Wooded street use by birds in Buenos Aires city: the role of local characteristics and urban parks connectivity

Every day, the urban environment expands on rural and natural areas. Therefore, knowing the environmental factors that determine bird diversity in urban areas is essential for the management and design of sustainable cities. In this study, we analyze how birds use wooded streets in the Buenos Aires city. We selected 26 wooded streets with different levels of tree cover, human disturbance (pedestrian and car traffic) and degree of connectivity with urban parks. We analyzed the relationship between bird richness, taxonomic and functional diversity and the environmental variables using Generalized Linear Models. We also modeled the standardized effect size of functional diversity to evaluate the environmental filtering variation on wooded streets. Bird richness, taxonomic and functional diversity were negatively related to human disturbance, whereas taxonomic diversity was positively related to urban parks connectivity and to tree height and its variation. The environmental filtering was greater on streets with a large amount of pedestrians, which were dominated by omnivorous birds that foraged gregariously on the ground. Results suggest that an urban design with streets connected with parks and having taller trees and a greater tree height variation would contribute to greater bird diversity. Moreover, the level of human disturbance caused by pedestrian traffic should be controlled to avoid a decrease of bird ecosystem functions.