Wildlife crossings cut down on roadkill

  • Overpasses like this one near Canmore, Alberta, help protect wildlife

    Bill Ruediger
  • A bear that didn't make it

    Phil Tanimoto photo
 

MISSOULA, Mont. - A radio-collared Canada lynx cautiously approaches the Trans-Canada Highway in Alberta's Bow River Valley. A large recreation vehicle rumbles into view. The cat hesitates, then nervously skitters back into the brush. About 50 yards from the roadside, it lies down for about a half hour before rising to make another attempt to cross.

If it's lucky, the lynx will make the crossing alive, though there's a good chance it will become a victim of this continent's most efficient predator - the automobile.

Each year, drivers kill millions of animals. Deer, squirrels, skunks and chipmunks are the most common victims; the toll also includes reptiles, amphibians, birds and rare and endangered species such as grizzly bears, wolves and lynx that roam large areas. In 1991, researchers estimated that more than half a million deer were killed along highways nationwide. Even in sparsely populated Montana, the state Department of Transportation counted 2,800 dead animals rotting along roadsides between Dec. 1, 1997 and May 31, 1998.

Highways also act as boundaries for many wildlife populations, fragmenting their habitat and creating problems with inbreeding.

"Real-life killing and hurting of animals goes on every day of the year on our roads," said Bill Ruediger, a Forest Service ecologist. "They're all being creamed."

A fractured landscape

Ruediger first became aware of the impact of roads on wildlife while working as the government's lead biologist on threatened animals.

"I started asking myself why mid-size carnivores are becoming less common, even after we stopped trapping them and started protecting them," he said. "I began thinking roads may be a big factor.

"You may have only one lynx for 25 to 50 square miles. Or a wolverine for 100 square miles. They must be able to cross the highway system in order to exist. We must begin looking at ways to make highways more permeable."

Even the Northern Rockies between Yellowstone and the Yukon, an area many ecologists say holds the last wildlands large enough to save dwindling carnivores like the grizzly and wolf, are riddled with dangerous road crossings. Far-ranging species face at least four highway crossings in Wyoming, 17 highways (including two interstates) in Idaho, 23 highways (including two interstates) in Montana, and 17 in British Columbia and Alberta.

Primary and secondary highways cover more than 2 percent of the lower 48 - an area the size of Georgia.

"Historically, (the federal highway system) has received exemptions from the environmental process," Ruediger said. "Once a road is in, it is assumed to be an indelible piece of the landscape."

That view is slowly changing across the West. In the past, funding for wildlife mitigation has been rare, says Paul Garrett, a biologist with the Federal Highway Administration. But this year, Congress approved up to $3 billion for wildlife mitigation projects.

In northwest Montana, Chris Servheen, the grizzly bear recovery coordinator for the U.S. Fish and Wildlife Service, hopes bears and Canada lynx will soon have safe passage from Glacier National Park south into the Bob Marshall Wilderness. Servheen's team of researchers will begin tracking radio-collared bears 24 hours a day, from the town of Essex east to the border of the Blackfeet Indian Reservation.

They hope the $200,000 study will show where and when bears prefer crossing roads - near streams, where vegetation is closest to the highway, or at night. The next step could be constructing a series of overpasses or underpasses along the highway.

"Hopefully, this is something we can do to get a handle on the train wreck instead of waiting for populations to become endangered or threatened," Servheen told the Great Falls Tribune.

Similar projects 200 miles to the north at Canada's Banff National Park are proving successful. Banff residents once referred to the Trans-Canada Highway in the Bow River Valley as the "meatmaker" because of the numbers of elk, wolves, deer and other animals killed in collisions there. In 1996, seven wolves died on that stretch of highway and two others were struck by trains.

Now, chain-link fences herd animals toward several underpasses and a 160-foot-wide overpass covered with soil and landscaped with shrubs.

So far, black bear, cougar, elk, pine marten - but no wolves or grizzlies yet - have used the $2 million overpass which was completed this spring, says Bruce Leeson of Parks Canada. Wolves have used the underpasses.

In other parts of the West, engineers have experimented with less costly ways to help wildlife cross highways.

In northeastern Utah, fences funnel animals to "deer crosswalks' along state routes 248, 32 and U.S. 40 near Park City. White stripes on the roads serve as visual cues for the deer and as warnings for motorists. Researchers estimate 175 deer per year were being hit by cars on one section of U.S. 40 before they installed the crosswalks. That number has dropped 40 percent.

Near the Ninepipes Reservoir on the Flathead Indian Reservation in northwest Montana, hundreds of painted turtles are smashed each summer as they cross Highway 93 (HCN, 10/13/97). Tribal officials are considering constructing "amphibian underpasses' beneath the highway. Similar tunnels have already cut down the number of smashed tortoises along one California desert road, as well as the number of toads killed along a busy highway outside Houston.

One Canadian biologist believes he has the ultimate solution to roadkill - just bury roads underground.

"If you want to relieve fragmentation and minimalize stimulus from human activity and vehicle traffic, sinking the road is the only way to go," says Brian Horesji (pronounced Hor-EE-see). Horesji suggests burying segments of road for at least a kilometer (about two-thirds of a mile) and planting vegetation on top. "In areas with historical movement or with segregated populations, you may want to bury the road for several miles.

"The cost is going to be more than a regular surface road, but no more than an elevated highway."

The writer works in Missoula, Montana.

You can contact ...

* Bill Ruediger at the Forest Service regional office in Missoula, 406/329-3100.

High Country News Classifieds