Wildlife Bridges offer deer, antelope safe passage over highways

From the Wyoming Tribute Eagle, Nov 7, 2014:


A herd of eight pronghorn antelope mosey over a bridge.

From their perspective, the bridge’s surface looks just like the prairie on either side of the span. Thanks to the 4-foot high berms on the edge of the 150-foot-wide overpass, the pronghorn show no sign of awareness of the highway traffic below.

This wildlife overpass, located approximately 3 miles west of Pinedale, was one of two built by the Wyoming Department of Transportation in 2012.

Like an ordinary bridge, the arches spanning the highway are made of concrete, said WYDOT engineer John Eddins. However, the man-made surface is covered with 3 feet of dirt, topped with native vegetation.

“The shrubs and other vegetation are species that are most palatable to wildlife,” Eddins said. “By contrast, in the area next to the highway where we don’t want wildlife, the vegetation consists of the least palatable species.”

In addition to these overpasses, six underpasses for wildlife were built to go under U.S. Highway 189/191 in a 12-mile stretch in the vicinity of Trapper’s Point between Bonderant and Pinedale. And 13 miles of 8-foot high fencing keeps wildlife off the highway.

Hall Sawyer, a research scientist with Western EcoSystems Technology, Inc. of Cheyenne, has been keeping track of wildlife activity on these passages using motion-activated cameras.

From October 2012 through December 2013, at least 36,071 mule deer and pronghorn have moved through the new crossings. Final numbers will be available later in 2015 following the final year of the study.

“Pronghorn tend to use the overpasses more than the underpasses,” Hall said. “This isn’t surprising since we’ve found elsewhere that they don’t tend to go into the enclosed space of the underpasses. Mule deer readily use both underpasses and overpasses.”


Read more: http://www.wyomingnews.com/things_to_do/wildlife-bridges-offer-deer-antelope-safe-passage-over-highways/article_292a60f5-322f-56d0-a9d4-0fc4c41259fe.html

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