These structures can satisfy wildlife’s need to move across our Western ranges. They can also facilitate grazing. Both are needed for habitat restoration and wildlife conservation.
NOTE: This post initially appeared on WSJ.com on June 20, 2017. Feature photo by Jeff Burrell/Wildlife Conservation Society
Why did the black bear cross the road?
Actually, it didn’t—because it didn’t have to.
A motion-activated camera shows that the bear in question took an overpass—essentially a large, camouflaged arch—that gracefully carves over U.S. Highway 93 in Montana, just north of the town of Evaro at the entrance to the Flathead Indian Reservation. Thirty-eight more of these man-made wildlife crossings allow all manner of critters to take a safe route over or under the stretch of highway between Evaro and Polson, 56 miles to the north.
But do the crossings, the last of which was completed in 2010, work? Cameras in 29 of the structures show almost 23,000 crossings in 2015, about double the number from five years earlier, according to data compiled by the Western Transportation Institute, a research arm of Montana State University in Bozeman. Even more intriguing, scientists found through scenes caught on camera that some animals—deer and bear among them—were teaching their young to use the crossings.
As significant, a November 2016 Western Transportation Institute report based on five years of animal-vehicle collision data showed that roadkill numbers for large wild mammals fell 80% along sections of the highway served by three of the more prominent crossings, while such deaths increased along sections with no structures.
Crossings, especially when combined with miles-long fences that steer animals toward them, “can substantially reduce collisions,” says Marcel Huijser, a Western Transportation Institute road ecologist and the report’s lead author.
Something of a novelty in the U.S. a decade ago, wildlife crossings are proliferating all across North America and are increasingly being built into the design of new highway projects where vehicle and wildlife crashes are a major threat. Last fall, Washington state’s Transportation Department began putting up two sweeping, 66-foot wide arches that will form the backbone of the Keechelus Lake Wildlife Overcrossing, one of more than 30 crossings that will be built into a multiyear makeover of a 15-mile stretch of Interstate 90 east of Snoqualmie Pass.
Safety—for both animals and humans—is the main driver in crossings growth in the U.S. Collisions between wildlife and vehicles have risen 50% in the past 15 years, and such accidents now cost Americans $8 billion annually in damages and cleanup costs, according to research by ARC Solutions, a coalition of conservationists, ecologists, engineers and planners that advocates for crossing construction.
About 200 people a year die and 29,000 are hurt in wildlife-vehicle crashes in the U.S., according to data published by Defenders of Wildlife, a conservation group. For animals, it’s a slaughterhouse: There may be as many as 1.5 million wildlife-vehicle collisions a year—and the animals almost always die, the group says.
“We shouldn’t be acclimating to roadkill,” says Nina-Marie Lister, a landscape ecologist and ARC adviser who teaches at Ryerson University in Toronto. Crossings, she says, are a solution to a “problem that we all own but no single government agency is in charge of solving.”
Awareness of both roadkill data and the effectiveness of crossings is growing. “It’s a values shift, like seat belts. Nobody had them when I was growing up but these days everyone wears them,” says Jeremy Guth, an ARC founder and a trustee of the Woodcock Foundation, which works on land-conservation issues.
Also driving growth in crossings is conservation, or the notion of using them to reconnect wildlife habitats fragmented by roads and bridges. The Trappers Point Wildlife Crossing over U.S. 191 near Pinedale, Wyo., completed in 2012, diverts thousands of mule deer and pronghorns over the highway as they seek passage to the spring and fall pastures they’ve used for millennia.
In Southern California, environmentalists are seeking to help raise an estimated $55 million to build the Liberty Canyon Wildlife Crossing over Highway 101 in Agoura Hills, 35 miles west of Los Angeles. The project’s main goal is to provide safe passage over the 10-lane freeway for mountain lions in the surrounding Santa Monica Mountains whose population has dwindled because of suburban sprawl and habitat fragmentation. Among them is the solitary young lion known as P-22 that has settled in Los Angeles’s 4,310-acre Griffith Park after somehow safely crossing both the 405 and 101 freeways from mountains to the east.
“We’re confident we’re going to raise every bit of the money we need because P-22 is such a great story,” says Beth Pratt, California director of the National Wildlife Federation, which is seeking to raise $10 million this year to help fund the engineering and design portion of the project. “We have a lonely bachelor lion living in L.A., cut off from a potential mate. The crossing is his chance for happiness.”
Mr. Guth, meanwhile, says he was recently invited to St. Mary Parish, La., to consult with wildlife officials seeking to save an indigenous population of black bears that are essentially stranded in the Atchafalaya Basin, America’s largest contiguous hardwood swamp. Cut off from upland populations by highways, the bears have begun to inbreed, and their only hope of long-term survival may be crossings that connect them to upland populations, he says.
“The old model of conservation—acquire large islands of habitat for wildlife and check the box, done—well, we know that alone doesn’t work anymore,” says Ms. Pratt. “We have to look at large landscape corridors for all wildlife.”
For people , the aim is no longer just utilitarian—an afterthought of road construction—but something more aesthetically pleasing.
The I-90 Keechelus Lake crossing is the product of an intensive collaboration of wildlife scientists at Central Washington University and engineers, architects and planners from the Washington state Transportation Department and the U.S. Forest Service. The idea was to build a structure that animals more or less see as a path through the woods, yet one whose sweeping arches will become something of a landmark for the 27,000 motorists who travel that section of the freeway every day.
“There’s no reason,” says Ms. Lister, “that they can’t be pretty, even iconic.”
Mr. Wells is a writer in Chicago. Email him at firstname.lastname@example.org.
Appeared in the June 21, 2017, print edition as ‘Animal Crossings Go Beyond the Pedestrian.’