100908070605
Greater White-Fronted Goose
Mean number per surveyMean number per survey
0 1
2 3
4 5
6 7
8 9
10 11
202220212020201920182017201620152014201320122011201020092008200720062005 All Waterfowl
Mean number per survey
NBC 104332 (2-27-2023)
FIGURE 5-4
Mean Number of Neotropical Migrants Detected per Survey on TNBC Reserves in the Natomas Basin, 2005–2022

0.0 0.5

1.0 1.5

2.0 22 2120191817161514131211100908070605
Western Kingbird

0.0 0.5

1.0 1.5

2.0 22 2120191817161514131211100908070605
Tree Swallow
0 1
2 3
4 22 2120191817161514131211100908070605
Barn Swallow
0 2
4 6
8 10
22 2120191817161514131211100908070605
Cliff Swallow
Mean number per surveyMean number per survey

0.000

0.125

0.250

0.375

0.500
202220212020201920182017201620152014201320122011201020092008200720062005 Neotropical Migrants
Mean number per survey
NBC 104332 (2-27-2023)
FIGURE 5-5
Mean Number of Shorebirds Detected per Survey on
TNBC Reserves in the Natomas Basin, 2005–2022

0.0 0.5

1.0 1.5

2.0 22 2120191817161514131211100908070605
Least and Western Sandpipers
0 2
4 6
8 10
12 14
16 22 2120191817161514131211100908070605
Dunlin
0 1
2 3
4 5
6 7
22 2120191817161514131211100908070605
Killdeer
0 2
4 6
8 10
12 22 2120191817161514131211100908070605
Long-Billed Dowitcher
Mean number per surveyMean number per survey

0.0 0.5

1.0 1.5

2.0 2.5
202220212020201920182017201620152014201320122011201020092008200720062005 Shorebirds
Mean number per survey
Y ellow-Billed Magpie
Mean number per survey

0.0 0.5

1.0 1.5

2.0 202220212020201920182017201620152014201320122011201020092008200720062005 Canada Goose
Mean number per survey
0 1
2 3
4 5
202220212020201920182017201620152014201320122011201020092008200720062005 y = -0.0876x + 1.3292
R2 = 0.809
y = 0.229x + 0.1011
R2 = 0.8245
NBC 104332 (2-27-2023)
FIGURE 5-6
Mean Number of Y ellow-Billed Magpies and Canada Geese Detected per Survey on TNBC Reserves in the Natomas Basin, 2005–2022 Loggerhead Shrike Seasonal Trends

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Proportion of surveys with detections
Mean number detected per survey
Mean Prop
Loggerhead Shrike (Basin-Wide Surveys)
Proportion of surveys with detections
Mean number detected per survey
Mean Prop
Loggerhead Shrike (Reserve Surveys)
Proportion of surveys with detections
Mean number detected per survey
Mean Prop
2005 2022 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 2005 2022 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 0 0.05

0.1 0.15

0.2 0

0.05 0.1

0.15 0.2

0.25 0.3

0.35 0

0.2 0.4

0.6 0.8
1 1.2
0 0.5
1 1.5
2 2.5
3 3.5
4 0

0.05 0.1

0.15 0.2
0 0.05

0.1 0.15

0.2 0.25

0.3 NBC 104332 (2-27-2023)
FIGURE 5-7
Mean Number of Loggerhead Shrikes Detected and the Proportion of Surveys on which Shrikes were Detected on TNBC Reserves in the Natomas Basin, 2005–2022 White-Faced Ibis Seasonal Trends

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Proportion of surveys with detections
Mean number detected per survey
Mean Prop
White-Faced Ibis (Basin-Wide Surveys)
Proportion of surveys with detections
Mean number detected per survey
Mean Prop
2005 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 2022 2005 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 2022 White-Faced Ibis (Reserve Surveys)
Proportion of surveys with detections
Mean number detected per survey
Mean Prop

0.00 0.05

0.10 0.15

0.20 0.25

0.30 0
10 20
30 40
50 60
70 80
90 0

0.1 0.2

0.3 0.4

0.5 0.6

0.7 0.8
0 50
100
150
200
250
300
350
400
450
500
0 0.05

0.1 0.15

0.2 0.25

0.3 0.35
0 10
20 30
40 50
60 NBC 104332 (2-27-2023)
FIGURE 5-8
Mean Number of White-Faced Ibis Detected and the Proportion of Surveys on which Ibis Were Detected on TNBC Reserves in the Natomas Basin, 2005–2022 2005 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 2022 2005 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 2022 Tricolored Blackbird Seasonal Trends

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Proportion of surveys with detections
Mean Number detected per survey
Mean Prop
Tricolored Blackbird (Basin-Wide Surveys)
Proportion of surveys with detections
Mean Number detected per survey
Mean Prop
Tricolored Blackbird (Reserve Surveys)
Proportion of surveys with detections
Mean Number detected per survey
Mean Prop

0.00 0.10

0.20 0.30

0.40 0.50

0.60 0.70

0.80 0
10 20
30 40
50 60

0.00 0.10

0.20 0.30

0.40 0.50

0.60 0
50 100
150
200
250
300
350

0.00 0.05

0.10 0.15

0.20 0
10 20
30 40
50 NBC 104332 (3-1-2023)
FIGURE 5-9
Mean Number of Tricolored Blackbird Detected and the Proportion of Surveys on which Blackbirds Were Detected on TNBC Reserves in the Natomas Basin, 2005–2022 2005 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 2022 2005 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 2022

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
Proportion of Surveys with Detections
Mean Number Detected Per Survey
Mean Prop
Burrowing Owl Seasonal Trends
Burrowing Owl (Basin-Wide Surveys)
Proportion of Surveys with Detections
Mean Number Detected Per Survey
Mean Prop
Burrowing Owl (Reserve Surveys)
Proportion of Surveys with Detections
Mean Number Detected Per Survey
Mean Prop
NBC 104332 (2-27-2023)
FIGURE 5-10
Mean Number of Burrowing Owl Detected and the Proportion of Surveys on which Owls were Detected on TNBC Reserves in the Natomas Basin, 2005–2022

0.00 0.01

0.02 0.03

0.04 0.05

0.06 0.07

0.08 0.00

0.05 0.10

0.15 0.20

0.25 0.0

0.1 0.2

0.3 0.4

0.5 0.6

0.7 0.8

0.0 1.0

2.0 3.0

4.0 5.0

6.0 7.0

8.0 0.00

0.02 0.04

0.06 0.08

0.10 0.0

0.1 0.2

0.3 0.4

0.5 0.6
Proportion of Surveys with Detections
Mean Number Detected per Survey
Mean Prop
NBC 104332 (3-2-2023)
FIGURE 5-11
Mean Number of Pacific Pond Turtles and Unidentified Turtles and the Proportion of Surveys on which Turtles were Detected on TNBC Reserves in the Natomas Basin, 2005–2022 0 0.02

0.04 0.06

0.08 0

0.05 0.1

0.15 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Appendix A
NBHCP Reserve Land Cover Data

The Natomas Basin Conservancy

NBHCP Reserve Land Cover Data

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
A-1
April 2023

Table A-1. Reserve Lands: Extent (acres) of Each Land Cover Type, 2005–2022 Reserve and Land
Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 North Basin Reserve
Atkinsona
Fallow (including
fallow rice) 108 70.2 44.3 – 122.7 161.2 161.2 108.7 64.4 93.2 48.8 44.3 44.3 145.7 52.5 104.4 11.2 11.2 Fresh emergent
marsh 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Grass hay – – 21.3 – – – – – – 15.5 15.5 15.5 9.7 9.7 20.1 62.2 54 106.5 Grassland (created) – 20.8 20.8 20.8 20.8 20.8 20.8 20.8 20.8 20.8 20.8 20.8 15.5 15.5 15.5 15.5 – – Milo – – 48.9 – – – – – – – – – – – – – – –
Nonnative annual
grassland 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Other row crops 9.8 52.5 – – – – – – – – – – – – – – – – Rice 48.9 44.4 52.5 145.7 44.3 – – 52.5 96.9 52.5 96.97 101.4 101.4 – 93.2 – 48.9 48.9 Riparian scrub 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.4 Riparian woodland 9 9 9 9 9 9 9 9 9 9 9.1 9.1 9.1 9.1 9.1 9.1 6.3 6.3 Ruderal 3.6 3.6 0.7 0.7 0.7 – – – – – – – 11.2 11.2 – – – – Seasonal wetland 0.1 0.1 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2.9 Valley oak
woodland 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1 1 1 1 1 1 1 1 Wheat 21.3 – – 21.3 – – – – – – – – – – – – 52.5 –
Bennett North
Fallow – 67 147.8 10.8 10.8 – – – – – – – – – – – 147.8 – Fresh emergent
marsh (created) 7 7 74 74 74 74 74 74 74 74 74 74 74 74 74 74 74 74 Grassland (created) 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 2.6 Rice 213.8 146.9 – 137 137 147.8 147.8 147.8 147.8 147.8 147.7 147.8 147.8 147.8 147.8 147.8 – 147.8 Riparian scrub 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ruderal 3.2 3.2 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 Bennett South
Fallow (including
fallow rice) 87.2 – – – – 4.4 26.9 – 13.2 – – 13.7 – – 72.7 13.7 68.8 Fresh emergent
marsh (created) 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 19.1 Irrigated grassland – – – – 4.4 5.3 – – – – – – – – – – – – Grassland (created) 22.7 28.1 28.7 24.3 24.3 24.3 24.3 24.3 24.3 24.3 24.3 24.3 24.3 24.3 24.3 24.3 24.3 24.3 The Natomas Basin Conservancy

NBHCP Reserve Land Cover Data
Table A-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
A-2
April 2023

Reserve and Land
Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Grass hay – – – – – – – – – – – – 26.9 13.7 – – – –
Open water 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Rice – 81.8 82 86.4 82 59.7 59.5 86.4 73.2 86.4 86.4 72.7 59.5 72.7 13.7 86.4 72.7 17.7 Riparian scrub 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Ruderal 0.8 0.8 – – – – – – – – – – – – – – – –
Bolen North
Fallow (to allow
field leveling) – – – – – – 112.5 – – – – – 112.5 – – – – – Rice 112.5 112.5 112.5 112.5 112.5 112.5 – 112.5 112.5 112.5 112.5 112.5 – 112.5 112.5 112.5 112.5 112.5 Bolen South
Alfalfa – – 43.9 43.9 43.9 43.9 43.9 43.9 43.9 43.9 43.9 43.9 43.9 43.9 43.9 43.9 43.9 72.17 Fallow 101.7 – – – – – 57.8 – – – – 57.8 57.8 – – – – – Grass hay – – – – – – – 57.8 57.8 57.8 57.8 – – 57.8 57.8 57.8 57.8 29.6 Valley oak
woodland 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Wheat – 101.7 57.8 57.8 57.8 57.8 – – – – – – – – – – – – Bolen West
Fallow (including
fallow rice) – – 155.1 – – – – 155.1 – – – – 155.1 – – – – 155.1 Rice – – – 155.1 155.1 155.1 155.1 – – 155.1 155.1 155.1 – 155.1 155.1 155.1 155.1 – Milo – – – – – – – – 155.1 – – – – – – – – –
Frazerb
Fresh emergent
marsh (created) 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 74.7 Grassland (created) 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 7.3 Nonnative annual
grassland 10.6 10.6 10.6 10.6 10.6 10.6 10.6 10.6 7.9 7.9 7.9 7.9 7.9 7.9 7.9 7.9 7.9 7.9 Open water – – – – – – – – 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 2.7 Huffman East
Alfalfa – – – – – – 15.6 – – – – – – – – – – –
Fallow 15.6 – – – – – – – 15.6 27.3 14.9 – – – 118.8 – – – Grass hay – – 15.6 15.6 – – – 15.6 – – – 15.6 15.6 15.6 15.6 15.6 15.6 15.6 Rice 118.8 118.8 118.8 118.8 118.8 118.8 118.8 118.8 18.8 107.1 119.5 118.8 118.8 118.8 – 118.8 118.8 118.8 Wheat – 15.6 – – 15.6 15.6 – – – – – – – – – – – –
Huffman Westc
Alfalfa 67.9 67.9 67.9 67.9 122.6 44.5 99.5 99.5 99.5 99.5 99.5 99.5 99.5 99.5 44.5 99.5 157.9 139.4 The Natomas Basin Conservancy

NBHCP Reserve Land Cover Data
Table A-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
A-3
April 2023

Reserve and Land
Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Fallow – – – – – – – – – – – – – – 58.4 – – –
Grass hay – – – – – – 58.4 58.4 58.4 – 58.4 58.4 58.4 58.4 – 58.4 – 19.0 Milo – – – – – – – – – – – – – – – – – –
Other row and
grain crops – – 58.4 58.4 – – – – – – – – – – – – – –
Tomatoes – – 54.7 54.7 – – – – – – – – – – – – – –
Wheat 113.1 113.1 – – 58.4 113.3 – – – 58.4 – – – – 54.9 – – – Lucich Northd
Fresh emergent
marsh (created) 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 224.9 Disturbed/bare – – – – – – – 27.4 11.1 – – – – – – – – – Grassland (created) – 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Nonnative annual
grassland 23.9 24 27.5 27.5 27.5 27.5 27.5 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Ruderal 15.8 15 15 15 15 15 15 14.9 14.9 26 26 26 26 26 26 26 26 26 Seasonal wetland 3.5 3.5 – – – – – – – – – – – – – – – – Open water – – – – – – – – 16.3 16.3 16.3 16.3 16.3 16.3 16.3 16.3 16.3 16.3 Lucich South
Rice 328.1 328.1 328.1 328.1 328.1 328.1 331.2 331.2 331.2 331.2 331.2 331.2 331.2 331.2 331.2 331.2 331.2 196.2 Fallow rice – – – – – – – – – – – – – – – – – 135.0
Fresh emergent
marsh (created) 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 21.3 Ruderal 3.1 3.1 3.1 3.1 3.1 3.1 – – – – – – – – – – – – Nestor
Fallow – – – 233.1 – 233.1 233.1 – – – – – – – 233.1 – – 233.1 Rice – – 233.1 – 233.1 – – 233.1 233.1 233.1 233.1 233.1 233.1 233.1 – 233.1 233.1 – Ruby Ranch
Developed—low
density 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Fallow 87.3 – – – 87.3 – – – – – – 87.3 – – – – – 87.3
Other row and
grain crops – 87.3 87.3 – – – – – – – – – – – – – – –
Rice – – – 87.3 – 87.3 87.3 87.3 87.3 87.3 87.3 – 87.3 87.3 87.3 87.3 87.3 – Ruderal 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 Vestal
Milo – – – – – – – – – 93.9 – – – – – – –
The Natomas Basin Conservancy

NBHCP Reserve Land Cover Data
Table A-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
A-4
April 2023

Reserve and Land
Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Rice – 93.8 93.8 93.8 93.8 93.8 93.8 93.9 93.9 – 93.9 93.9 93.9 93.9 93.9 93.9 93.9 – Fallow rice – – – – – – – – – – – – – – – – – 93.9
Valley oak
woodland – 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 Central Basin Reserve
Betts-Kismat-Silva
Developed—low
density 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 4.9 Fresh emergent
marsh (created) 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 140.3 Irrigated grassland 0 95.5 – – – – – – – – – – – – – – – – Nonnative annual
grassland 188.2 92.7 188.2 188.2 188.2 188.2 188.2 188.3 188.3 188.3 188.3 188.3 188.3 188.3 188.3 188.3 188.3 188.3 Nonriparian
woodland 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 Riparian scrub 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 Riparian woodland 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 Seasonal wetland 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Bianchi West
Rice – – 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 110.2 Elsie
Developed - High
Density – – – – – – – – – – – – – – – – – –
Fallow rice – – 158 – – 158 158 – – – – – – – – – – 158 Rice – – – 158 158 – – 158 158 158 158 158 158 158 158 158 158 – Frazer South
Fallow rice – – 110.3 110.3 – – – – – – – – – – – – – 110.3 Rice – – – – 110.3 110.3 110.3 110.3 110.3 110.3 110.3 110.3 110.3 110.3 110.3 110.3 110.3 – Sills
Fallow 11.9 294.5 – – – – 25.6 25.6 25.6 134.6 – – – – – – – 169.4 Grass hay – – – – – – – – – 25.6 25.6 25.6 25.6 93.7 38.2 25.6 25.6 25.6 Other row and
grain crops – – 12.3 280.8 – – – – – – – – – – – – –
Rice 420.2 137.6 436.4 167.9 448.7 448.7 410.6 410.6 423.1 288.6 423.1 423.1 423.1 355 410.6 423.1 423.1 253.7 Sunflower – – – – – – 12.6 12.6 – – – – – – – – –
The Natomas Basin Conservancy

NBHCP Reserve Land Cover Data
Table A-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
A-5
April 2023

Reserve and Land
Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Silva South 1
Nonnative annual
grassland 0.2 0.2 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Rice – – – – – – – – 28.8 28.8 28.8 28.8 28.8 28.8 28.8 28.8 28.8 28.8 Tufts
Fallow – – – – 146.7 – – – – – – – – – – – – –
Rice 147.7 147.7 147.7 147.7 1 147.7 147.7 147.7 147.7 147.7 147.7 147.7 147.7 147.7 147.7 147.7 147.7 147.7 Fisherman’s Lake Reserve
Alleghanye
Alfalfa 27.5 27.5 27.5 27.5 27.5 27.5 – – – – – – – – – – – – Fallow – – – 18.9 6 18.9 6 0.7 – – – – – 18.9 – 39.5 10 18.9 Grass hay 18.9 18.9 – – 12.9 – 12.9 12.9 18.9 18.9 0.7 – – 0.7 12.9 – – – Other row and
grain crops – – – – – – 26.8 6 26.8 – 26.8 0.7 27.5 26.8 27.5 – – – Ruderal 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 7.9 8.8 0.5 0.5 Sunflower – – – – – – 0.7 26.8 0.7 27.5 – – 18.9 – – – – – Valley oak
woodland 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1.1 1.1
Wheat – – 18.9 – – – – – – – 18.9 45.7 – – – – 18.9 –
Disturbed/bare – – – – – – – – – – – – – – – – – 10
Cummingse
Fallow 17.7 – – – – – – – – – – – – 22.5 22.5 – – –
Fresh emergent
marsh (created) 37.1 37.1 37.1 37.1 37.1 37.1 37.1 37.2 37.2 37.2 37.2 37.2 37.2 37.2 37.2 37.2 37.2 37.2 Grassland (created) 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 Nonnative annual
grassland 4.8 4.8 22.5 22.5 22.5 22.5 22.5 22.5 22.5 22.5 22.5 – – – – – – – Ruderal 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 1.4 – – Safflower – – – – – – – – – – – 22.5 22.5 – – – – –
Valley oak
woodland 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1.2 1 – – Wheat (hay crop) – 17.7 – – – – – – – – – – – – – – – – Clover – – – – – – – – – – – – – – – 21.8 14.3 14.3
Natomas Farmse
Disturbed/bare – – – – – – 44.8 0.7 – – – – – – – – – – The Natomas Basin Conservancy

NBHCP Reserve Land Cover Data
Table A-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
A-6
April 2023

Reserve and Land
Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Fresh emergent
marsh (created) 35.2 35.2 35.2 35.2 35.2 35.2 35.2 35.2 35.2 35.2 35.2 35.2 35.2 35.2 35.1 35.1 35.1 35.1 Grass hay – – 44.1 44.1 44.1 44.1 – – – – – – – – – – – – Grassland (created) 9.2 10.8 10.8 10.8 10.8 10.8 10.1 11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 11.6 Nonnative annual
grassland 4.1 4.1 4.1 4.1 4.1 4.1 4.1 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 5.4 Ruderal 3.1 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Valley oak
woodland 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 Wheat 44.1 44.1 – – – – – – – – – – – – – – – –
Rosa Central
Alfalfa – – – – – – – – – 100.1 100.1 100.1 – – – – – – Fallow 100.1 – 100.1 – – – 44.6 – – – – – – – – – – –
Grass hay – – – 100.1 100.1 100.1 – 55.4 44.6 – – – 100.1 – – – – – Sunflower – – – – – – 55.4 44.6 55.4 – – – – 100.1 – – 100.1 100.1 Wheat – 100.1 – – – – – – – – – – – – 100.1 100.1 – –
Other Row and
Grain Crops – – – – – – – – – – – – – – – – –
Rosa East
Alfalfa – – – – – – – 104.3 104.3 104.3 104.3 104.3 – – – – – – Fallow 104.3 – – – – – – – – – – – – – – – – 36.7
Other row and
grain crops – – 104.3 104.3 – – – – – – – – 104.3 – – – – – Riparian woodland 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 Safflower – – – – 104.3 – 67.2 – – – – – – – – – – –
Sunflower – – – – – 104.3 36.7 – – – – – – 104.3 – – 104.3 67.6 Valley oak
woodland 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Wheat – 104.3 – – – – – – – – – – – – 104.3 104.3 – –
Souza
Alfalfa 10.8 10.8 10.8 10.8 10.8 10.9 10.9 11 – – – – – – – 18 27.7 39.7 Disturbed/bare – – – – – – 17.7c 17.7 – – – – – – – – – – Fallow – 12 12 – – – – – – – – 11 – 16.7 – – – –
Grass hay – – – – – – – – 39.7 16.7 – – – – – 21.6 12 – Non-riparian
woodland 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 The Natomas Basin Conservancy

NBHCP Reserve Land Cover Data
Table A-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
A-7
April 2023

Reserve and Land
Cover Type 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 Other row and
grain crops – 16.7 16.7 28.7 28.7 28.7 – – – – 11 – – – – – – – Ruderal 0.1 0. 1 0.1 0.1 0.1 – – – – – – – – – – – – –
Safflower – – – – – – – 11 – – – – – – – – – –
Sunflower – – – – – – 11 – – 22.9 – – 28.7 – – – – –
Wheat 28.7 – – – – – – – – – 28.7 28.7 11 22.9 39.6 – – – a Acreage of reserve decreased in 2010 and 2021 due to the Sacramento Area Flood Control Agency (SAFCA) acquiring property for the Natomas Levee Improvement Project (NLIP).

b Open water was mapped in 2013 due to the enlargement of an existing linear water conveyance feature.

c Acreage of reserve decreased in 2010 due to SAFCA acquiring property for the NLIP.

d Open water mapped in 2013 due to the construction of new linear water conveyance feature.

e Acreage of reserve decreased in 2011 due to SAFCA acquiring property for the NLIP.

Powerline Road
Lucich North
Frazer
Legend
NBHCP Area Boundary Land Cover
Fresh Emergent Marsh (Created)
Grassland (Created)
Non-native Annual Grassland
Open Water
Ruderal ³

0.3 0 0.3
Miles
Aerial Source: ESRI/Maxar (2021/2022)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-1_frazer_lucich_hab.mxd 19393 Date: 04 Jan 2023/ Figure A-1
North Basin Reserve—Frazer and Lucich North Tracts, 2022 Powerline Road
Sankey Road
Nestor
Lucich South
Bennett North
Willey
Bolen North
Verona
Bolen West
Lauppe South
Bolen South
Huffman East
Bennett South
Legend
Reserve Lands
Land Cover
Alfalfa
Developed
Fallow
Fresh Emergent Marsh (Created)
Grass Hay
Grassland (Created)
Open Water
Rice
Riparian Scrub
Ruderal
Sunflower ³

0.3 0 0.3
Miles
Aerial Source: ESRI/Maxar (2021/2022)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-2_bennett_north_nestor_hab.mxd 19393 Date: 04 Jan 2023/ Figure A-2
North Basin Reserve—Nestor, Bennett North,
Ben
nett South, Willey, and Lucich South Tracts, 2022
Powerline Road
Sankey Road
SacramentoRiver
Verona
Bolen West
Willey
Bolen North
Bolen South
Bennett North
Nestor
Bennett South
Lucich South
Legend
Reserve Lands
NBHCP Area Boundary
Land Cover
Alfalfa
Developed - High Density
Fallow
Grass Hay
Grassland (Created)
Non-native Annual Grassland
Open Water
Rice
Ruderal
Sunflower
Valley Oak Woodland ³

0.2 0 0.2
MilesAerial Source: ESRI/Maxar (2021/2022)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-3_bolen_hab.mxd 19393 Date: 04 Jan 2023/ Figure A-3
North Basin Reserve—
Bolen West, Bolen North, Bolen South, and Verona Tracts, 2022 Riego Road
Powerline Road
Sac
ram
ento
River
Lauppe South
Huffman West
Huffman East
VestalAtkinson
Bennett South
Lucich South
Legend
Reserve Lands
NBHCP Area Boundary
County Boundary
Land Cover
Alfalfa
Fallow
Fresh Emergent Marsh (Created)
Grass Hay
Grassland (Created)
Nonnative Annual Grassland
Rice
Riparian Scrub
Riparian Woodland
Valley Oak Woodland
³

0.1 0 0.1
Miles
Aerial Source: ESRI/Maxar (2019)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-4_huffmanE_lucsouth_bennetsouthA.mxd 19393 Date: 04 Jan 2023/ Figure A-4
North Basin Reserve—Lauppe South, Huffman West, and Huffman East Tracts, 2022 Riego Road
Powerline Road
SacramentoRiver
Sutter CountySutter County
Sacramento CountySacramento County
Atkinson
Vestal
Huffman West
Ruby Ranch
Huffman East
Reserve Lands
NBHCP Area Boundary
County Boundaries
Land Cover
Alfalfa
Developed
Fallow
Fresh Emergent Marsh
Grass Hay
Nonnative Annual Grassland
Rice
Riparian Scrub
Riparian Woodland
Ruderal
Seasonal Wetland
Valley Oak Woodland
³

0.1 0 0.1
MilesAerial Source: ESRI/Maxar (2022)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-5_atkinsonruby_hab_new.mxd 19393 Date: 04 Jan 2023/ Figure A-5
North Basin Reserve—Atkinson, Vestal,
and
Ruby Ranch Tracts, 2022
Elverta Road
Sacramen to Coun tySacramen to Coun ty
Sutter C ountySutter C ounty
·| } þ99
Sills
Elsie
Tufts Richter
Bianchi West
Paulsen South
Legend
Reserve Lands
Major Road
County Boundary
Land Cover
Developed
Fallow
Grass Hay
Non-native Annual Grassland
Open Water
Rice ³

0.3 0 0.3
Miles
Aerial Source: ESRI/Maxar (2022)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-6_sills_hab_A.mxd 19393 Date: 04 Jan 2023/ Figure A-6
Central Basin Reserve—Elsie, Sills,
Bia
nchi West, Paulsen South, Richter, and Tufts Tracts, 2022 Sacram ento CountySacram ento County
Sutter CountySutter County
Silva Betts
Frazer South
Kismat
Silva South 1
Legend
Reserve Lands
County Boundary
NBHCP Area Boundary
Land Cover
Developed
Fallow
Fresh Emergent Marsh (Created)
Nonnative Annual Grassland
Nonriparian Woodland
Riparian Scrub
Riparian Woodland
Seasonal Wetland
³

0.2 0 0.2
MilesAerial Source: ESRI/Maxar (2022)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-7_bks_hab.mxd 19393 Date: 04 Jan 2023/ Figure A-7
Central Basin Reserve—Frazer South, Betts,
Kis
mat, Silva, and Silva South 1 Tracts, 2022
GardenHighway
Del Paso Road
Sacramento River
Rosa East
Rosa Central
Souza
Natomas Farms
Non-Reserve
Legend
Reserve Lands
NBHCP Area
Boundary
Land Cover
Alfalfa
Fallow
Fresh Emergent Marsh (Created)
Grassland (Created)
Nonnative Annual Grassland
Nonriparian Woodland
Open Water
Riparian Woodland
Ruderal
Sunflower
Valley Oak Woodland ³

0.2 0 0.2
MilesAerial Source: ESRI/Maxar (2022)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-8_souza_nat_Rosa_hab.mxd 19393 Date: 04 Jan 2023/ Figure A-8
Fisherman's Lake Reserve—Rosa Central, Rosa East,
Sou
za, and Natomas Farms Tracts, 2022
San Juan Road
Garden Highway
Sacram
ento
River
Cummings
Alleghany
Legend
Reserve Lands
NBHCP Area Boundary
Land Cover
Cover Crop
Disturbed / Bare
Fallow Row and Grain Crops
Fresh Emergent Marsh (Created)
Grassland (Created)
Ruderal
Valley Oak Woodland ³

0.1 0 0.1
MilesAerial Source: ESRI/Maxar (2022)
\\PDCCITRDSGIS01\Projects_1\NBC\04002_04\arcmap\report_2022\Appendix_A\figureA-9_all50_cummings_habA.mxd 19393 Date: 04 Jan 2023/ Figure A-9
Fisherman's Lake Reserve—Cummings and Alleghany Tracts, 2022 Appendix B
Botanical Survey Results

The Natomas Basin Conservancy

Botanical Survey Results

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-1
April 2023

Table B-1. Cumulative List of Plant Species Observed on the Natomas Basin Conservancy Reserves, 2005–2022 Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Ferns and Fern Allies
Azollaceae Mosquito Fern Family
Azolla filiculoides Mosquito fern X X X X X X X X X X X X Equisetaceae Horsetail Family
Equisetum telmateia ssp. braunii Giant horsetail X X Marsileaceae Marsilea Family
Marsilea vestita ssp. vestita Hairy waterclover X X X Monocotyledons
Alismataceae Water-Plantain Family
Alisma lanceolatum* Lance-leaved water-
plantain

X X X X X X X X X X X X X X X X X X X
Alisma trivial (Alisma plantago-
aquatica)
Common water-plantain X
Echinodorus berteroi Burhead X X X X X X
Sagittaria longiloba Gregg arrowhead X X X Sagittaria montevidensis ssp. calycina California arrowhead X X X X X X X X X X X X Araceae (Lemnaceae) Arum Family
(Duckweed Family)

Lemna sp. Duckweed X X X X X X X X X X X
Cyperaceae Sedge Family
Bolboschoenus maritimus (Scirpus
maritimus)
Prairie bulrush X X X
Cyperus esculentus Nutsedge X X X X X X X X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-2
April 2023

X X X X
Schoenoplectus acutus (Scirpus acutus
var. occidentalis)
Common tule X X X X X X X X X X X X X X X
Schoenoplectus mucronatus (Scirpus
mucronatus)*
Ricefield bulrush X X X X X X X X
Hydrocharitaceae Waterweed Family
Elodea canadensis Canadian pondweed X
Juncaceae Rush Family
Juncus balticus Baltic rush X X X
Juncus bufonius Toad rush X X X X X X X X X X X X X X X Juncus effusus Soft rush X X X X X
Poaceae Grass Family
Agrostis avenacea* Pacific bentgrass X X X X X X X Alopecurus carolinianus Tufted foxtail X X X Alopecurus saccatus Foxtail X X X X X X
Arundo donax* Giant reed X
Avena barbata* Slender wild oats X X X X X X X X X X X X X X X Avena fatua* Common wild oats X X X X X X X X X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-3
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Briza minor* Little quaking grass X X
Bromus catharticus* Rescue brome X X X X X Bromus diandrus* Ripgut brome X X X X X X X X X X X X X X X X X X X X X X X X Bromus hordeaceus* Soft chess X X X X X X X X X X X X X X X X X Bromus madritensis ssp. rubens* Foxtail chess X X
Cortaderia jubata Pampas grass X
Crypsis schoenoides* Swamp grass X X X
Cynodon dactylon* Bermuda grass X X X X X X X X X X X X X X X X X X X X X X X Deschampsia danthonioides Annual hairgrass X X X X X X X Digitaria sanguinalis* Hairy crabgrass X X X X X X X X X X X X Distichlis spicata Saltgrass X X X X X X X X X Echinochloa crus-galli* Barnyardgrass X X X X X X X X X X X X X X Eleusine tristachya* Threespike goosegrass X Elymus glaucus Blue wildrye X X X X X X X Elymus triticoides (Leymus triticoides) Creeping wildrye X X X Eragrostis pectinacea var. pectinacea Tufted lovegrass X Eragrostis sp.* Lovegrass X
Festuca arundinacea* Reed fescue X X Festuca bromoides (Vulpia
bromoides)*
Foxtail fescue X X X X
Festuca microstachys (Vulpia
microstachys)
Small fescue X X X X X X
Festuca myuros (Vulpia myuros)* Rattail fescue X X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-4
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Festuca perennis (Lolium
multiflorum)*
Italian ryegrass X X X X X X X X X X X X X X X X X X X X X X X X X Glyceria occidentalis Sweet flotegrass X X X X X X X X X X Holcus lanatus* Velvetgrass X X
Hordeum brachyantherum Meadow barley X X X X X X X Hordeum marinum ssp. gussoneanum* Mediterranean barley X X X X X X Hordeum murinum* Foxtail barley X X X X X X X X X X X X X X X X X X X X Leersia oryzoides Rice cutgrass X X
Leptochloa fusca subsp. Fascicularis
(Leptochloa fascicularis)
Bearded sprangletop X X X X X X X X X X X X X X X X X X Muhlenbergia rigens Deergrass X
Oryza sativa* Rice X X X X X X X X X X X X X X X Paspalum dilatatum* Dallisgrass X X X X X X X X X X X X X X X X X X Paspalum distichum Knotgrass X X X X X X X X X X Phalaris aquatica* Harding grass X X X Phalaris minor* Littleseed canarygrass X X X X X X X X X X X Phalaris paradoxa* Paradox canarygrass X X X X X X Poa annua* Annual bluegrass X X X X X X X X X X X X X Polypogon interruptus* Ditch beard grass X X X X X X X Polypogon monspeliensis* Rabbit’s-foot grass X X X X X X X X X X X X X X X X X X X X X Setaria pumila* Yellow bristle grass X X X X X Sorghum bicolor* Milo X X
Sorghum halepense* Johnsongrass X X X X X X X X X X X X X X X X X X X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-5
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Sporobolus indicus Small smutgrass X
Stipa pulchra (Nassella pulchra) Purple needlegrass X X Triticum aestivum* Wheat X X X
Pontederiaceae Mud Plantain Family
Heteranthera limosa* Ducksalad X X X X
Typhaceae Cattail Family
Typha angustifolia Narrow-leaved cattail X X X Typha domingensis Southern cattail X X X X X X X X X X X X X X X X X X Typha latifolia Broadleaf cattail X X X X X X X X X X X X X X X Dicotyledons
Aceraceae Maple Family
Acer negundo Box-elder X X X
Adoxaceae Muskroot Family
Sambucus nigra subsp. canadensis
(Sambucus mexicana)
Blue elderberry X X
Amaranthaceae Amaranth Family
Asclepias fascicularis Narrow-leaf milkweed X
Amaranthaceae Amaranth Family
Amaranthus albus* Pigweed amaranth X
Amaranthus sp. Amaranth X X X X
Anacardiaceae Sumac Family
Toxicodendron diversilobum Poison-oak X X
Apiaceae Carrot Family
The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-6
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Ammi visnaga* Bisnaga X X X X
Conium maculatum* Poison hemlock X Daucus carota* Wild carrot X
Foeniculum vulgare* Sweet fennel X X X X X Torilis arvensis* Hedge parsley X X
Araliaceae Ginseng Family
Hedera helix* English ivy X
Asclepiadaceae Milkweed Family
Asclepias fascicularis Narrow-leaf milkweed X X Asteraceae Sunflower Family
Achyrachaena mollis Blow-wives X X X X X Ambrosia sp. Ragweed X X X
Anthemis cotula* Mayweed X X
Baccharis pilularis Coyote brush X X X X X X Baccharis salicifolia Mulefat X
Carduus pycnocephalus* Italian thistle X X X X X X Centaurium pulchellum Branched centaury X X
Centaurea solstitialis* yellow star-thistle X X X X X X X X X X X X X X X X X X Centromadia fitchii Fitch’s spikeweed X X X Cichorium intybus* Chicory X X X X X X X Cirsium vulgare* Bull thistle X X X X X X X X X X X X X X X X X X Dittrichia graveolens* Stinkwort X X X X X X Eclipta prostrata False daisy X X X X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-7
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Erigeron canadensis (Conyza)* Horseweed X X X X X X X X X X X X X X X X X Gnaphalium luteoalbum* Cudweed everlasting X X X X X X X X X X X X X X X Helianthus annuus Annual sunflower X
Helminthotheca echioides (Picris
echioides)*
Bristly ox-tongue X X X X X X X X X X X X X X X X X X X X X X X X X Heterotheca grandiflora Telegraphweed X X
Holocarpha virgata ssp. virgata Common tarweed X X Hypochaeris glabra* Soft cat’s-ear X
Lactuca saligna* Willow lettuce X X Lactuca serriola* Prickly lettuce X X X X X X X X X X X X X X X X X X X X X X X X X Lasthenia glaberrima Smooth goldfields X
Leontodon saxstilis (taraxacoides)* Hairy hawkbit X Logfia gallica (Filago gallica)* Narrow-leaved filago X Matricaria discoidea (Chamomila
suaveolens)*
Pineapple weed X X X
Microseris elegans Elegant microseris X
Psilocarphus brevissimus var.
brevissimus
Woollyheads X
Psilocarphus tenellus Slender woollyheads X Senecio vulgaris* Common groundsel X X X X X X X X X X X Silybum marianum* Milk thistle X X X X X X X X X X X X X X X X X X X X X Soliva sessilis* Lawn burweed X
Sonchus asper ssp. asper* Prickly sow thistle X X X X X X X X X X X X Sonchus oleraceus* Common sow-thistle X X X X X X X X X X X X X X X X X X X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-8
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Symphyotrichum subulatum (Aster
subulatus var. ligulatus)
Annual water-aster X X X X X X X X X X X X X Taraxacum officinale Dandelion X X Tragopogon porrifolius* Salsify X
Xanthium spinosum Spiny coccklebur X
Bignoniaceae Bignonia Family
Catalpa bignonioides* Catalpa X
Boraginaceae Borage Family
Amsinckia menziesii var. intermedia Common fiddleneck X X X X X X X X X X Heliotropium curassavicum Heliotrope X X X X X Plagiobothrys stipitatus var.
micranthus
Stipitate popcornflower X
Brassicaceae Mustard Family
Brassica nigra* Black mustard X X X X X X X X X X Brassica rapa* Field mustard X X X X X X X X X X X X Capsella bursa-pastoris* Shepherd’s-purse X X X X X X X X X X X X X X X X Cardamine oligosperma Idaho bittercress X Hirschfeldia incana* Shortpod mustard X X X X
Lepidium dictyotum Alkali pepperweed
Lepidium didymus (Cornopus
didymus)*
Lesser swinecress X X X X X X X X X X
Lepidium latifolium* Perennial pepperweed X X X X X X X X Planodes virginicum (Sibara virginica) Common rockcress X X Raphanus sativus* Wild radish X X X X X X X X X X X X X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-9
April 2023

X X X X
Convolvulaceae Morning Glory Family
Convolvulus arvensis* Field bindweed X X X X X X X X X X X X X X X X X X X X X X X X Cressa truxillensis Alkali weed X X X X Crassulaceae Stonecrop Family
Crassula aquatica/solieri Water pygmy-weed X X Crassula tillaea* Moss pygmy-stonecrop X
Elatinaceae Waterwort Family
The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-10
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Elatine ambigua* Asian waterweed X X X X Elatine brachysperma/rubella Waterweed X X
Euphorbiaceae Spurge Family
Chamaesyce maculata* Spotted spurge X X Chamaesyce serpyllifolia ssp.
serpyllifolia
Thyme-leaved spurge X X
Eremocarpus setiger (setigerus) Doveweed X X X Fabaceae Legume Family
Acmispon americanus (Lotus
purshianus)
Spanish lotus X
Glycyrrhiza lepidota Wild licorice X X X Lotus corniculatus* Bird’s-foot trefoil X X X X X X Lupinus bicolor Miniature lupine X X X X X X
Medicago polymorpha* Bur-clover X X X X X X X X X X X X X X X X X X X Medicago sativa* Alfalfa X X X X X X Melilotus alba* White sweetclover X X X X X X X Melilotus indica* Indian sweetclover X X X X Robinia pseudoacacia* Black locust
Trifolium campestre* Hop clover X X X Trifolium dubium* Suckling clover X X X X Trifolium fragiferum* Strawberry clover X Trifolium glomeratum* Clustered clover X
Trifolium gracilentum Pinpoint clover X
The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-11
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Trifolium hirtum* Rose clover X X
Trifolium pratense* Red clover X
Trifolium repens* White clover X X
Trifolium subterraneum* Subterranean clover X Vicia sativa* Common vetch X X X X X
Vicia villosa* Hairy vetch X X X X X X X X Fagaceae Oak Family
Quercus lobata Valley oak X X X X X X X X X X X X X Gentianaceae Gentian Family
Zeltnera muehlenbergii (Centaurium
muehlenbergii)
Monterey centaury X X X X X
Geraniaceae Geranium Family
Erodium botrys* Big stork’s-bill X X X X X X X X X X X Erodium cicutarium* Red-stemmed filaree X X X X X X X X X X X X X X X Erodium moschatum* White-stemmed filaree X X X X X X X X X X Geranium dissectum* Cut-leaf geranium X X X X X X X X X X X X X X X X X X X Geranium molle* Dove’s-foot geranium X X
Haloragaceae Water-Milfoil Family
Myriophyllum sp. Water milfoil X X
Juglandaceae Walnut family
Juglans hindsii (Juglans californica var.
hindsii)
California black walnut X X X X X
Lamiaceae Mint Family
The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-12
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Lamium amplexicaule* Henbit deadnettle X X X Lycopus americanus American bugleweed X
Mentha pulegium* Pennyroyal X X
Stachys ajugoides/albens Hedge nettle X
Trichostema lanceolatum Vinegarweed X X
Lythraceae Loosestrife Family
Ammannia coccinea/robusta Redstem X X X X X X X X X X X Lythrum hyssopifolia* Hyssop loosestrife X X X X X X X X X X X X X X X Malvaceae Mallow Family
Abutilon theophrasti* Velvet-leaf X X X X X X X X X X X X X Malva neglecta* Common mallow X X X X X X X X X Malva nicaeensis* Bull mallow X X X X X X X X X X X X X X X Malvella leprosa Alkali mallow X X X X X X X X X X X X X X X X X X X X Modiola caroliniana* Carolina bristle-mallow X Montiaceae (Split from
Portulacaceae)
Miner’s Lettuce Family
Calandrinia ciliata Red maids X X X X X X X X X X X Claytonia perfoliata Miner’s lettuce X X X X Moraceae Mulberry Family
Ficus carica* Edible fig X X X X X X X
Morus alba* White mulberry X X X
Myrtaceae Myrtle Family
Eucalyptus camulduensis* River red gum X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-13
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Eucalyptus globulus* Blue gum X
Eucalyptus polyanthemos* Silver dollar gum X Oleaceae Olive Family
Fraxinus latifolia Oregon ash X X X X Onagraceae Evening-Primrose Family
Epilobium brachycarpum Panicled willow-herb X X X X X X X X Epilobium campestre (Epilobium
pygmaeum)
Smooth spike-primrose X
Epilobium ciliatum Fringed willowherb X X X X X X X X X X X X X X X X X X X Ludwigia peploides Floating water-primrose X X X X X X Ludwigia peploides ssp.
montevidensis*
Floating water-primrose X X X X X X X X
Ludwigia peploides ssp. peploides Floating water-primrose X X X X Oenothera elata Evening primrose X X
Orobanchaceae (split from
Scrophulariaceae)
Broomrape Family
Castilleja attenuata Valley tassels X
Triphysaria eriantha Johnny-tuck X
Triphysaria pusilla Dwarf owl’s clover X
Oxalidaceae Oxalis Family
Oxalis corniculata* Yellow sorrel X
Oxalis sp.* Sorrel X
Phrymaceae (split from
Scrophulariaceae)
Lopseed Family
The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-14
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Mimulus guttatus Seep-spring monkeyflower X X Plantaginaceae Plantain Family
Bacopa eisenii (Bacopa eisenmanii) Eisen water-hyssop X X X X X X X X Dopatrium junceum* Horsefly’s eye X
Gratiola ebracteata Bractless hedge-hyssop X
Kickxia elatine* Sharp-leaved fluellin X
Lindernia dubia Yellowseed false pimpernel X
Plantago coronopus* Buckhorn plantain X
Plantago lanceolata* English plantain X X X X X X Plantago major* Common plantain X
Veronica anagallis-aquatica* Water speedwell X X X X Veronica arvensis* Corn speedwell X
Veronica peregrina ssp. xalapensis Purslane speedwell X X X X X X X X X X X X X Veronica persica* Persian speedwell X
Platanaceae Plane Family
Platanus racemosa Western sycamore X X X X Polygonaceae Buckwheat Family
Persicaria amphibian (Polygonum
amphibium)
Water smartweed X X X
Persicaria hydropiper (Polygonum
hydropiper)*
Common smartweed,
marsh pepper

X X X X X X X X
Persicaria lapathifolia (Polygonum
lapathifolium)
Willow smartweed X X X X X X X X X X X
The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-15
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Polygonum aviculare subsp.
depressum (Polygonum arenastrum)*
Common knotweed X X X X X X X X X X X X X X X X X X X X X X X Rumex conglomeratus* Clustered dock X
Rumex crispus* Curly dock X X X X X X X X X X X X X X X X X X X X X X X X Rumex dentatus* Toothed dock X X
Rumex pulcher* Fiddle dock X X X X X
Portulacaceae Purslane Family
Portulaca oleracea* Common purslane X X
Primulaceae Primrose Family
Anagallis arvensis* Scarlet pimpernel X X X X X X X X X X X X X X X X X X Ranunculaceae Buttercup Family
Myosurus minimus Common mousetail X X X Ranunculus bonariensis var. trisepalus Carter’s buttercup X X X X Ranunculus muricatus* Prickle-fruited buttercup X X X X X X Ranunculus sp. Buttercup X
Rhamnaceae Buckthorn Family
Frangula californica (Rhamnus
californica)
California coffeeberry X
Rosaceae Rose Family
Pyracantha angustifolia* Firethorn X
Rosa californica California wild rose X X X X X Rubus armeniacus* Himalayan blackberry X X X X X X X X X X X X X Rubus ursinus California blackberry X X X X X X X X X The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-16
April 2023

Scientific Name
(previous scientific name)a Common Name
North Basin Reserve Central Basin Reserve
Fisherman’s
Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lucich North
Lucich South
Nestor
Ruby Ranch
Vestal
BKS
Bianchi West
Elsie
Frazer South
Sills
Tufts
Alleghany
Cummings
Natomas Farms
Rosa East & Central
Souza
Rubiaceae Madder Family
Cephalanthus occidentalis var.
californicus (formally in Rosaceae
family)
Buttonwillow X X X X X X X X
Galium aparine Bedstraw X X X X X X
Salicaceae Willow Family
Populus fremontii Fremont cottonwood X X X X X X X X X X X X X X Salix exigua Narrow-leaved willow X X X
Salix gooddingii Black willow X X X X X X X X X X Salix lasiolepis Arroyo willow X X X X X X Scrophulariaceae Figwort Family
Limosella acaulis Broad-leaved mudwort X X
Simaroubaceae Quassia Family
Ailanthus altissima* Tree-of-heaven X
Solanaceae Nightshade Family
Datura stramonium* Jimson weed X X
Lycopersicon esculentum* Tomato X
Physalis lancifolia* Narrowleaf tomatillo X X X X X Physalis philadelphica* Tomatillo X X X
Solanum americanum Common nightshade X X X X X X X X Urticaceae Nettle Family
Urtica urens* Dwarf nettle X
Verbenaceae Vervain Family
The Natomas Basin Conservancy

Botanical Survey Results
Table B-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
B-17
April 2023

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Appendix C
Avian and Other Covered Species Survey Results

The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-1
April 2023

Table C-1. Common and Scientific Names of Wildlife Species Observed on NBHCP Reserves, 2004–2022 Common Name Scientific Name
Mammals
Coyote Canis latrans
Raccoon Procyon lotor
River otter Lontra canadensis
Striped skunk Mephitis mephitis
Mink Neovison vison
Long-tailed weasel Neogale frenata
California ground squirrel Otospermophilus beecheyi
Botta’s pocket gopher Thomomys bottae
Deer mouse Peromyscus maniculatus
California meadow vole Microtus californicus
Muskrat Ondatra zibethicus
House mouse Mus musculus
Brown rat Rattus norvegicus
Black-tailed jackrabbit Lepus californicus
Desert cottontail Silvilagus audubonii
Mule deer Odocoileus hemionus
Hoary bat Lasiurus cinereus
Mexican free-tailed bats Tadarida brasiliensis mexicanus Birds
Greater white-fronted goose Anser albifrons
Snow goose Chen caerulescens
Canada goose Branta canadensis
Tundra swan Cygnus columbianus
Wood duck Aix sponsa
Gadwall Anas strepera
American wigeon Anas americana
Eurasian wigeon Anas penelope
Mallard Anas platyrhynchos
Blue-winged teal Anas discors
Cinnamon teal Anas cyanoptera
Northern shoveler Anas clypeata
Northern pintail Anas acuta
Green-winged teal Anas crecca
Canvasback Aythya valisineria
Redhead Aythya americana
Ring-necked duck Aythya collaris
Greater scaup Aythya marila
Lesser scaup Aythya affinis
Bufflehead Bucephala albeola
Common goldeneye Bucephala clangula
The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results
Table C-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-2
April 2023

Common Name Scientific Name
Hooded merganser Lophodytes cucullatus
Common merganser Mergus merganser
Ruddy duck Oxyura jamaicensis
Ring-necked pheasant Phasianus colchicus
Wild turkey Meleagris gallopavo
California quail Callipepla californica
Pied-billed grebe Podilymbus podiceps
Eared grebe Podiceps nigricollis
Horned grebe Podiceps auritus
American white pelican Pelecanus erythrorhynchos
Double-crested cormorant Phalacrocorax auritus
American bittern Botaurus lentiginosus
Great blue heron Ardea herodias
Great egret Ardea alba
Snowy egret Egretta thula
Cattle egret Bubulcus ibis
Green heron Butorides virescens
Black-crowned night-heron Nycticorax nycticorax
White-faced ibis Plegadis chihi
Turkey vulture Cathartes aura
Bald eagle Haliaeetus leucocephalus
Osprey Pandion haliaetus
White-tailed kite Elanus leucurus
Northern harrier Circus cyaneus
Sharp-shinned hawk Accipiter striatus
Cooper’s hawk Accipiter cooperii
Red-shouldered hawk Buteo lineatus
Swainson’s hawk Buteo swainsoni
Ferruginous hawk Buteo regalis
Red-tailed hawk Buteo jamaicensis
Rough-legged hawk Buteo lagopus
American kestrel Falco sparverius
Merlin Falco columbarius
Prairie falcon Falco mexicanus
Peregrine falcon Falco peregrinus
Virginia rail Rallus limicola
Sora Porzana carolina
Common gallinule Gallinula galeata
American coot Fulica americana
Sandhill crane Grus canadensis
Killdeer Charadrius vociferus
Black-necked stilt Himantopus mexicanus
American avocet Recurvirostra americana
The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results
Table C-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-3
April 2023

Common Name Scientific Name
Greater yellowlegs Tringa melanoleuca
Lesser yellowlegs Tringa flavipes
Long-billed curlew Numenius americanus
Western sandpiper Calidris mauri
Least sandpiper Calidris minutilla
Baird’s sandpiper Calidris bairdii
Dunlin Calidris alpina
Short-billed dowitcher Limnodromus griseus
Long-billed dowitcher Limnodromus scolopaceus
Wilson’s snipe Gallinago gallinago
Wilson’s phalarope Phalaropus tricolor
Red-necked phalarope Phalaropus lobatus
Ring-billed gull Larus delawarensis
California gull Larus californicus
Herring gull Larus argentatus
Caspian tern Sterna caspia
Black tern Chlidonias niger
Forster’s tern Sterna forsteri
Rock pigeon Columba livia
Eurasian-collared dove Streptopelia decaocto
Mourning dove Zenaida macroura
Barn owl Tyto alba
Great horned owl Bubo virginianus
Burrowing owl Athene cunicularia
Short-eared owl Asio flammeus
Lesser nighthawk Chordeiles acutipennis
White-throated swift Aeronautes saxatalis
Black-chinned hummingbird Archilochus alexandri
Anna’s hummingbird Calypte anna
Rufous hummingbird Selasphorus rufus
Belted kingfisher Ceryle alcyon
Acorn woodpecker Melanerpes formicivorus
Nuttall’s woodpecker Picoides nuttallii
Downy woodpecker Picoides pubescens
Northern flicker Colaptes auratus
Western wood-pewee Contopus sordidulus
Willow flycatcher Empidonax traillii
Pacific-slope flycatcher Empidonax difficilis
Black phoebe Sayornis nigricans
Say’s phoebe Sayornis saya
Ash-throated flycatcher Myiarchus cinerascens
Western kingbird Tyrannus verticalis
Loggerhead shrike Lanius ludovicianus
The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results
Table C-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-4
April 2023

Common Name Scientific Name
Warbling vireo Vireo gilvus
California scrub-jay Aphelocoma californica
Yellow-billed magpie Pica nuttalli
Common Raven Corvus corax
American crow Corvus brachyrhynchos
Horned lark Eremophila alpestris
Tree swallow Tachycineta bicolor
Violet-green swallow Tachycineta thalassina
Northern rough-winged swallow Stelgidopteryx serripennis Cliff swallow Petrochelidon pyrrhonota
Barn swallow Hirundo rustica
Oak titmouse Baeolophus inornatus
Bushtit Psaltriparus minimus
White-breasted nuthatch Sitta carolinensis
Bewick’s wren Thryomanes bewickii
House wren Troglodytes aedon
Marsh wren Cistothorus palustris
Ruby-crowned kinglet Regulus calendula
Golden-crowned kinglet Regulus satrapa
Western bluebird Sialia mexicana
Mountain bluebird Sialia currucoides
Swainson’s thrush Catharus ustulatus
Hermit thrush Catharus guttatus
American robin Turdus migratorius
Northern mockingbird Mimus polyglottos
European starling Sturnus vulgaris
American pipit Anthus rubescens
Cedar waxwing Bombycilla cedrorum
Phainopepla Phainopepla nitens
Orange-crowned warbler Vermivora celata
Yellow warbler Dendroica petechia
Yellow-rumped warbler Dendroica coronata
Black-throated gray warbler Dendroica nigrescens
Townsend’s warbler Dendroica townsendi
MacGillivray’s warbler Oporornis tolmiei
Common yellowthroat Geothlypis trichas
Wilson’s warbler Wilsonia pusilla
Western tanager Piranga ludoviciana
Spotted towhee Pipilo maculatus
California towhee Pipilo crissalis
Chipping sparrow Spizella passerina
Lark sparrow Chondestes grammacus
Savannah sparrow Passerculus sandwichensis
The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results
Table C-1. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-5
April 2023

Common Name Scientific Name
Fox sparrow Passerella iliaca
Song sparrow Melospiza melodia
Lincoln’s sparrow Melospiza lincolnii
White-crowned sparrow Zonotrichia leucophrys
Golden-crowned sparrow Zonotrichia atricapilla
Dark-eyed junco Junco hyemalis
Black-headed grosbeak Pheucticus melanocephalus
Blue grosbeak Guiraca caerulea
Lazuli bunting Passerina amoena
Red-winged blackbird Agelaius phoeniceus
Tricolored blackbird Agelaius tricolor
Yellow-headed blackbird Xanthocephalus xanthocephalus
Brewer’s blackbird Euphagus cyanocephalus
Great-tailed grackle Quiscalus mexicanus
Brown-headed cowbird Molothrus ater
Western meadowlark Sturnella neglecta
Bullock’s oriole Icterus bullockii
House finch Carpodacus mexicanus
Lesser goldfinch Carduelis psaltria
American goldfinch Carduelis tristis
House sparrow Passer domesticus
Reptiles
Pacific pond turtle Actinemys marmorata
Red-eared slider Trachemys scripta elegans
Pacific gopher snake Pituophis catenifer catenifer
Western yellow-bellied racer Coluber constrictor mormon California king snake Lampropeltis getulus californiae Giant gartersnake Thamnophis gigas
Valley gartersnake Thamnophis sirtalis fitchi
Western fence lizard Sceloporus occidentalis
California alligator lizard Gerrhonotus multicarnatus multicarnatus Amphibians
Sierran tree frog Pseudacris Sierra
Bullfrog Rana catesbeiana
The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-6
April 2023

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The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-7
April 2023

Table C-2. Total Numbers of Bird Detections on NBHCP Mitigation Lands during 2022 Avian Surveys Common Name
North Basin Reserve
Willey
Central Basin Reserve Fisherman’s Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lauppe North
Lauppe South
Lucich North
Lucich South
Nestor
Ruby Ranch
Verona
Vestal
Betts Kismat Silva
Bianchi West
Elsie
Elverta Silva South
Frazer South
Paulson South
Richter
Sills
Tufts
Alleghany 50
Cummings
Natomas Farms
Rosa Central
Souza
Total
Greater White-fronted Goose 0 335 4 0 0 0 196 0 0 0 0 470 0 0 60 0 270 0 381 0 90 965 33 60 15 300 70 0 0 0 0 72 3,321 Snow Goose 0 0 0 0 0 0 0 0 0 8 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11 Canada Goose 4 132 2 0 0 0 81 0 0 0 0 221 0 0 0 0 0 0 558 0 0 0 0 0 0 0 0 0 4 93 0 7 1,102 Wood Duck 0 0 2 0 0 0 4 0 0 0 0 1 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 0 6 3 0 0 28 American Wigeon 0 45 0 0 0 0 5 0 0 0 0 32 0 0 0 0 0 0 88 0 0 0 0 6 0 0 0 0 4 0 0 0 180 Mallard 9 65 17 12 0 0 88 16 0 4 7 148 51 2 0 0 0 3 262 23 0 14 0 13 0 45 9 0 32 38 6 0 864 Blue-winged Teal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 40 0 0 0 0 0 0 0 0 0 0 0 0 0 40 Cinnamon Teal 0 4 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 36 2 0 0 0 0 0 10 0 0 0 0 0 0 62 Northern Shoveler 0 0 0 0 0 0 0 0 0 500 120 2 40 0 0 0 0 0 13 210 0 0 0 64 0 0 0 0 0 0 0 0 949 Northern Pintail 60 1 0 0 0 0 3 0 0 400 0 3 0 0 0 0 0 0 16 120 0 0 0 53 0 0 0 0 0 0 0 0 656 Green-winged Teal 0 0 0 0 0 0 0 0 0 250 0 12 160 0 0 0 0 0 30 8 0 0 84 0 0 0 0 0 0 0 0 0 544 Canvasback 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 4 Redhead 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 Greater Scaup 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 0 4 0 0 0 17 Lesser Scaup 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 2 Bufflehead 0 0 0 0 0 0 0 0 0 0 0 8 0 0 0 0 0 0 60 0 0 0 0 0 0 0 0 0 0 2 0 0 70 Common Goldeneye 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 18 0 0 0 0 0 0 0 0 0 0 3 0 0 22 Hooded Merganser 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0 0 7 Common Merganser 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 5 4 0 0 9 Ruddy Duck 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 2 Wild Turkey 73 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 73 California Quail 15 0 0 0 2 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 18 Pied-billed Grebe 0 31 3 0 0 0 23 0 0 0 0 24 1 0 0 0 0 0 45 0 0 0 0 0 0 1 0 0 1 3 0 0 132 American White Pelican 0 3 0 0 0 0 121 0 0 0 1 175 9 0 0 0 0 0 80 0 0 0 0 0 0 0 0 0 0 20 0 0 409 Double-crested Cormorant 0 15 1 0 0 0 11 0 0 0 0 114 4 0 0 0 0 0 57 0 0 0 0 0 0 0 0 0 0 28 0 0 230 American Bittern 0 0 0 1 0 0 1 2 0 0 0 0 3 0 0 0 0 0 0 1 0 0 0 0 0 0 4 0 0 0 0 0 12 Great Blue Heron 6 27 4 2 0 3 25 14 0 7 4 34 30 4 3 4 8 0 27 5 1 17 6 4 0 21 8 0 1 15 1 0 281 Great Egret 15 16 8 13 2 3 29 101 8 66 45 58 96 0 3 6 3 3 98 37 5 56 19 35 1 40 17 0 6 44 1 1 835 Snowy Egret 1 0 0 0 0 0 7 1 0 20 0 22 10 0 0 0 0 0 61 7 0 6 33 19 0 3 1 0 4 12 5 0 212 Cattle Egret 0 0 0 0 0 0 0 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 Green Heron 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 Black-crowned Night-Heron 2 48 0 0 0 0 14 11 0 0 8 7 35 0 0 0 2 0 121 5 0 3 2 0 0 1 3 0 0 0 1 0 263 White-faced Ibis 53 0 0 210 0 0 20 346 0 185 16 15 223 0 0 0 0 0 37 135 0 120 0 22 0 27 3 0 0 0 0 0 1,412 Turkey Vulture 11 2 0 0 0 1 3 1 0 1 0 7 2 0 0 1 0 1 1 0 0 3 1 0 0 0 0 0 0 0 1 0 36 White-tailed Kite 12 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 0 0 1 0 0 0 0 0 0 1 0 0 0 22 Northern Harrier 1 3 5 5 0 2 2 1 0 2 1 1 4 3 3 1 0 1 4 0 1 1 1 1 2 2 3 0 1 3 0 0 54 Cooper's Hawk 1 0 1 0 0 0 0 0 0 0 0 2 0 0 0 1 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 7 Red-shouldered Hawk 0 0 1 0 0 0 0 0 3 0 0 0 0 0 0 1 2 0 10 0 0 0 0 0 0 0 0 0 0 0 0 0 17 Swainson's Hawk 2 0 1 0 2 2 1 0 0 2 1 0 2 0 0 1 0 0 2 0 0 0 0 0 0 0 0 0 0 0 4 0 20 Red-tailed Hawk 15 3 4 2 4 3 6 2 4 2 1 9 13 4 7 0 6 3 36 6 6 16 11 0 2 15 5 3 2 3 2 0 195 The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results

Table C-2. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-8
April 2023

Common Name
North Basin Reserve
Willey
Central Basin Reserve Fisherman’s Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lauppe North
Lauppe South
Lucich North
Lucich South
Nestor
Ruby Ranch
Verona
Vestal
Betts Kismat Silva
Bianchi West
Elsie
Elverta Silva South
Frazer South
Paulson South
Richter
Sills
Tufts
Alleghany 50
Cummings
Natomas Farms
Rosa Central
Souza
Total
American Kestrel 11 0 0 0 0 1 0 1 4 1 0 1 3 1 0 0 4 0 4 0 1 2 2 0 0 1 0 0 0 0 2 1 40 Prairie Falcon 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Common Gallinule 0 1 0 0 0 0 9 0 0 0 0 7 0 0 0 0 0 0 32 0 0 0 0 0 0 0 0 0 0 0 0 0 49 American Coot 0 116 3 0 0 0 7 0 0 0 0 102 0 0 0 0 0 0 638 0 0 0 5 0 0 0 0 0 0 1 0 0 872 Sandhill Crane 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 Killdeer 4 20 4 7 0 0 9 14 8 6 5 2 38 4 5 3 4 31 60 10 9 5 11 5 0 9 2 1 3 5 9 1 294 Mountain Plover 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 Black-necked Stilt 0 0 0 2 0 0 0 0 0 6 0 3 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 16 American Avocet 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 2 Greater Yellowlegs 4 0 0 0 0 0 11 0 0 32 32 32 18 0 4 0 0 0 4 9 0 0 16 7 0 1 0 0 0 0 0 0 170 Long-billed Curlew 0 0 0 0 0 0 0 0 0 0 87 0 0 0 0 0 0 0 0 1 0 0 0 10 0 0 0 0 0 0 0 0 98 Least Sandpiper 0 0 0 0 0 0 0 0 0 0 32 3 0 0 0 0 0 0 0 40 0 0 0 0 0 0 0 0 0 0 0 0 75 Dunlin 0 0 0 0 0 0 0 0 0 0 0 140 100 0 0 0 0 50 0 0 0 0 20 0 0 0 0 0 0 0 0 0 310 Long-billed Dowitcher 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 0 0 0 0 0 12 Wilson's Snipe 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 4 0 0 0 0 0 0 0 0 5 Ring-billed Gull 0 0 0 1 0 0 0 0 0 61 0 0 10 1 0 0 0 0 0 0 0 0 0 7 0 2 0 0 3 2 0 0 87 California Gull 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 Rock Pigeon 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 10 Eurasian Collared-Dove 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0 0 3 Mourning Dove 55 0 5 0 2 0 6 3 2 0 0 6 2 0 7 0 1 0 44 0 1 0 0 0 0 0 2 4 7 15 15 10 187 Great Horned Owl 0 1 2 0 0 0 0 1 1 0 0 2 0 5 0 0 0 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 17 Burrowing Owl 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 White-throated Swift 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 2 Anna's Hummingbird 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 2 Belted Kingfisher 1 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 1 0 0 7 Acorn Woodpecker 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 6 Nuttall's Woodpecker 11 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 3 0 3 0 0 19 Northern Flicker 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 7 Western Wood-Pewee 6 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 7 Black Phoebe 9 5 2 1 9 0 6 1 0 0 2 14 10 1 0 0 5 0 33 1 0 4 4 0 1 3 0 4 5 10 4 3 137 Say's Phoebe 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 3 Ash-throated Flycatcher 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 Western Kingbird 36 5 5 0 26 6 1 1 14 7 1 7 0 0 0 5 6 1 18 0 0 0 0 0 0 1 0 4 1 0 11 3 159 California Scrub-Jay 21 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 2 0 2 32 Yellow-billed Magpie 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 American Crow 13 0 0 0 1 0 0 7 9 0 28 0 1 0 4 0 5 1 0 0 0 0 0 0 0 0 0 0 0 5 24 7 105 Common Raven 0 2 0 2 2 0 0 0 0 0 0 0 2 0 0 0 0 0 2 0 0 1 2 0 0 2 0 0 0 0 0 0 15 Horned Lark 0 75 0 0 0 0 0 0 0 0 0 0 30 120 0 4 0 30 0 2 6 0 0 0 8 50 4 0 0 0 1 0 330 Tree Swallow 69 35 1 0 10 0 11 0 2 0 2 16 0 0 0 0 4 0 60 0 0 0 0 0 0 3 0 0 0 0 22 0 235 Cliff Swallow 15 7 7 0 7 10 10 2 4 8 9 16 4 0 13 1 5 0 180 0 7 18 12 0 1 21 0 0 20 46 3 0 426 The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results

Table C-2. Continued

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-9
April 2023

Common Name
North Basin Reserve
Willey
Central Basin Reserve Fisherman’s Lake Reserve
Atkinson
Bennett North
Bennett South
Bolen North
Bolen South
Bolen West
Frazer
Huffman East
Huffman West
Lauppe North
Lauppe South
Lucich North
Lucich South
Nestor
Ruby Ranch
Verona
Vestal
Betts Kismat Silva
Bianchi West
Elsie
Elverta Silva South
Frazer South
Paulson South
Richter
Sills
Tufts
Alleghany 50
Cummings
Natomas Farms
Rosa Central
Souza
Total
Barn Swallow 0 0 7 1 1 0 0 0 4 0 5 7 8 0 0 0 0 1 24 2 0 2 1 0 1 4 4 1 5 7 4 0 89 Unknown swallow 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 6 Oak Titmouse 11 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 13 Bushtit 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 0 0 0 0 0 7 0 0 18 Bewick's Wren 10 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 11 House Wren 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 Marsh Wren 0 86 13 0 0 0 108 0 0 0 0 143 37 0 0 0 0 0 266 0 0 0 0 0 0 0 0 0 2 4 0 0 659 Ruby-crowned Kinglet 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Western Bluebird 21 0 0 0 0 0 0 0 2 0 0 5 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 2 2 0 3 0 39 American Robin 0 0 0 0 2 0 0 0 5 4 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 12 Northern Mockingbird 3 0 0 0 3 0 0 0 1 0 0 0 0 1 0 0 2 0 13 0 4 0 0 0 0 0 0 1 5 13 10 8 64 European Starling 167 0 0 0 112 0 0 30 160 5 167 0 0 0 0 11 0 0 63 0 0 0 0 0 0 0 0 12 0 10 17 18 772 American Pipit 12 20 25 31 0 0 5 22 0 0 1 0 0 45 20 14 1 15 5 0 26 7 0 1 24 85 60 0 1 1 0 0 421 Phainopepla 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 Yellow-rumped Warbler 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 2 0 0 15 Common Yellowthroat 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 12 6 0 0 22 Wilson's Warbler 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 Spotted Towhee 19 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 20 California Towhee 7 0 0 0 4 0 0 0 0 0 1 0 0 0 0 0 2 0 3 0 0 0 0 0 0 0 0 42 0 0 0 1 60 Lark Sparrow 24 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 26 Savannah Sparrow 140 104 159 137 12 174 24 197 3 52 22 92 102 93 81 142 73 55 56 69 48 95 177 27 17 234 91 0 20 12 21 2 2,531 Song Sparrow 0 3 16 0 0 0 12 0 0 0 0 17 14 0 0 1 0 0 12 0 0 0 0 0 0 2 1 0 6 5 0 0 89 White-crowned Sparrow 54 34 2 19 5 32 9 0 0 0 0 0 3 27 2 0 2 0 71 0 0 22 0 0 0 0 0 0 38 6 0 0 326 Golden-crowned Sparrow 0 0 0 0 3 0 14 0 0 0 0 0 0 0 0 0 0 0 32 0 0 0 0 0 0 0 0 0 0 5 0 0 54 Red-winged Blackbird 299 97 3262 74 78 5 732 733 51 84 578 437 9035 3 20 9 277 400 3303 326 1,502 180 117 47 0 563 241 5 376 121 74 25 23,054 Tricolored Blackbird 0 0 220 80 0 0 151 80 50 20 2 0 300 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 903 Western Meadowlark 38 155 114 35 1 96 70 21 2 27 16 89 36 121 94 52 135 6 254 58 38 35 48 29 8 117 73 0 2 22 3 0 1795 Yellow-headed Blackbird 0 0 0 0 0 0 0 0 0 0 0 0 10 0 0 0 0 0 1 0 0 0 0 0 0 2 0 0 0 0 0 0 13 Brewer's Blackbird 15 26 832 100 81 0 0 116 216 77 0 5 1,000 3 45 11 238 408 97 0 61 74 33 39 5 26 66 0 0 0 2 0 3,576 Great-tailed Grackle 0 22 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 6 0 1 0 0 0 0 0 0 0 0 35 Brown-headed Cowbird 9 2 75 0 3 0 11 0 0 0 0 0 10 0 0 0 0 400 59 0 2 2 9 0 0 2 0 0 2 9 2 2 599 Bullock's Oriole 5 0 0 0 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 8 House Finch 167 2 36 4 23 8 15 0 27 0 0 6 2 1 41 8 33 1 94 1 0 36 17 0 0 22 0 7 9 33 27 19 639 Lesser Goldfinch 28 0 0 0 6 2 0 2 0 0 0 0 0 0 0 0 9 0 12 0 0 2 0 0 0 0 0 0 0 3 4 1 69 American Goldfinch 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 0 0 0 4 House Sparrow 6 1 2 0 0 0 4 0 9 1 0 2 0 1 0 0 2 0 22 0 0 0 0 0 0 0 0 0 0 0 0 0 50

The Natomas Basin Conservancy

Avian and Other Covered Species Survey Results

Biological Effectiveness Monitoring for the
Natomas Basin Habitat Conservation Plan Area
2022 Annual Survey Results
E-10
April 2023

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Natomas Basin E042002017SAC cover_3a.indd 08.01.02 dash Draft Environmental Impact Report/
Environmental Impact Statement
Draft Natomas Basin Habitat Conservation Plan
August 2002
State Clearinghouse No. 1997062064
Sutter County
U.S. Fish and Wildlife Service
City of Sacramento
Natomas Basin E042002017SAC cover_3a.indd 08.01.02 dash U.S. Fish and Wildlife Service
2800 Cottage Way, W-2605
Sacramento, CA 95825
www.fws.gov
Sutter County
1160 Civic Center Blvd.

Yuba City, CA 95993
www.co.sutter.ca.us
City of Sacramento
1231 I Street, Suite 300
Sacramento, CA 95814
www.cityofsacramento.org
August 2002
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-1

EIR/EIS
Executive Summary
ES-1 Introduction
This Draft Environmental Impact Report/Environmental Impact Statement for the Revised Natomas Basin Habitat Conservation Plan (EIR/EIS) presents the environmental impacts that have the potential to occur as a result of implementing the Proposed Action described in Chapter 1 of this EIR/EIS. The Proposed Action comprises the conservation measures of the revised Draft Natomas Basin Habitat Conservation Plan, Sacramento and Sutter Counties, California1 (HCP), incidental take permits (ITPs) for covered activities included in the HCP, and an implementing agreement or agreements (IA[s]) to secure participation and compliance of the permittees. The permittees (see Section 2.1) are the City of Sacramento, Sutter County, and the Natomas Basin Conservancy. The City and Sutter County are lead agencies under the California Environmental Quality Act (CEQA), and the U.S. Fish and Wildlife Service (USFWS) is the lead agency under the National Environmental Policy Act (NEPA) (see Section 1.3.1). In addition to the City, Sutter County, and the Conservancy, Reclamation District No. 1000 (RD 1000) and the Natomas Central Mutual Water Company (Natomas Mutual) have also participated in the HCP development process, and the impacts of their proposed covered activities are analyzed in this EIR/EIS (see Section 1.2.1 for a discussion of RD 1000’s and Natomas Mutual’s history and status of participation in the development of the HCP evaluated in this EIR/EIS).
2 Each of the permittees has a specific designated permit area for its covered activities. The permittees, their permit areas and covered activities, and the conservation measures for which each permittee is responsible are discussed in detail in Chapter 2 of this EIR/EIS.

The HCP has been developed to provide and implement a multispecies conservation program to minimize and mitigate impacts of planned urban development and management activities of the Natomas Basin Conservancy (see Section 2.3 for a discussion of the HCP’s underlying covered activities associated with the Proposed Action). The HCP also has been prepared to meet the requirements of the California Department of Fish and Game (CDFG) in support of planned applications, or revisions to current applications, to receive incidental take authorization for state-listed species under Section 2081 of the California Fish and Game Code (see Section 1.3.2 for additional discussion of CDFG participation).

The conservation measures in the HCP apply to 22 special-status species (the “covered species”). A list of the covered species is presented in Section 2.4.3 of this EIR/EIS. Sections I and II of the HCP also include a discussion of the covered species.

1 City of Sacramento, Sutter County, Natomas Basin Conservancy, July 2002. 2 On the basis of ongoing discussions with USFWS on whether the water agencies (RD 1000 and Natomas Mutual) can obtain incidental take coverage for pesticide use, the water agencies have decided not to file applications for permits at this time.

They have, however, identified proposed conservation measures (see Section 2.4.6.3 of this EIR/EIS) for their covered activities that exclude pesticide use, and these measures are incorporated in the HCP evaluated in this EIR/EIS (see Section

2.3.3 of this EIR/EIS). The water agencies could elect to apply for an ITP at a future date and would be required at that time to execute an IA that demonstrates implementation and compliance with the HCP. A summary of the water agencies’ participation in the HCP is in Section 1.2.1.

EXECUTIVE SUMMARY
ES-2 REVISED NATOMAS BASIN HCP E042002017SAC/161795(EXECUTIVE SUMMARY.DOC)

EIR/EIS
The HCP evaluated in this EIR/EIS supercedes the prior HCP for the Natomas Basin that was prepared and approved in 1997 (see Section 1.2).

This Executive Summary includes the following sections:
/g183 Purpose and Need/Objectives (ES-2)
/g183 Study Area (ES-3)
/g183 Proposed Action and Alternatives (ES-4)
/g183 Areas of Controversy (ES-5)
/g183 Issues to be Resolved (ES-6)
/g183 Summary of Impacts (ES-7)
A summary of the alternatives is in Table ES-1, and a comparative summary of the impacts of the Proposed Action and the alternatives to the Proposed Action is provided in Table ES-2.

ES-2 Purpose and Need/Objectives
The USFWS’s purpose (in accordance with NEPA requirements) in issuing ITPs, entering into an IA(s), and approving the HCP is to authorize the incidental take of the covered species resulting from the covered activities in the Natomas Basin. As stated in the USFWS’s Habitat Conservation Planning Handbook (USFWS and National Marine Fisheries Service, 1996), a key facet of the HCP program is to reduce conflicts between listed species and economic development activities, and create a framework that would encourage “creative partnerships” among the public and private sectors and state, municipal, and federal agencies in the interests of endangered and threatened species and habitat conservation. The need for the action is based on the potential that activities proposed by the permittees could result in the take of federally listed species and other unlisted species that could become listed in the future. The USFWS must respond to the ITP application related to activities that have the potential to result in the take of covered species within each permittee’s permit area.

The primary objectives under CEQA for the City and Sutter County are to implement their respective general plans and other planning documents (see Section 2.2 and Chapter 4, Environmental Consequences) for lands within the Natomas Basin. These plans represent a foreseeable urban development scenario evaluated for the HCP. The Proposed Action addresses incidental take of the covered species resulting from 17,500 acres of planned development in the Natomas Basin (this also includes the 1,983-acre Metro Air Park project in unincorporated Sacramento County, which is covered by a separate ITP, as described in Section 1.2.1). These development activities have the potential to result in the take of listed species and permanent disturbance to their habitats within the 53,537-acre Natomas Basin.

The objective for the Conservancy is to implement the provisions of the HCP on lands acquired for management by the Conservancy in a way that promotes biological conservation and provides incidental take coverage.

EXECUTIVE SUMMARY
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-3

EIR/EIS
ES-3 Study Area
The study area for this EIR/EIS is primarily the Natomas Basin. The study area also includes Area B, which is the out-of-basin mitigation area in which habitat reserve lands could be acquired (see Section 2.4.5.6). (The EIR/EIS study area includes the HCP Plan Area.) The individual permit areas for each of the permittees are discussed in Section 2.2.

ES-4 Proposed Action and Alternatives
The alternatives evaluated in this EIR/EIS are summarized in Table ES-1.

TABLE ES-1
EIR/EIS Alternatives
Title Brief Description
Revised Natomas Basin HCP
(Proposed Action)
Provide incidental take coverage for the following covered activities:
/g183 Urban development of 17,500 acres in the City of Sacramento, Sutter County, and Metro Air Park (see Section 2.3.1)
/g183 Development, operations, and maintenance of the system of habitat reserves envisioned under the HCP
Implement conservation measures for 22 special-status species. See Table 2-1 for a listing of these species; Section 2.4.6 for conservation measures to be implemented by the City of Sacramento, Sutter County, Metro Air Park; RD 1000, and Natomas Mutual.

Establish a system of habitat reserves based on a ratio of one-half acre of land to be acquired for each acre of land developed (8,750 acres total, based on 17,500 acres to be developed). See Section 2.4.5 for a description of the acquisition, management, and funding program for the habitat reserves.

Increased Mitigation
(Alternative 1)
Same as the Proposed Action, but acquisition of habitat reserves would be based on a 1:1 ratio (17,500 acres of reserves with 17,500 acres of land development).

Habitat-Based Mitigation
(Alternative 2)
Same as the Proposed Action, but acquisition of habitat reserves would be based on habitat value of the lands subject to urban development.

Based on the methodology described in Section 2.6.2, this would result in the need to acquire 17,569 acres of lands to be managed as habitat reserves.

Reserve Zones
(Alternative 3)
Same as the Proposed Action, but the acquisition criteria for habitat reserves would be geographically focused based on the habitat needs of the giant garter snake and Swainson’s hawk. For a description of the five reserve zones, see Section 2.6.3.

Reduced Potential for Incidental
Take (Alternative 4)
Same as the Proposed Action, but the land development area covered under the ITPs would be reduced from 17,500 acres to 12,000 acres.

No Action Alternative
(Alternative 5)
Incidental take permits would not be issued and the HCP would not be implemented. Land development would occur, but would develop mitigation measures for the covered species on a case-by-case basis.

EXECUTIVE SUMMARY
ES-4 REVISED NATOMAS BASIN HCP E042002017SAC/161795(EXECUTIVE SUMMARY.DOC)

EIR/EIS
ES-4.1 Independent Implementation
As discussed in Section I.A of the HCP (and in Section 2.3 of this EIR/EIS), the individual permittees (i.e., the City, Sutter County, Conservancy, RD 1000, and Natomas Mutual) would obtain individual ITPs from the USFWS for activities within each permittee’s respective permit area. Similarly, each of these permittees also would obtain individual Section 2081 permits (or amendments to existing 2081 permits) from the CDFG for activities conducted within each permittee’s respective permit area. Each permittee would be required to mitigate independently the impacts of its covered activities (i.e., if any one of the permits was revoked, the other permits would remain in effect). The conservation strategy in the HCP, as it pertains to specific permittees, can be used by the various applicants to obtain the necessary take permits needed to conduct otherwise lawful activities within each permittee’s respective permit area. Because of the potential for independent implementation of the HCP by permittees, this EIR/EIS assesses impacts from individual permittees as well as overall impacts of the Proposed Action and alternatives (see Chapter 4, Environmental Consequences).

ES-5 Areas of Controversy
Areas of controversy known to the lead agencies, including issues raised by agencies and the public, must be identified in the Executive Summary of an EIR. (California Code of Regulations, Section 15123). The scoping phase of the EIR/EIS, conducted between December 18, 2000 and January 16, 2001, identified the following key areas of concern for consideration in the EIR/EIS:
/g183 Nuisance effects of habitat reserves on adjacent land uses /g183 Potential for the habitat reserves to increase conflicts between waterfowl and aircraft from Sacramento International Airport
/g183 Need to provide increased mitigation (e.g., a higher ratio for reserve acquisition) or protect key existing habitat areas
/g183 Consideration of future development beyond the 17,500 acres considered in the HCP ES-6 Issues To Be Resolved
Issues to be resolved, including the choice among alternatives and whether or how to mitigate significant effects, must be identified in the Executive Summary of an EIR (California Code of Regulations, Section 15123). The choice among the alternatives evaluated in the EIR/EIS is the primary issue to be resolved as part of the EIR/EIS process.

ES-7 Summary of Impacts and Mitigation Measures
This section presents a summary of the impacts of implementing the Proposed Action (i.e., the proposed Natomas Basin HCP) or alternatives. The proposed conservation strategy (see Section 2.1.3) is designed to: (1) avoid the environmental effects that could cause take; and (2) minimize and mitigate the impacts of take that could occur. The potential direct, indirect,

EXECUTIVE SUMMARY
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-5

EIR/EIS
and cumulative effects of the Proposed Action and alternatives are described and evaluated in Chapter 4, Environmental Consequences, for the resource areas listed below. (The affected environment for each of these resource areas is presented in Chapter 3, Affected Environment.)
/g183 Geology and Soils (Section 4.2)
/g183 Water Resources (Section 4.3)
/g183 Biological Resources (Section 4.4)
/g183 Cultural Resources (Section 4.5)
/g183 Land Use/Consistency with Adopted Plans and Policies (Section 4.6) /g183 Social and Economic Conditions (Section 4.7)
/g183 Traffic (Section 4.8)
/g183 Noise (Section 4.9)
/g183 Air Quality (Section 4.10)
/g183 Public Health and Safety (Section 4.11)
Table ES-2, at the end of this Executive Summary, provides a comparative overview of the impacts of the Proposed Action and the alternatives for each of the resource areas assessed in this EIR/EIS. The table is focused on the impacts of developing the habitat reserves (see Section 4.1.3 for a discussion of prior environmental analyses). Detailed analysis of impacts is contained in Chapter 4, Environmental Consequences.

ES-7.2 Summary of Impacts
Overall, the critical resources assessed in this EIR/EIS are the species covered by the ITPs.

On the basis of the assessment of direct, indirect, and cumulative impacts presented in Section 4.4, implementing the HCP or the other alternatives would not result in significant environmental impacts. The impacts to species resulting from implementation of the HCP would be less than significant, because of either the conservation measures in the HCP or additional mitigation measures prescribed in Section 4.4.

Implementing the HCP could result in the potential for impacts to occur to other resources.

Potentially significant impacts are identified relating to water quality, cultural resources, agricultural lands, traffic, noise, and air quality. Impacts associated with land development have been addressed in prior environmental documents as referenced in Section 4.1 and in Appendix C. Where new significant impacts are identified, mitigation measures are proposed to reduce the extent of the impacts to a less-than-significant level. With the exception of the loss of farmland resulting from creating the habitat reserves, all new impacts are expected to be reduced to a less-than-significant level with the mitigation measures proposed. Impacts attributable to loss of farmland in the Natomas Basin from creation of habitat reserves are not likely to be mitigated to a less-than-significant level and, therefore, represent an unavoidable adverse consequence of the Proposed Action.

EXECUTIVE SUMMARY
ES-6 REVISED NATOMAS BASIN HCP E042002017SAC/161795(EXECUTIVE SUMMARY.DOC)

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action

4.2 Geology and Soils
Impact: Less-than-significant increases in
erosion resulting from development of
habitat reserves.

Impact: Greater impacts
than the Proposed Action,
but less than significant.

Impact: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

4.3 Water Resources
Impact: Less-than-significant increases in
flood potential resulting from management
of habitat reserves.

Impact: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

Impact: Potentially significant decreases in
stormwater quality resulting from
development of habitat reserves. Can be
mitigated to a less-than-significant level
with mitigation.

EIR/EIS Mitigation Measure: Construction
of habitat reserves shall adhere to the
requirements of the State Water
Resources Control Board’s General
Permit for Stormwater Discharges
Associated with Construction Activity, as
amended from time to time, by filing an
NOI with the Central Valley Regional
Water Quality Control Board. For
development activities on each reserve
site, the Conservancy shall prepare a
Stormwater Pollution Prevention Plan that
includes best management practices
consistent with the City’s Administrative
and Technical Procedures for Grading and
Erosion and Sediment Control and
Sacramento County’s Erosion and
Sediment Control Standards and
Specifications, regardless of whether the
reserves are located in Sacramento or
Sutter County. Best management
practices shall focus on the control of
Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar to
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

EXECUTIVE SUMMARY
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-7

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
sediment discharge into local drains (e.g.,
through installation of barriers such as silt
fences and through tracking controls) and
the release of hazardous materials from
construction operations (e.g., through the
use of designated staging areas with
onsite controls).

Impact: Less-than-significant impacts
associated with future water availability in
the Natomas Basin.

Impact: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

4.4 Biological Resources
Impact: Marsh habitat as measured by rice
fields, canals and drains, and ponds and
seasonally wet areas would decline in the
Natomas Basin by 8,087 acres (35
percent), 404 acres (23 percent), and 21
acres (22 percent), respectively because
of authorized development. Permanent
reserves would be established, including
2,187.5 acres of managed marsh and
4,350 acres of rice.

EIR/EIS Mitigation Measure: As part of the
process for development review, the City
and Sutter County will include a provision
that public or private development projects
that could support jurisdictional wetlands
will result in no net loss of wetlands and
will ensure that that wetlands functions
and values will be maintained.

Impact: Impacts to marsh
habitat associated with
authorized development
would be the same as
under the Proposed Action.

Permanent reserves would
be established, including
4,350 acres of managed
marsh and 8,750 acres of
rice.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Impacts to marsh
habitat associated with
authorized development
would be the same as
under the Proposed Action.

Permanent reserves would
be established, including a
combined rice/managed
marsh reserve acreage of
9,687 acres.

EIR/EIS Mitigation
Measure: Same as
Proposed Action
Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Marsh habitat as
measured by rice fields,
canals and drains, and
ponds and seasonally wet
areas would decline in the
Natomas Basin by 5,752
acres (25 percent), 277
acres (16 percent), and
15 acres (15 percent),
respectively because of
authorized development.

Permanent reserves
would be established,
including 1,500 acres of
managed marsh and
3,000 acres of rice.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Marsh habitat is
expected to decrease by
approximately the same
acreage as under the
Proposed Action because
of urban development.

Unknown benefits
associated with habitat
creation.

EXECUTIVE SUMMARY
ES-8 REVISED NATOMAS BASIN HCP E042002017SAC/161795(EXECUTIVE SUMMARY.DOC)

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
Impact: Upland habitat in the Natomas
Basin would decrease by 9,188 acres
(42 percent) because of authorized
development. Permanent reserves would
be established, including 2,187.5 acres of
uplands.

Impact: Impacts to upland
habitat associated with
authorized development
would be the same as
under the Proposed Action.

Permanent reserves would
be established, including
4,350 acres of uplands.

Impact: Impacts to upland
habitat associated with
authorized development
would be the same as
under the Proposed Action.

Permanent reserves would
be established, including
8,074 acres of uplands.

Impact: Same as
Proposed Action.

Impact: Upland habitat in
the Natomas Basin would
decrease by 6,063 acres
(28 percent) because of
authorized development.

Permanent reserves
would be established,
including 1,500 acres of
uplands.

Impact: Upland habitat is
expected to decrease by
approximately the same
acreage as under the
Proposed Action because
of urban development.

Unknown benefits
associated with habitat
creation.

Impact: Loss of riparian habitat in the
Natomas Basin generally would not occur.

Impact: Same as
Proposed Action.

Impact: Up to 8 acres (8 percent) of oak
groves in the Natomas Basin would
potentially be removed because of urban
development.

Impact: Same as
Proposed Action.

Impact: Expected to be
approximately the same
as Proposed Action.

Impact: Vernal pools could be affected in
North Natomas and potentially in other
areas of the Natomas Basin.

Impact: Same as
Proposed Action.

Impact: Expected to be
approximately the same
as Proposed Action.

Impact: Approximately 8,512 acres of
potential habitat for the giant garter snake
would be affected by authorized
development in the Natomas Basin.

Preservation of wetland habitat and
creation and management of reserves that
support 6,562 acres of giant garter snake
habitat mitigates the impacts of the
covered activities on giant garter snakes
to a less-than-significant level.

Impact: Impacts to giant
garter snake habitat would
be the same as under the
Proposed Action.

Approximately 13,125
acres of giant garter snake
habitat would be supported
by the system of habitat
reserves.

Impact: Impacts to giant
garter snake habitat would
be the same as under the
Proposed Action.

Approximately 9,687 acres
of giant garter snake
habitat would be supported
by the system of habitat
reserves.

Impact: Same as
Proposed Action.

Impact: Approximately
6,044 acres of potential
habitat for the giant garter
snake would be affected
by authorized
development in the
Natomas Basin.

Approximately 4,500
acres of giant garter
snake habitat would be
supported by the system
of habitat reserves.

Impact: Giant garter
snake habitat is expected
to decrease by
approximately the same
acreage as under the
Proposed Action because
of urban development.

Unknown benefits
associated with habitat
creation.

EXECUTIVE SUMMARY
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-9

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
Impact: Two Swainson’s hawk nesting
territories with remaining nest trees (NB-3
and NB-6) have the potential to be
abandoned because of authorized
development.

Impact: Same as the
Proposed Action.

Impact: Expected to be
approximately the same
as the Proposed Action.

Impact: Swainson’s hawk foraging habitat
in the Natomas Basin would decrease by
9,188 acres (42 percent) because of
authorized development. Permanent
reserves would be established including
2,187.5 acres of uplands that would be
managed for Swainson’s hawk foraging
habitat value.

Impact: Impacts to
Swainson’s hawk foraging
habitat associated with
authorized development
would be the same as
under the Proposed Action.

Permanent reserves would
be established, including
4,350 acres of uplands.

Impact: Impacts to
Swainson’s hawk foraging
habitat associated with
authorized development
would be the same as
under the Proposed Action.

Permanent reserves would
be established, including
8,074 acres of uplands.

Impact: Same as
Proposed Action.

Impact: Swainson’s hawk
foraging habitat in the
Natomas Basin would
decrease by 6,063 acres
(28 percent) because of
authorized development.

Permanent reserves
would be established
including 1,500 acres of
uplands.

Impact: Swainson’s hawk
foraging habitat is
expected to decrease by
approximately the same
acreage as under the
Proposed Action because
of urban development.

Unknown benefits
associated with habitat
creation.

Impact: Overall effects to other covered
species associated with habitat loss and
creation would be less than significant.

Impact: Similar to
Proposed Action.

Impact: Same as
Proposed Action.

Impact: Expected to be
approximately the same
as Proposed Action.

Impact: Potentially significant effects to
some other special-status species (e.g.,
dwarf downingia, rose mallow, Cooper’s
hawk, American bittern, black tern, lark
sparrow, white-tailed kite, Pacific-slope
flycatcher, Bewick’s wren) can be
mitigated to a less than significant level
with mitigation.

EIR/EIS Mitigation Measure:

Preconstruction surveys required pursuant
to Section V.A.1 of the HCP shall
encompass the habitat areas that could
support dwarf downingia or rose mallow. If
dwarf downingia or rose mallow are found
during the habitat surveys, mitigation shall
conform to the mitigation requirements for
Delta tule pea and Sanford’s arrowhead
as described in the HCP and in
Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Expected to be
approximately the same
as Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Expected to be
approximately the same
as Proposed Action.

EXECUTIVE SUMMARY
ES-10 REVISED NATOMAS BASIN HCP E042002017SAC/161795(EXECUTIVE SUMMARY.DOC)

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
accordance with the California Native
Plant Protection Act.

Preconstruction surveys required pursuant
to Section V.A.1 of the HCP shall
encompass the habitat areas where
nesting birds could occur. In accordance
with the requirements of the Migratory Bird
Treaty Act, vegetation containing an
occupied nest and an appropriate-sized
buffer around the nests of Cooper’s
hawks, American bitterns, black terns, lark
sparrows, white-tailed kites, Pacific-slope
flycatchers, and Bewick’s wrens shall not
be removed until the nest has been
abandoned by the nesting pair or the
young have
fledged.

Impact: No impact to fish species of
concern would occur.

Impact: Same as
Proposed Action.

Impact: Net reduction in waterfowl habitat
would be less than significant.

Impact: Similar to the
Proposed Action.

4.5 Cultural Resources
Impact: Potentially significant increase
in the potential to disturb unknown,
subsurface cultural resources resulting
from development of habitat reserves.

Can be mitigated to a less-than-significant
level with mitigation.

EIR/EIS Mitigation Measure: Parcels
being considered for habitat reserves shall
undergo preconstruction literature review
and/or field surveys, based on the
discretion of a qualified archaeologist.

Based on the findings of the cultural
resource review and the potential for land
disturbance to occur on the reserve, the
Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar to
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

EXECUTIVE SUMMARY
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-11

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
Natomas Basin Conservancy could be
required to complete an archaeological
report and implement site-specific mitigation
measures as a condition for restoration.
and
In the event that any historic or
archaeological features (surface or
subsurface) or deposits, including locally
darkened soil (“midden”) that could conceal
cultural deposits, animal bone, shell,
obsidian, mortars, or human remains, are
uncovered during construction, work within
100 feet of the find shall cease and a
qualified archaeologist and a representative
of the Native American Heritage
Commission shall be consulted to develop,
if necessary, further mitigation measures to
reduce any archaeological impacts to a
less-than-significant level before
construction continues.
and
When Native American archaeological,
ethnographic, or spiritual resources are
involved, all identification and treatment
shall be conducted by qualified
archaeologists who are either certified by
the Society of Professional Archaeologists
(SOPA) or who meet the federal standards
as stated in the Code of Federal
Regulations (36 CFR 61), and Native
American Representatives who are
approved by the local Native American
community as scholars of their cultural
traditions. In the event that no such Native
American is available, persons who
represent tribal governments and/or
organizations in the locale in which

EXECUTIVE SUMMARY
ES-12 REVISED NATOMAS BASIN HCP E042002017SAC/161795(EXECUTIVE SUMMARY.DOC)

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
resources could be affected shall be
consulted. When historic archaeological
sites or historic architectural features are
involved, all identification and treatment is to
be carried out by historical archaeologists or
architectural historians. These individuals
shall meet either SOPA or 36 CFR 61
requirements.
and
If human bone of unknown origin is found
during construction, all work shall stop in
the vicinity of the find and the County
Coroner shall be contacted immediately. If
the remains are determined to be Native
American, the Coroner shall notify the
Native American Heritage Commission who
shall notify the person it believes to be the
most likely descendant. The most likely
descendant shall work with the contractor to
develop a program for reinternment of the
human remains and any associated
artifacts. No additional work is to take place
within the immediate vicinity of the find until
the identified appropriate actions have been
carried out.

4.6 Land Use/Consistency With Adopted Plans and Policies Impact: Less-than-significant land use
compatibility/plan inconsistency impacts.

Impact: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

EXECUTIVE SUMMARY
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-13

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
Impact: Significant loss of farmland. Not
likely to be mitigated to a less-than-
significant level.

EIR/EIS Mitigation Measure: To the extent
practicable (and to the extent that
biological goals are not compromised),
development of site-specific management
plans will incorporate provisions that
consider farmlands and agricultural use.

Impact: Greater impacts
than the Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Greater impacts
than the Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar to the
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

4.7 Social and Economic Conditions
Impact: Less-than-significant changes in
local employment and tax revenues to
Sacramento and Sutter counties.

Impact: Greater impacts
than the Proposed Action,
but less than significant.

Impact: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

4.8 Traffic
Impact: Potentially significant increase
in the potential for traffic safety conflicts
resulting from development of habitat
reserves. Can be mitigated to a
less-than-significant level with mitigation.

EIR/EIS Mitigation Measure: Prior to
commencing substantial habitat reserve
development activities, the Conservancy
shall evaluate traffic levels on any
adjacent rural roadways that would
provide construction access. Where
potential traffic-safety impacts are
identified, the Conservancy and/or its
contractor shall prepare a Traffic Control
Plan that addresses potential impacts to
public safety and other construction-
related nuisances. The Traffic Control
Plan shall be reviewed and approved by
the City of Sacramento and/or Sutter
County, and should be submitted for
review by Sacramento County for projects
Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar to
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

EXECUTIVE SUMMARY
ES-14 REVISED NATOMAS BASIN HCP E042002017SAC/161795(EXECUTIVE SUMMARY.DOC)

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
located within the unincorporated portion
of Sacramento County. Traffic
management measures to be included in
the Traffic Control Plan include, but are
not limited to, the following:
/g183 Provide adequate warning to users of
the roadway in the vicinity of the
construction, through signs or other
means visible from the roadway
/g183 Provide adequate assistance to the
public in navigating the construction
site through the use of flagmen
/g183 Install adequate signage for
construction zones and detours
/g183 If traffic and circulation would be
interrupted for an extended period of
time, provide for the opportunity for
public input from affected residents

EXECUTIVE SUMMARY
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-15

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action

4.9 Noise
Impact: Potentially significant increase in
noise-related nuisances resulting from
development of habitat reserves. Can be
mitigated to a less-than-significant level
with mitigation.

EIR/EIS Mitigation Measure: Prior to
commencing substantial habitat reserve
development activities, the Conservancy
shall determine if residences or other
sensitive receptors are located within 1000
feet of the construction site. If sensitive
receptors are located within 1000 feet of
the construction site, operation of
construction equipment and vehicles
would occur between the hours of 7:00 am
and 6:00 pm, Monday through Saturday,
and between 9:00 am and 6:00 pm on
Sunday.

Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar to
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

EXECUTIVE SUMMARY
ES-16 REVISED NATOMAS BASIN HCP E042002017SAC/161795(EXECUTIVE SUMMARY.DOC)

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action

4.10 Air Quality
Impact: Potentially significant increase in
NOx and PM10 resulting from
development of habitat reserves. Can be
mitigated to a less-than-significant level
with mitigation.

EIR/EIS Mitigation Measure: The
following measures shall be implemented
to reduce emissions of ozone precursors
during construction activities on the
habitat reserves.
/g183 To the extent feasible, the Natomas
Basin Conservancy shall work with
contractors who include low-NOx,
heavy-duty construction vehicles.
/g183 Construction activities shall be
phased to reduce the simultaneous
operation of construction equipment.
/g183 The contractor shall perform routine
tuning and maintenance of
construction equipment.
/g183 The contractor shall use existing on-
site electric power sources in place of
diesel generators to the extent that
these sources are available.
and
The following measures shall be
implemented to reduce construction-
related emissions of fugitive dust (PM10).
/g183 The contractor shall reduce or
suspend grading and excavation
activity during windy periods (i.e.,
winds in excess of 15 miles per hour).

Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Greater impacts
than the Proposed Action.

Can be mitigated to a
less-than-significant level
with mitigation.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Same as
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar to
Proposed Action.

EIR/EIS Mitigation
Measure: Same as
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

EXECUTIVE SUMMARY
E042002017SAC/161795(EXECUTIVE SUMMARY.DOC) REVISED NATOMAS BASIN HCP ES-17

EIR/EIS
TABLE ES-2
Summary of Potential Environmental Impacts Associated with Proposed Action and Alternatives Proposed Action
Alternative 1:

Increased Mitigation
Alternative 2:

Habitat-Based Mitigation
Alternative 3:

Reserve Zones
Alternative 4:

Reduced Potential for
Incidental Take
Alternative 5:

No Action
/g183 The contractor shall post and enforce
speed limits on unpaved driving
areas.
/g183 The contractor shall apply water twice
daily to disturbed areas and active
construction sites.
/g183 The contractor shall treat completed
sites with soil binders or vegetation.

Dirt shall be washed off trucks and other
equipment before leaving the construction
site.

4.11 Public Health and Safety
Impact: Less-than-significant public health
and safety impacts resulting from the
creation of habitat reserves within the bird-
strike zones of Sacramento International
Airport.

Impact: Greater impacts
than the Proposed Action,
but less than significant.

Impact: Same as
Proposed Action.

Impact: Similar to
Proposed Action.

Impact: Similar effects are
expected with case-by-
case mitigation.

E042002017SAC/161795(COVER SHEET & ABSTRACT.DOC) REVISED NATOMAS BASIN HCP

EIR/EIS
Cover Sheet
Title of Proposed Action: Issuance of Incidental Take Permits and Adoption and Implementation of the Natomas Basin
Habitat Conservation Plan
Responsible Official: Anne Badgley
Regional Director
U.S. Fish and Wildlife Service
911 NE 11th Avenue
Portland, Oregon 97232
Contact Person: Vicki Campbell
Division Chief, Conservation Planning
U.S. Fish and Wildlife Service
Sacramento Fish and Wildlife Office
2800 Cottage Way, W-2605
Sacramento, California 95825
(916) 414-6600
Legal Authority: Endangered Species Act of 1973, as amended, Section 10(a), as implemented by 50 CFR 17.32(b)(1).

Location of Proposed Action: Natomas Basin
Sacramento and Sutter Counties, California
Applicant Names:

City of Sacramento
1231 I Street
Suite 300
Sacramento, California 95814
(916) 264-7601
Contact: Grace Hovey
Sutter County
10461 Old Placerville Road
Suite 110
Sacramento, California 95827
916) 361-8384 extension 203
Contact: Paul Junker
Natomas Basin Conservancy
1750 Creekside Oaks Drive
Suite 290
Sacramento, California 95833
(916) 649-3331
Contact: John Roberts
EIR/EIS Preparer Name: CH2M HILL
2485 Natomas Park Drive, Suite 600
Sacramento, CA 95833
E042002017SAC/161795(COVER SHEET & ABSTRACT.DOC) REVISED NATOMAS BASIN HCP

EIR/EIS
Abstract
This environmental impact report/environmental impact statement (EIR/EIS) describes the affected resources and evaluates the potential impacts to those resources in the Natomas Basin and Area B as a result of implementing the Proposed Action. The Proposed Action comprises: (1) applications for Section 10(a)(1)(B) and Section 2081 permits or permit modifications for each of the permittees; (2) approval of the revised Natomas Basin Habitat Conservation Plan (HCP) and issuance of permits by the United States Fish and Wildlife Service and the California Department of Fish and Game; (3) implementation of the HCP; (4) adoption of the Implementing Agreement(s); and (5) the issuance of incidental take permits (ITPs). The permittees are the City of Sacramento, Sutter County, and the Natomas Basin Conservancy, Reclamation District No. 1000, and Natomas Central Mutual Water Company.

The objective of the Proposed Action is to reconcile the needs of 22 special-status species with planned land development and water facility operations in the Natomas Basin.

Issuance of the ITP would authorize the incidental take of several listed wildlife species resulting from urban development and other activities in the Natomas Basin. These species include the federally listed giant garter snake (Thamnophis gigas), valley elderberry longhorn beetle (Desmocerus californicus dimorphus), vernal pool species (Branchinecta spp., Lepidurus packardi), Colusa grass (Neostapfia colusana), Orcutt grasses (Orcuttia spp.), the California tiger salamander (Ambystoma californiense), a federal and state candidate species, and the state-listed Swainson’s hawk (Buteo swainsoni). The Implementing Agreement(s) would also cover a suite of other wildlife and plant species if they were to become listed in the future.

The HCP would establish a comprehensive program for the preservation and protection of habitat for threatened and endangered species potentially found on approximately 53,537 acres of undeveloped and agricultural land in northwestern Sacramento County and southern Sutter County (Natomas Basin and Area B). The acquisition of lands or conservation easements for the purpose of creating and managing permanent habitat reserves would be the primary mechanism for mitigating impacts to listed species. Habitat reserves would be managed by the Natomas Basin Conservancy and would consist of managed marsh habitats, upland habitats, rice fields (which would typically be leased for use to rice farmers), and associated buffers and infrastructure. The HCP also includes management measures that are intended to avoid or minimize effects on species during activities by RD 1000 and Natomas Mutual and during urban development activities.

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EIR/EIS
Contents
Chapter Page
Executive Summary...................................................................................................................... ES-1 ES-1 Introduction.............................................................................................................. ES-1 ES-2 Purpose and Need/Objectives .............................................................................. ES-2 ES-3 Study Area................................................................................................................ ES-3 ES-4 Proposed Action and Alternatives ........................................................................ ES-3 ES-4.1 Independent Implementation ................................................................ ES-4 ES-5 Areas of Controversy .............................................................................................. ES-4 ES-6 Issues To Be Resolved ............................................................................................. ES-4 ES-7 Summary of Impacts and Mitigation Measures.................................................. ES-4 ES-7.2 Summary of Impacts ............................................................................... ES-5

1. Purpose and Need/Objectives...................................................................................................1-1

1.1 Introduction....................................................................................................................1-1

1.1.1 Summary of Key Issues ................................................................................1-1

1.1.2 Document Overview.....................................................................................1-3

1.2 Habitat Conservation Planning in the Natomas Basin ............................................1-3

1.2.1 Recent Habitat Conservation Planning Efforts .........................................1-4

1.2.2. Court Opinion.............................................................................................1-10

1.3 Requirements for Environmental Review................................................................1-11

1.3.1 Lead Agencies..............................................................................................1-11

1.3.2 California Department of Fish and Game................................................1-11

1.4 Purpose and Need/Objectives ..................................................................................1-12

1.4.1 Purpose and Need (USFWS)......................................................................1-12

1.4.2 Objectives (City of Sacramento and Sutter County)...............................1-13

1.4.3 Decisions to be Made ..................................................................................1-15

1.4.4 Other Discretionary Actions ......................................................................1-15

1.4.5 Independent Implementation....................................................................1-16

1.5 Regulatory Framework...............................................................................................1-16

1.5.1 Endangered Species Act .............................................................................1-16

1.5.2 National Environmental Policy Act..........................................................1-18

1.5.3 California Environmental Quality Act .....................................................1-18

1.5.4 California Endangered Species Act ..........................................................1-18

1.5.5 Migratory Bird Treaty Act..........................................................................1-19

1.5.6 Native Plant Protection Act .......................................................................1-19

1.5.7 Local Plans and Ordinances.......................................................................1-20

1.6 Consultation and Coordination/Issues of Controversy ........................................1-20

1.6.1 Scoping..........................................................................................................1-22

1.6.2 Agency Coordination..................................................................................1-23

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2. Proposed Action and Alternatives........................................................................................... 2-1

2.1 Plan Participants ...........................................................................................................2 - 2

2.2 Study Area and Permit Areas ..................................................................................... 2-3

2.2.1 City of Sacramento........................................................................................ 2-3

2.2.2 Sutter County................................................................................................. 2-3

2.2.3 Natomas Basin Conservancy....................................................................... 2-6

2.2.4 Reclamation District No. 1000..................................................................... 2-8

2.2.5 Natomas Mutual ........................................................................................... 2-8

2.3 Covered Activities ........................................................................................................ 2-8

2.3.1 Land Use Agencies ..................................................................................... 2-11

2.3.2 Natomas Basin Conservancy..................................................................... 2-12

2.3.3 Water Agencies............................................................................................ 2-12

2.3.4 Activities not Covered by the Incidental Take Permits......................... 2-13

2.4 Description of Proposed Action................................................................................ 2-13

2.4.1 Habitat Conservation Plan Purpose......................................................... 2-14

2.4.2 Permits and Approvals .............................................................................. 2-14

2.4.3 Covered Species .......................................................................................... 2-15

2.4.4 Biological Goals and Objectives................................................................ 2-15

2.4.5 Habitat Reserve Development Strategy................................................... 2-17

2.4.6 Conservation Measures.............................................................................. 2-25

2.4.7 Monitoring and Adaptive Management.................................................. 2-44

2.4.8 Funding ........................................................................................................ 2-46

2.4.9 Unforeseen Circumstances/ “No Surprises”.......................................... 2-47

2.4.10 Overall Program Review and Midpoint Review.................................. 2-47

2.5 Approach to Developing Alternatives..................................................................... 2-48

2.6 EIR/EIS Alternatives .................................................................................................. 2-49

2.6.1 Alternative 1: Increased Mitigation.......................................................... 2-50

2.6.2 Alternative 2: Habitat-based Mitigation .................................................. 2-50

2.6.3 Alternative 3: Reserve Zones..................................................................... 2-51

2.6.4 Alternative 4: Reduced Potential for Incidental Take............................ 2-52

2.6.5 Alternative 5: No Action Alternative ....................................................... 2-53

2.7 Alternatives Eliminated from Further Consideration ........................................... 2-54

2.7.1 Change in Permit Duration ....................................................................... 2-54

2.7.2 Prohibiting Out-of-Basin Mitigation ........................................................ 2-54

2.7.3 Sacramento County Participation............................................................. 2-55

2.7.4 Development Cap ....................................................................................... 2-56

2.7.5 Increased Mitigation Fee............................................................................ 2-56

2.7.6 Acquire Active Habitat Only..................................................................... 2-57

2.7.7 Fixed Reserves............................................................................................. 2-57

2.8 Environmentally Preferable/Superior Alternative................................................ 2-58

3. Affected Environment................................................................................................................ 3-1

3.1 Introduction ................................................................................................................... 3-1

3.2 Geology and Soils ......................................................................................................... 3-3

3.2.1 Area Geology................................................................................................. 3-3

3.2.2 Area Soil Types.............................................................................................. 3-3

3.2.3 Geologic and Soil Hazards .......................................................................... 3-4

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3.3 Water Resources ............................................................................................................3-5

3.3.1 Flooding and Drainage.................................................................................3-5

3.3.2 Water Quality.................................................................................................3-7

3.3.3 Water Supply .................................................................................................3-8

3.4 Biological Resources....................................................................................................3-10

3.4.1 Land Use and Habitats in the Natomas Basin.........................................3-10

3.4.2 Special-Status Species .................................................................................3-22

3.4.3 Waterfowl .....................................................................................................3-52

3.5 Cultural Resources ......................................................................................................3-52

3.5.1 Archaeological and Historical Significance of the Natomas Basin.......3-53

3.5.2 City of Sacramento ......................................................................................3-54

3.5.3 Sacramento County.....................................................................................3-55

3.5.4 Sutter County...............................................................................................3-55

3.6 Land Use.......................................................................................................................3-56

3.6.1 Surrounding Land Uses..............................................................................3-56

3.6.2 Existing and Planned Land Uses...............................................................3-56

3.6.3 Relevant Land-Use Planning Goals and Policies ....................................3-59

3.6.4 Agriculture in the Natomas Basin.............................................................3-61

3.7 Socioeconomics ............................................................................................................3-62

3.7.1 City of Sacramento and Sacramento County...........................................3-62

3.7.2 Sutter County...............................................................................................3-63

3.8 Traffic and Circulation................................................................................................3-64

3.8.1 City of Sacramento ......................................................................................3-64

3.8.2 Sacramento County.....................................................................................3-65

3.8.3 Sutter County...............................................................................................3-65

3.9 Noise..............................................................................................................................3-65

3.9.1 City of Sacramento ......................................................................................3-65

3.9.2 Sacramento County.....................................................................................3-66

3.9.3 Sutter County...............................................................................................3-66

3.10 Air Quality..................................................................................................................3-66

3.10.1 Sacramento Valley Air Basin ...................................................................3-66

3.10.2 Regulatory Background............................................................................3-67

3.11 Public Health and Safety ..........................................................................................3-69

3.11.1 Background on Wildlife Hazards at Airports .......................................3-69

3.11.2 Sacramento International Airport and Vicinity ....................................3-71

4. Environmental Consequences...................................................................................................4-1

4.1 Introduction....................................................................................................................4-1

4.1.1 Resources Considered and Summary of Impacts .....................................4-1

4.1.2 Approach to Cumulative Impacts Analysis ..............................................4-3

4.1.3 Previous Evaluation of Effects of Covered Activities ............................4-10

4.1.4 Approach to Analysis of Independent Implementation by Individual Permittees.................................................................................4-12

4.2 Geology and Soils........................................................................................................4- 14

4.2.1 Proposed Action ..........................................................................................4-14

4.2.2 Alternative 1. Increased Mitigation ..........................................................4-16

4.2.3 Alternative 2. Habitat-based Mitigation ..................................................4-16

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4.2.4 Alternative 3. Reserve Zones..................................................................... 4-17

4.2.5 Alternative 4. Reduced Potential for Incidental Take............................ 4-17

4.2.6 Alternative 5. No Action Alternative ....................................................... 4-17

4.2.7 Effects Under Independent Implementation .......................................... 4-17

4.2.8 Cumulative Impacts ................................................................................... 4-18

4.3 Water Resources.......................................................................................................... 4-18

4.3.1 Proposed Action.......................................................................................... 4-19

4.3.2 Alternative 1. Increased Mitigation.......................................................... 4-23

4.3.3 Alternative 2. Habitat-based Mitigation .................................................. 4-24

4.3.4 Alternative 3. Reserve Zones..................................................................... 4-24

4.3.5 Alternative 4. Reduced Potential for Incidental Take............................ 4-24

4.3.6 Alternative 5. No Action Alternative ....................................................... 4-24

4.3.7 Effects Under Independent Implementation .......................................... 4-25

4.3.8 Cumulative Impacts ................................................................................... 4-26

4.4 Biological Resources ................................................................................................... 4-26

4.4.1 Methodology ............................................................................................... 4-27

4.4.2 Significance Thresholds ............................................................................. 4-27

4.4.3 Previous Evaluation of Effects of Covered Activities............................ 4-28

4.4.4 Changes to Habitat from Covered Activities.......................................... 4-29

4.4.5 Proposed Action.......................................................................................... 4-31

4.4.6 Alternative 1 – Increased Mitigation........................................................ 4-95

4.4.7 Alternative 2 – Habitat-based Mitigation .............................................. 4-101

4.4.8 Alternative 3. Reserve Zone Alternative ............................................... 4-104

4.4.9 Alternative 4. Reduced Development.................................................... 4-105

4.4.10 Alternative 5. No Action Alternative ................................................... 4-108

4.4.11 Independent Implementation ............................................................... 4-109

4.4.12 Cumulative Impacts ............................................................................... 4-127

4.5 Cultural Resources.................................................................................................... 4-127

4.5.1 Proposed Action........................................................................................ 4-128

4.5.2 Alternative 1. Increased Mitigation Ratio.............................................. 4-130

4.5.3 Alternative 2. Habitat-based Mitigation ................................................ 4-130

4.5.4 Alternative 3. Reserve Zones................................................................... 4-130

4.5.5 Alternative 4. Reduced Potential for Incidental Take.......................... 4-131

4.5.6 Alternative 5. No Action Alternative ..................................................... 4-131

4.5.7 Effects Under Independent Implementation ........................................ 4-131

4.5.8 Cumulative Impacts ................................................................................. 4-132

4.6 Land Use .................................................................................................................... 4-132

4.6.1 Proposed Action........................................................................................ 4-133

4.6.2 Alternative 1. Increased Mitigation Ratio.............................................. 4-135

4.6.3 Alternative 2. Habitat-based Mitigation ................................................ 4-136

4.6.4 Alternative 3. Reserve Zones................................................................... 4-136

4.6.5 Alternative 4. Reduced Potential for Incidental Take.......................... 4-137

4.6.6 Alternative 5. No Action Alternative ..................................................... 4-137

4.6.7 Effects Under Independent Implementation ........................................ 4-138

4.6.8 Cumulative Impacts ................................................................................. 4-139

4.7 Socioeconomics.......................................................................................................... 4-139

4.7.1 Proposed Action........................................................................................ 4-140

CONTENTS
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4.7.2 Alternative 1. Increased Mitigation ........................................................4-142

4.7.3 Alternative 2. Habitat-based Mitigation ................................................4-143

4.7.4 Alternative 3. Reserve Zones ...................................................................4-144

4.7.5 Alternative 4. Reduced Potential for Incidental Take ..........................4-144

4.7.6 Alternative 5. No Action Alternative......................................................4-144

4.7.7 Effects Under Independent Implementation.........................................4-144

4.7.8 Cumulative Impacts..................................................................................4-145

4.8 Traffic ..........................................................................................................................4-145

4.8.1 Proposed Action ........................................................................................4-146

4.8.2 Alternative 1. Increased Mitigation ........................................................4-147

4.8.3 Alternative 2. Habitat-based Mitigation ................................................4-148

4.8.4 Alternative 3. Reserve Zones ...................................................................4-148

4.8.5 Alternative 4. Reduced Potential for Incidental Take ..........................4-148

4.8.6 Alternative 5. No Action Alternative......................................................4-149

4.8.7 Effects Under Independent Implementation.........................................4-149

4.8.8 Cumulative Impacts..................................................................................4-149

4.9 Noise............................................................................................................................4-150

4.9.1 Proposed Action ........................................................................................4-151

4.9.2 Alternative 1. Increased Mitigation ........................................................4-152

4.9.3 Alternative 2. Habitat-based Mitigation ................................................4-152

4.9.4 Alternative 3. Reserve Zones ...................................................................4-152

4.9.5 Alternative 4. Reduced Potential for Incidental Take ..........................4-153

4.9.6 Alternative 5. No Action Alternative......................................................4-153

4.9.7 Effects Under Independent Implementation.........................................4-153

4.9.8 Cumulative Impacts..................................................................................4-154

4.10 Air Quality................................................................................................................4-154

4.10.1 Proposed Action ......................................................................................4-155

4.10.2 Alternative 1. Increased Mitigation ......................................................4-156

4.10.3 Alternative 2. Habitat-based Mitigation ..............................................4-157

4.10.4 Alternative 3. Reserve Zones .................................................................4-157

4.10.5 Alternative 4. Reduced Potential for Incidental Take ........................4-157

4.10.6 Alternative 5. No Action Alternative....................................................4-158

4.10.7 Effects Under Independent Implementation.......................................4-158

4.10.8 Cumulative Impacts................................................................................4-158

4.11 Public Health and Safety ........................................................................................4-159

4.11.1 Proposed Action ......................................................................................4-159

4.11.2 Alternative 1. Increased Mitigation Ratio ............................................4-163

4.11.3 Alternative 2. Habitat-based Mitigation ..............................................4-164

4.11.4 Alternative 3. Reserve Zones .................................................................4-164

4.11.5 Alternative 4. Reduced Potential for Incidental Take ........................4-164

4.11.6 Alternative 5. No Action Alternative....................................................4-165

4.11.7 Effects Under Independent Implementation.......................................4-165

4.11.8 Cumulative Impacts................................................................................4-165

4.12 Other Impact Categories.........................................................................................4-166

4.12.1 Irreversible Environmental Changes....................................................4-166

4.12.2 Relationship Between Short-term Uses of the Environment and the Maintenance and Enhancement of Long-term Productivity........ 4-166

CONTENTS
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4.12.3 Unavoidable Environmental Effects .................................................... 4-166

4.12.4 Growth-inducing Impacts ..................................................................... 4-167

5. List of Preparers........................................................................................................................... 5-1 U.S. Fish and Wildlife Service ........................................................................................... 5-1 California Department of Fish and Game ....................................................................... 5-1 City of Sacramento..............................................................................................................5 - 1 Sutter County....................................................................................................................... 5-1 CH2M HILL......................................................................................................................... 5-1 Planning Dynamics Group ................................................................................................ 5-2

6. References .................................................................................................................................... 6-1

7. Glossary ........................................................................................................................................ 7-1

8. Index .............................................................................................................................................. 8-1 Appendices
A Public Notices
B Fish and Wildlife Service Species List and CNDDB Summary Lists C Summary of Previous Environmental Review of Planned Urban Development Tables
ES-1 EIR/EIS Alternatives....................................................................................................... .ES-3 ES-2 Summary of Potential Enviro nmental Impacts Associated With Proposed Action and Alternatives .................................................................................ES-6 1-1 Cross-Reference for CEQA Contents ............................................................................... 1-4 2-1 Proposed Covered Species............................................................................................... 2-16 2-2 Mitigation Ratios........................................................................................................... .... 2-27 2-3 Composition of Development Fee .................................................................................. 2-46 2-4 Mitigation Requirements Under Alternative 2............................................................. 2-51 3-1 Description of Land Use/Habitat Categories ............................................................... 3-17 3-2 Land Uses/Habitat Categories in th e City of Sacramento and Annexation Area (acres) ........................................................................................................................ 3-18 3-3 Canals in the City of Sacramento and Annexation Area (miles)................................ 3-18 3-4 Land Uses in Unincorporated Sacramento County (acres)......................................... 3-20 3-5 Canals in Unincorporated Sa cramento County (miles)............................................... 3-20 3-6 Land Uses in Sutter County ............................................................................................ 3-21 3-7 Canals in Sutter County (miles) ...................................................................................... 3-22 3-8 List of Special-Status Species Identified by USFWS as Potentially Occurring in the Natomas Basin........................................................................................................ 3-23 3-9 Summary of Total Areas by Jurisd iction in the Natomas Basin................................. 3-56 3-10 Summary of City of Sacramento General Plan Land-Use Goals................................ 3-59

CONTENTS
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3-11 Summary of Sutter County General Plan Land-Use Goals .........................................3-60 3-12 Farmland Mapping and Monitoring Program Acreage in Study Area .....................3-61 3-13 Estimated Population Within the Natomas Basin and Vicinity, Sacramento County...........................................................................................................3-6 3 3-14 Estimated Population Within the Nat omas Basin and Vicinity, Sutter County.......3-64 3-15 Ambient Air Quality Standards ......................................................................................3-68 3-16 Air Quality Attainme nt Designations ............................................................................3-69 4-1 Acreage of Urban Development Co vered by the Proposed Action ...........................4-29 4-2 Change in Land Use Acreage from Planne d Development in the Natomas Basin.... 4-30 4-3 Change in Canal Length from Planned Development in the Natomas Basin (miles) 4-31 4-4 Change in Canal Acreage from Planned Development in the Natomas Basin ........4-31 4-5 Change in Potential Habitat for Delta Tule Pea (acres) ...............................................4-39 4-6 Change in Potential Habitat for Sanford’s Arrowhead (acres) ...................................4-41 4-7 Vernal Pool Species Covered by the ITPs ......................................................................4-43 4-8 Change in Potential Habitat for Giant Garter Snake (acres) .......................................4-50 4-9 Change in Potential Habitat for Nort hwestern Pond Turtle (acres) ..........................4-59 4-10 Change in Potential Habitat for White-faced Ibis (acres) ............................................4-63 4-11 Change in Potential Habitat for Tricolored Blackbird (acres).....................................4-66 4-12 Change in Potential Habitat fo r Swainson’s Hawk (acres) .........................................4-69 4-13 Change in Foraging Habitat Within 1 Mile of Swainson’s Hawk Nest Sites (acres)................................................................................................................4-72 4-14 Change in Potential Habitat for Aleutian Canada Goose (acres) ...............................4-77 4-15 Change in Potential Habitat for Burrowing Owl (acres) .............................................4-79 4-16 Change in Potential Habitat for Bank Swallow (acres)................................................4-82 4-17 Change in Potential Habitat for Loggerhead Shrike (acres)........................................4-84 4-18 Mitigation Ratios Un der Alternative 2 .........................................................................4-101 4-19 Land Use Acreage in the Natomas Basin under Baseline and Future Conditions Under Alternative 4 (acres) .......................................................................4-106 4-20 Existing and Future Ri ce Field Distribution ................................................................4-163 Figures
1-1 Regional Location........................................................................................................... .....1-2 1-2a Jurisdictions.............................................................................................................. ............1-6 1-2b 1997 Land Use and Jurisdictions .......................................................................................1-7 2-1 City of Sacramento Permit Area........................................................................................2-4 2-2 Sutter County Permit Area.................................................................................................2- 5 2-3 Natomas Basin Conservancy Permit Area.......................................................................2-7 2-4 Water Delivery System and Water Drainage System.....................................................2-9 2-5 Reserve Zone Alternative.................................................................................................2-2 3 3-1 1997 Land Use............................................................................................................... .....3-13 3-2 Current Natural Areas......................................................................................................3 -15 3-3 Giant Garter Snake Records.............................................................................................3-41 3-4 Other Species Records ......................................................................................................3 -43

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3-5 Active Swainson’s Hawk Nests ...................................................................................... 3-45 4-1 Habitat management Plans in the Vi cinity of the EIR/EIS Plan Area ........................ 4-5 4-2 Bird Strike Zones........................................................................................................... .. 4-161 E042002017SAC/161795(001.DOC) REVISED NATOMAS BASIN HCP 1-1

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CHAPTER 1
Purpose and Need/Objectives

1.1 Introduction

1.1.1 Summary of Key Issues
This Environmental Impact Report/Environmental Impact Statement for the Revised Natomas Basin Habitat Conservation Plan (EIR/EIS) presents the environmental impacts that have the potential to occur as a result of approving a habitat conservation plan, issuing incidental take permits (ITPs) for covered activities included in the proposed revised Draft Natomas Basin Habitat Conservation Plan, Sacramento and Sutter Counties, California1 (HCP), and the adoption of an implementing agreement or agreements (IA[s]). The HCP, ITPs, and IA(s) collectively comprise the Proposed Action assessed in this EIR/EIS.

The applicants seeking ITPs for covered activities within the Natomas Basin are referred to as permittees (see Section 2.1). The Natomas basin is shown in Figure 1-1. The five permittees are:
• City of Sacramento (land use agency permittee)
• Sutter County (land use agency permittee)
• Natomas Basin Conservancy (Conservancy) (plan operator and permittee) • Reclamation District No. 1000 (RD 1000) (water agency permittee) • Natomas Central Mutual Water Company (Natomas Mutual) (water agency permittee)2 The City and Sutter County are lead agencies under the California Environmental Quality Act (CEQA), and the U.S. Fish and Wildlife Service (USFWS) is the lead agency under the National Environmental Policy Act (NEPA) (see Section 1.3.1).

Each of the permittees has a specific designated permit area for its covered activities. The permittees, their permit areas and covered activities, and the conservation measures for which each permittee is responsible are discussed in detail in Chapter 2 of this EIR/EIS. The permittees seek to obtain ITPs for covered activities for a 50-year term.

The HCP has been developed to provide and implement a multispecies conservation program to minimize and mitigate impacts of the covered activities of the Proposed Action (see Section 2.3 for a discussion of the covered activities associated with the Proposed Action). The HCP also has been prepared to meet the requirements of the California Department of Fish and Game (CDFG) in support of planned applications, or revisions to

They have, however, identified proposed conservation measures (see Section 2.4.6.3 of this EIR/EIS) for covered activities that exclude pesticide use, and these measures are incorporated in the HCP evaluated in this EIR/EIS (see Section 2.3.3 of this EIR/EIS). The water agencies could elect at a future date to apply for an ITP and would be required at that time to execute an IA that demonstrates implementation and compliance with the HCP. A summary of the water agencies’ participation in the HCP is in Section 1.2.1.
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current applications, to receive incidental take authorization for state-listed species under Section 2081 of the California Fish and Game Code (see Section 1.3.2 for additional discussion of CDFG participation). The IA(s) would secure participation and compliance of the permittees.

The conservation measures in the HCP apply to 22 special-status species (the “covered species”). (See Section 2.4.3 of this EIR/EIS for a listing of the covered species. Also see Sections I and II of the HCP for a discussion of the covered species.) The HCP that is evaluated in this EIR/EIS supercedes the prior HCP for the Natomas Basin that was previously prepared and approved in 1997 (see Section 1.2).

1.1.2 Document Overview
This EIR/EIS is a joint CEQA/NEPA document prepared in accordance with CEQA and NEPA and the implementing guidelines for EIRs and implementing regulations for EISs.

The lead agencies (see Section 1.3.1) have independently evaluated, directed, and supervised the preparation of the document.

Chapter 1 of the EIR/EIS briefly summarizes the Proposed Action (see Chapter 2 for a detailed description of the Proposed Action) and provides historical information on habitat conservation planning efforts in the Natomas Basin (Section 1.2). It also presents the requirements for environmental review of the Proposed Action (Section 1.3) and the purpose and need/objectives of the lead agencies (Section 1.4). The pertinent regulations that apply to the Proposed Action (Section 1.5) and the public scoping and consultation that was conducted (Section 1.6) are also discussed.

In addition to Chapter 1, this EIR/EIS contains the following sections:
• Chapter 2: Proposed Action and Alternatives
• Chapter 3: Affected Environment
• Chapter 4: Environmental Consequences
• Chapter 5: List of Preparers
• Chapter 6: References
• Chapter 7: Glossary
• Chapter 8: Index
Table 1-1 provides a cross-reference for components that are required under CEQA, and their location in this document.

1.2 Habitat Conservation Planning in the Natomas Basin
This section presents an overview of the historical activities of habitat conservation planning in the Natomas Basin, including the legal action associated with the original Natomas Basin HCP that was previously approved in 1997 (1997 HCP) and the CDFG’s prior involvement.

The intent of this discussion is to provide a context for the revised HCP and the CEQA/NEPA analysis conducted in this EIR/EIS.

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TABLE 1-1
Cross-Reference for CEQA Contents
Section of CEQA
Guidelines Topic Location in EIR/EIS
15122 Table of Contents or Index Both a Table of Contents and an Index (Chapter 8) are provided.
15123 Summary Executive Summary provided at beginning of document.
15124 Project Description Project description information is found in Chapters 1: Purpose and Need/Objectives and 2: Proposed
Action and Alternatives.
15125 Environmental Setting Environmental setting information is found in Chapter 3: Affected Environment.
15126 Consideration and Discussion of
Alternatives/Environmental Impacts
The alternatives are described in Chapter 2 and
evaluated in Chapter 4: Environmental
Consequences.

The environmental impacts of the Proposed Action
are discussed in Chapter 4.
15127 Limitations on Discussion of
Environmental Impacts
Resources not addressed in the EIR/EIS are briefly
described in Section 4.1.
15128 Effects Not Significant Refer to Section 4.1 and individual analysis sections in Chapter 4.
15129 Organizations and Persons
Consulted
Refer to Chapter 5: List of Preparers and Chapter
6: References.
15130 Discussion of Cumulative Effects Cumulative effects are addressed throughout Chapter 4. See Section 4.1 for a discussion of
cumulative effects.
15131 Economic and Social Effects Refer to Section 4.7 (Social and Economic Effects).

1.2.1 Recent Habitat Conservation Planning Efforts
In 1994, the Sacramento Area Flood Control Agency (SAFCA) proposed a flood control project for the Natomas Basin that was subject to the jurisdiction of the U.S. Army Corps of Engineers (ACOE). In its Biological Opinion for the project (March 11, 1994, together with an amendment to that opinion on May 19, 1995), the USFWS determined that the project would remove an obstacle to urbanization in the Natomas Basin and that such development would result in the take of federally listed species. Accordingly, the ACOE’s authorization for SAFCA’s flood control project was approved with the condition that an HCP be prepared for the Natomas Basin. Following the ACOE’s action, the local land use agencies took the lead in the effort to obtain incidental take authorization from the USFWS. The agencies that assumed responsibility for the preparation and implementation of the HCP were the City, Sacramento County, and Sutter County, with additional participation by RD 1000 and Natomas Mutual. The USFWS was responsible for approving the HCP. The jurisdictional boundaries of the local municipalities within the Natomas Basin are shown on Figure 1-2a.

Underlying land uses within these jurisdictional areas as of 1997 are shown on Figure 1-2b.

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Subsequent to the determination of the need for an HCP, the local land use agencies proceeded independently to prepare individual HCPs for their permit areas. In 1997, the City submitted its application to the USFWS in advance of the other agencies.

The City’s HCP was revised and approved by the USFWS on the basis of public and agency comment, and the USFWS issued an ITP to the City in December 1997. Environmental review of the City’s 1997 HCP under NEPA and CEQA consisted of an Environmental Assessment/Finding of No Significant Impact prepared by the USFWS (USFWS, 1997a) and an Initial Study/Negative Declaration prepared by the City (City of Sacramento, 1996), respectively.

Sutter and Sacramento counties submitted their HCP to the USFWS on an informal basis in October 1998. The USFWS, however, suspended review of the Sutter and Sacramento County HCPs because a lawsuit, discussed below, was filed challenging the City’s HCP and ITP. As of the publication of this EIR/EIS, Sacramento County has not submitted an HCP for unincorporated lands in the Natomas Basin.

Although Sacramento County is not an applicant in the HCP process for which this EIR/EIS has been prepared, a separate but similar HCP has been prepared for Metro Air Park (Metro Air Park Property Owners’ Association, 2000), which is a 1,983-acre 3 special planning area of the County of Sacramento approved for commercial and industrial development adjacent to Sacramento International Airport (see Figure 1-2a). Metro Air Park comprises 1,983 acres of the 17,500 acres of the planned urban development. An ITP was issued to the Metro Air Park Property Owners Association on February 21, 2002. The Record of Decision for the Final EIS for the Metro Air Park HCP (USFWS, 2001) was signed on February 21, 2002. (The MAP Draft and Final EIS is incorporated by reference into this EIR/EIS).

RD 1000 and Natomas Mutual also have participated in basinwide habitat conservation planning efforts. Prior to the issuance of the NOP/NOI for this EIR/EIS, however, the water agencies elected not to participate in the HCP evaluated in this EIR/EIS based on concerns about potential liability associated with possible legal challenges to the draft HCP. As a result, the initial NOI/NOP for this EIR/EIS, which was published on December 18, 2000, did not include the water agencies as a participant in the HCP and the EIR/EIS.

Subsequent to the publication of the December 18, 2000 NOI/NOP, the City and the water agencies entered into an indemnification agreement (April 2001) to address the water agencies’ concerns about liability related to participating in the HCP and to support a collaborative HCP process. The intent of the indemnification agreement (April 2002) was to provide clarification of the responsibilities of the City and the water agencies in the event that legal challenges were made to the HCP regarding land use issues.

Thus, in early 2001, RD 1000 and Natomas Mutual re-joined the City, Sutter County, and the Conservancy in developing the draft HCP evaluated in this EIR/EIS. As part of the water agencies’ involvement, they identified general conservation measures for operations, maintenance, and minor construction activities. A revised NOP/NOI noticing the

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involvement of the water agencies in the HCP process was published in local newspapers and in the Federal Register on August 18, 2001. Incorporation of the water agencies’ conservation measures into the HCP, including clarification and further refinement of RD 1000’s and Natomas Mutual’s proposed conservation measures, occurred throughout 2001.

An integral part of developing the HCP has been the USFWS’s and the CDFG’s review and comment on the draft HCP. In conjunction with this review, the resource agencies requested further clarification on the permittees’ (including the water agencies’) covered activities. In December 2001 and January 2002, several meetings were held to clarify aspects of the permittees’ covered activities, and in early January 2002 the HCP was revised to address these comments. Additional detail of the water agencies’ covered activities, including a request for coverage for use of pesticides (e.g., aquatic herbicides, rodenticides) in accordance with label instructions, was provided to the USFWS and CDFG. In early January 2002, the USFWS clarified that the local USFWS office would be unable to process a request for take coverage for pesticides and rodenticides, given the regional USFWS guidance policy (USFWS, Inclusion of Pesticide and Herbicide Applications as a Covered Activity in an Endangered Species Act Section 10(a)(1)(B) Permit, July 1998) limiting take authorization for such chemicals. Subsequent meetings occurred with the water agencies and the USFWS (including discussions with the regional representative from the USFWS in Portland) to discuss the water agencies’ BMPs and other activities, including pesticide and rodenticide use. It was determined that coverage of such chemicals would require further review by the USFWS. To begin this extensive review, the USFWS requested that the water agencies provide: (1) a list of pesticides for which coverage was requested and (2) any environmental analysis of the effects of those pesticides on species covered in the proposed ITPs.

In late January and February 2002, discussions were held among the USFWS, the land use agencies, and the water agencies. The USFWS indicated that a substantial length of time would be required to prepare and process adequate scientific information necessary for the USFWS to analyze the biological effects of each chemical on the covered species. The land use agencies also expressed concern regarding the length of time it would take for the water agencies to prepare and submit their initial list of chemicals and appropriate supporting biological analysis. Thus, they recommended that the HCP exclude chemical coverage for the water agencies. It was further suggested that the water agencies continue to be included in the HCP for the other covered activities (mechanical activities such as mowing and non- chemical channel maintenance activities). In March 2002, the Boards of Directors of both water agencies elected not to continue participation in the joint HCP because coverage for pesticide use would not be granted by the USFWS. The water agencies continue to be represented in the HCP as a permittee in the event they choose at a future date to apply for incidental take permits for the activities (excluding pesticides) covered by the HCP and evaluated in this EIR/EIS.

By late May 2002, the draft HCP was nearing completion and the EIR/EIS contained an analysis of the water agencies covered activities, excluding pesticide use. The land use agencies contacted the water agencies to determine if RD 1000 would continue to serve as a lead agency for the EIR. On May 31, 2002, the water agencies stated that they would not serve as a co-lead agency on the EIR because pesticide coverage was not addressed in the HCP and the associated EIR/EIS.

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On June 5, 2002, the water agencies presented information to the USFWS on pesticides for which coverage is requested. Because the water agencies decided in March 2002 not to file applications for incidental take permits on the basis of pending discussions with the USFWS on pesticide coverage, and because of the substantial period of time required to analyze the impacts of various pesticides and rodenticides on the covered species proposed by the water agencies in their June 5, 2002 letter, this EIR/EIS does not analyze such proposed covered activities The EIR/EIS does analyze other covered activities requested by the water agencies prior to December 2001 (i.e., the activities presented in the HCP). The water agencies will continue to work with the USFWS to address coverage for pesticide use independent of the current HCP.

To facilitate implementation of the Proposed Action, the City, Sutter County, and the Conservancy have filed applications for incidental take permits pending resolution of the water agencies’ request for coverage of pesticide use. Because environmental analysis of the water agencies’ covered activities has been conducted in conjunction with their previous participation in the HCP process, this EIR/EIS retains that analysis in the event that the water agencies elect to move forward with a separate HCP or an amendment to this HCP and associated environmental review at a future unknown date. Consequently, this EIR/EIS also evaluates both the potential environmental effects that could occur if the water agencies choose to file an application and the effects if the water agencies do not participate (i.e., implementation of the HCP and ITP issuance only to the City of Sacramento, Sutter County, and the Conservancy).

1.2.2. Court Opinion
As discussed above, the City received incidental take authorization from the USFWS in December 1997. In February 2000, the National Wildlife Federation and other plaintiffs filed suit against the USFWS’s issuance of the ITP to the City. The lawsuit also challenged the HCP’s compliance with the requirements of the Endangered Species Act (ESA) (National Wildlife Federation, et al. V. Secretary of the Interior Bruce Babbitt, August 15, 2000). The plaintiffs claimed that the USFWS violated various provisions of the Endangered Species Act (ESA) when it issued a “No-Jeopardy” opinion in its Biological Opinion in support of the issuance of the ITP. In addition, the plaintiffs asserted that the USFWS violated NEPA by preparing an Environmental Assessment rather than an EIS.

In August 2000, the United States District Court for the Eastern District of California issued a Memorandum of Opinion and Order (Order). The Court ruled in favor of the plaintiffs on six of nine actions. The Court ruled in favor of the USFWS on the remaining three issues: (1) the 1997 HCP met the minimum requirements of the ESA, (2) uncertainties regarding the biology of certain species addressed in the HCP did not undermine the legal adequacy of the HCP, and (3) the USFWS based its decisions on best available scientific and commercial evidence. (The revisions made to the HCP assessed in this EIR/EIS as a result of the Opinion are summarized in Table I-2 of the HCP.) Pursuant to a Settlement Agreement executed by the parties in the federal suit (effective May 10, 2001), the Order was modified to allow incidental take protection for limited land development within the City, with the provision of specific mitigation requirements.

Pursuant to the Order, the City has prepared a revised HCP (together with Sutter County, the Conservancy, RD 1000, and Natomas Mutual). The revised HCP prepared jointly by the City, Sutter County, the Conservancy, RD 1000, and Natomas Mutual is the subject of this EIR/EIS.

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1.3 Requirements for Environmental Review
This section presents the requirements for environmental review associated with the Proposed Action, including the obligations of the state and federal lead agencies and the role of the CDFG.

1.3.1 Lead Agencies
The City and Sutter County have issued and intend to issue permits allowing urban development within the Natomas Basin, and this development has the potential to result in the incidental take of listed plant and animal species. Similarly, the ongoing management activities of the Conservancy, RD 1000, and Natomas Mutual have the potential to result in incidental take of these same species. Incidental take can be authorized subject to approval by the USFWS (for additional information regarding this process, see Section 1.5.1). The City, Sutter County, and the Conservancy have submitted a draft HCP and have requested ITPs from the USFWS. Contingent upon the USFWS’s approval of the HCP, the USFWS will issue ITPs individually to the permittees (based on the permittees’ meeting the USFWS’s issuance criteria) and adopt IA(s). The permittees also intend to seek incidental take authorization from the CDFG. (The CDFG’s involvement in the HCP and process for consideration of incidental take is described below.)
The USFWS’s action to issue the ITPs, approve the HCP, and approve an IA is subject to environmental review under NEPA. The City, Sutter County, Conservancy, and water agency discretionary actions related to approval of the HCP (and IA[s]) and to the application for take authorization are subject to CEQA. The USFWS is the lead agency for the NEPA process, and the City and Sutter County are joint lead agencies for the CEQA process.

1.3.2 California Department of Fish and Game
In its role as a Responsible Agency under CEQA, CDFG will rely on this EIR/EIS in considering the issuance or modification of incidental take authorization to individual permittees. The CDFG has a parallel process to the USFWS’s process for allowing the incidental take of species. The CDFG process is implemented in accordance with the California Endangered Species Act (CESA) and is described in Section 2081 of the Fish and Game Code and its implementing regulations. Concurrent with the USFWS’s issuance of an ITP to the City in December 1997, CDFG issued a Section 2081 permit to the City for incidental take authorization for development in the Natomas Basin and implementation of the Natomas Basin HCP. Prior to the federal action against the USFWS, a similar lawsuit was filed with the Sacramento County Superior Court challenging CDFG’s issuance of the 2081 permit. The Superior Court ruled in favor of CDFG. An appeal was filed on February 14, 2000, but was later withdrawn pursuant to the May 10, 2001 Settlement Agreement. At this time, the City’s 2081 permit remains in effect.

The CDFG has participated in the development and review of the current HCP. On the basis of the public review of the HCP and the concurrent environmental review process under NEPA and CEQA, CDFG will consider amending its 2081 permit to the City and issuing 2081 permits to Sutter County and the Conservancy. The CDFG is a Responsible Agency under CEQA, and will use this EIR as its CEQA document for its actions pursuant to Section 2081.

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1.4 Purpose and Need/Objectives
This section presents the USFWS’s purpose and need (in accordance with the requirements of NEPA) and the objectives of the City, Sutter County and the Conservancy (in accordance with the requirements of CEQA). The specific biological objectives of the permittees, which are listed in Section I.C of the HCP and summarized in Section 2.4.4 of this EIR/EIS, are also incorporated in total into the purpose and need/objectives to establish and maintain a biologically sound and interconnected habitat reserve system. The purpose and need and objectives of the Proposed Action were used in the development of alternatives to the Proposed Action (see Sections 2.5 and 2.6).

1.4.1 Purpose and Need (USFWS)
This section presents the purpose and need and the objectives of the lead agencies. It also presents overall the objectives of the Conservancy (as a permittee) and the water agencies (as potential future permittees).

1.4.1.1 Purpose
Under NEPA, the USFWS’s purpose in issuing ITPs, entering into an IA(s), and approving the HCP is to authorize the incidental take of the covered species resulting from the covered activities in the Natomas Basin. As stated in the USFWS’s Habitat Conservation Planning Handbook (USFWS and National Marine Fisheries Service, 1996), a key facet of the HCP program is to reduce conflicts between listed species and economic development activities and to create a framework that would encourage “creative partnerships” among the public and private sectors and state, municipal, and federal agencies in the interests of endangered and threatened species and habitat conservation.

The specific purpose of the Proposed Action is to:
• Protect, conserve and enhance listed and unlisted species and their habitat for the continuing benefit of the people of the United States
• Ensure compliance with the ESA, NEPA, and other applicable federal laws and regulations
• Provide permanent protection and management of listed species and their habitat, and achieve long-term survival through the permittees’ participation in a mitigation program
• Implement the biological goals and objectives as specified in Section I.C of the HCP and Section 2.4.4 of this EIR/EIS

1.4.1.2 Need
The need for the action is based on the potential that activities proposed by the permittees could result in the take of federally listed species and other unlisted species that could become listed in the future. The USFWS must respond to the ITP application related to activities that have the potential to result in the take of covered species within each permittee’s permit area.

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1.4.2 Objectives (City of Sacramento and Sutter County) The CEQA lead agencies are also permittees. Their objectives include implementing the biological goals detailed in the HCP (Section I.C), which are summarized in Section 2.4.4 of this EIR/EIS.

The primary objectives under CEQA for the City and Sutter County are to implement their respective general plans and other planning documents (see Section 2.2 and Chapter 4) for lands within the Natomas Basin. These plans represent a foreseeable urban development scenario evaluated for the HCP. The Proposed Action addresses incidental take of the covered species resulting from 17,500 acres of planned development in the Natomas Basin (this also includes the 1,983-acre Metro Air Park project in unincorporated Sacramento County, which is covered under a separate permit, as described in Section 1.2.1). These development activities have the potential to result in the take of listed species and permanent disturbance to their habitats within the 53,537-acre Natomas Basin.

The specific objectives of the City and Sutter County are presented below.

1.4.2.1 City of Sacramento
The specific objectives of the City of Sacramento are to:
• Obtain an ITP from the USFWS. The ITP is necessary to authorize the incidental take of federally listed species that could result from the City’s planned development in the basin. • Obtain CDFG approval of modifications to the City’s 2081 permit to authorize the incidental take of state-listed species.
• Implement approved land use plans guiding urban development in the City’s permit area (including the “panhandle” lands proposed for annexation in the North Market Boulevard/Del Paso Road area).
• Minimize and mitigate the effects of take of the covered species. • Implement the biological goals and objectives as specified in Section I.C of the HCP and Section 2.4.4 of this EIR/EIS.

1.4.2.2 Sutter County
The specific objectives of Sutter County are to:
• Obtain an ITP from the USFWS. The ITP is necessary to authorize the incidental take of federally listed species that could result from Sutter County’s planned development in the basin.
• Obtain CDFG approval of a 2081 permit to authorize the incidental take of state-listed species.
• Implement approved land use plans guiding urban development in Sutter County’s permit area.
• Minimize and mitigate the effects of take of the covered species. • Implement the biological goals and objectives as specified in Section I.C of the HCP and Section 2.4.4 of this EIR/EIS.

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1.4.2.3 Other Permittees
The overall objective for the Conservancy is to implement the provisions of the HCP on lands acquired for management by the Conservancy in a way that promotes biological conservation and provides incidental take coverage.

The specific objectives of the Conservancy are to:
• Obtain an ITP for federally listed species within the Natomas Basin and Area B that would support the acquisition, development, and management of habitat reserves in accordance with the HCP.
• Obtain CDFG approval of a 2081 permit to authorize the incidental take of state-listed species.
• Minimize and mitigate the effects of take of the covered species and enhance habitat values to support covered species.
• Conduct reserve acquisition and development in accordance with Conservancy bylaws and provisions.
• Implement reserve management plans for ongoing management of reserve lands within its permit area.
• Implement the biological goals and objectives as specified in Section I.C of the HCP and Section 2.4.4 of this EIR/EIS.

The primary objective for RD 1000 and Natomas Mutual is to continue to engage in activities associated with their system of facilities, including water canals and drainage ditches, in a way that promotes biological conservation and provides incidental take coverage.

The specific objectives of RD 1000 are to:
• Obtain an ITP from the USFWS for federally listed species within the Natomas Basin to support the continuation of RD 1000 management activities in a manner conducive to species’ needs.
• Obtain CDFG approval of a 2081 permit to authorize the incidental take of state-listed species.
• Minimize and mitigate the effects of take of the covered species. • Implement the biological goals and objectives as specified in Section I.C of the HCP and Section 2.4.4 of this EIR/EIS.

The specific objectives of Natomas Mutual are to:
• Obtain an ITP from the USFWS for federally listed species within the Natomas Basin to support the continuation of Natomas Mutual management activities in a manner conducive to species’ needs.
• Obtain CDFG approval of a 2081 permit to authorize the incidental take of state-listed species.

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• Minimize the effects of take of the covered species.
• Implement the biological goals and objectives as specified in Section I.C of the HCP and Section 2.4.4 of this EIR/EIS.

1.4.3 Decisions to be Made
Overall, the decision to be made by the USFWS is whether or not the issuance of ITPs for the federally listed species in the Natomas Basin would be consistent with issuance criteria for the permit. Specifically, the decisions to be made by the USFWS are:
• Is the proposed take incidental to an otherwise lawful activity? • Are the impacts of the proposed taking minimized and mitigated to the maximum extent practicable?
• Have the permittees ensured that adequate funding will be provided to implement the measures proposed in the HCP?
• Is the proposed take such that it will not appreciably reduce the likelihood of the survival and recovery of the species in the wild?
• Are there other measures that should be required as a condition of the permit? The USFWS could choose to issue permits conditioned on implementation of the HCP as submitted, issue permits conditioned on implementation of the HCP (as submitted together with other measures specified by the USFWS), or deny the permits.

The decision to be made by the permittees is whether the implementation of the HCP within their permit areas would result in significant environmental impacts to their respective permit areas, including whether the implementation of the HCP is consistent with other regulations and policies for these areas.

1.4.4 Other Discretionary Actions
As discussed in Section 1.3.1, this EIR/EIS is intended to support the actions of the USFWS in issuing ITPs and entering into an IA(s) for the HCP, and to support the actions of the City, Sutter County, the Conservancy, RD 1000, and Natomas Mutual in applying for ITPs, entering into an IA(s), and implementing the HCP. In addition, the EIR/EIS is also intended to support the following discretionary actions:
• Issuance of take permits by CDFG under Section 2081 of the Fish and Game Code. • Issuance of take authorization related to specific urban development applications (e.g., Tentative Subdivision Maps) within the permit areas of the City and Sutter County. • Issuance of incidental take authorization for other covered activities (e.g., infrastructure development and other public works projects) within the permits areas of the City and Sutter County.
• The Conservancy’s activities related to the conservation strategy in the HCP, including the application of acquisition criteria and the creation of habitat reserves.

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1.4.5 Independent Implementation
As discussed in Section I.A. of the HCP (and in Section 2.3 of this EIR/EIS), the individual permittees (i.e., the City, Sutter County, Conservancy, RD 1000, and Natomas Mutual) would obtain individual ITPs from the USFWS for activities within each permittee’s respective permit area. Similarly, each of these permittees also would obtain individual Section 2081 permits (or amendments to existing 2081 permits) from the CDFG for activities conducted within each permittee’s respective permit area. Each permittee would be required to mitigate independently the impacts of its covered activities (i.e., if any one of the permits were revoked, the other permits would still remain in effect). The conservation strategy in the HCP, as it pertains to specific permittees, can be used by the various applicants to obtain the necessary take permits needed to conduct otherwise lawful activities within each permittee’s respective permit area. Because of the potential for independent implementation of the HCP by permittees, this EIR/EIS assesses impacts from individual permittees as well as overall impacts of the Proposed Action and alternatives (see Chapter 4: Environmental Consequences).

1.5 Regulatory Framework
Key relevant federal, state, and local regulations and guidelines applicable to implementation of the Proposed Action are described below.

1.5.1 Endangered Species Act
The 1973 Endangered Species Act (16 U.S.C. 1531-1544) provides for the conservation of ecosystems (both through federal action and by encouraging the establishment of state programs) upon which threatened and endangered species of fish, wildlife, and plants depend. The ESA is enforced by the USFWS, and by the National Marine Fisheries Service for salmon and other anadromous fish. Key provisions of the ESA are described below.

1.5.1.1 Section 9
Section 9 of the ESA and accompanying federal regulations prohibit the unauthorized taking of fish and wildlife species listed as threatened or endangered by government, private companies, and individuals. As defined in the ESA, taking means “to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect or to attempt to engage in such conduct.” By regulation, the USFWS have defined harm as any act that “actually kills or injures” listed wildlife. Harm could also include “significant habitat modification or degradation where it actually kills or injures wildlife by significantly impairing essential behavioral patterns, including breeding, feeding, or sheltering.”

1.5.1.2 Section 10
In recognition that take cannot always be avoided, Section 10(a)(1)(B) of the ESA allows USFWS to authorize taking of endangered and threatened species by non-federal entities that is incidental to, but not the purpose of, otherwise lawful activities. Similar provisions are found in Section 7 for actions by federal agencies (see below). Under Section 10(a)(1)(B), such authorizations are granted through the issuance of ITPs. Applicants for such permits must submit conservation plans (i.e., HCPs) that specify:

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• The impact(s) that will likely result from the taking • The measures the permittee will take to minimize and mitigate those impacts • The source of funding available to implement the measures • Alternatives to the taking and the reason the alternatives were not chosen • Any other measures considered by the USFWS as necessary or appropriate for minimizing or mitigating the impacts of the taking
Section 10(a)(1)(B) also was intended by Congress to authorize the Services to approve HCPs for unlisted as well as listed species, and to issue ITPs that cover unlisted species where coverage is already being provided for listed species. If an applicant proposing an individual HCP chooses to include an unlisted species, additional mitigation would not be required within the ITP permit area upon the listing of that species. Under the Natomas Basin HCP, the USFWS would issue ITPs based on implementation measures contained in the HCP that would cover 22 listed and unlisted species.

1.5.1.3 Section 7
Under Section 7 of the ESA, federal agencies must ensure that actions they authorize, fund, or carry out are not likely to jeopardize the continued existence of endangered or threatened species or result in the destruction or adverse modification of designated critical habitat of listed species by federal agency actions. Because issuance of an ITP is a federal action, the USFWS would conduct an internal consultation on the ITP. This EIR/EIS is being prepared to support possible issuance of an ITP, which requires compliance with ESA Section 7.

1.5.1.4 Unforeseen Circumstances / “No Surprises”
On February 28, 1998, the U.S. Fish and Wildlife Service and National Marine Fisheries Service published a final rule codifying “No Surprises” into federal regulation at 50 C.F.R.

Sections 17.22(b)(5) and 17.32(b)(5). The “No Surprises” regulations state, in part, that, “In negotiating unforeseen circumstances, the [USFWS] Director will not require the commitment of additional land, water, or financial compensation or additional restrictions on the use of land, water, or other natural resources beyond the level otherwise agreed upon for the species covered by the conservation plan without the consent of the permittee. If additional conservation and mitigation measures are deemed necessary to respond to unforeseen circumstances, the Director may require additional measures of the permittee where the conservation plan is being properly implemented, but only if such measures are limited to modifications within the conserved habitat areas, if any, or to the conservation plan's operating conservation program for the affected species, and maintain the original terms of the conservation plan to the maximum extent possible. Additional conservation and mitigation measures will not involve the commitment of additional land, water, or financial compensation or additional restrictions on the use of land, water, or other natural resources, otherwise available for development or use under the original terms of the conservation plan without the consent of the permittee.” The regulation also states that the assurances of the No Surprises regulations apply only “where the conservation plan is being properly implemented, and apply only with respect to species adequately covered by the conservation plan.”
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a species or geographic area covered by a conservation plan (e.g., the listing of a new species, or a fire or other natural catastrophic event in areas prone to such events), which can reasonably be anticipated and planned for by the applicants and the USFWS.

1.5.2 National Environmental Policy Act
The National Environmental Policy Act of 1969, as amended, (42 U.S.C. 4321 et seq.), requires that all federal agencies proposing major actions significantly affecting the quality of the human environment prepare a detailed statement of environmental effects. NEPA stipulates the factors to be considered in environmental impact statements and requires that federal agencies employ an interdisciplinary approach in related decision-making. The USFWS, pursuant to NEPA and its internal guidelines, implements NEPA through cooperating with state and local agencies and concerned public and private organizations in making informed environmental decisions to conserve, protect, and enhance fish and wildlife and their habitats for the continued benefit of the public.

1.5.3 California Environmental Quality Act
The California Environmental Quality Act (Pub. Res. Code §21000 et seq.), as amended, requires that state and local government agencies identify the significant environmental effects of their actions and either avoid those significant environmental effects or mitigate those significant environmental effects, where feasible. The City, Sutter County, and RD 1000 implement CEQA through cooperating with other state and local agencies in identifying and either avoiding, minimizing, or mitigating effects to the environment as a result of activities that they undertake or for which they provide approval. Although Natomas Mutual, a private water company, does not independently implement CEQA, it must comply with CEQA. Thus, RD 1000 serves as the public agency with discretionary authority for Natomas Mutual’s activities for purpose of CEQA.

1.5.4 California Endangered Species Act
The California Endangered Species Act is part of the Fish and Game Code of the State of California. As a guide to state agencies, CESA states that “…the policy of the state [is] that state agencies should not approve projects as proposed which would jeopardize the continued existence of any endangered species or threatened species or result in the destruction or adverse modification of habitat essential to the continued existence of those species, if there are reasonable and prudent alternatives consistent with conserving the species or its habitat which would prevent jeopardy.” The act also states that such reasonable and prudent measures must at the same time maintain the project purpose to the greatest extent possible.

Similar to the federal ESA, CESA prohibits import, export, take, possession, purchase, or sale of listed plant and animal species except as otherwise provided in other provisions of the Fish and Game Code. The state restrictions on take differ from those under the ESA in how take is defined. For CESA, take is defined to mean “hunt, pursue, capture, or kill or attempt the same.” Noticeably absent from this definition are certain types of takings prohibited under the ESA (e.g., to harm or harass a listed species). Accordingly, CESA prohibits the direct take of listed species except as otherwise provided under the Fish and Game Code.

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Take of state-listed species may be authorized under CESA. Section 2081 of the Fish and Game Code authorizes CDFG to permit the take of state-listed endangered species, threatened species, and candidate species if all of the following conditions are met:
• The take is incidental to an otherwise lawful activity. • The impacts of the authorized take are minimized and fully mitigated. The measures required to meet this obligation must be roughly proportional in extent to the impact of the authorized taking on the species. Where various measures are available to meet this obligation, the measures required shall maintain the permittee’s objectives to the greatest extent possible. All required measures shall be capable of successful implementation.
• The permit is consistent with any CDFG regulations.
• The permittee must ensure adequate funding to implement the minimization and mitigation measures, and for monitoring compliance with and effectiveness of those measures.
• The permit will not jeopardize the continued existence of the species.

Sacramento City CouncilNovember 18, 2025

Sacramento City Council
November 18, 2025