Bee diversity in urban green areas of a tropical metropolis: a multi-sampling approach

Human land use and land cover changes threaten biodiversity and ecosystem services, including pollination. Bees, which are key pollinators of many angiosperms, are particularly vulnerable to land use change. In this context, fragments of native vegetation can serve as crucial refuges for these insects, especially in heavily disturbed areas such as urban environments. In this study, we present an inventory of bee species found in green areas, such as parks and protected areas of a 2 million people tropical metropolis located in a highly biodiverse region, Belo Horizonte, MG, Brazil. Bees were sampled at five sites using three different methods: active sampling, scent traps, and pan traps. We identified a total of 97 species belonging to the five families of bees found in Brazil, and most (79.3%) of them were sampled by only one of the sampling methods applied. The generalist native bee species Eulaema nigrita Lepeletier, 1841, Trigona spinipes (Fabricius, 1793), Paratrigona lineata (Lepeletier, 1836), and the invasive species Apis mellifera Linnaeus, 1758 were the most abundant at all sampling sites. The use of complementary sampling methods allowed the recording of highly diverse bee assemblages, one of the most complete lists so far in the region. This knowledge is the first step towards an integrated urban planning that also aims at the conservation of ecosystem services. Ultimately, this study shows that a more comprehensive description of pollinator fauna requires complementary sampling methods, which are essential for effective management and monitoring plans of urban biodiversity.