A tale of two worlds: spatial arrangement of avian communities in a Neotropical city

Abstract Urbanization is considered one of the most critical processes related to biodiversity loss worldwide. Birds are one of the most commonly studied groups in urban ecosystems due to their quick response to environmental changes. Despite the current knowledge related to urban bird communities, information associated with the specific factors shaping avian communities in cities is still scarce, especially in the Neotropics. In this study, we performed a citywide survey for birds in the city of Xalapa (Mexico), to compare the species composition of urban communities with those of two reference sites adjacent to the urban area. We hypothesized that the compositional similarity would either be defined by their spatial proximity to their respective reference site or that it would be shaped by resources intrinsic to the city. Considering the nature of our data, we performed a subgroup analysis using randomly selected groups for the urban and reference sites to compare similar samples. We used Sørensen (incidence-based) and Bray-Curtis (abundance-based) cluster analyses and found that the urban bird community composition is better explained by the vegetation cover than by the proximity to the reference sites. We confirmed this association with the results of the GLM, showing a statistically significant association with the vegetation cover. Our results are relevant in terms of urban design, considering that promoting the improvement of vegetation in cities could potentially help avian communities in these changing environments.