Bee communities in forestry production landscapes: interactive effects of local-level management and landscape context

Abstract

Land-use change is a key driver of pollinator declines worldwide. Plantation forests are a major land use worldwide and are likely to expand substantially in the near term, especially with projected cellulosic biofuel production. But little is known about the potential local and landscape-scale impacts of plantation forestry on bees, the most important group of pollinators worldwide. We studied the effects of local management, landscape context, and their interaction on bee abundance and species richness in the southeastern US, in pine plantations and other nearby land uses. We sampled bee communities using aerial netting and pan trapping in 85 sites over 3 years. We found that both landscape composition and configuration are important factors for bee diversity and abundance at the landscape scale, though interestingly many landscape factors showed contrasting directional responses for diversity versus abundance. Removing the four most common species, all in the genus Lasioglossum (and which comprised ~ 45% of all specimens) largely harmonized the results between diversity and abundance. In addition, we found several interactions between local management and landscape factors, all consistent with the idea that compositional heterogeneity and configurational complexity are more important for bee communities in poorer-quality local habitat. Our results underscore the importance of considering (1) both landscape configuration and composition in analyses, and (2) interactions between local management and landscape factors. The interactions in particular highlight the need to maintain landscape compositional heterogeneity and configurational complexity, particularly in heavily managed landscapes.