Green space within urban areas can provide important habitat for breeding and migratory birds. In addition to being the third-most populous city in the U.S., Chicago also offers a diversity of habitat types—including grasslands, oak savannas, and wetlands—that are now rare throughout the agriculture-dominated state of Illinois. These habitats, and their location along Lake Michigan, make this region attractive for both migratory and breeding birds. The Bird Conservation Network has identified specific locations in and around Chicago that are considered “hotspots” of high avian species richness. These hotspots are dispersed throughout the metropolitan region, and more than twenty of them fall within areas zoned as open space for recreation, conservation, and parks inside the city boundary. However, many areas zoned as open space in Chicago are not considered bird hotspots. This raises an important question: What local and landscape-scale variables distinguish open spaces that attract high avian species richness from open spaces that do not?
For each hotspot and non-hotspot in areas zoned as open space, we analyzed characteristics at the local scale (e.g., percent canopy cover, percent impervious surface, area of open space) and the landscape scale (e.g., road density within 1km, canopy cover within 1km, and distance to nearest off-site water source). We used classification and regression trees (CART models) to identify the variables that most strongly predict bird species richness within the city of Chicago.
Results/Conclusions
Preliminary results indicate that Chicago bird hotspots are distinguished from non-hotspots by both local and landscape scale factors, especially size of the open space and distance to nearest water source. Ultimately, a better understanding of the factors that are commonly associated with species richness in urban green spaces will help land managers and conservation professionals more effectively plan, preserve, restore, and manage for biodiversity in cities.