Three years after construction began, it’s time to dump dirt on the project. Specifically, 6,000 cubic yards of a “super” soil followed by the planting of 5,000 native flora. I’m talking about the world’s largest wildlife crossing, which has reached another construction milestone as the bridge nears completion.
This prepared soil is the beginning of the end of construction for the Wallis Annenberg Wildlife Crossing, which broke ground on Earth Day in 2022. Located in Agoura Hills, California, the nearly one-acre overpass stretches over a 10-lane section of U.S. 101.
The physical bridge structure is essentially complete, having required 26 million pounds of concrete, Beth Pratt of the National Wildlife Federation (NWF) told KCAL. The NWF Regional Executive Director added, “We just put the soil on top, and then we start burying utility lines and extend it over the access road.”
Multiple layers of soil will be needed to create a wildlife habitat on the overpass, and the soil application alone will take several weeks. However, when the Annenberg Wildlife Crossing is done, the bridge will reconnect the bisected areas of the Santa Monica Mountains National Recreation Area. With more than 150,000 acres, SMMNRA is the country’s largest urban national park. But the freeways have long isolated the local fauna, from butterflies and cottontails to bobcats and mountain lions.
According to the project, as far back as the 1980s, researchers identified the Liberty Canyon area as a choke point for wildlife. However, it wasn’t until the National Park Service began a decades-long study of the region’s mountain lion population that the 101 freeway was deemed “the most significant barrier to the ecological health of the region.”
More than 300,000 vehicles travel along U.S. 101 daily. That’s enough traffic to give a driver anxiety—try being a local critter having to dart across the road just to find dinner.
P-22, arguably the most famous mountain lion in and outside of Hollywood, surprised everyone by crossing freeways on his own. He eventually became the poster cat for the “Save L.A. cougars” campaign. Unfortunately, he was euthanized in late 2022 after being found with severe injuries, likely due to a vehicle collision, and a myriad of other health issues.
Mountain lions are the main conservation focus of this wildlife bridge. The big cats are territorial, and being locked in by freeways limits their roaming range and biodiversity. Without the crossing to expand their habitat, SoCal cougars could be extinct within 50 years. They also continue to be killed by vehicles.
“In the Liberty Canyon area where we’re putting the crossing, within the last four years, we’ve had four mountain lions killed just in that general area,” Pratt said.
Not just providing access to more sources of food, shelter, and mates, but the bridge would also offer an escape route from wildfires and other disasters. The Annenberg Wildlife Crossing is expected to reach completion next year.
