Safeguarding pollinators requires specific habitat prescriptions and substantially more land area than current policy suggests

Abstract

Habitat loss and fragmentation are major drivers of global pollinator declines, yet even after recent unprecedented periods of anthropogenic land-use intensification the amount of habitat needed to support pollinators remains unknown. Here we use comprehensive datasets to determine the extent and amount of habitat needed. Safeguarding wild bee communities in a Canadian landscape requires 11.6-16.7% land-cover from a diverse range of habitats (~1.8-3.6x current policy guidelines), irrespective of whether conservation aims are enhancing species richness or abundance. Sensitive habitats, like tallgrass woodlands and wetlands, were important predictors of bee biodiversity. Conservation strategies that under-estimate the extent of habitat, spatial scale and specific habitat needs of functional guilds are unlikely to protect bee communities and the essential pollination services they provide to crops and wild plants.

Occupancy of Bombus affinis (Hymenoptera: Apidae) in Minnesota is highest in developed areas when standardized surveys are employed

“…Together these results suggest that when planning the location of floral plantings for B. affinis conservation, locations within 0.5 km of woody areas may be optimal choices. The positive association of B. affinis with natural land use, which consisted largely of forest and wetland, within close proximity aligns with the results of Pindar and Raine (2023), who found that wetland habitats (treed swamp and marsh) had the greatest impact on Bombus diversity and abundance within 0.5 km. While the Phi coefficient of association analysis was unable to detect associations between B. fervidus and any of the natural land cover classes in our study, Novotny et al (2021) found an association between this species and forest habitat.…”

“…Changes in land use patterns due to human activities, such as urban development and agricultural intensification represent significant challenges for bumble bee conservation (Winfree 2010). Pindar and Raine (2023) predict that 11.6–16.7% of land in North America must be preserved or restored to suitable habitat to support regional bee conservation goals. They found that forest (mixed and deciduous), wetland, tallgrass savannah, and open/barren (abandoned extraction) habitat types supported the highest abundance and diversity of bumble bees in Ontario, CA, which shares similarities with the landscape in Minnesota.…”