Mountain Lions: A Bridge Out of Extinction

Why the urgent need wildlife crossings across Los Angeles and Southern California, affects us as much as mountain lions.

Illustration by Rachael Uriarte

The Cat That’s Lost The Cream

Stuck in a habitat ghetto fenced in by freeways on which hundreds of thousands of cars roar past every day, Santa Monica mountain lions find themselves on the brink of extinction.

Fewer than 15 mountain lions currently pace around just 275 square miles in and around the Santa Monica Mountains National Recreation Area, an area which is bordered by the Pacific Ocean, the 405 and 101 freeways, farms, and Los Angeles’s massive urban sprawl.

Conducted by researchers at the University of California, Los Angeles and University of California, Davis in conjunction with the National Park Service, a 2019 study paints a bleak picture. Habitat loss and fragmentation have driven mountain lion populations to dangerously low levels of genetic diversity, without urgent action, one of southern California’s last big cats will become extinct in as little as 15 years.

Lead by Dr. John Benson, a wildlife ecologist with the La Kretz Center for California Conservation Science at UCLA; the study specifically looked at the mountain lion populations in the Santa Monica and Santa Ana mountains. They documented the lowest genetic diversity for American mountain lions, aside from Florida panthers (despite the different common names, panthers, cougars and mountain lions are the same species).

“We can look to what happened to Florida panthers as a cautionary tale. When their genetic diversity reached very low levels in the 1990s, panthers nearly went extinct due to factors associated with inbreeding depression,” Benson said.

The biologically dire phenomenon known as “inbreeding depression” happens when a lack of gene diversity begins to negatively affect the ability of mountain lions to survive and reproduce healthy offspring.

Roadkill is another decimating factor in the survival of Santa Monica mountain lions. The US-101 freeway is a deadly adversary to mountain lions. Its original construction in 1926 transformed a previously continuous habitat range into isolated islands. Since their biologists began researching mountain lions in the Santa Monica Mountains in 2002, the National Park Service said motorists have struck and killed 17.

However, there is a reason for hope. Benson explained that the mountain lions’ chances of persisting could be increased. “Our modeling suggested that if mountain lions from the surrounding areas are able to move into the Santa Monica Mountains every year or two, they should be able to largely maintain their genetic diversity.”

Freeways are “formidable barriers to movement,” and the solution to these human-made hurdles is a massive wildlife crossing across the US-101 freeway. The crossing would provide vital connectivity and also benefit the population by allowing young animals born in the Santa Monica Mountains to safely disperse elsewhere, significantly reducing the likelihood of inbreeding and vehicle collisions.

“Fifty-plus years ago when the US-101 freeway was built, no one was thinking about wildlife connectivity,” said Dr. Seth Riley, a wildlife ecologist for the National Park Service.

Thinking about it from a human standpoint, just two decades ago, no one thought that we would be able to connect with people in 240 or fewer characters, collect “followers,” or somewhat more sinisterly, match with strangers in our area with just a swipe or tap of a finger. As our needs for interaction with other humans has evolved, wildlife like the Santa Monica mountain lion’s opportunity to make their own low-tech tinder matches is being stifled.

Actively monitoring the mountain lion population, the National Park Service said that the first successful documented crossing of US-101 was ten years ago back in 2009. Puma-12 (P-12) crossed from Simi Hills to the Santa Monica Mountains near Liberty Canyon Road. But such successful crossings are rare.

P-32 also managed to cross the US-10 in April 2014 and made it across State Route 23, Highway 118 and Highway 126, but his luck ran out, and he was struck and killed trying to cross the I-5 a year later.

In a press release around the time of P-32’s crossing Dr. Riley explained just how significant it was that P-32 (a juvenile) was able to disperse out of the Santa Monica Mountains — giving him a chance to avoid larger males and eventually establish his own territory.

What happened to P-32 illustrates the challenges that mountain lions in the Santa Monica Mountain region face. “P-32 conquered all kinds of freeways and highways to reach the Los Padres, but it was probably another dominant male that made him leave the area and attempt one last crossing, which obviously was not successful.” Dr. Riley commented in a later press release after P-32’s death.

Illustration by Rachael Uriarte

Like Social Media, but for Wildlife

Liberty Canyon is an ideal location to build a wildlife crossing because of the vast swaths of protected public land on either side of the freeway.

The crossing will give a host of animals, not just mountain lions, the ability to move and expand their ranges, allowing them to connect with new mates, strengthening their genetic pool, and helping to ensure their survival.

Specifically though, for mountain lions at risk of inbreeding depression, the crossing is natures’ answer to digital-dating. “They can’t get out of here to get dates, and cats can’t get in to get dates. … For those of us in LA, having a romance prospect quashed by traffic is something we can all relate to,” says Beth Pratt, the National Wildlife Federation’s regional executive director in California.

The Santa Monica Mountains Conservancy, a government organization dedicated to the preservation and management of local open space and wildlife habitat, helped the California Department of Transportation (Caltrans) establish the feasibility of the Liberty Canyon wildlife crossing, said that the structure “which will be the largest and best designed of its kind in the world” will help wildlife movement on either side of the US-101 continue unimpeded.

Back in autumn of 2018, Caltrans said that they had approved the plan to build the wildlife crossing.

The project’s estimated cost of $87 million was expected to be funded through a mix of private philanthropy, corporate donations, and public conservation grants.

Advocacy groups led by the National Wildlife Federation, a wildlife nonprofit that has focused on the protection of mountain lions with its Save LA Cougars campaign, said that they are aware that the crossing will require one of the most ambitious fundraising campaigns ever held on behalf of local wildlife.

To date, Pratt says they have raised $13.5 million for the project, and if kept on track with fundraising, she is positive they will break ground in 2021.

So far, the Save LA Cougars campaign said that the Liberty Canyon wildlife crossing project has managed to secure large private donations to the tune of $1 million from the Annenberg Foundation and $250,000 from the Leonardo DiCaprio Foundation.

Together with the National Wildlife Federation, the California Wildlife Conservation Board has also said they’ll contribute matching funds, for a total of $8 million.

The new 165-foot-wide by 200-foot-long bridge across US-101 would be vegetated to resemble natural wildlife habitat with such features as noise barriers along the edges; vegetation would then block headlights and blend the overcrossing.

The point is to make the crossing, from the wildlife’s point of view almost indistinguishable to their habitat on either side of the freeway, encouraging movement away from the hurtling shots of cars below.

Illustration by Rachael Uriarte

The Thin Yellow Line

In a sea of exotic wildlife teetering on the brink of extinction, why is there concern about Santa Monica mountain lions who according to the California Department of Fish and Wildlife are “are not threatened nor endangered,” and are just classified as a “specially protected species”?

Mountain Lions are the proverbial thin yellow line when it comes to the ecosystem. Allowing them to go extinct creates a significant imbalance with severe repercussions for humans living in the area. In the eastern United States, where mountain lions are now extinct, uncontrolled growth of deer populations has led to overgrazed vegetation, an increase in tick-borne illnesses in humans, and a higher percentage of vehicle-deer collisions than in the western states where mountain lions still reside.

State Farm data on deer collisions with vehicles shows that most states with the lowest risk of deer collision were all on the west coast. The likelihood of their driver’s hitting a deer in California in 2018 was 1 in 1,125 in comparison to 1 in 63 in Pennsylvania (even adjusting for population size you are still far more likely to hit a deer in Pennsylvania than California).

And it’s not just an increase in auto-insurance and a damaged car you have to worry about when it comes to vehicle/large wildlife collisions. A report on the “Impact of Wildlife-Vehicle Conflict” last year in California estimates that over $1 billion in loss of life, injury, and property damage costs have occurred because of wildlife collisions.

A recent vehicle collision with a single mountain lion in Lake County injured nine people, six of whom had suffered significant injuries and had to be helicoptered to nearby hospitals.

“These kinds of collisions are tragically common, and they take a big toll on both human drivers and our state’s imperiled mountain lion populations,” said Dr. Tiffany Yap, a biologist at the Center for Biological Diversity.

Yap is also the primary author of a petition to have the Southern California mountain lions classified under the state’s Endangered Species Act. The petition says mountain lions have profound impacts on their environment, intrinsically supporting the overall health of ecosystems.

“We’ve asked state officials to protect mountain lions under the California Endangered Species Act. If that proposal is approved, it will lead to more wildlife crossings and other steps that could make our roads safer for people and cougars,” detailed Dr. Yap.

With a silent but global pandemic of Lyme disease (Tickpocalypse) spreading, mountain lions could be our unlikely saviours. Since 2016 the Center for Disease Control has reported a year on year increase in the number of reported cases of Lyme disease and other tick-transmitted diseases in humans. It’s worth noting deer alongside mice are also the primary carriers of ticks in the United States. Despite reports of bicyclists being eaten, a mountain lion’s primary diet consists of deer.

As southern California’s apex predator, mountain lion kills are an essential food source for other wild animals, like California condors (who eat mice) and gray foxes. Their presence has a knock-on effect on vegetation, insects, bird, and ultimately, humans.

Whether it’s inbreeding depression, food-chain poison, or roadkill, mountain lions are under siege, penned up in human-made habitat cells just living themselves into extinction. Wildlife crossings serve as their bridge out of extinction.

“Without a clear legal mandate to protect mountain lions from the threats that are killing them and hemming them in on all sides, these iconic wild cats will soon be gone from Southern Californias,” said Dr. Yap.

British. Writer and Conservationist. Child of the Commonwealth.

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