California will build the largest wildlife crossing in the world Experts hope the bridge will enable mountain lions to find potential mates and increase the local population's genetic diversity. (National Parks Service/AP Photo/Marcio Jose Sanchez)
California will build the largest wildlife crossing in the world
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A planned animal overpass set to stretch over Los Angeles' 101 Freeway has entered its final design phase. That's according to Christopher Weber reporting for the Associated Press. Dubbed the Liberty Canyon Wildlife Crossing, the 200-foot-long bridge is on track for groundbreaking within the next two years and slated to open by 2023. It is expected to provide safe passage for lions, coyotes, and deer. It will also provide safe passage for lizards, snakes and other wild creatures.

According to Weber, the crossing will enable Southern California's native wildlife to more freely roam the region's urban sprawl. Currently, animals hoping to cross the highway are at high risk of becoming roadkill. As a result, most are essentially trapped in the Santa Monica Mountains, unable to venture out in search of food and potential mates.

This limited geographic range poses a particular threat to mountain lions. Per a study published in the journal Ecological Applications this March, two isolated populations in the Santa Ana and Santa Monica Mountains face extinction. This could happen within the next 50 years. That's due to low genetic diversity and mortality linked with human activity and environmental changes. 

By connecting solitary big cats with other members of the species, the Liberty Canyon overpass could curb mountain lion inbreeding. It could reintroduce genetic diversity to local populations.

"When the freeway went in, it cut off an ecosystem," Beth Pratt tells the AP's Weber. "We're just now seeing impacts of that." Pratt is the director of the National Wildlife Federation's California branch.

Pratt adds, "They can't get out of here to get dates, and cats can't get in to get dates. ...For those of us in L.A., having a romance prospect quashed by traffic is something we can all relate to."

Weber explains that 80 percent of the funds needed to construct the $87 million bridge will come from private sources. The remaining 20 percent will be drawn from public funds allocated toward conservation campaigns. According to authorities, the Liberty Canyon Wildlife Crossing will be not only the first of its kind built near a major metropolis. But it will be the largest in the world.

As a #SaveLACougars campaign report notes, the proposed design features a 165-foot-wide by 200-foot-long bridge. It will be constructed at the freeway's 33.0 mile marker. Stretching across 10 lanes of highway traffic, the overpass will also include an extension above nearby Agoura Road. Per Avishay Artsy of a KCRW local radio show, the crossing will strive to resemble an extension of the surrounding mountainside. It will boast extensive plant cover, as well as sound- and light-blocking barriers.

Rob Ament, a road ecology program manager at Montana State University's Western Transportation Institute spoke with National Geographic's Starre Vartan in April. He said that under- and overpasses can reduce mortality rates and monetary costs associated with wildlife-vehicle collisions by 85 to 95 percent. 

First introduced in France during the 1950s, such crossings are popular in Europe. They are becoming increasingly common across the world. Last December, cameras spotted the first wild animal to use an overpass built above Washington State's Interstate 90. In October, California opened its first wildlife crossing at a spot near Temecula, around 60 miles north of San Diego.

Southern California's most famous mountain lion, a male known as P-22, is the poster child for the #SaveLACougars campaign. Pratt calls him "the Brad Pitt of the cougar world." Because he lives in a park miles from the crossing, he likely won't end up using it, but many of his relatives are poised to benefit from the bridge. That's according to AP's Weber. Lions rarely cross local freeways successfully, but the Orange County Register's Martin Wisckol writes that a 4-year-old male dubbed P-61 made his way across the 405 freeway unimpeded just last month. P-22 made a similar journey years ago. He crossed the 405 and 101 highways to reach his current home in Griffith Park.

According to the cougar campaign's report, P-22's living situation is "less than ideal," as he is now virtually trapped in the confines of the Los Angeles park. He is unlikely to be joined by a potential mate anytime soon. As the report states, "Building a wildlife crossing will help other mountain lions avoid P-22's fate."

Clark Stevens is an architect with the Santa Monica Mountain's Resource Conservation District. He tells Weber that "ideally, the animals will never know they're on a bridge."
He concludes, "It's landscape flowing over a freeway. It's putting back a piece of the ecosystem that was lost."

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CRITICAL THINKING QUESTION
What would your reaction be to seeing animals using the wildlife bridge? Why?
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