Wildlife crossings reconnnect habitats, allowing animals to cross roads safely. They are widely used in Europe, where efforts to protect wildlife have involved underpasses, amphibian tunnels, and tunnels for small mammals such as otters, hedgehogs, and badgers. The Humane Society reports that the more than 600 tunnels installed under both major and minor roads in the Netherlands have helped to substantially increase population levels of the endangered European badger.

State Route 46 was elevated over this bear underpass so crossing animals could clearly see from one side of the road to the other. Notice the fences on either side of the crossing.

Benefits

Reversing habitat fragmentation is especially important for migratory animals and those with large home ranges, according to Earth Ministry (http://www.earthministry.org/3e/pmap/wildcorridors.htm). Larger habitats support greater biodiversity, larger populations, and a wider range of food sources and shelter. They also allow populations to interbreed, improving long-term genetic viability.

Practical considerations

Evidence shows that placement of the structures is critical, since animals will not use passages that are not placed along existing habitat corridors. Carnivores prefer structures close to major drainages and tend to avoid crossings close to town or with high levels of human activity. Well-maintained fences along the highway rights-of-way are critical to guiding wildlife to the structures while restricting their access to the highway itself.

Research shows that individual animals require time to adjust to wildlife crossings. For instance, a study by the University of Calgary suggests the animal overpasses in Banff National Park are not yet helping the animals most in need of protection. Parks Canada spent millions building special animal overpasses and underpasses so animals could cross the highway safely. Roadkill numbers are down and deer and elk use them regularly. But UC researchers say bears and wolves are not using them and are still getting hit.

See also

• Road fauna
• Wildlife corridor

Sources

• Critter Crossings (http://www.fhwa.dot.gov/environment/wildlifecrossings/) by the Federal Highway Administration.
• Earth Ministry (http://www.earthministry.org/3e/pmap/wildcorridors.htm)
• Wildlife Crossings—Wild Animals and Roads (http://www.hsus.org/ace/16206) by the Humane Society.
• Factors affecting the permeability of wildlife passages in Banff National Park, Alberta, Canada. (http://abstracts.co.allenpress.com/pweb/esa2000/abstracts/ANT-3-83-12.html) WALTHO, N. (York University, York, Ontario, M3J 1P3, Canada); A.P.CLEVENGER (University of Calgary, Calgary, Alberta, T2N 1N4, Canada); K.GUNSON and B.CHRUSZCZ (Parks Canada, Banff, Alberta, T0L 0C0, Canada)
• Wildlife crossings cut down on roadkill (http://www.hcn.org/servlets/hcn.Article?article_id=4624) by Mark Matthews, HighCountryNews.org (http://www.hcn.org/index.jsp).