The bees kneeds! Investigating the impact of agricultural landscape composition on native pollinator populations in southern Ontario

Native pollinator diversity provides significant pollination services in many agroecosystems in Ontario and globally, with estimated economic valuations running to hundreds of billions of dollars. Habitat studies are lacking in Canada but are critical to understanding species-specific niches, as well as pollinator abundance and diversity patterns in various landscape compositions. As such, there is a critical need for more research investigating the nesting and foraging requirements of these native species. Our objectives are to assess differences in pollinator diversity (restricted to wild bees (Apoidea) and flower flies (Syrphidae)) and abundance among three habitat types (forest, field margin and restored prairie grass) on agricultural land and to understand how biodiversity is affected by habitat type, patch size and connectivity. We conducted two field seasons, deploying three Malaise traps per farm (10 farms in 2018/20 farms in 2021) with one trap within each habitat of interest. Samples were collected every three days, over an eight-week sampling period. Targeted transects were also performed to check whether traps were consistently missing any species. A substantial amount of data were collected across both field seasons, and preliminary results show an extremely high diversity of flower flies in the region as well as pockets of unusually high aphidophagous flower fly abundance. Our research provides a novel dataset with an inclusive focus on both wild bees and flower flies that can be used to benefit farmers, landowners, and NGOs to inform government policy to improve food security of essential crops while simultaneously protecting our threatened native pollinators.