Drivers of avian diversity in urban greenspaces in the Atlantic Forest

Urbanization reduces diversity and alters avian assemblages worldwide. Urban greenspaces can alleviate this effect by promoting habitat for some species, but the relevance of urban greenspaces for megadiverse, Neotropical avifauna is misunderstood. Here, we evaluated whether bird diversity (taxonomic, phylogenetic and functional) and composition would vary with urban greenspace features (size, degree of isolation, heterogeneity and noise) in seven urban greenspaces in southeastern Brazilian coast. Taxonomic diversity was positively related to greenspace size and habitat heterogeneity. Phylogenetic diversity metrics and functional dispersion were not associated with urban greenspace features. Urban greenspaces were dominated by common urban exploiter and non-native species (e.g. Feral Pigeon, Columbia livia, and House Sparrow, Passer domesticus), tanagers (Thraupidae) and tyrants (Tyrannidae), insectivorous and ground foragers, and habitat generalists (only 6 % of forest specialists). Large (and probably more forested) and quiet greenspaces favored forest-dependent species. Species turnover was high among greenspaces (beta = 0.64) but was not related to greenspace features. Our results suggest that the number of urban greenspaces, and the larger and/or heterogeneous urban greenspaces, favor higher taxonomically diverse bird communities; and that noise or a noise-related urban feature can erode abundance of forest-dependent species in urban, Neotropical landscapes.

Automated summary

Our study found that the size and habitat heterogeneity of urban greenspaces are positively related to the taxonomic diversity of birds, while phylogenetic diversity and functional dispersion are not associated with urban greenspace features. Urban greenspaces are dominated by common urban exploiter and non-native species, and large and quiet greenspaces favor forest-dependent species.