Piecing together cities to support bird diversity: Development and forest edge density affect bird richness in urban environments

Abstract

Urban areas are quickly expanding in the southeastern United States with varying effects on biodiversity. Maintaining bird richness in cities is essential for conserving ecosystem function. In this study, we determined the relative importance of landscape composition and configuration on urban avian richness in the southeastern U.S. We used linear models to explore the influence of the proportion, size, aggregation, and edge density of forests, wetlands, and developed land cover types on urban avian species richness and feeding guild diversity. We found that the proportion of developed land in a city, a composition metric, and forest edge density of cities, a configuration metric, had consistent negative effects on bird richness and feeding guild diversity. These results differ from previous studies that have found landscape configuration to have a minimal influence on bird richness. Urban revegetation should therefore focus on reducing expansion of developed land and reducing edge density of large forest patches.