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.
Wyoming is no exception. There the researchers found nearly 3,800 miles of fences in their study area alone — twice the length of the U.S.-Mexico border. Their research tracked GPS-collared pronghorn (Antilocapra americana) and mule deer (Odocoileus hemionus) during two years of their migrations to better understand how fences affect the animals’ movements and which kinds of fences may be most difficult.
Fences aren’t always bad for wildlife — some can keep animals off roads, for instance — but they can also pose threats.
For animals like pronghorn and mule deer, fences can halt or change migration routes. Animals that attempt to go over or under also risk becoming entangled and perishing. Juveniles are particularly at risk. A 2005 Utah State University study of ungulate migration across Colorado and Utah found the youngsters died in fences 8 times more often than adults. Many others died of starvation or predation when they weren’t able to cross fences and were separated from their mothers.
The Big Threat of Fences Across the West • The Revelator
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.
Wyoming is no exception. There the researchers found nearly 3,800 miles of fences in their study area alone — twice the length of the U.S.-Mexico border. Their research tracked GPS-collared pronghorn (Antilocapra americana) and mule deer (Odocoileus hemionus) during two years of their migrations to better understand how fences affect the animals’ movements and which kinds of fences may be most difficult.
Fences aren’t always bad for wildlife — some can keep animals off roads, for instance — but they can also pose threats.
For animals like pronghorn and mule deer, fences can halt or change migration routes. Animals that attempt to go over or under also risk becoming entangled and perishing. Juveniles are particularly at risk. A 2005 Utah State University study of ungulate migration across Colorado and Utah found the youngsters died in fences 8 times more often than adults. Many others died of starvation or predation when they weren’t able to cross fences and were separated from their mothers.
The Big Threat of Fences Across the West • The Revelator