"The American West contains 620,000 miles of fencing, threatening the migration of pronghorn, mule deer and other species."
"With the arrival of spring each year, pronghorn that winter in the Upper Green River Valley of Wyoming begin a journey of more than 100 miles to their summer habitat near Grand Teton National Park.
It’s one of the longest migrations of large mammals remaining in North America. But their trek — and a similar one made by mule deer — is made more difficult by human developments along the way, particularly fences.
“The total length of fencing around the world may now exceed that of roads by an order of magnitude, and continues to grow due to a global trend towards land partition and privatization,” wrote researchers of new U.C. Berkeley-led study published in the Journal of Applied Ecology."