Ten kilometres west of the Banff townsite, this is the first of six wildlife overpasses travellers will pass under as they make their way westward through Banff National Park. In the park are six overpasses and, well camouflaged and unnoticed by most visitors, 38 underpasses, for a total of 44 crossings. In the 1990s this section of the Trans Canada was widened at a cost of $400 million, a quarter of which was earmarked for wildlife protection. That money went to building over 180 kilometres of fence and the 44 crossings.
One of the great biological successes in recent times, the wildlife crossings in Banff National Park have proven effective in not only reducing, and in some cases even eliminating, animal mortality along the Trans Canada Highway as it passes through the park, but helping to maintain genetic health. While everyone from scientists to citizens was skeptical of their efficacy when built, two decades of study have shown that the crossings have been used by over 200,000 animals, ranging from grizzlies, elk and moose to toads, beaver and garter snakes.
The program has proven so successful that biologists from around the world now come to Banff to study the wildlife protection system implemented here, taking the knowledge back to their homelands to be used in creating their own systems.
From a distance, the grey cement bridge looks unremarkable. Two tunnels on either side of the Trans-Canada Highway arc in semi-circles that end bluntly on the pavement below. But on top, away from passing motorists’ eyes, lies a grassy oasis. Against the odds, pine trees and wildflowers have taken root here, giving the overpass a fringe of greenery. On the edges, wire fencing provides safe passage for roaming animals...
...Thirty kilometres west of the Banff townsite, he pulls over alongside another fence that runs all the way to the British Columbia border. Since the 1980s, the Canadian government has allotted more than $400 million to upgrade and twin the four-lane highway, with a quarter of the budget set aside for projects that would reduce wildlife collisions, a growing concern. Parks Canada decided they would use part of that money to fence the entire highway — roughly 180 kilometres — and construct several dozen wildlife crossing structures in hopes of lowering the mortality rate.
Michel opens a padlocked gate set into the fence and descends a steep, soggy embankment toward what looks like a drainage culvert along Redearth Creek. Signs warn us in bold typeface to keep out. At the bottom, the culvert reveals itself to be one of the park’s camouflaged wildlife underpasses. Black bears and mountain lions prefer to use these shadowy, damp tunnels, says Michel, whereas grizzlies and ungulates prefer the open sightlines offered by the overpasses.
In November, Parks Canada marked the 20th anniversary of the completion of the first wildlife overpass in Banff National Park. Though many biologists and citizens were skeptical of the wildlife bridges when they were first built, the six overpasses and 38 underpasses that criss-cross the Trans-Canada are today considered a worldwide conservation success story, reducing wildlife collisions by 80 per cent and buoying Banff biologists to rock-star status in the realm of transportation ecology. Delegations from around the world now visit Banff to learn more about their crossing structures in hopes of building similar systems in their home countries, where new roads are cutting through wilderness areas at unprecedented rates.
[Tony] Clevenger now has 17 years-worth of data proving the efficacy of the crossings. Among large carnivores, mortality rates are 50 to 100 per cent lower along sections of the highway where overpasses and underpasses exist. In those same sections, mortality rates for elk are almost zero, compared to 100 elk-vehicle collisions per year in the mid-1990s. Clevenger’s research has shown that 11 species of large mammals in Banff have used the structures more than 200,000 times, including unexpected species such as red fox, hoary marmot, boreal toads, wolverines, lynx, garter snakes and beavers.
In 2014, a Montana State University study found that not only are grizzly bears using the crossing structures, but the structures are also helping to maintain genetically healthy populations among the bears that use them. Grizzlies were crossing with enough frequency to ensure populations on either side of the highway weren’t genetically isolated from each other.
From Canadian Geographic