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Roads are everywhere in Canada. They connect communities and are integral to the daily function of Canadian society. Canada has over a million kilometres of roads and their impacts on the natural environment are considerable. For the average Canadian, many road-related impacts may go largely unnoticed. Road ecology is the study of the impact of roads on the natural world.
Despite a myriad of road related impacts, there are three major ways in which animals are negatively impacted by roads:
Animals are killed or injured in vehicle collisions
Habitat is degraded or lost when roads are constructed
Roads can create a barrier, preventing animals from moving across the landscape
Every year, more than a million large mammals are killed on North American roads. In Canada, an estimated 14 million birds die from roadway collisions every year. In Southeastern Ontario, scientists have estimated that a 37 km section of highway kills an average of 75 vertebrates (birds, mammals, reptiles, and amphibians) daily and over 16,000 animals annually.
Across Canada, a variety of species are especially vulnerable to road mortalities. In particular, animals that reproduce slowly and require large habitats are most at risk. In southeastern B.C., for example, roads are a major source of mortality for grizzly bears. Grizzly bears generally only raise one or two cubs a year so only a handful of deaths each year can have significant impacts on the population. Smaller animals such as amphibians and reptiles are often unafraid of vehicles or the roadway, and as a result they are among the most commonly killed animals on Canadian roadways. Road mortality is especially concerning for those species that are currently at risk of extinction in Canada. For example, the Blanding’s turtle is a medium-sized, long-lived turtle found in the Great Lakes region and Nova Scotia. Roads and their associated mortality present a major threat to the continued persistence of this species in Canada.
Roads destroy and degrade habitat in a variety of ways. Light, noise, and chemical pollution associated with roads impact numerous species of Canadian wildlife. For example, a widespread chemical preservative in the rubber of car tires was responsible for the death of thousands of coho salmon in Washington State, just south of British Columbia. A vast mix of chemicals are continually introduced into our environment as a result of roads and vehicles. Similarly, roads contribute significant light and noise pollution which potentially interferes with the behaviors and survival of countless Canadian wildlife species. In Newfoundland, researchers have documented hundreds of stranded young Atlantic Puffins on roadways. These young birds become disoriented by the light pollution of the road and without the help of wildlife volunteers, they may not successfully return to the ocean.
Disruption of Connectivity
Across the nation, roads and especially high traffic highways present major obstacles to animal movement. When traffic volumes rise, certain species of large mammals cannot cross the highway. For wide ranging carnivores such as wolverines in Western Canada, researchers have even discovered genetic differences in animals on either side of a major highway. Without movement across highways, wildlife populations can become isolated, inbred, and more likely to go extinct. Similarly, migratory animals must access a variety of habitats across the landscape. If roads prevent them from accessing important feeding or breeding areas, their populations may not persist.
To minimize the negative impacts of roadway, transportation and government agencies have introduced a variety of wildlife-friendly infrastructure projects. The most basic projects involve roadside signage that warns drivers of the possible presence of wildlife, encouraging them to slow down. While this form of wildlife signage is common across Canada, studies have shown that signage is unlikely to decrease the occurrence of wildlife vehicle collisions.
To significantly reduce the occurrence of wildlife vehicle collisions, transportation agencies can install wildlife fencing that prevents animals from accessing the road. For example, research shows that wildlife fencing successfully prevents between 85 to 95 vehicle and wildlife collisions for large mammals. Wildlife underpasses and overpasses are pieces of green infrastructure that allow animals to safely pass under and over the roadway. When taken all together, wildlife fencing, underpasses and overpasses significantly mitigate wildlife mortality while also creating successful movement corridors so animals can access important habitats. Compared to the immense cost of building and maintaining roadways in Canada, the cost of wildlife infrastructure is relatively low. In fact, studies have shown that strategically placed wildlife infrastructure can save governments money in the long run. By preventing wildlife vehicle collisions, the real economic costs of vehicle, human and wildlife damage can offset the price of the infrastructure in only a couple of decades.
Wildlife Collision Prevention Program
The Wildlife Collision Prevention Program (WCPP) is an organization that strives to reduce wildlife vehicle collisions through public outreach and education.
To reduce the risk of collisions, the WCPP provides extensive education material on their website and in public outreach. For example, the WCCP suggests that motorists reduce their vehicle speed when they see a wildlife warning sign. The decrease of speed increases drivers' ability to steer, reduces their stopping distance, and decreases the force of impact in the event of collision.
By learning about the wildlife in the area and their activities patterns (e.g., more active at dawn and dusk), motorists can drive defensively, and plan to travel during less risky times of the day.
“Roads really constrain our lives and have significant noise and air pollution impacts on humans too. Just as roads are destroying the lives of wild creatures, they're destroying their own lives as well."
Ben Goldfarb, Journalist and Author