Canada’s Overpasses Save Wildlife

When I was in Banff, Canada, my mind was a little bit blown by the highway overpasses.

What was different or special about them?

Well, they looked like any other overpasses, except they had lush green trees and other vegetation on top (not to mention, they were set against a striking mountain backdrop). These overpasses, I later learned, were designed as wildlife migration corridors.

What is important about wildlife corridors?

The overpasses reduce animal-vehicle collisions (good for both animals and people) and allow wildlife to move freely among otherwise isolated areas. This movement helps keep gene pools healthy, preventing issues like developmental deformities, reduced reproduction rates, and risk of extinction.

What was the initial reaction to the idea of building these overpasses for wildlife?

When construction of these wildlife bridges first began in 1966, the project was met with skepticism, criticism, and even mockery—a “harebrained” scheme, and a waste of taxpayer dollars.

What was the ultimate result – Success or failure?

But the data provides a strong case. These overpasses have reduced wildlife collisions with vehicles by more than 80%!

How do animals know to use the overpasses?
Well, for one thing, fencing is used to help funnel wildlife to the crossings. And some animals are earlier adopters than others. Deer and elk were the first to adopt in this case. For animals that are more wary, such as wolves or grizzly bears, it can take up to five years or more for them to use a new crossing.

One initial skepticism was that animals could even be coaxed into using manmade bridges. Yet, wildlife cameras show that a broad variety of animals, including elk, bear, and small mammals like marmots, beavers, and wolverines use the crossings regularly. Research also shows toads, salamanders and snakes are using the crossings.

Do all animals use the overpasses?

Nope! There is no single solution for all species. Grizzly bears and elk do tend to prefer the open sightlines of the overpasses. Meanwhile, camouflaged culverts, acting as wildlife underpasses, are favored by black bears and mountain lions who prefer long, low and narrow passage.

Do wildlife overpasses work elsewhere in world?

Banff and its wildlife corridors have become a global model for countries looking to reduce wildlife deaths along roadways. Biologists from countries like Belize, Argentina, and even Mongolia have visited Banff to learn more about implementing wildlife passageways. However, different species and ecosystems require different configurations, so continuous experimentation is needed to find what works best in each location.

The bottom line:
Human activity, like highway construction, increasingly fragments natural habitats and the wildlife populations within them. And that’s a serious problem. Wildlife corridors, in all their forms, help provide wildlife with an increased opportunity for long-term survival.

Sources:

• Animal over- and underpasses are a huge conservation success story!
• As Banff’s famed wildlife overpasses turn 20, the world looks to Canada for conservation inspiration

Photo by WikiPedant at Wikimedia Commons