Urbanization and landscape effects on taxonomic and functional wild bee diversity in small towns and rural areas

Background
Planning and managing urban landscapes for greater biodiversity and creating effective conservation strategies requires understanding the relationships between biodiversity and different types of urbanization. Here, we described the variation between small-town and rural areas in two dimensions of biodiversity – taxonomic and functional. We compared community composition and alpha and beta diversity levels of bees between small town and rural sites. We also analyzed the impact of landscape composition on bee communities.
Results
Our results showed that bee abundance, species richness, Shannon–Wiener diversity index, and functional alpha diversity parameters did not differ between small towns and rural areas. Taxonomical overall beta diversity also did not show significant differences between the areas studied. However, we found higher taxonomical turnover and lower taxonomical nestedness for bees in urban areas than in rural areas. Simultaneously, the functional overall beta diversity was higher in rural than urban areas. Moreover, the results showed negative relationships between bees’ abundance and species richness with the density of impervious surface area (ISA) and cropland cover.
Conclusions
Our results show that even very small towns can influence bee communities, causing decrease in dissimilarity at the functional level, and landscape changes such as increased urbanization and crop cover have a significant negative impact on bees.