Wildlife Corridors that Work

In Canada’s Banff National Park, animals traverse the Trans-Canada Highway via 22 underpasses and two overpasses. These are among the oldest wildlife corridors on the North American continent. And they work. Estimates are that the overpasses and underpasses have cut roadkill on Highway 22 by as much as 96%.



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The success of these bridges has led engineers to plan over- and underpasses in other states. An overpass is planned on Highway 70 near Vail in Colorado and on Interstate 90 east of Snoqualmie Pass in Washington’s Cascade Mountains, as well as in Utah and Florida. Two amphibian tunnels in Massachusetts allow spotted salamanders to move from their breeding grounds to higher habitat. In Arizona, construction is underway on State Route 260 to build 11 underpasses, and six bridges over streams. Already, research shows that the underpasses and the fencing that funnel elk to the underpasses have made SR 260 much safer for both elk and people: Elk versus vehicle collisions dropped 85% in the first year fencing was erected on a section of the highway, and the reduction in accidents has saved almost $1 million per year.

Larger pieces of land that form corridors between protected areas are the focus of intense research, mapping and planning. The Pinhook Swamp, for example, connects the wetlands of the Okefenokee National Wildlife Refuge in southern Georgia with the pine flatwoods and cypress swamps of the Osceola National Forest in northern Florida.

“Pinhook is a vital travel route for Osceola’s population of Florida black bear, a subspecies that is considered threatened in the Sunshine State,” writes Jessica Sachs in National Wildlife. “It’s the largest protected wildlife corridor east of the Mississippi River.”

Pinhook is also critical for the threatened flatwoods salamander and countless insects, worms and mollusks. “Drain even 100 yards of swamp and you’ve thrown up a roadblock between populations of amphibians and invertebrates on either side,” says U.S. Forest Service Biologist David Dorman.

In Wyoming, efforts are underway to fully protect the Path of the Pronghorn, a migration route from Grand Teton National Park to the upper Green River Basin in western Wyoming. This 350-mile round-trip is the longest migration of any land species living between central Canada and Tierra del Fuego. The route has been used by pronghorn, a species of antelope, for 6,000 years. It passes from the protected park through mainly BLM and Forest Service land (about 92% of the route) and crosses some private land (about 8%). “The BLM lands are open lands subject to a multitude of uses, and the Forest Service lands are not specifically protected,” points out Joel Berger, from the Wildlife Conservation Society. “Any industrialization of these lands must be approved in advance from the Forest Service.”

Two current corridors for jaguars are operating between Mexico and Arizona and New Mexico, in desert country that is largely uninhabited and with only a few roads. A jaguar was first spotted in Arizona in 1996, when scientists realized that the beautiful animals were crossing the U.S.–Mexico border. The Wildlands Project has mapped the corridors and is helping to raise the funds to buy some of the ranches in the northernmost jaguar breeding grounds in Sonora. The key to protection is also the presence of people in the region working to protect the jaguars. Staff members of Mexican NGOs, like Naturalia are providing incentives to local people for maintaining wildlife habitat for jaguars. Such incentives are already working. Cowboys and ranchers in the core breeding area are being paid to photograph the large cats with camera “traps.” This corridor is threatened, however, by the U.S. Department of Homeland Security’s planned construction of a fence along the border. More than 40 organizations have signed a letter to Congress and Homeland Security requesting a halt to construction of the fence, insisting that security operations comply with national environmental laws.

Corridors are planned or in existence throughout the world. The Netherlands contains over 600 wildlife underpasses and ecoducts that have been used to protect wild boar, red deer, roe deer and the endangered European badger. In India, a 37-mile-long, six-mile-wide corridor connects important tiger habitats in the Eastern Himalaya and the Western Ghats mountain ranges.

Dedicated groups in North America and throughout the world have been working for years on protecting wildlife corridors with painstaking research, mapping and on-the-ground negotiations with private landowners and state and federal agencies. In North America, the Wildlands Project, Yellowstone to Yukon and the Wildlife Conservation Society are among many organizations working hard to develop corridors and to publicize the need for them. Please consider giving them your support.