New Tool Measures Road Traffic's Impact on Wildlife

by Elyse Tipton

September 25, 2009

Topics: Conservation | Road Ecology

For 10 years, Maine Audubon has led a charge to make roads less harmful to wildlife. Now our scientists have developed the "Traffic Volume Wildlife Tool" to help land-use and transportation experts make wildlife-friendly decisions about where to locate and upgrade roads and wildlife crossings.

Roads, traffic, and wildlife don’t mix well. Roads fragment and destroy habitat, contaminate it with chemicals, and create channels for invasive species to spread. Traffic, meanwhile, kills animals outright. Wildlife-vehicle collisions are the number-one human-caused killer of wildlife in the United States—and they kill and injure people, too.

While road width and traffic speed have an impact on wildlife, the most-significant threats are road location and traffic volume (number of vehicles using the road per day). The new tool identifies traffic-volume levels to assess the risks, at various levels, to groups of amphibians, reptiles, birds, and mammals. What volume of vehicles, for example, creates enough noise that breeding birds avoid grassland habitat near the road? What volume means, coyote, mink, shrew, weasel, fox, and bats will die when vehicles pass through wetland habitat daily? What level of traffic volume means turtles can’t cross a road to their feeding pond?

To create the Traffic Volume Wildlife Tool, Maine Audubon scientists Barbara Charry and Jody Jones used studies that measured road and traffic impacts to wildlife in a variety of habitats in North America and Europe. As climate change alters habitat and threatens wildlife, tools to keep habitats connected are critically important. Species "trapped" by roads will face extinction.

Charry, a wildlife biologist who is an expert in "road ecology," is presenting the tool this fall at the 2009 International Conference on Ecology and Transportation in Duluth, Minnesota, thanks to a fellowship grant awarded by TogetherGreen, a national collaboration of Audubon and Toyota.

For more information, please call (207) 781-2330, ext. 225.