Species and functional diversity — A better understanding of the impact of urbanization on bee communities

We examined site patterns in bee species for diversity and functional diversity in urban, suburban and rural areas. We sampled bees from all three habitat types and compiled a database of functional traits for each species. While species diversity decreased with urbanization, as expected, components of functional diversity showed differences between urban and suburban habitats. Functional dispersion (FDis) increased significantly in suburban areas as compared to urban sites, while functional divergence (FDiv) and functional redundancy (Fred) were higher in urban areas. Functional richness (FRic) and evenness (FEven) were not affected by urbanization. Moreover, assemblages in highly urbanized environments have a substantially different functional composition. Solitary species, cleptoparasites, soil nesters, bees with trophic specialization, and those with a short flight period turned out to be more sensitive to urbanization changes. This study highlights the importance of examining functional diversity in assessing human-induced biodiversity loss and its impacts on ecosystem functioning in urbanized areas. These results have significant implications for improving our understanding of the mechanisms of suburban community ecology and conserving bees in urban habitats.