A study published in “Proceedings of the Royal Society B” last week predicted a dire outcome for local mountain lion populations, should isolation in a small section of the Santa Monica Mountains continue.
According to the paper, drafted by scientists from UCLA, UC Santa Cruz, the National Park Service and other government institutions, continuous inbreeding will cause the population to almost certainly go extinct. The paper said that, according to data from one population studied, if inbreeding is not prevented, mountain lions could face a 99.7 percent chance of going extinct in the Santa Monica Mountains.
The small population of mountain lions — estimated by the National Park Service to number around 15 — has long struggled with isolation since Los Angeles’ freeways have fenced in the once free-roaming carnivores. The issue became famous when State Senator Fran Pavley began the campaign for a $60 million wildlife overpass to connect populations of mountain lions divided by the Ventura (101) Freeway in 2014.
When asked by KPCC why the NPS couldn’t simply relocate some mountain lions from one side of a freeway to the other, John Benson (one of the study’s leaders) said that’s not a solution.
“There are other animals in the Santa Monica Mountains that are isolated than just mountain lions,” Benson told the radio station. “We know that other populations of animals like bobcats, coyotes, even some birds are also isolated, so having this highway crossing would allow many more animals to cross the freeway and keep them from being isolated, too. It would benefit not just the mountain lions but many other wildlife populations and really mimic a naturally functioning ecosystem.”
When asked on social media why the Santa Monica Mountains National Recreation Area appears to be favoring mountain lions over other animals who live in the mountains — potentially putting pets and domesticated animals at greater risk — rangers said the crossing will not increase the net number of mountain lions.
“There is no indication that a crossing would increase the number of mountain lions in the Santa Monica Mountains — it would simply restore movement north and south of the freeway,” Ranger Kate wrote. “The cats born south of the freeway (especially males) need to be able to disperse out of the mountains and, of course, we also need some number of animals to come from the north to the south to introduce new genetic material. You could even make the argument that the potential for interaction with humans could even be reduced with a better habitat connection in place, since many of the cats that end up in residential areas are sub-adults looking to disperse but hitting a wall, figuratively speaking.”