Effects of an Early Mass-flowering Crop on Wild Bee Communities and Traits in Power Line Corridors Vary With Floral Resources and Landscape Context

Abstract Context Power line corridors have been repeatedly assessed as habitat for wild bees; however, few studies have examined them as bee habitat relative to nearby crop fields and surrounding landscape context. Objectives We surveyed bee communities in power line corridors near (within 150-300 m) to and isolated (>1 km) from lowbush blueberry fields in both a simple and a complex landscape context. Additionally, we examined the influences of floral resources and bee life-history traits. Methods We surveyed wild bees and floral resources in power line corridors in Maine, USA, during 2013-2015. We calculated landscape composition surrounding sites at four spatial scales and gathered bee trait information from the literature. We assessed differences in bee communities across growing regions and site types with generalized linear models. Results We collected many of Maine’s wild bee species and observed a rare plant-pollinator relationship within power line corridors. We found greater bee abundance and species richness throughout the more complex Midcoast landscape, while our expected enhancement from mass-flowering lowbush blueberry fields was evident only with bee species richness in the simpler Downeast landscape. Landscape composition and floral diversity varied between the two growing regions, though landscape composition had more influence over bee communities than floral diversity. Solitary species and ground-nesting species were more sensitive to landscape context than social or cavity-nesting species. Conclusions Power line corridors provide crucial refugia for crop pollinating wild bees in resource-poor landscapes. Further exploration of population dynamics and pollination efficiency may clarify this relationship.