Can small vacant lots become important reservoirs for birds in urban areas? A case study for a Latin American city

Abstract

Vacant lots are considered unmanaged and informal greenspaces that can have high ecological value in urbanized landscapes. They are very common in many cities and have been widely studied in North America and Europe. However, few studies exist in other areas such as in Latin America, a megadiverse region but also one of the most urbanized places in the World. In this study, we compare habitat structure and bird communities in control sites (large expanses covered by native vegetation) with those found in small (<10 ha) and large (40–80 ha) vacant lots in order to determine if these greenspaces can function as bird reservoirs in a Latin American city. In terms of habitat structure, control sites were significantly richer in average shrub and tree species and more complex in structure followed by large vacant lots. Small vacant lots had significantly lower values of vegetation vertical complexity, density and plant diversity. Overall, 51 bird species were registered in control sites, 50 species in large vacant lots and 56 bird species in small vacant lots. In spite of habitat and area differences between types of study sites, we did not find differences in bird species richness or diversity, although we did detect differences in species composition, with more invasive exotic birds in small vacant lots. Control sites and large and small vacant lots had exclusive species not found in the other sites, and 34 species were shared between the three types of sites. Our results suggest that vacant lots, large or small, could be important reservoirs of bird diversity in urban areas, despite being immersed in intense levels of urbanization and being submitted to other anthropogenic disturbances. Future studies must consider the value of vacant lots as important tools for conservation in urban areas.