Land-use is a main driver of biodiversity loss, yet its influence on community composition and species turnover across scales is still equivocal. Ecological disturbance such as agricultural management at the local scale or deforestation and habitat fragmentation at the landscape scale can cause either biotic differentiation or homogenization. Bees have different responses to land uses depending on their niche specialization. While generalist species such as Apis mellifera thrive in areas with higher disturbance, specialist groups thrive in undisturbed habitats. Little is known about how local and landscape factors influence shifts bee communities in the tropics, where native bees evolved in highly heterogeneous habitats, yet land uses are transforming into simplified agricultural lands. This study asks how differences in local habitat structure, agricultural management and landscape configuration affect bee communities across agricultural mosaics in Anolaima, Colombia. We evaluate whether and how local and landscape factors influence (1) bee diversity (richness, abundance and evenness); (2) shifts in the dominance of native vs. Apis bees; and (3) species turnover (beta diversity). We conducted bee and vegetation surveys in sixteen locations in Anolaima in 2016. We measured local habitat factors on different scales, including flower abundance, ground cover, and tree diversity. We also conducted landscape analysis at three scales (200m, 500m, 1 km). We analyzed different components of bee diversity using Hill numbers, and the influence of local and landscape factors using GLMs.
We found local and landscape factors differentially influence native bees and A. Mellifera. The diversity of native bees increases in areas with complex vegetational structure, where honeybees are less abundant. Richness of native bees increased in areas with more flowers and less intensive agricultural management. Honeybee abundance increased in farms with intensive management and surrounded by more unshaded crops at the landscape scale. Beta diversity was influenced by landscape factors such as the percent of unshaded crops and distance to complex habitat. The high influence of landscape factors suggests bee dispersal strongly mediates the local and regional composition of bee communities in Anolaima. This study suggests increasing dominance of Apis mellifera in lands transitioning towards industrial agriculture in Anolaima. The study also shows that diverse and complex habitat at the local scale acts as refugee for native bees, providing opportunities for bee conservation by modifying local management practices.