As traffic increases, crossing Highway 2 is tougher for critters
A river otter hides in the reeds of a slough along Highway 2. With increased traffic on the road, crossing is becoming more difficult.
As the U.S. Highway 2 corridor gets busier, biologists from Glacier National Park and the U.S. Geological Survey are working to create maps that identify places where critters most commonly cross the highway, so that when future road improvements are made, wildlife crossings could be added.
This summer through a grant from the Glacier National Park Conservancy, biologist Brad Anderson has been gathering data on the wildlife crossings along the highway, from Route 206 all the way to East Glacier Park. While previous studies have looked at keystone creatures like grizzly bears, not much was known about where other, less studied species, cross the road.
Anderson gathered data of wildlife sightings by humans in a variety of ways — open houses, a booth at the fair, road kill reports, even knocking on doors at local businesses. The study also used trail camera footage from game trails that were known to cross the road.
All told, he gathered some 375 observations. Not surprisingly, deer and elk were the most noted species people saw crossing the road, but more than a dozen wolves have been sighted recently and a surprising number of beavers, often unsuccessfully, cross the highway as well.
Highways can have a huge impact on wildlife. Nationwide, 71 million acres of wildlife habitat have been lost to primary highways. But creating crossings, even on busy roads, has been proven to work.
On Highway 93 through the Confederated Salish and Kootenai Tribes Reservation, crossing structures along the Highway 93 corridor have resulted in a 70 to 80 percent drop in car-animal collisions.
In Banff National Park in Canada, a crossing there dropped elk kills from an average of 100 per year to zero.
Locally, the House of Mystery curve has the highest reports of roadkills.
The work being done today dovetails into a previous study done by park biologist John Waller, that looked at grizzly bear crossings in the corridor and traffic. That study, Waller noted, found that when traffic levels reached about 100 cars per hour, grizzlies simply didn’t cross the road.
Today, Highway 2 during peak traffic is seeing about 130 cars per hour. At night, however, that number drops to almost zero. But as the valley’s population grows, the crossing window is diminishing as there’s more traffic on the road at all hours of the day.
The idea of the study is to have wildlife crossings built into future design plans for the corridor. Trying to engineer them into a study after the fact is expensive. Some crossings are relatively inexpensive. Fences combined with oversized culverts, for example, have proven effective on other roads.
In some places in Canada, wildlife crossings are even built over the highway.