How To Save A Lion: Avoid Extinction With The World’s Largest Animal Bridge | Features

2022 has been a very difficult year for the local cougars. On Friday, August 26, a juvenile mountain lion, called P90 by scientists, was killed on Highway 33 after completing a hike that started in the Santa Monica Mountains.

The previous month, his brother P89 was struck and killed on the 101. The deaths were the sixth and seventh of local mountain lions on the roads this year, a horrific toll given that the entire National Recreation Area of Santa Monica Mountains can only support 10-15 adult lions. Fortunately, long-term help may be on the way.

Here’s the thing: Although the Santa Monica Mountains National Recreation Area (SMMNRA) is a natural habitat for mountain lions (aka Puma concolor, cougar, panther, catamount; the largest species of cat in the Americas), they need huge territories, especially the males. These solitary animals are largely left alone, except when it’s time to mate or a mother is raising her kittens. The SMMNRA’s rambling geography and proximity to dangerous highways, along with the lions’ space requirements, limit the number of adult males the territory can support. And there just isn’t enough space left for juvenile males once they’ve separated from their mother. So they look to the open spaces to the north, across the 101. That’s why the 101 lions killed are usually juvenile males.


In addition to the overpopulation of cats in the Santa Monica Mountains, lions there also face a genetic time bomb caused by inbreeding. With the Deadly 101 preventing migration to surrounding mountain lion habitat, the Santa Monica lions can neither escape to find new mates nor can new arrivals bring new “blood” and genes to the territory.

The lack of genetic diversity in the SMMNRA cougar gene pool went from a theoretical problem to a real one recently when park naturalists noticed indications of genetic abnormalities such as folded tails and cryptorchidism (testicles not descended) to go with what they already knew about lions. forced inbreeding.

With this development, it is clear that the SMMNRA lions now face an existential threat. National Park Service (NPS) researchers have announced that their lions have a nearly 100% chance of extinction within the next 50 years due to a decline in genetic diversity. The only solution is to increase the breeding population of lions. And the only way to do that, short of captive breeding, is to connect the SMMNRA to the cougar populations to the north: the Santa Susana Mountains, the Simi Hills, and ultimately the National Forest of Los Padres.

The lions, of course, tried to do it themselves risking the 101.


To the (long-term) rescue of the lions comes an ambitious project that has been in the works for several years: the largest wildlife bridge in the world. The planned animal-only overpass at Agoura Hills will connect 10 traffic lanes between the Las Virgenes and Kanan exits and facilitate the connection of lion-friendly open spaces.

Officially called the Wallis Annenberg Liberty Canyon Wildlife Crossing, the corridor had a ribbon-cutting ceremony in April with the governor, environmental leaders, and (of course) many bureaucrats in attendance. The $90 million project (paid for by environmental groups and the state) will allow lone mountain lions (and other animals) to cross the 101, reach public lands to the north, and hopefully find the mate of their dreams on the other side.

We spoke to the project’s designer, architect Clark Stevens, who also serves as head of the Santa Monica Mountains Resource Conservation District. Stevens discussed the “difficult geometry” of the Liberty Canyon location, hemmed in by Agoura Road – which will also be bridged by the viaduct – and nearby office buildings. The appeal of the site was its links to the open space to the north and fewer barriers than the alternatives. Stevens sees the site as “the last best place” for the crossing.

The objective of the corridor is not to increase the number of cougars in the Santa Monicas but to ensure their long-term viability through genetic diversity. As National Wildlife Federation Regional Director Beth Pratt says, “The population is self-limiting, and wildlife crossing aims to increase genetic diversity and ensure a healthy population that will persist in perpetuity. , not to increase the size of the population”.

Now on to the bad news. Like everything in the California government, and especially Caltrans, the hallway won’t be finished anytime soon, no matter how many love-starved (or just starved) cougars die in the meantime. The opening is planned for 2025 . . . and this is the “provisional” date!


It is hoped that the Liberty Canyon Corridor will not only help the Santa Monica cougars solve their long-term genetic challenge, but will do the same for other endangered species.

“While the Wallis Annenberg Wildlife Crossing will help save this local population of cougars, it also reconnects a regional ecosystem for all wildlife, large and small,” says Pratt. “The same genetic isolation that mountain lions have suffered from also appears in NPS research on birds and lizards. This crossing will be a living habitat above Highway 101, with not only mountain lions crossing it, but also butterflies, lizards, birds and frogs that live there.

A very small club of big cats (see box) has made it past 101 and likely more after 2025, but that’s only the start of the species’ journey to genetic health. Future successful cruisers could stop permanently in the modestly sized hills of Simi. Others will likely continue north and cross the 118 into the Santa Susana Mountains, which stretch from Highway 23 to South Mountain near Santa Paula. It’s a nice stretch of semi-wild, but those areas probably already have resident mountain lions.

Breeding nirvana will likely only come in the form of access to the sprawling Los Padres National Forest, but that requires yet another treacherous crossing, this time of Highway 126. It’s no easy task. , but at least the SMMNRA mountain lions will have a fighting chance of survival if they can make it to 2025.

Other smaller upgrades will also help the lions’ chances. According to Pratt, “The Liberty Canyon area is the most significant barrier to connectivity in the region, but certainly not the only road that needs fixing. We have better success rates with cougars crossing on roads like 118 or 126, but we need to do better. Indeed, we are considering more level crossings or other means of improving connectivity, such as exclusion fencing, culvert improvements, etc. Some of this work has already begun.


What about southern California cougars not found in the Santa Monicas? An example of a big cat beyond the SMMNRA is the famous “Hollywood Cat”, P22, which has successfully called Griffith Park home for many years. How many followed his paw prints to Ventura or Los Angeles counties is hard to say. These solitary, often nocturnal and elusive animals keep a low profile and are notoriously difficult to count unless captured, drugged and tagged. Wildlife experts presume a decently sized population in our Los Padres National Forest, but neither this agency nor anyone else knows how many there are. (Estimates for the entire state of California are 4,000 to 6,000 mountain lions.) Sightings are rare, and even the most intrepid hikers are likely to see only lion tracks and droppings. But lions are certain to be present almost anywhere their mule deer prey grazes.

Another complication: widespread drought is thought to be pushing some cougars closer to suburban areas with easier access to water. According to Patrick Lieske, forest biologist at the Los Padres National Forest, “drought is a significant concern for cougars and other wildlife. Lack of water and prey in natural habitats frequently causes large mammals (bears and cougars) to the land-wild-urban interface (WUI), where they are more likely to interact with humans.As a result, many areas of California are seeing increased activity in these WUI areas this year.

Various factors have pushed mountain lions deeper into our consciousness in recent years. Between the publicity around the NPS tagging and tracking program, the fame of P22 and the road deaths on the 101, you would think the population has increased. But Pratt says it well: “Cougars have always been in the Santa Monica Mountains. It’s probably the technology that gives the false impression that there are more of them, when it’s just that we have Ring cameras everywhere now picking them up in places they’ve always been and then the videos or the observations are widely shared on social networks. The National Park Service saw no evidence that the number of animals in the Santa Monica Mountains or Simi Hills or their interactions with people increased during their 20-year study.

In Ventura County, environmental groups and the county government teamed up in 2019 to do their part for lions and other large mammals. They implemented their own effort to connect the open spaces. This was done through the state’s first countywide wildlife corridor ordinance. Not a single corridor, rather the ordinance established a list of protections and regulations for a set of wildlife corridors connecting the county’s “big three” wilderness areas (SMMNRA, Simi Hills/Santa Susanas, Los Padres). The ordinance survived challenges this year by labor and development groups. Jeff Kuyper, director of Los Padres ForestWatch, says the new regulations have been “successful so far,” despite the challenges. He hopes the regulations will become a model for other counties and is proud to see Ventura County at the forefront of habitat protection and connectivity.

Let’s end on a hopeful note. Although local cougars face tremendous challenges from drought, inbreeding, disconnected open spaces, deadly highways, territorial alpha males and rodenticides, real efforts are underway to give them a fighting chance. survival into the next century. And as Pratt says, it’s “pretty remarkable that a wildlife habitat exists on one of the busiest highways in the world!” »

For more information on the Wallis Annenberg Wildlife Crossing, visit or

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