L.A. Breaks Ground on the Largest Wildlife Crossing in the World

Bridges, overpasses, underpasses, tunnels—wildlife and ecosystems have had to adjust to human-made infrastructure for centuries. But now, humans are paving the way for wildlife with Los Angeles' newest wildlife crossing.

According to a recent press release from the National Wildlife Federation, a wildlife overpass will be constructed over the 101 Freeway's 10 traffic lanes at Liberty Canyon in Agoura Hills, California. Construction officially began in April 2022, and the project is set to be completed by 2025.

The project is the first of its kind in the state of California, and it sets the stage for future urban wildlife conservation efforts.

Additionally, the wildlife crossing will be named the Wallis Annenberg Wildlife Crossing for the philanthropist whose foundation donated $25 million. However, the entire project received roughly $90 million in funding.

"Wildlife crossings restore ecosystems that had been fractured and disrupted," said Wallis Annenberg, chairman, president, and CEO of the Annenberg Foundation. "They reconnect lands and species that are aching to be whole. I believe these crossings go beyond mere conservation, toward a kind of environmental rejuvenation that is long overdue."

The crossing will be about 200 feet long, extending across the freeway that receives over 3,000 vehicles per day. The crossing supports migration for coyotes, bobcats, and deer. And it'll even support small-sized species like lizards and birds.

By providing these animal species with a clear route across urban infrastructure, we can (hopefully) see an increase in biodiversity. And we might even see a decrease in the negative impacts of habitat fragmentation.

Habitat Fragmentation in Southern California

After 25 years of research, the National Park Service (NPS) determined that wildlife is heavily impacted by habitat fragmentation—aka when natural ecosystems are divided into smaller regions as a result of human activity, climate change, natural disasters, or other factors.

Industrialization and urbanization are two leading causes of habitat fragmentation. Unfortunately, to make room for human activity (i.e. infrastructure, developments, and more) we've pushed animals out of their habitats—or prevented them from migrating when they need to. Thus, animal species were forced to adapt.

Unfortunately, some species aren't seeing positive adaptation results. Biologists found that the 101 Freeway in Southern California had become a barrier. One that prevented migration and halted gene flow for multiple species—including mountain lions.

Mountain lions in Southern California are experiencing a decrease in population size and a decrease in genetic variation. According to a 2022 study published in the journal Theriogenology, between 2019 and 2020, researchers identified nine mountain lion individuals "exhibiting physical signs of inbreeding depression."

Specifically, some mountain lions are experiencing increased levels of abnormal sperm or have kinked tails—both of which are a result of a loss of genetic diversity. Hence the need for conservation efforts in the region. According to Jeff Sikich, a lead field researcher in the study, the new Los Angeles wildlife crossing comes at the right time.

"This crossing is timely, considering our recent discovery of the first physical signs of inbreeding depression occurring in our isolated mountain lion population in the Santa Monica Mountains," Sikich said in the NPS news release. "Habitat fragmentation is the key challenge wildlife is facing here." 

Fortunately, the new infrastructure aims to reverse the harm animal species are facing as a result of habitat fragmentation. And hopefully, we'll see more wildlife crossings or conservation efforts across the globe.