Identifying habitats that best support pollinator communities in agricultural landscapes

Most flowering plants and one third of all food crops are pollinated by insects, but pollinator communities on farms tend to be less diverse due to frequent disturbance, low plant diversity, and lack of natural habitat. Bolstering of native pollinators and other beneficial insects (e.g. predators and parasitoids) in agricultural landscapes requires an understanding of their nesting and foraging requirements, but these studies are currently lacking in Canada. We aim to quantify the abundance and diversity of wild bees (Apoidea) and flower flies (Syrphidae) in three common farm ‘refuge’ habitat types: forest patches, grassy field margins, and hedgerows. In May of 2021 we deployed Malaise traps across 20 southern Ontario farms that had all three habitat types (one trap per habitat, 60 traps total), sampling insects every three days for eight weeks. We also performed botanical surveys in all grassy field margins and hedgerows, and sweep net transects at a subset of the sites to identify species that may be underrepresented in Malaise traps. With over 1,150 samples we collected as many as 10M insects, and target groups are still in the process of being identified and databased. Preliminary results indicate that the farms have a relatively high diversity of flower flies and occasionally a spike in the abundance of aphidophagous flower flies. The ultimate goal of this research is to inform farmers, landowners, and policymakers about how they can manage their landscapes to support native beneficial insects communities and benefit from their ecosystem services.