(2nd Place) Wild bee species have distinct habitat associations and idiosyncratic scales of response

Despite concern that habitat loss is threatening wild bees, surprisingly little is known about the habitat needs of any particular bee species. The spatial scale at which particular bee species respond to habitat in their landscape is also largely unknown. While it is often assumed that larger bees respond at larger scales, empirical evidence for this relationship is limited. To address these issues, we assessed the habitat associations and scales of response of 89 bee species collected at 198 sites in New Jersey, Pennsylvania and New York, then tested whether these scales of response could be explained by body size or other functional traits.

No habitats were universally good or bad, but a few stood out. In particular, deciduous forest and pasture elicited mostly positive responses, while wetlands and high-intensity development elicited mostly negative responses. These results suggest that bee conservation – which typically focuses on only open meadows – should expand to include diverse habitat types, especially deciduous forests. Scales of response were right skewed, peaking at 100-300 m, but with a tail extending to the max of 8 km (mean = 2 km). Scales of response were also unpredictable, varying both within and among species, and being unrelated to bees’ functional traits. These results suggest that the spatial scales at which bees respond to their environment are not easily understood, and may instead be determined by a combination of idiosyncratic species-level traits (e.g. dispersal behavior) and aspects of the landscape itself (e.g., patch size and arrangement).