Frogs are the biggest victims of road kill. These 'ecopassages' help save them

·5-min read

Vehicle collision death — colloquially known as road kill — poses a great threat to species that share the space around infrastructure like roads and highways throughout Canada, especially frogs.

According to new research out of the University of Toronto, in Ontario alone, over one million critters are killed by collisions with vehicles every year, with the main victims being frogs. And while giving them a leg up, or under, the road through ecopassages and overpasses is the best way to help preserve some of these animals, not all Canadian provinces allot funding for such projects.

Nicole Regimbal is a fourth-year undergraduate student double majoring in ecology and evolutionary biology and environmental ethics at U of T. For her thesis, she examined years of data from the Toronto and Region Conservation Authority (TRCA) to understand which species of frogs were most vulnerable to road mortality.

We were focused on amphibians because they’re already experiencing the effects of biodiversity loss.

Some of the data Regimbal used was based on yearly surveys of rural highways north of the GTA, which were conducted between 2015–2019. They looked at the specific issues at locations where there were expectations of road mortality. The surveys involved field crews who walked road segments on a weekly basis to look for road kill to identify to their best ability. The surveys estimate there were over a million amphibians, reptiles, mammals and birds from habitats in and around these roads that are killed every year.

Regimbal found that the species of frogs most impacted by road collisions were the American toad, the green frog, the grey tree frog and the Northern leopard frog.

“We were focused on amphibians because they’re already experiencing the effects of biodiversity loss and they’re really impacted by road mortality,” she tells Yahoo Canada News. “Amphibians are bearing the brunt of it and it’s not something we really think about because they’re so small.”

Northern Leopard Frog sitting on a gravel path basking in the sun.
Northern Leopard Frog sitting on a gravel path basking in the sun.

Regimbal looked at a site that had three ecopassages, underground tunnels bordered by fences, which help species in the area safely cross under the infrastructure. By reviewing trail camera footage from inside the ecopassages, she found that almost all the amphibian species she was researching were using them, except the grey tree frog.

“That was OK because there were no reported mortalities at that site...we didn’t see any road mortalities for any of our species,” she says. “It’s effective and it’s being used by almost everyone.”

The thesis Regimbal worked on will now be used to inform TRCA’s recommendations for construction of ecopasses in the GTA.

It’s effective and it’s being used by almost everyone.

Jonathan Ruppert is a senior research scientist with the TRCA and an ecology and evolutionary biology professor at U of T who advised Regimbal on her thesis. He says in Ontario, these projects are generally funded by municipal or regional governments, and occasionally the provincial government. The TRCA will look for opportunities when regions do roadway resurfacing or expansion to put in ecopassages alongside that work.

“Often it’s cost effective to do it alongside when you’re already digging up a road,” he says. “It becomes cost prohibitive to do it after the fact.”

Other parts of the country are grappling with the high cost of such projects, despite a grim number of deaths amongst various species along roads and highways.

The Ryder Lake Amphibian Protection Project was launched in Chilliwack, B.C. in 2015. Along with surveying and education, the project also includes a toad tunnel and fencing to help with the frequent migration of amphibians from wetlands and ponds to forests so they can complete their life cycles. Along with funding from Environment and Climate Change Canada, the project heavily relied on donations of materials from a regional concrete business and other resources from a construction firm. Since its construction, 400 adult amphibians have used the tunnel, along with 200,000 juvenile toads.

Jesse Zeman, executive director of the B.C. Wildlife Federation, says the province of B.C., and particularly the Ministry of Transportation, doesn’t budget for these types of initiatives. He uses the village of Radium Hot Springs and the number of bighorn sheep that have been killed in the region by vehicles, as an example.

Construction on Highway 1 in the area has forced traffic to reroute through Kootenay National Park, resulting in a spike of vehicle collision deaths of mammals, like deer, in the area. Additionally, the population of big-horned sheep has been halved in the last 20 years — only about 120 of them remain. In the past, about 10 were being killed every year. Now the number is 20.

It’s cost effective to do it alongside when you’re already digging up a road.

Local residents are taking it upon themselves to fundraise by selling T-shirts for an overpass in the area, since the animals often are on or near the highway licking road salts or eating grass.

“The overarching challenge is that the Ministry of Transportation budget simply does not acknowledge or budget for wildlife movement,” Zeman says.

Banff was one of the first places in Canada to explore such a project. In 1996, the town built two wildlife overpasses, which cost $1.5 million each. By 2014, it had 38 wildlife underpasses and six wildlife overpasses.

Surveys found that more than 12 species use the structures, including wolves, bears, lynx and coyotes. The structures have helped the decline of wildlife-vehicle collision in the region by 80 per cent.

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