Local and landscape metrics identify opportunities for conserving cavity-nesting birds in a rapidly urbanizing ecoregion

Abstract

Urban centers are rapidly expanding globally, resulting in regional forest-cover transformations that shift from temperate forest biomes to a heterogeneous mix of urban development, forest patches, and agriculture. Data on habitat use within remaining forest patches embedded across land use types, particularly in urban land use, are needed to optimize conservation strategies as urban growth continues. In the rapidly urbanizing southern Piedmont, USA, small pine patches have become more frequent across the landscape and are found embedded within second-growth forest, agricultural, and urban land use matrices. We used point-count surveys and N-mixture models to determine the effect of patch- and landscape-scale drivers on cavity-nesting bird abundance, including the threatened Brown-headed Nuthatch ( Sitta pusilla ), in pine forest patches. Model-averaged estimates suggest Brown-headed Nuthatches are more abundant in large patches in a heterogeneous matrix that includes urban residential development. Three other cavity-nesting species declined in abundance as a function of reduced canopy cover. White-breasted Nuthatches increased and Tufted Titmice decreased in abundance in response to patch area. By identifying factors that predict abundance at local and landscape scales for ecologically sensitive and generalist species, we can more effectively contribute to regional conservation efforts in urban ecosystems, extending conservation in practice beyond protected areas.