Untangling the effects of the vegetative and built landscape on breeding riparian bird communities in Cincinnati, OH, USA: Land cover, scale, and woody vegetation

Background/Question/Methods With over half of humanity now residing in cities and growing, urban environments present a unique challenge for conserving our planet's biodiversity. Riparian systems are of particular interest because of the ecological services they provide both to people and to an array of other animals and plants. We chose to study urbanization effects on riparian systems along an urban gradient within metropolitan Cincinnati, Ohio, U.S.A. Based on our research, we report on how breeding bird community diversity and composition responds 1) locally to woody vegetation structure and composition, and 2) across the landscape to the vegetative and built aspects of the urban environment, at different scales (50, 100, 250, 500, 800, 1000 m). We use the HERCULES land cover dataset to examine the influence of elements of the biophysical structure of the urban environment – buildings, building type and vegetation – separately. In order to ascertain potential mechanisms, we explored how life-history characteristics permit some species to utilize and even thrive in urban areas, while others cease to exist, based on the following functional groups: migration, foraging, brooding strategy, and endemism. We used information-theoretic statistical methods to compare models and variables. Results/Conclusions Individual species responded differently to landscape variables at a variety of scales. Native woody vegetation composition was significant for several native species models. We provide management recommendations for land managers, landscape architects, urban planners, and citizens that can enhance native species diversity around urban streams.