Portland, United States of America

SYMP 15-2 - Global patterns and correlates of urban biodiversity

Cities are novel ecosystems characterized by fragmented and disturbed environments, high densities of fabricated structures and impervious surfaces, and elevated levels of certain resources. Globally, these commonalities, in combination with human mediated biotic interchange, may result in the homogenization of species composition among cities. In addition, cities are often located in species rich regions where native species are threatened by habitat loss and species introductions. Given the World’s urban population is growing 1% per-annum on average, a better understanding of the global patterns and drivers of urban biodiversity is necessary for sustainable planning and conservation. We compiled city-wide bird species lists for 54 cities and city-wide floras of spontaneously established vascular plants for 110 cities. The lists encompass 36 countries on six continents and represents the largest compilation of urban biodiversity data to date. We examined patterns of species diversity within and among cities and their environmental and anthropogenic correlates.