Railways pose several threats and obstacles to wildlife all over Canada. Animals often fall victim to collisions with trains, but also experience habitat degradation and loss due to rail tracks, become barred from reaching certain areas and other members of their species, and can even be endangered by the introduction of exotic species by trains.
It is hard to establish the frequency and complete impact of train collisions with wildlife as such deaths are less visible and less studied than roadkill. Roadkill does more damage to vehicles than railway deaths do to trains, so roads have attracted more attention and study. However, we know that the impact of trains is severe for both large mammals and smaller animals attempting to cross the tracks. Tracks constitute an attractive area to large mammals looking for food, such as bears, which have been found through isotope hair analyses to feed on carcasses of run-over animals or eating plants that grow on the railway verges . Trains can also spill grain as they pass through forests at high speeds, turning tracks into an inviting buffet. Overall, elk and deer are some of the most common victims of Canadian trains. The black bear is the carnivore with the highest mortality due to railway traffic, with an estimated higher number of collisions than with cars on highways. In British Columbia, 13 black bears were killed on a 15 km railway section between 1994 and 1996. Another study in British Columbia has found that the annual loss of moose alone to train collisions in the winters between 1969 and 1982 ranged from several hundred to more than a thousand animals.
Smaller mammals, amphibians, and reptiles collide with trains while resting or crossing tracks. Birds such as owls often become disoriented by train lights and are hit. They are also commonly killed by electrocution, wire strikes, and rail entrapment, which may lead to slow death due to dehydration or hunger. Animals with low agility that struggle to overcome obstacles or that are susceptible to stress, such as box turtles, frogs, and toads, commonly become trapped in rail tracks.
In addition to directly killing animals through collisions and electrocution, railways contribute to barrier effects for wildlife. The tracks may become obstacles to small animals’ migration, while “traffic noise, vibrations, chemical pollution, and human presence can impact animal populations living close to railways”. The construction of a railway may cut a habitat in half, leading to habitat fragmentation, or degrade and even destroy parts of a habitat through soil and water pollution and soil erosion.
Lastly, pest species such as rats, mice, and even ants can become invasive when transported over long distances by human activity, including by trains.
Overall, researchers agree that more study is needed into both the harmful effects of railways to wildlife and possible mitigation measures. There are some common solutions that help curtail wildlife deaths and mitigate barrier effects, as well as habitat loss and fragmentation:
Natural passes such as culverts and tunnels, underpasses and overpasses, as well as barriers (trees, poles, etc.) and fencing near high-mortality spots.
Sound-signaling and warning systems similar to those in place to warn human travelers. Through associative learning, sharp sounds and flashing before trains approach can teach animals to connect the emergence of those signals with imminent danger.
Habitat management such as pruning to remove fruiting plants that can be attractive to wildlife; such measures, however, require regular maintenance.
Supplemental feeding stations that can be placed far from railways to influence animal movement in the opposite direction.
Targeted reduction of train speed at mortality hotspots and during migration periods.
Rail fastenings, rail dampers, under-sleeper pads, and noise barriers.
In southeastern BC, there is the highest mortality of subadult grizzly bears in the world. There are three main ways a subadult bear will die: the road, railway, and conflict with people. The road and rail account for about 50% of the mortality.
Dr. Clayton Lamb, Research Scientist Biodiversity Pathways