Local and landscape features of wooded streets influenced bird taxonomic and functional diversity

Abstract

Wooded streets diminish the negative consequences of urban growth on biodiversity. However, bird use of wooded streets has been little studied, in most cases analyzing bird species richness and abundance in developed countries. In this study, we analyzed the relationship between environmental variables of wooded streets of Buenos Aires City (Argentina) and bird taxonomic and functional diversity as well as species and functional trait composition. We placed 26 100m × 50m transects within the wooded streets of the urban center. Bird surveys were performed during the austral spring and summer. Species richness, Pielou’s evenness, Shannon index, Functional dispersion (FDis), and species and functional trait composition were analyzed. Taxonomic and functional diversity were negatively related to pedestrian and motorized vehicle traffic. On the other hand, taxonomic diversity was related positively to streets with varied tree heights. Native taxonomic diversity and functional diversity increased near green areas. The coverage of high buildings was negatively related to the native taxonomic diversity. Bird species associated with humans, such as the Rock Dove (Columba livia) and the Eared Dove (Zenaida auriculata) increased their abundances in sites with high pedestrian and motorized traffic. The House Wren (Troglodytes aedon), the Baywinged Cowbird (Agelaioides badius), and the Red-bellied Thrush (Turdus rufiventris) were positively related to varied tree heights. Birds that feed on the ground and the undergrowth were negatively associated with the coverage of high buildings. It is imperative to preserve green areas and to control motorized vehicle traffic in order to improve the environmental quality of wooded streets for supporting bird diversity.