In the orange Montana twilight, Marcel Huijser paces a bridge spanning U.S. Route 93, trying to think like a bear. This graceful arc, surfaced not with pavement but with soil and shin-high grasses, is a triumph of conservation engineering: Built by the Montana Department of Transportation in collaboration with the Confederated Salish and Kootenai Tribes, the bridge is one of 41 crossing structures in a 56-mile stretch of highway that help animals from moose to mountain lions safely traverse the road.
Yet Huijser, an ecologist who studies wildlife crossings, can't help but imagine ways to improve it. The grass, for example, fails to block the headlights of the Missoula-bound traffic 26 feet below. Huijser's remote cameras once captured a black bear fleeing from an approaching car's glare. "A visual screen would be helpful," he says, thoughtfully stroking the grizzled beard that covers his lean face. "It could just be a wooden fence."
To most people, roads connote progress. But Huijser sees asphalt as a challenge to surmount. One minute he's pointing out brush piles that allow rodents to navigate the overpass, and the next he's describing his vision for modular bridges that can be relocated to accommodate new migration routes as climate change pushes species northward.
Huijser's passion derives from his native Netherlands, where infrastructure is both a threat to wildlife and a tool for conservation. In the Netherlands – a country that has just one-ninth the landmass of Montana, and almost 17 times as many people – preserving wildlife has become an urgent, and necessarily urban, task. The nation boasts over 600 wildlife crossings, including the world's largest, the half-mile long Natuurbrug Zanderij Crailoo, which spans a railway, a sports complex and a business park.
Road ecology was an obvious choice when Huijser sought a wildlife research focus in the '90s in the Netherlands. In a place where bears and wolves have been extinct for centuries, that meant sweating the small stuff: specifically Erinaceus europaeus, the European hedgehog, dying by the hundreds of thousands on Dutch roads. Huijser's research revealed that planners could prevent hog-kill by building crossings at hedgehogs' favorite territory: the margins between forests and grasslands. "One of my statements during my Ph.D. defense was that they're really edgehogs," he says, sheepish at the pun.
In 1998, at a Florida conference on – what else? – road ecology, Huijser met Bethanie Walder, now his wife and, until recently, public lands director for a New Mexico-based conservation group, WildEarth Guardians. In 2002, he relocated to Missoula for a job with Montana State University's Western Transportation Institute (WTI) and discovered that U.S. agencies had different priorities than European ones – primarily reducing collisions with the large, common animals that frequently damage cars and injure people.
That's important, of course: Huijser has shown that wildlife crossings often pay for themselves by reducing crash expenses. But the focus on collisions often neglects the needs of small or rare species. Because deer use underpasses while grizzlies prefer overpasses, for instance, an ungulate-centric approach doesn't help threatened bears. "If you took a conservation perspective," Huijser explains, "you'd design structures of different type, dimensions and location."
The U.S. 93 project takes such a perspective – thanks largely to the tribes, whose legal muscle and concern for wildlife led to crossings being incorporated in state plans to widen the highway through the Flathead Indian Reservation. Huijser's camera-traps and track beds – groomed swaths of dirt that reveal hoof- and paw-prints – suggest the efforts are working. At least 20 different species have used the crossings, including bobcats, badgers and grizzlies. What's more, the structures have reduced crashes by at least 50 percent, suggesting that conservation and safety are compatible goals.
"That research is being used to justify projects across the West, around the country, and internationally," says Rob Ament, WTI's road ecology program manager. Huijser has consulted on Chinese and Mongolian highways, and last year published a study suggesting that Brazil (where he'll teach this fall) could profit from crossings for capybaras, enormous rodents that roam in herds and cause traffic fatalities.
Yet while he calls his cost-benefit studies his most important work, finance isn't his primary motivation. "We have to consider what it's worth to have animals on the landscape," Huijser says. "That hasn't been part of our economic analyses. But our well-being depends on having wildlife around us."
This story was funded by the Solutions Journalism Network.