PARENT SESSION
Oral Session #20: Urban Ecosystems: Comparisons Across Biomes, Patterns and process.
Presiding: M. Carreiro
Monday, August 5. 1:00 PM to 3:45 PM. Grand Ballroom West, Radisson.

Extinction, invasion, homogenization and heterogeneity: The effects of urbanization on bird communities.

Blair, Robert^*,1,2, ¹ Dept of Zoology, Oxford, Ohio² Dept of Fisheries, Wildlife, and Conservation Biology, St. Paul, Minnesota

ABSTRACT- Urbanization affects the environment in myriad ways and at multiple levels of biological organization. Many researchers have suggested that one effect of urbanization is the replacement of native species with invasive ones and consequent global homogenization. Unfortunately, few researchers have actually documented the process. Here, I explore this idea by comparing the occurrence of birds along gradients of urban land-use in SW Ohio and northern California and examining the effects of urbanization at the species, community, landscape, and global levels. At the species level, urbanization leads to local patterns of extinction and invasion. These patterns, in turn, affect community richness and diversity, which are mirrored in landscape heterogeneity. At the global level, local extinction of endemic species, followed by invasion by weedy, ubiquitous species leads to faunal homogenization between ecoregions.

KEY WORDS: urban, species assemblage, Ohio, California