15 Wallis Annenberg Wildlife Crossing

For paving the way toward a more integrated ecosystem

It’s a cruel paradox: The motorways that allow humans to travel more freely blunt the ability of animals to roam. Each new slab of concrete that divides a habitat strands wildlife populations on either side, disrupting their ecosystem—and sometimes impacting their very odds of survival. 

The 100-year-old Highway 101 has done just that to the mountain lion community in Southern California. “The most immediate threat is roadkill, but the bigger problem is genetic isolation,” says Beth Pratt, regional executive director of the National Wildlife Federation. “If no new mountain lions can come into the community, they’re forced to inbreed. They’re starting to show birth defects that eventually could lead to them becoming sterile.”

Tearing up the 10-line highway wasn’t exactly an option. So the National Wildlife Federation and its partners took a different track: building a lush, animal-friendly walkway that spans the massive highway, providing a path between the protected lands on either side. Buffered by high walls of vegetation to block traffic noise, the Wallis Annenberg Wildlife Crossing, just north of the Santa Monica Mountains, won’t simply be a highway for wildlife, but also a habitat in and of itself. “Mountain lions and coyotes will cross it, but birds, lizards, plants and other animals will live on it,” says Pratt. 

Giving animals access to safe crossing is a win for drivers as well. A 2021 study estimated that collisions with large animals cost the state at least US$1 billion in cleanup and damages from 2016 through 2020. (During that same period, roughly 300 mountain lions and 550 black bears were killed by vehicles in California.) And across the United States, another study estimates some 200 humans are killed each year as a result of the 1 million collisions that occur between wildlife and motor vehicles. 

Yet even in a naturalist’s paradise like California, the team still had to do some serious selling of the project. California philanthropist Wallis Annenberg first issued a US$1 million challenge grant in 2016 to kickstart the needed funds for the state’s transportation agency, Caltrans, to design and engineer the blueprints. More than 5,000 private and philanthropic organizations, government agencies and corporate institutions stepped up with donations.

It may have helped that wildlife advocates chose a very charismatic creature to be the face of the project: P-22 (so named for his radio tracking collar) is a male mountain lion made famous in a National Geographic photo that captured him in his full glory in front of the iconic Hollywood sign. At some point, he’d likely made his way across the highway, but is now stuck—alone—on the other side.

In 2021, the Annenberg Foundation doubled down with another US$25 million in project funding and the California Wildlife Conservation Board followed suit, pushing project donations to US$87 million—and accelerating the start of construction, originally slated to start in 2025, by three years.

“There’s a reason I wanted to support this crossing and issue this challenge: We need to move beyond mere conservation, toward a kind of environmental rejuvenation,” says Annenberg. “It’s a way of saying, there are solutions to our deepest ecological challenges, and this is the kind of fresh new thinking that will get us there.”

Along with creative fundraising and extensive environmental reviews, the project team had to coordinate a dizzying array of interested parties: Caltrans, the National Park Service, the Santa Monica Mountains Conservancy, the Mountains Recreation & Conservation Authority, the Resource Conservation District of the Santa Monica Mountains and the National Wildlife Federation. A broad team of wildlife crossing experts also contributed to the planning and design phase, coordinated by Living Habitats.

“Strong partnerships across the board will be critical to these efforts,” California Governor Gavin Newsom said at the groundbreaking, which happened this year on Earth Day, 22 April. Once completed in 2025, the Wallis Annenberg Wildlife Crossing will be the largest wildlife corridor on the planet. Newsom called it “an inspiring example of the kind of creative collaborations that will help us protect our common home for generations to come.”

It’s also likely to be a treasure trove of lessons learned for similar projects, thanks to the federal government’s new US$350 million five-year Wildlife Crossings Pilot Program, which aims to fund other habitat connectivity projects. 

“It takes everybody rowing in the same direction to pull something like this off,” Pratt says. “And this is being done in the Los Angeles area, which people write off as just traffic and concrete. It’s really a very hopeful project.”