Presentation by Seth Riley, adjunct associate professor, Institute of Environment and Sustainability, UCLA | Wildlife Branch Chief, Department of Ecology and Evolutionary Biology, U.S. National Parks Service.

The role of national parks is to preserve the natural resources present in the parks, including the wildlife resources. At Santa Monica Mountains National Recreation Area, the primary challenges for effective wildlife conservation are understanding and mitigating the effects of urbanization, including habitat loss and fragmentation. We have also documented multiple threats to wildlife communities in this urban landscape. Stream amphibian populations are threatened by altered stream structure and permanence, which allows exotic predators to persist in urbanized watersheds. Fragmentation results in the loss of terrestrial reptile species from smaller habitat patches. For some of the more widespread species that remain, we have seen that fragmentation is already associated with significant genetic differentiation. For the most wide-ranging mammalian carnivores, we have seen that species such as coyotes, bobcats, and mountain lions are surprisingly adaptable to development. Yet carnivores too face significant threats. Roads, particularly large freeways, and urban development form major barriers to movement for carnivores, leading to significant reductions in gene flow. Toxicants are present at high levels in all three species, cause direct mortality, can affect immune response, and can have significant population-level effects. Wildfires have become more common and larger, significantly impacting multiple animal communities. Our long-term studies have shown that there is great value in preserving urban wildlife communities in Southern California, but that significant challenges remain.

Seth Riley grew up in Washington, DC. He graduated in 1988 from Stanford University with a B.A. in Human Biology. From 1988-1990 Seth worked as a wildlife biologist for the National Park Service at the Center for Urban Ecology in Washington. He went to the University of California, Davis, where he graduated with a Ph.D. in Ecology in 1999. His dissertation work was on the ecology of bobcats and gray foxes in urban and rural areas of Golden Gate National Recreation Area. After graduating Seth worked as a post-doctoral fellow at Davis studying hybridization between native and introduced tiger salamanders. At the beginning of 2000, Seth began in his current position as Wildlife Ecologist. His current projects include a bobcat telemetry study, a mountain lion GPS telemetry study, stream surveys for amphibians, pitfall/drift fence trapping to determine terrestrial reptile and amphibian distribution and abundance, and a number of projects on the impacts of freeways on wildlife.