Andrena clarkella

Justification:
Clark’s Mining Bee is a holarctic bee that occurs across northern Europe and northern North America. Using all observations of the species, the extent of occurrence is over 36 million km2. There have been numerous observations of the species since 2015, which are well distributed across its known range. It is a pollen specialist that visits plants from the genus Salix (Salicaceae), and occurs in wide ranging habitats, including grasslands, shrublands, forests, and human altered landscapes. Across the range of the species, impacts from climate change, habitat loss and degradation, and exposure to pesticides have been observed. These threats may be acting on the species at local levels. This species has been ranked in the European regional assessment (2014) as data deficient due to questions about the population size of the species. Since this ranking, the species has been recorded in abundance across many parts of the species range. Because this species is widespread, has been recently observed in abundance, and occurs in several habitat types, it is unlikely that it is threatened with extinction at this time. As such it is assessed as Least Concern for now.

Food habits comment: Clark’s Mining bee is a dietary specialist, collecting pollen from plants in the genus Salix (Salicaceae). Habitat comment: This species has been recorded in forests, forest edges, forest clearings, gardens and parks (Szczepko-Morawiec et al. 2024) , shrublands, and grasslands (Chesshire et al. 2023) at elevations below 1,030 m. Reproduction comment: This species nests underground like all other Andrena (Danforth et al. 2019). Nests have been recorded in small clusters and dense aggregations (Else 2001) . This species has been found to prefer soil nesting substrate that is moderately moist (Szczepko-Morawiec et al. 2024). Nest cells from other members of this genus are located at the ends of the lateral burrows, which are typically lined with a waxy Dufour’s gland secretion (Cane 1981) that serves to both isolate the provision from pathogens in the surrounding soil and to regulate water uptake from the soil atmosphere (Cane and Love 2021). Females provision each cell with a ball of pollen moistened with nectar on which they lay a single egg (Michener 2007). The cleptoparasitic bee, Nomada leucophthalma has been observed in the nest of this species (Else 2001). Phenology comment: This species has been recorded across a broad phenological window, with most records from March through May (Chesshire et al. 2023). Adults are assumed to emerge annually (Danforth et al. 2019).

Threat comments: Certain aspects of this species' biology may make it more vulnerable to some threats. Andrena clarkella is a ground nesting species, and nests may be harmed by certain agricultural practices such as tilling, which can kill bees nesting close to the surface (Williams et al. 2010). This species is a dietary specialist, which has been linked to higher risk of extinction due to reduced host plant availability, especially under climate change scenarios (Roberts et al. 2011) and reduced effective population sizes (Packer et al. 2005). Additionally, Andrena have been reported to have low reproductive output because of the short adult life span, and a low rate of brood cell provisioning (reviewed in Danforth et al. 2019). Other threats to bees generally include habitat loss or modification, climate change, pesticide use, exposure to pathogens from managed bee species, and competition with honey bees (Brown and Paxton 2009; Potts et al. 2010; Wojcik et al. 2018; Grab et al. 2019; Raven and Wagner 2021). Threats Threats: Timing: Scope: Severity: Impact Score: 1. Residential & commercial development -> 1.1. Housing & urban areas 1. Residential & commercial development -> 1.2. Commercial & industrial areas 2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.3. Agro-industry farming 7. Natural system modifications -> 7.1. Fire & fire suppression -> 7.1.1.Increase in fire frequency/intensity 7. Natural system modifications -> 7.1. Fire & fire suppression -> 7.1.2. Suppression in fire frequency/intensity 8. Invasive and other problematic species, genes, and diseases -> 8.1 Invasive non-native/alien species/diseases -> 8.1.2. Named species 9. Pollution -> 9.3 Agricultural and forestry effluents -> 9.3.3 Herbicides and Pesticides 11. Climate change & severe weather -> 11.1. Habitat shifting & alteration 11. Climate change & severe weather -> 11.2.Droughts 11. Climate change & severe weather -> 11.3.Temperature extremes Conservation Actions Conservation needs No known conservation actions are in place for this species. Protected/Managed area comment: Observations of this species are known from Bureau of Land Management (BLM), Department of Defence, U.S. Fish and Wildlife, National Park Service, and U.S. Forest Service land, but this does not confer any specific protections to the species. Management comment: Specific conservation needs for this species have not been identified. Due to the importance of supporting wild bee populations for pollination services, general conservation practices are recommended including, restoring, creating, and preserving natural high-quality habitats to include suitable forage and nesting sites; limiting pesticide use on or near suitable habitat, particularly during the adult bee’s flight period; promoting farming and urban practices that increase pollinator-friendly plants in margin space; minimizing exposure of wild bees to diseases transferred from managed bees; and lastly, avoiding honey bee introduction to high-quality native bee habitat. Conservation Actions Needed 1. Land/water protection -> 1.2. Resource & habitat protection 2. Land/water management -> 2.3. Habitat & natural process restoration 4. Education & awareness -> 4.3. Awareness & communications 5. Law & policy -> 5.2. Policies and regulations Research needs Research need comment: More information is needed about the population status, population trend, existing threats, range limits, habitat, and ecology of this species. Surveys targeting this species are needed throughout its range to determine its persistence throughout its historic range. Research Needed 1. Research -> 1.2. Population size, distribution & trends 1.3. Life History and Ecology 1.5. Threats 1.6 Conservation actions 3. Monitoring -> 3.1. Population trends 3.4. Habitat trends Assessment Date of assessment (month-day-year): 3-17-2025 Assessors names (use * to indicate primary assessor, typically the participant with most experience/knowledge of the species): Saff Killingsworth Reviewer(s): Contributors(s): Faye Benjamin, Bethanne Bruninga-Socolar, Tina Harrison, Molly MacLeod, Michael Roswell, Rachael Winfree For a full list of the 162 institutions that contributed to the Chesshire et al. dataset, please see Chesshire et al. 2023, S1. Facilitator(s) and compiler(s): Paige R. Chesshire, Erica E. Fischer, Nicolas J. Dowdy, Terry L. Griswold, Alice C. Hughes, Michael C. Orr, John S. Ascher, Laura M. Guzman, Keng-Lou James Hung, Neil S. Cobb and Lindsie M. McCabe Red List Category and Criteria: Least Concern Justification: Clark’s Mining Bee is a holarctic bee that occurs across northern Europe and northern North America. Using all observations of the species, the extent of occurrence is over 36 million km2. There have been numerous observations of the species since 2015, which are well distributed across its known range. It is a pollen specialist that visits plants from the genus Salix (Salicaceae), and occurs in wide ranging habitats, including grasslands, shrublands, forests, and human altered landscapes. Across the range of the species, impacts from climate change, habitat loss and degradation, and exposure to pesticides have been observed. These threats may be acting on the species at local levels. This species has been ranked in the European regional assessment (2014) as data deficient due to questions about the population size of the species. Since this ranking, the species has been recorded in abundance across many parts of the species range. Because this species is widespread, has been recently observed in abundance, and occurs in several habitat types, it is unlikely that it is threatened with extinction at this time. As such it is assessed as Least Concern for now. Rank reasons This species is a holarctic solitary bee that occurs across northern Europe and northern North America. Using all verified records of the species, the range extent is over 36 million km2. This species occurs in grasslands, shrublands, forests, suburban, and agricultural areas. It is a dietary specialist and forages from the plant genus Salix. Across the range of the species, impacts from climate change, pesticide exposure, and habitat loss and degradation have been observed. These threats may be acting on the species at local levels. Because the species is widespread, has been recently observed across much of its range, and occurs in several habitat types it is unlikely to be threatened with extinction at this time. NatureServe Specific Text (NOT OTHERWISE INCLUDED IN ABOVE TEXT): For Rank Calculator: 1. Element occurrences (using separation distance of 5,000 m): 3,826 (E) 1. Estimated Number of Element Occurrences Comments: Using all records from the last 30 years (since 1995), this species is known from at least 3,800 occurrences using a 5 km separation distance. 2. Population size: Unknown 3. Viability/Ecological integrity (choose one) 1. Number of occurrences with good viability/ecological integrity: Unknown 2. Percent of area occupied (For Species with Known AOO): N/A 4. Environmental Specificity: B. Narrow. Specialist or community with key requirements common. 1. Environmental specificity comments: This species is a dietary specialist, using pollen from the plant genus Salix (Salicaceae), which likely restricts its distribution and phenology. 5. Intrinsic Vulnerability: B. Moderately vulnerable 1. Intrinsic vulnerability comments: Andrena have been reported to have low reproductive output because of the short adult life span, and a low rate of brood cell provisioning (reviewed in Danforth et al. 2019). 6. Trend 1. Short Term Trend: Unknown 2. Comments: Abundance estimates and population trends are not known for this species. 3. Long Term Trend: Unknown 4. Comments: Abundance estimates and population trends are not known for this species. For Biotics Global Element Characterization: 1. Habitat Forest/Woodland, Shrubland/chaparral, Grassland/Herbaceous, Cropland/Hedgerow, Suburban/Orchard 2. Food Habits 1. Adult: nectarivore 2. Immature: nectarivore Literature References: Brown, Mark J. F., and Robert J. Paxton. 2009. “The Conservation of Bees: A Global Perspective.” Apidologie 40 (3): 410–16. Cane, James H., and Byron G. Love. 2021. “Hygroscopic Larval Provisions of Bees Absorb Soil Water Vapor and Release Liquefied Nutrients.” Apidologie 52 (6): 1002–16. Cane, J. H. 1981. “Dufour’s Gland Secretion in the Cell Linings of Bees (Hymenoptera: Apoidea).” Journal of Chemical Ecology 7 (2): 403–10. Chesshire, Paige R., Erica E. Fischer, Nicolas J. Dowdy, Terry L. Griswold, Alice C. Hughes, Michael C. Orr, John S. Ascher, et al. 2023. “Completeness Analysis for over 3000 United States Bee Species Identifies Persistent Data Gap.” Ecography, February. https://doi.org/10.1111/ecog.06584. Danforth, Bryan N., Robert L. Minckley, John L. Neff, and Frances Fawcett. 2019. The Solitary Bees: Biology, Evolution, Conservation. Princeton University Press. Else G. R. 2001. Profile of Andrena clarkella. Bees, Wasps and Ants Recording Society. GBIF.org (13 February 2024) GBIF Occurrence Download https://doi.org/10.15468/dl.w5txw8 GBIF.org A (23 January 2025) GBIF Occurrence Download https://doi.org/10.15468/dl.sa4f3 GBIF.org (05 March 2025) GBIF Occurrence Download https://doi.org/10.15468/dl.etkz44 Grab, Heather, Michael G. Branstetter, Nolan Amon, Katherine R. Urban-Mead, Mia G. Park, Jason Gibbs, Eleanor J. Blitzer, Katja Poveda, Greg Loeb, and Bryan N. Danforth. 2019. “Agriculturally Dominated Landscapes Reduce Bee Phylogenetic Diversity and Pollination Services.” Science 363 (6424): 282–84. Michener, Charles Duncan. 2007. The Bees of the World. Vol. 1. JHU Press. Packer, Laurence, Amro Zayed, Jennifer C. Grixti, Luisa Ruz, Robin E. Owen, Felipe Vivallo, and Haroldo Toro. 2005. “Conservation Genetics of Potentially Endangered Mutualisms: Reduced Levels of Genetic Variation in Specialist versus Generalist Bees.” Conservation Biology: The Journal of the Society for Conservation Biology 19 (1): 195–202. Potts, Simon G., Jacobus C. Biesmeijer, Claire Kremen, Peter Neumann, Oliver Schweiger, and William E. Kunin. 2010. “Global Pollinator Declines: Trends, Impacts and Drivers.” Trends in Ecology & Evolution 25 (6): 345–53. Raven, Peter H., and David L. Wagner. 2021. “Agricultural Intensification and Climate Change Are Rapidly Decreasing Insect Biodiversity.” Proceedings of the National Academy of Sciences of the United States of America 118 (2). https://doi.org/10.1073/pnas.2002548117. Roberts, Stuart, Simon Potts, Koos Biesmeijer, Michael Kuhlmann, William Kunin, and Ralf Ohlemüller. 2011. “Assessing Continental-Scale Risks for Generalist and Specialist Pollinating Bee Species under Climate Change.” BioRisk : Biodiversity & Ecosystem Risk Assessment 6 (December):1–18. Rousseau, Josée S., S. Hollis Woodard, Sarina Jepsen, Brianne Du Clos, Alison Johnston, Bryan N. Danforth, and Amanda D. Rodewald. 2024. “Advancing Bee Conservation in the US: Gaps and Opportunities in Data Collection and Reporting.” Frontiers in Ecology and Evolution 12. https://doi.org/10.3389/fevo.2024.1346795. Tomozei, B. 2014. Andrena clarkella (Europe assessment). The IUCN Red List of Threatened Species 2014: e.T19199798A21309062. Accessed on 06 March 2025. Szczepko-Morawiec, K., B. Wiśniowski, E. Motyka, Waldemar Celary, and Andrzej Kruk. 2024. “Ecological Amplitude and Indication Potential of Mining Bees (Andrena Spp.): A Case Study from the Post-Agricultural Area of the Kampinos National Park (Poland).” Scientific Reports 14 (1): 9738. Williams, A. Park, B. I. Cook, and S. E. Smerdon. 2022. “Rapid Intensification of the Emerging Southwestern North American Megadrought in 2020–2021.” Nature Climate Change 12 (3): 232–34. Williams, N. M., Elizabeth E. Crone, T’ai H. Roulston, Robert L. Minckley, Laurence Packer, and Simon G. Potts. 2010. “Ecological and Life-History Traits Predict Bee Species Responses to Environmental Disturbances.” Biological Conservation 143 (10): 2280–91. Wojcik, Victoria A., Lora A. Morandin, Laurie Davies Adams, and Kelly E. Rourke. 2018. “Floral Resource Competition Between Honey Bees and Wild Bees: Is There Clear Evidence and Can We Guide Management and Conservation?” Environmental Entomology 47 (4): 822–33.

Conservation needs No known conservation actions are in place for this species. Protected/Managed area comment: Observations of this species are known from Bureau of Land Management (BLM), Department of Defence, U.S. Fish and Wildlife, National Park Service, and U.S. Forest Service land, but this does not confer any specific protections to the species. Management comment: Specific conservation needs for this species have not been identified. Due to the importance of supporting wild bee populations for pollination services, general conservation practices are recommended including, restoring, creating, and preserving natural high-quality habitats to include suitable forage and nesting sites; limiting pesticide use on or near suitable habitat, particularly during the adult bee’s flight period; promoting farming and urban practices that increase pollinator-friendly plants in margin space; minimizing exposure of wild bees to diseases transferred from managed bees; and lastly, avoiding honey bee introduction to high-quality native bee habitat.

Research need comment: More information is needed about the population status, population trend, existing threats, range limits, habitat, and ecology of this species. Surveys targeting this species are needed throughout its range to determine its persistence throughout its historic range.

(a. any taxonomic concerns about the validity of the species? b. any taxonomic revisions underway that would require a species reassessment.