Wildlife crossings can protect wildlife, restore habitats and save lives

By Jackson Walker

On December 3, 2016, a mountain lion named P-39 attempted to cross the 118 highway in Southern California’s Simi Valley in search of new territory for her newborn kittens.
P-39, as she was named by the researchers who are tracking the pumas of the Santa Monica Mountains, was killed by oncoming traffic. Two weeks later, two of her three kittens met the same fate in the same place, trying to find out what happened to their mother.

17 months later, Amber Stanley, her 4-year-old son, Jack, and her 2-year-old daughter, Autumn, were driving north on Interstate 95 in South Carolina when they struck an alligator trying to cross the road. They swerved, crashed into a tree and died in the resulting fire.

People and animals suffer from wildlife vehicle collisions (WVC) that are the inevitable results of roads that are built right through the heart of wildlife habitats. Humans created the problem, but we can fix it.

The solution? More government agencies are turning to wildlife crossing structures to save lives. Not only can wildlife crossings prevent fatal collisions, they can also reconnect severed habitats.

“We’ve screwed up so much on this planet. The way we’ve treated other life forms is morally indefensible,” said Beth Pratt, California Director for the National Wildlife Federation. “We owe it to do whatever we can to coexist.”

But coexistence isn’t easy. The quest to save the Santa Monica mountain lions from extinction takes work. And money – a lot of it.
The Liberty Canyon wildlife bridge over the 101 freeway, when completed sometime in 2023, will be the biggest and most expensive wildlife crossing ever built at an estimated $87 million. According to Pratt, who is leading the fundraising for the project, “$87 million seems like a pretty small price tag so these mountain lions don’t die out forever.”

The Santa Monica mountain lions face extinction because they are trapped on a land island, boxed in by US Highway 101 to the north, the densely urbanized LA basin to the east, developed areas in Ventura County to the west, and the Pacific Ocean to the south. With nowhere to go, the mountain lions are forced to inbreed, which leads to low genetic diversity and reproductive failure.

Being cooped up is also making them kill each other. Mountain lions are fiercely territorial, requiring up to 200 square miles each. When another lion intrudes, the results are often deadly. Simply put, the mountain lions need this bridge to survive. That’s why the National Wildlife Federation, the National Park Service, and California’s Department of Transportation are working overtime to get it done. It’s a race against time, and the consequences couldn’t be greater.

“We’re talking about wildlife species vanishing from the earth,” Pratt warned.

Putting up a wildlife bridge like Liberty Canyon is like building any other bridge, but with 1,000 extra steps. The first question is where to build it? Siting is paramount because fences help funnel animals towards the crossing.

If the fences are poorly placed, they can restrict wildlife movement, thereby contributing to the habitat connectivity issues they were put in place to solve. For this reason, existing wildlife corridors (basically animal highways) that have been dissected by roads are good places to start.

Once corridors are identified, wildlife crossing experts then pick places that are going to have the most bang for the taxpayer buck. Julia Kintsch, one of the world’s leading experts on wildlife crossing siting and design, always asks herself two questions before beginning construction: “Where is it going to reduce collisions by the greatest amount? And where is it going to have the greatest benefit for wildlife connectivity?” The happy medium between the two is the sweet spot for siting.

Kintsch is in charge of assessing the success of Colorado Highway 9’s wildlife crossings on reducing wildlife vehicle collisions. Kintsch and her research team discovered that the crossings reduced WVCs along Highway 9 by 90%. Now, deer, elk, sheep, bears and other fuzzy fauna cross the highway without fretting about being hit by a car, and drivers going over and under the crossings can breathe a sigh of relief. Knowing that Bambi and company can cross safely gives people peace of mind.

Once a site has been chosen, funding has to be established. Wildlife crossing projects are collaborative efforts involving transportation and conservation agencies. Five years ago, those organizations barely spoke to each other. But recently, as the importance of wildlife crossings has gone mainstream, things are changing.

“They started having meetings and realized that their missions overlapped,” said Anthony Clevenger, the “rockstar researcher of the wildlife crossing world” according to Pratt.

Transportation folks want to reduce the 1 to 2 million WVCs that occur every year in the U.S., and conservationists want to connect habitats. Wildlife crossings solve both of these problems.

As for the funding, it’s largely up to how much the local communities are willing to pay. Public outreach efforts and public meetings are key. “If you don’t have that community support, it’s not happening,” Kintsch said.

It’s important to inform people that crossings actually save them money in the long run by preventing collisions in the first place. Nationwide, WVCs cost about $8,388,000,000 annually, according to the Federal Highway Administration. In the wildlife crossing world, an ounce of prevention really is worth a pound of the cure.

Some organizations are hesitant to help build crossings because they have an old-school approach to conservation that believes all you need is one big reserve for all the animals to live in and they’ll be fine. Recent conservation research suggests it isn’t the size of the reserve that matters the most, but how well it connects to other protected areas. Nature must be connected to work, but even some conservation groups don’t see this.

As Clevenger put it, “They don’t realize that what they’re doing has continental-scale ramifications for habitat connectivity.”

Likewise, some communities, like the residents of Island Park in Idaho, just don’t want wildlife crossings in their area. After it was brought to the public’s attention that large numbers of elk, moose, pronghorn, and a handful of grizzlies migrating from Yellowstone National Park to Idaho’s Sand Creek desert were being decimated when crossing Highway 20, a small but vocal group from Island Park opposed the plan for a crossing.

They saw the overpass as an unnecessary, expensive cost and a blatant sign of government overreach. Decision-makers decided to nix the much-needed crossing. The community of Island Park chose a death sentence for migrating wildlife over the lifeline of a wildlife crossing.

Fortunately, for drivers and wildlife, the example of Island Park is an exception. Wildlife crossings are gaining in popularity, and animals are using them every day to safely cross the road and explore new areas to call home.

Once the location is settled, the funding is secured and the crossing is built, it’s up to the animals to start using it. Most animals quickly learn where the crossings are and integrate them into their movement patterns. Faster learners teach slower learners by showing them where the overpass is. Word gets out, and the animals come.

“There’s definitely a learning curve,” Clevenger said, but after a few years, even the most reclusive and skittish animals start using them regularly.

In some cases, animals take to the crossings immediately, as was the case for the Parleys Canyon wildlife bridge in Utah. Save People Save Wildlife, a Park City nonprofit that campaigns for wildlife crossing projects, nicknamed I-80, a six-lane highway cutting through major wildlife habitats, “Slaughter Row” for its high concentration of WVCs. They pressured Utah’s Department of Transportation to build an overpass, and in December 2018, it was completed.

Experts predicted that local wildlife would take years to get used to the new infrastructure, but within a matter of weeks, the bridge’s hidden camera captured a wide variety of animals, from squirrels to mountain lions, using the bridge.

“It was phenomenal,” said Erin Ferguson, a member of Save People Save Wildlife. “Weeks after it opened, all kinds of animals were using it. Wildlife are much smarter than people give them credit for.”

However, wildlife crossings are not the be-all-end-all panacea for wildlife conservation. They are a proven solution to connecting habitats that have already been fragmented. But the priority should be preventing habitat fragmentation from happening in the first place.

The old-school view of having big reserves is compatible with the new-school view of connectivity because, as Clevenger said, “If you don’t have the base preserve in place, the [crossing] structure is useless.”

What makes the Liberty Canyon wildlife bridge different is its sheer size, expensive price tag, and call-to-action purpose of being specifically designed to prevent the local extinction of an entire species, as opposed to reducing WVCs like most other crossings. Oddly enough, for the Santa Monica mountain lions, being run over by cars isn’t generally a problem because they rarely try crossing the 10-lane 101 highway — they just turn around.

The Liberty Canyon bridge is also an important public relations and educational project. It has received an enormous amount of publicity, which has raised awareness across the country and around the world that wildlife crossings can help people and animals coexist.

“A lot of places and people don’t know about these techniques, and they’ll learn from Liberty Canyon. It has far-reaching implications with regards to wildlife conservation, not just in Southern California, but worldwide,” Clevenger said.

This publicity couldn’t come at a better time. Many developing nations are experiencing an avalanche of transportation projects, some of which are slated to go through areas with some of the highest biodiversity in the world. Thanks to Liberty Canyon, these countries can learn from the U.S.’s mistakes and implement crossings into road design before there is a WVC or connectivity problem.

“Retrofitting is an engineering nightmare, it’s tough. Looking forward, you’ll just see these things become embedded in planning,” Pratt said.
Kintsch agreed. “Whenever new highway projects are being planned, measures to mitigate WVCs and increase connectivity should be taken into account. ‘Hey, we’re doing this highway project? How do we also make this better for wildlife?’”

Thanks to the countless hours of work people like Kintsch, Clevenger, Pratt and Ferguson put in to help get wildlife crossing structures built, we now know that what is best for wildlife is what is best for us.

Wildlife crossings have shown us that people and wildlife can get along. Now is the time to build bridges between us and the natural world.