2024
Survey Report
for
Foraging Crotch’s Bumble Bee
(Bombus crotchii)
on the
Woodward Specific Plan Development Project
Prepared for:
Sophia Mit
chell and Associates
P.O Box 1700
Gualala, California 95445
Prepared by:
Alden Environmental, Inc.
3245 University Ave., #1188
San Diego, CA 92104
August 15, 2024
ALDEN
ENVIRONMENTAL, INC
TABLE OF CONTENTS
Page
INTR
ODUCTION ......................................................................................................................... 1 METHODS .................................................................................................................................... 1 RESULTS ...................................................................................................................................... 2 REFERENCES .............................................................................................................................. 2
LIST OF FIGURES
Follows
Number Title P age
1 R
egional Location ....................................................................................................2 2 Project Location .......................................................................................................2 3 Crotch’s Bumble Bee Survey Areas ........................................................................2
LIST OF TABLES
Number Title P age
1 2024 C
rotch’s Bumble Bee Survey Information .....................................................1
LIST OF ATTACHMENTS
Letter Title
A F
ield Forms
2024 Foraging CBB Survey Report for the Woodward Specific Plan Development Project Site 1 INTRO
DUCTION
This report documents the methods and results of a survey conducted on the Woodward Specific Plan Development Project site for foraging Crotch’s bumble bee ( CBB; Bombus crotchii ), a candidate for listing as endangered under the California Endangered Species Act (CESA). The study area encompasses approximately 27 acres of vacant and developed land located within the City. This area includes the approximately 8.5-acre proposed project site and designated 200-foot buffer. The study area is bordered to the south b y East Mission Road and to the west by North Twin Oaks Valley Road. Woodward Street bisects the study area at the western boundary of the project site (Figures 1 and 2). The study area is located within the United States Geological Survey (USGS) San Marcos 7.5-minute topographic quadrangle.
METHODS
A f ora
ging bumble bee survey for the CBB was conducted during the period May 16 through July 12, 2024 (Table 1). The survey followed the Survey Considerations for CESA Candidate Bumble Bee Species issued by the CDFW on June 6, 2023.
Table 1
2024 Crotch’s Bumble Bee Survey Information
Site
Visit # Date Biologist(s) Survey Times
(start-stop) Weather Conditions (start/stop)
1 5/16 Brian Lohstroh 1000-1445 50% cover, 65°F, wind 0-3 mph/ 40%, 73°F, wind 3-8 mph
2 6/6 Brian Lohstroh 1000-1445 50% cover, 73 °F, wind 5-8 mph/ 0%, 82°F, wind 6-10 mph
3 7/12 Brian Lohstroh 0830-1345 40% cover, 73°F, wind 1-5 mph/ 20%, 86°F, wind 2-8 mph
Pri
or to beginning the survey, a habitat assessment was conducted to identify suitable foraging habitat for the CBB. The assessment included reviewing California Department of Fish and Wildlife (CDFW) Survey Considerations for California Endangered Species Act Candidate Bumble Bee Species (2023), as well as reviewing available bumble bee data (iNaturalist and Bumble Bee Watch) and California Natural Diversity Database (CNDDB) to identify any reported CBB observations in the site vicinity. In addition, current vegetation mapping prepared for the project, historic aerial photographs, and site photographs were reviewed to identify areas that may support suitable foraging resources (flowering plants) for the species as well as nesting locations.
Potential habitat for the CBB on site was determined from those existing conditions.
According to the Survey Considerations (CDFW 2023), it is recommended that at least 3 site visits take place spaced 2 to 4 weeks apart during the period of highest detection probability for foraging CBB (i.e., the April – August Colony Active Period for the species) and when floral resources are
2024 Foraging CBB Survey Report for the Woodward Specific Plan Development Project Site
2 present. Three site visits were made to the survey area approximately 3-5 weeks apart during the Colony Active Period when floral resources were present (Table 1).
The Survey Considerations (CDFW 2023) state that site visits should be made at least 1 hour after sunrise and at least 2 hours before sunset, although ideally between 9 am and 1 pm on warm, but not hot, sunny days (65-90 degrees Fahrenheit) with low wind (less than 8 miles per hour). The recommended rate of survey is 1 person- hour per 3 acres of suitable habitat. The survey was conducted under these conditions (Table 1; Appendix A).
The survey included walking meandering transects through the survey areas and looking for foraging Bombus species. All flowering plants in bloom, as well as bee/wasp species, were recorded in field notes during each site visit (Appendix A). No netting or handling of any insects was conducted. The entirety of the survey area was surveyed 3 times.
Approximately 14 acres within the study area were determined to support flowering plants where the CBB could forage. This acreage is dominated by Diegan Coastal Sage Scrub (DCSS) and disturbed DCSS habitats. Total flower coverage in the survey area ranged from 10% to 50% throughout the 3 surveys.
The remaining 13 acres is not suitable for CBB, as it contains no flowers and is either developed or highly disturbed.
RESULTS
The nearest record of the species is an iNaturalist research grade record from M arch 2024, approximately 1.15 miles to the west of the site, in an undeveloped area just east of the Edwin and Francis Hunter Arboretum. CNDDB records indicate this species has been recorded on June 15, 2020, approximately 2.5 miles from the project site within the San Marcos Double Peak Park.
One CBB was observed during the 6/6 survey within the project boundary in the southern central portion of the study area. Additional Bombus species were also observed during each of the three surveys. Twelve Yellow-faced bumble bees (Bombus vosnesenskii), including one queen, were observed on 5/16; twenty five, including one male, were observed on 6/6; and sixteen were observed on 7/12. Sixteen California bumble bee ( Bombus californicus) were also observed on 7/12. Other bee and wasp species observed throughout the survey included the European honey bee (Apis mellifera), Hover fly (Syrphidae), tarantula hawk (Pepsis thisbe), Robber fly (Asilidae), California digger bee ( Anthophora californica), Mexican cactus fly ( Copestylum mexicanum ), carpenter bee (Xylocopinae), and Figeater beetle (Cotinis mutabilis).
The DCSS habitat (including disturbed) on site supports suitable foraging and nesting resources for bumble bees as this habitat contains substantial nectar resources and burrowing animal species (lizards, gophers, etc). Therefore, the site is considered suitable nesting and foraging habitat for species.
2024 Foraging CBB Survey Report for the Woodward Specific Plan Development Project Site
3 REFERENCES
Bumble Bee Watch, September 14, 2024. https://www.bumblebeewatch.org/maps
California Department of Fish and Wildlife. 2023. Survey Considerations for California Endangered Species Act Candidate Bumble Bee Species. June 6. https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=213150&inline
iNaturalist, September 14, 2024.
https://www.inaturalist.org/observations?place_id=any&subview=map&taxon_id=271451
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Source: USGS Quads (San Marcos) Copyright:© 2013 National Geographic Society, i-cubedProject Boundary Figure 2
WOODWARD SPECIFIC PLAN
DEVELOPMENT PROJECT
CROTCH'S BUMBLE BEE SURVEYALDEN
ENVIRONMENTAL, INC
Woodward St
E Mission Rd
Queen
6/6/2024
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Survey Results
Crotch's Bumble Bee
(Bombus crotchii)
Vegetation
Southern Riparian Forest
Diegan Coastal Sage Scrub
Diegan Coastal Sage Scrub - Disturbed
Eucalyptus Woodland
Disturbed Habitat
Urban/ Developed
Vegetation Source: Rincon
Associates, Inc., February 2024
WOODWARD SPECIFIC PLAN
DEVELOPMENT PROJECT
CROTCH'S BUMBLE BEE SURVEYALDEN
ENVIRONMENTAL , INC
Atta
chment A
Survey Field Forms
Crotch’s Bumble Bee Survey Form
Project:
____________________________________________________________ Date:_____________ Surveyor:_____________________________ Survey Polygon: ___________ Survey Number:______ Acres Surveyed:_______________ Survey Time:_______________ Acres per Hour:_____________ Other Surveyors Present: ______________________________________________________________ Field Conditions
Time (24 hr) Temperature (˚F) Wind Speed (mph) Cloud Cover Start
End
Start
End
Vegetation Communities Surveyed (inc. dominant spp.)
Bumble Bee Species (Bombus spp.) # Other Hymenoptera (Bee/Wasp) Species Obs.
California bumble bee (B. californicus) western honey bee (Apis mellifera) Crotch’s bumble bee (B. crotchii) Ichnemonid wasp (Family: Ichneumonidae) Fernald cuckoo bumble bee (B. flavidus) drone fly (Eristalis tenax) black tail bumble bee (B. melanopygus) tarantula hawk (Pepsis thisbe) Sonoran (American) bumble bee (B. sonorous) Mexican cactus fly (Copestylum mexicanum) Vancouver bumble bee (B. vancouverensis nearcticus) California digger bee (Anthophora californica) Van Dyke bumble bee (B. vandykei) carpenter bee (Subfamily: Xylocopinae) Yellow-faced bumble bee (B. vosnesenskii)
Column Total
Nectar/Pollen Sources Present (*CBB preferences)
deerweed (Acmispon glaber) lupine (Lupinus)*
onion (Allium spp.) bur-clover (Medicago)*
fiddleneck (Amsinckia spp.) penstemon (Penstemon)
snapdragon (Antirrhinum)* phacelia / scorpionweed (Phacelia)* manzanita (Arctostaphylos) popcorn flower (Cryptantha/Plagiobothrys) milkweed (Asclepias)* sage (Salvia)*
milk-vetch (Astragalus) ragwort (Senecio)
goldenstar (Bloomeria spp.) clover (Trifolium)
Lilac/buckthorn (Ceanothus) vetch (Vicia)*
pincushion (Chaenactis)* Other:
thistle (Cirsium)*
clarkia (Clarkia)
bird's beak (Cordylanthus)
fascicled tarweed (Deinandra fasciculata)
larkspur (Delphinium)*
buckwheat (Eriogonum fasciculatum)
sunflower (Helianthus)
telegraph weed (Heterotheca)
goldfields (Lasthenia spp.)
honeysuckle (Lonicera)
Crotch’s Bumble Bee Observation(s) Log
Time Photo(s) No. Notes (Habitat, Nectar/Pollen Source, Behavior) Brian Lohstroh
1 Malacathamnus fasciculata
Solanum parishii
Scoliid wasp (Scoliidae)
Golden paper wasp (Polistes aurifer)
50%
Hirschfeldia incana
Woodward 46 Project
NA
5/16/24
14 4:45
2.94 1000
65 1445
73 40%
Site conditions: Approx 50% floral cover, dominated by SALMEL 12 0-3
3-8
12 (Incl. 1 Queen)
melliera, apiana
B. vos nectaring
Mirabilis laevis
Eriophyllum confertiflorum
Scrophularia californica
Diplaucus sp.
Echium candicans
Opunita sp.
Sambucus nigra
None
CSS: SALMEL, ARTCAL, ERIFAC, MALLAU.
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Habitat Photographs
5/16/24, Woodward 46
Crotch’s Bumble Bee Survey Form
Project:
____________________________________________________________ Date:_____________ Surveyor:_____________________________ Survey Polygon: ___________ Survey Number:______ Acres Surveyed:_______________ Survey Time:_______________ Acres per Hour:_____________ Other Surveyors Present: ______________________________________________________________ Field Conditions
Time (24 hr) Temperature (˚F) Wind Speed (mph) Cloud Cover Start
End
Start
End
Vegetation Communities Surveyed (inc. dominant spp.)
Bumble Bee Species (Bombus spp.) # Other Hymenoptera (Bee/Wasp) Species Obs.
California bumble bee (B. californicus) western honey bee (Apis mellifera) Crotch’s bumble bee (B. crotchii) Hover fly (Syrphidae) Fernald cuckoo bumble bee (B. flavidus) drone fly (Eristalis tenax) black tail bumble bee (B. melanopygus) tarantula hawk (Pepsis thisbe) Sonoran (American) bumble bee (B. sonorous) Mexican cactus fly (Copestylum mexicanum) Vancouver bumble bee (B. vancouverensis nearcticus) California digger bee (Anthophora californica) Van Dyke bumble bee (B. vandykei) carpenter bee (Subfamily: Xylocopinae) Yellow-faced bumble bee (B. vosnesenskii)
Column Total
Nectar/Pollen Sources Present (*CBB preferences)
deerweed (Acmispon glaber) lupine (Lupinus)*
onion (Allium spp.) bur-clover (Medicago)*
fiddleneck (Amsinckia spp.) penstemon (Penstemon)
snapdragon (Antirrhinum)* phacelia / scorpionweed (Phacelia)* manzanita (Arctostaphylos) popcorn flower (Cryptantha/Plagiobothrys) milkweed (Asclepias)* sage (Salvia)*
milk-vetch (Astragalus) ragwort (Senecio)
goldenstar (Bloomeria spp.) clover (Trifolium)
Lilac/buckthorn (Ceanothus) vetch (Vicia)*
pincushion (Chaenactis)* Other:
thistle (Cirsium)*
clarkia (Clarkia)
bird's beak (Cordylanthus)
fascicled tarweed (Deinandra fasciculata)
larkspur (Delphinium)*
buckwheat (Eriogonum fasciculatum)
sunflower (Helianthus)
telegraph weed (Heterotheca)
goldfields (Lasthenia spp.)
honeysuckle (Lonicera)
Crotch’s Bumble Bee Observation(s) Log
Time Photo(s) No. Notes (Habitat, Nectar/Pollen Source, Behavior) B. vos nectaring
B. vos nectaring
Brian Lohstroh
Malacathamnus fasciculata
Solanum parishii
50%
Hirschfeldia incana
Woodward 46 Project
NA
14 4:45
2.94 1000
1445
Site conditions: Approx 50% floral cover, dominated by SALMEL melliera, apiana
Mirabilis laevis
Eriophyllum confertiflorum
Scrophularia californica
Diplaucus sp.
Echium candicans
Opunita sp.
Sambucus nigra
None
CSS: SALMEL, ARTCAL, ERIFAC, MALLAU.
73 82
5-8
6-10
0%
1 26
25 (Queen)
Incl. 1 male
B. vos, crotchii nectaring
Golden paper wasp (Polistes aurifer)
Scoliid wasp (Scoliidae)
6/6/24
12:18p
3 Yes
2 Suspected queen (large size) foraging on Salvia mellifera. Departed to south, downslope. v
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Habitat Photographs
6/6/24, Woodward 46
Crotch’s Bumble Bee Survey Form
Project:
____________________________________________________________ Date:_____________ Surveyor:_____________________________ Survey Polygon: ___________ Survey Number:______ Acres Surveyed:_______________ Survey Time:_______________ Acres per Hour:_____________ Other Surveyors Present: ______________________________________________________________ Field Conditions
Time (24 hr) Temperature (˚F) Wind Speed (mph) Cloud Cover Start
End
Start
End
Vegetation Communities Surveyed (inc. dominant spp.)
Bumble Bee Species (Bombus spp.) # Other Hymenoptera (Bee/Wasp) Species Obs.
California bumble bee (B. californicus) western honey bee (Apis mellifera) Crotch’s bumble bee (B. crotchii) Hover fly (Syrphidae) Fernald cuckoo bumble bee (B. flavidus) Drone fly (Eristalis tenax) black tail bumble bee (B. melanopygus) Tarantula hawk (Pepsis thisbe) Sonoran (American) bumble bee (B. sonorous) Robber fly (Asilidae) Vancouver bumble bee (B. vancouverensis nearcticus) California digger bee (Anthophora californica) Van Dyke bumble bee (B. vandykei) Carpenter bee (Subfamily: Xylocopinae) Yellow-faced bumble bee (B. vosnesenskii)
Column Total
Nectar/Pollen Sources Present (*CBB preferences)
deerweed (Acmispon glaber) lupine (Lupinus)*
onion (Allium spp.) bur-clover (Medicago)*
fiddleneck (Amsinckia spp.) penstemon (Penstemon)
snapdragon (Antirrhinum)* phacelia / scorpionweed (Phacelia)* manzanita (Arctostaphylos) popcorn flower (Cryptantha/Plagiobothrys) milkweed (Asclepias)* sage (Salvia)*
milk-vetch (Astragalus) ragwort (Senecio)
goldenstar (Bloomeria spp.) clover (Trifolium)
Lilac/buckthorn (Ceanothus) vetch (Vicia)*
pincushion (Chaenactis)* Other:
thistle (Cirsium)*
clarkia (Clarkia)
bird's beak (Cordylanthus)
fascicled tarweed (Deinandra fasciculata)
larkspur (Delphinium)*
buckwheat (Eriogonum fasciculatum)
sunflower (Helianthus)
telegraph weed (Heterotheca)
goldfields (Lasthenia spp.)
honeysuckle (Lonicera)
Crotch’s Bumble Bee Observation(s) Log
Time Photo(s) No. Notes (Habitat, Nectar/Pollen Source, Behavior) B. vos nectaring
B. vos nectaring
B. vos nectaring
Brian Lohstroh
Hirschfeldia incana
Woodward 46 Project
NA
14 melliera, apiana
Eriophyllum confertiflorum
Scrophularia californica
Diplaucus sp.
Echium candicans
Opunita sp.
Sambucus nigra
None
CSS: SALMEL, ARTCAL, ERIFAC, MALLAU.
73 7/12/24
0830
1345
86 2-8
1-5
40%
20%
5:15
2.67 Site conditions: Approx 10% floral cover, dominated by MALLAU with some ERIFAC 16 Incl. 7 males
16 16
Mud dauber wasp (Sceliphron caementarium)
Figeater beetle (Cotinis mutabilis)
Malosma laurina
Heteromeles arbutifolia
Acourtia microcephala
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