Suburban forest patches have high functional and phylogenetic diversity in bird communities

The fast conversion of natural habitats into cities is a worldwide environmental change, negatively affecting ecosystem processes and functioning. Understanding how changes in taxonomic richness and composition are associated with the reduction in functional traits and evolutionary history in different levels of urbanization is important to minimize the impacts of urban landscapes on ecological communities. We investigated the effect of anthropogenic predictors on taxonomic, functional, and phylogenetic diversity of bird communities along the urbanization gradient of a South American city. We surveyed birds and collected data on patch size, isolation, and noise from 43 patches classified as natural (n = 13), suburban (n = 22), and urban (n = 8). We analyzed how anthropogenic factors affect patch diversity (richness) and composition (similarity among patches) in terms of taxonomic, functional, and phylogenetic diversities. We found that suburban patches had higher functional richness and that these patches had species and phylogenetic history that are typically present either in urban or natural areas. Further, we found that noise reduced taxonomic and phylogenetic richness, contributing to changes in species composition and diversity loss in highly urbanized patches. Although some species can be highly sensitive to human impacts, suburbs have less intense anthropogenic activities (e.g. traffic) maintaining higher functional diversity and likely ecosystem functioning than urban areas. Our results suggest that cities can protect biodiversity if we reduce urban noise and maintain green areas, as commonly observed in the suburbs.