Where did they go? Understanding the effects of urbanization on bird diversity in a Brazilian coastal city

Urbanization is recognized as an important cause of biodiversity loss. Urban areas present reduced number of bird species if compared to non-urban more pristine areas nearby. The goal of this research is to help improving the diversity of birds in urban areas by investigating why an urban area in the coast of Brazil sustains a small fraction of the species that could occur in the region. We conducted observations during two years in Serra, Brazil, resulting in the identification of 27 bird species visiting a residential garden. Studies in the region have reported 275 species. We used GIS maps and aerial photos to analyse the landscape, then discussed that numeric discrepancy and the possible reasons for the reduced diversity, contrasting it to the resources available in that landscape. Recent urbanization is likely to be a major cause of the low diversity, but the study area has been subject of change from the original ombrophilous dense forest to agriculture and pasture before the consolidation of the current urban land uses. Albeit the landscape is highly fragmented, diverse landcover types have recovered in recent decades, creating a mosaic of small isolated patches of forest, mangrove and restinga, the three major ecosystems in the region. We expect that our findings create a foundation for further exploration of measures and policies for implementing greenspace within cities that help reverting the current status and improving the diversity of birds in tropical cities.