The influence of building density on Neotropical bird communities found in small urban parks

Urban green spaces provide a habitat for a wide variety of bird species. However, changes in characteristics of the surrounding urban morphology could influence the contribution of such green spaces. In particular, bird communities inhabiting small urban parks (SUPs) may be vulnerable, given the high exposure of these spaces to surrounding conditions. In Neotropical cities, the influence of urban-matrix characteristics on bird communities found in SUPs is relatively unknown. In this study, we explored if an increase in surrounding urban matrix variables, such as building densities, average building height, and road coverage around SUPs, negatively influenced the richness and abundance of the bird communities inhabiting them. We tested the effects of matrix and several site-level variables (e.g., vegetation diversity) across 60 SUPs in Santiago, Chile. As the matrix around a SUP had increased building densities, bird richness and abundance of native and insectivorous species decreased and invasive, urban-dweller, and omnivorous species increased. As road coverage increased, both the richness and abundance tended to decrease across all bird categories. For site-level variables, SUP size, distance to nearest SUP, and native vegetation diversity had a significant effect on several bird categories. Our results indicate that city planners may need to take into account both the surrounding urban matrix and site-level characteristics in order to improve bird diversity within SUPs.