Dead Mountain Lion Highlights Need For Wildlife Tunnel

P-12, captured here with a remote camera trap, is the only lion documented to have successfully crossed the 101 Freeway during the course of the decade-long National Park Service study.

A mountain lion killed last month on the 101 Freeway in Agoura Hills could have brought new genetic material to the mountain lion population of the Santa Monica Mountains, the National Parks Service reported this week.

Preliminary DNA testing showed that the male mountain lion was travelling from north of the freeway into the Santa Monica Mountains, and into an isolated mountain lion population.

The mountain lion was hit and killed by a car while crossing the freeway near the Liberty Canyon exit, where wildlife advocates have long pushed for a wildlife tunnel crossing, according to the NPS.

“The fact that this young male chose to cross–unsuccessfully–at Liberty Canyon shows how critical this wildlife corridor is for maintaining genetic diversity in the Santa Monica Mountains,” said Dr. Seth Riley, an expert on urban wildlife with Santa Monica Mountains National Recreation Area (SMMNRA), in a release. “This section of the 101 Freeway is the ideal path into the Santa Monica Mountains because of the natural habitat on both sides of the freeway and the connections to large areas of open space.”

Constructing a tunnel would cost $10 million, according to the NPS, but Caltrans has twice come up short in applying federal transportation funding for the project.

Mountain lions in the Santa Monica Mountains face a lack of genetic diversity because they are hemmed in by freeways, the Pacific Ocean and the Oxnard agricultural plain. The lack of diversity is a threat to their long-term survival, according to the NPS.

Riley and his colleagues have worked with the Robert Wayne Lab at UCLA and the Holly Ernest Lab at UC Davis to document genetic differences in mountain lion populations north and south of the freeway. They have also documented multiple cases of first-order inbreeding, in which a father mates with his offspring.

In a decade-long study tracking 30 mountain lions, the NPS recorded only one lion successfully crossing the 101. A successful crossing by the mountain lion killed last month could have brought genetic diversity to the population south of the freeway.