For the 400-some Jackson Hole pronghorn migrating south over Trappers Point overpasses, traversing and wintering in developed gas fields is a fact of life.
The Pinedale Anticline Project Area and Jonah gas fields have been the most well-researched developments from a wildlife-impact standpoint. Now, a proposed 220-square-mile Encana project, called the Normally Pressured Lance field has biologists and conservationists turning their heads.The NPL field in Sublette County, currently being studied for approval by the Bureau of Land Management, overlaps both prime winter range and migration corridors for pronghorn, Wildlife Conservation Society biologist Renee Siedler said.
“Almost all of them are wintering, in an average winter, on the Pinedale Anticline Project Area,” Seidler said of the small Jackson Hole herd. “In a bad winter, it’s likely they then have to move through the Jonah or the proposed NPL. That’s what our data clearly shows.”
Because the precise location of winter range shifts year to year depending on weather, it’s difficult to pinpoint the implications of gas developments on pronghorn, Seidler said. The NPL project’s impacts to migration corridors are clearer, as shown by GPS data collected by Seidler and the Wildlife Conservation Society.