Proceedings of the Seventh Mountain Lion Workshop

106
MOUNTAIN LION MOVEMENTS AND PERSISTENCE IN A FRAGMENTED, URBAN
LANDSCAPE IN SOUTHERN CALIFORNIA
SETH P.D. RILEY, Santa Monica Mountain National Recreation Area, 401 W. Hillcrest Dr.,
Thousand Oaks, CA 91360, USA, email: seth_riley@nps.gov
RAYMOND M. SAUVAJOT, Santa Monica Mountain National Recreation Area, 401 W.
Hillcrest Dr., Thousand Oaks, CA 91360, USA
ERIC C. YORK, Santa Monica Mountain National Recreation Area, 401 W. Hillcrest Dr.,
Thousand Oaks, CA 91360, USA, email: eric_york@nps.gov
Abstract: As natural habitat is increasingly eliminated and fragmented by human land uses the
long-term prospects for conservation of carnivore populations become correspondingly worse.
This is especially true for larger carnivores such as mountain lions, which require significant
amounts of both space and prey. In rapidly urbanizing southern California, conservation of
carnivores in general, and of mountain lions in particular, is particularly challenging. In the
Santa Monica Mountains and surrounding areas, we have begun a project using GPS collars to
determine mountain lion movement and space use in a fragmented landscape. Our goal is to
determine whether lions are successfully traversing freeways and other human-made barriers
between large areas of natural habitat. Ultimately, we hope to determine whether enough natural
habitat can be preserved, and enough connectivity maintained between core habitat areas, to
maintain lion populations in such a landscape. We have collared lions already in the Santa
Monica Mountains, and determined that one large male is using the entire mountain range (home
range of 394 km 2 ), from a major freeway to the east to a developed agricultural valley to the
west, and from the Pacific Ocean to the south to a major freeway to the north. Given the small
number of lions likely persisting in the Santa Monica Mountains, connectivity is as important, if
not more important, than we anticipated. We continue to collar other lions in the study region to
evaluate whether any exchange occurs across barriers created by freeways and urban
development. While both the male and the female in the Mountains have approached the
freeway to the north, neither one has crossed it in the 9-12 months that we have been following
them. We are also investigating kill sites to determine kill rates, species of kills, and whether
lions are preying on any domestic animals. So far in the Santa Monica Mountains our data
indicate that lions are killing 3-4 deer/month of all different age/sex classes, and an occasional
coyote or raccoon. The collared animals are almost never seen by anyone, including the
researchers tracking them, even though they cross numerous roads and trails and sometimes
venture close to residential areas.
PROCEEDINGS OF THE SEVENTH MOUNTAIN LION WORKSHOP