PS 33-137 - Bee community composition across agricultural and forested landscapes in Maritime Canada

Background/Question/Methods

The conversion of natural habitat to agricultural land has a well-documented negative impact on wild bees. However, much of the research in North America has focused on the conversion of prairie grassland to agricultural land. In contrast, the impacts of agricultural intensification in other contexts are less well understood. The maritime province of New Brunswick, Canada is composed of more than 80% forest. Here, agricultural land is typically created by clearcutting forested areas. To better understand how habitat type impacts bumble bee communities across this landscape, we sampled bees at 43 sites spanning four different habitats across the province: tilled agriculture, pasture, forest and wetland. Bees were collected using blue vane traps during the spring of 2020. Bumble bees were sorted, pinned and identified to species.

Results/Conclusions

During the spring, bumble bee abundance was similar across habitat types; however, sites in tilled agriculture and pasture had a higher species richness than sites in forest and wetland. This was largely driven by the presence of parasitic species at the tilled agriculture and pasture sites. Our results suggest that the conversion of a heavily forested landscape to agricultural land may attract bumblebees. Future research into differences in floral diversity across the season, and into potential differences among nesting guilds is forthcoming. These results may have important implications for how we think about wild bee conservation in forest to agriculture settings. If clearcutting forest for agricultural land is attracting bees, the increased exposure to pesticides in these settings may ultimately have negative fitness consequences, acting as a sink in the landscape.