Urban landscapes have bird assemblages consisting of fewer habitat specialists compared to natural areas. However, development within urban landscapes is highly heterogeneous and may harbor species of conservation concern in both shared (i.e. residential yards) or spared (i.e. protected parks) land uses. Studies that investigate how urban management decisions affect biodiversity at multiple scales are required for effective conservation. Here, we used a hierarchical, multi-region, multi-species occupancy model to determine how avian species richness, community coincidence, and species of conservation concern differ with local-scale land management, and landscape-scale tree canopy cover and impervious surface across six major metropolitan areas (Phoenix, Arizona; Miami, Florida; Baltimore, Maryland; Boston, Massachusetts; Minneapolis/St. Paul, Minnesota and Los Angeles, California). We considered shared-use land typologies that included low-management lawns, high management lawns, water-conservation & wildlife-friendly yards, and spared-use included large peripheral & smaller interstitial parks.
Results/Conclusions
Our results suggest that urban bird communities are generally structured by landscape-scale characteristics rather than parcel-scale management, however, relationships were unique to each geographic region. Our spatially explicit, multi-region design revealed findings similar to other landscape-scale research that shows avian species richness is positively related to canopy cover, and negatively related to impervious surface. Across cities, community richness did not differ strongly between land uses, however parks supported communities with the most insectivores, migratory birds, and species of conservation concern. In addition, within metropolitan areas, yards with high-management lawns had the highest community similarity, while other yard types had similar turnover to parkland. These results demonstrate that residential landscapes have the potential to benefit local avian richness and reduce homogenization when residents prioritize management regimes that favor mature tree canopies, retain parks, and promote residential areas with natural features. Our community modeling approach also provides inference about the specific responses of individual bird species to parcel-scale management across geographic areas.