Bee diversity responses to forest and open areas in heterogeneous Atlantic Forest

Abstract

Agriculture driven landscape changes have caused worldwide forest loss and fragmentation, severely affecting biodiversity and ecosystem services, amongst which pollination is remarkably important. Bees are an essential pollinator group for forest plant populations and food production in tropical landscapes. They are also dependent on forested environments which are essential to maintaining their diversity and pollination services. We analysed bee diversity in forest patches and adjacent open areas to evaluate if bees can use complementary environments in heterogeneous altered tropical landscapes. The effect of landscape level heterogeneity and forest amount on bee diversity was also assessed. Our hypothesis was that bee communities will be richer and more diverse in highly forested and heterogeneous landscapes when compared to areas dominated by few human-made environments, but due to supplementary foraging behaviors, they will be more abundant in open areas where flower availability is higher. We actively sampled bees visiting flowers within forest patches and in surrounding open areas between the Cantareira and Mantiqueira mountain ranges in São Paulo, Brazil. We found both higher bee richness and diversity in open areas than in forest patches, partially denying our initial hypothesis but supporting that bees are more abundant in open areas. We found strong indication that landscapes with a higher amount of forest and environmental heterogeneity can provide more resources for bees through resource complementation processes, maintaining their diversity in the landscape. The presence of forest patches close to crop and open areas is of utmost importance for the conservation of bees and pollination services with important consequences for land management in tropical environments.