Improving biodiversity in urban gardens: Determinates of garden bird abundances in Greenville County, SC
As the scale of urbanization intensifies, maintaining natural or semi-natural ecosystems within these urban environments becomes increasingly important to conserving biodiversity. One of the largest ways the natural or semi-natural ecosystems are incorporated into urbanized areas is through gardens; suggesting their size, structure, and composition may contribute to maintaining local populations and regional conservation. In this study, we measured bird abundance and diversity in 18 urban gardens in Greenville County, SC. We used AIC model selection to determine what elements of these urban gardens and the local landscape around the garden affected bird abundance while accounting for detectability.
The abundance of three species was best predicted by features within a garden. American Robin (Turdus migratorius) abundance increased as percent mulch, percent shrubs, and total species increased, and decreased when vegetation between one and three feet increased. Abundance of Carolina Wrens (Thryothorus ludovicianus) increased as total species and vegetation between one and three feet increased, and decreased when percent shrubs and percent of ground covered by foliage less than three feet increased. Song Sparrow (Melospiza melodia) abundance increased as percent trees increased. These results give direction for what types of features should be included in a garden to attract certain species of birds and show that small changes in a garden can benefit local populations. Given that gardens are a prominent means of providing natural habitats in urban areas, supporting the further development of networks of suitable gardens may contribute to the larger goal of improving biodiversity within urban ecosystems.