Bee functional groups respond to vegetation cover and landscape diversity in a Brazilian metropolis

Context Urbanization is one of the largest causes of habitat loss and fragmentation, factors that modify community structure and can lead to species extinction. Since bees are the main pollinating agents in most ecosystems, losses of bee diversity can have negative consequences on plant diversity and associated services. Objectives This study aims to understand how bees and their functional traits, such as social behavior, nesting sites, trophic specialization and kleptoparasitism, are affected by an urban landscape. Methods Ten sites were selected with different levels of urbanization. Bees were sampled with entomological net for 6 h, one day per month, for 10 months. The response variables evaluated were species diversity, number of bees, and the richness of bee functional traits. Nine landscape metrics were used as predictors, including the proportion of vegetation cover and landscape diversity. Results Urbanization predictors negatively influenced bee richness but not diversity. Specialist bees were the most susceptible to urbanization, followed by ground nesters and solitary bees. Kleptoparasites also responded negatively to different urbanization metrics. Above-ground nesters and eusocial bees were more resilient to the urban environment and were not affected by urbanization. The proportion of vegetation cover and landscape diversity were the most important predictors for the preservation of bee diversity, followed by the proximity of fragments and the proportion of grasslands. Conclusions The most responsive and vulnerable functional groups—particularly specialists—should have conservation priority in cities. Analyses of richness and species diversity should not be decoupled from functional traits since doing so may overlook bees’ complex response to urbanization.