It’s spring: time for migratory pronghorn to leave the Green River Basin for their more verdant summer habitat to the north, but not without encountering “bottlenecks” along the way.
The definition of the geographic pinchpoints is straightforward: A “bottleneck” is any portion of migration corridor where “animals are significantly physically or behaviorally altered,” according to Wyoming’s migration policy.
As the herds drop off the Hoback Rim, the fleet-footed tawny-and-white ungulates hit the “Noble Basin Bottleneck.” It’s a strip of land, primarily on privately deeded ground, where the forest closes in on the open country pronghorn prefer.
To the northeast, another segment of the migratory Sublette Pronghorn Herd bound for Jackson Hole via the Gros Ventre River drainage faces the “Kendall Bottleneck.” There, the animals encounter a “very tight restriction between a dense residential subdivision that includes many fences and forested habitat to the west that is not preferred by migrating antelope.”
Those details about the Sublette Pronghorn Herd’s migrations, which are at “high risk” of being lost, come from the Wyoming Game and Fish Department’s recently completed 140-page “biological risk and opportunity assessment.” It’s the next step in the effort to designate and protect the historically significant “Path of the Pronghorn” migration, a process that Wyoming wildlife managers have been navigating for over six years.
The assessment examined one of the “most data-rich ungulate populations in the world,” and put some numbers and analysis to the landscape that the massive pronghorn herd depends on for survival. Biologists, for example, detailed how there are 13 bottlenecks within the Sublette pronghorn migration corridor. Although they take up the least amount of land within the 2.6-million-acre corridor at just 27,375 acres, nearly half of bottlenecks occur on private land. That’s important because private land is exempted from restrictions imposed by Wyoming’s migration policy.
“Bottlenecks, some of them were just ideal areas for private land ownership during the settlement era,” said Doug Brimeyer, a recently promoted Game and Fish deputy director. “People selected those kinds of habitats.”
A century-plus later, a herd of 20,000-plus pronghorn still recovering from a harrowing winter are passing through the same places. If access further diminishes, it’d be an enormous blow: Some 75% of the herd is migratory, according to Game and Fish.
Brimeyer knows the Sublette Pronghorn Herd’s migration routes and the threats they face about as well as anybody. As a Game and Fish biologist in July 1998, he fitted GPS collars onto pronghorn in Grand Teton National Park. Long before Wyoming even had a migration policy, movement data from that work and follow-up studies were used to justify a 2008 forest plan amendment that provided protections to the migration corridor, albeit only the portion on the Bridger-Teton National Forest.
Fast forward to the present, and Wyoming’s “risk assessment” provides a much more complete picture of what was protected on the national forest 17 years ago. There are even two new forest bottlenecks — one dubbed Bacon Creek and another Red Hills — that haven’t been mapped before, according to Meghan Riley, the Wyoming Outdoor Council’s wildlife program manager. That’s “significant,” she said, especially because the Bridger-Teton’s Forest Plan is up for revision.
Riley lauded Game and Fish’s exhaustive assessment. It was “pretty unflinching” in examining threats, she said, which were identified for the entire corridor and specifically for 10 different segments. Habitat fragmentation from residential development and the energy and mineral industries were at the top of the list, but threats were numerous and covered everything from cheatgrass incursion to highways and fences.
“I thought it was great the department made it clear that there are many things threatening connectivity for these animals,” Riley said, “and that you can’t protect the migration if you don’t address all of them.”
If it makes it the distance, the Sublette Herd’s migration would be the first pronghorn route designated under Wyoming’s new policy. Three mule deer corridors have been designated — for the Sublette, Platte Valley and Baggs herds — but all were completed prior to the state overhauling its process in response to industry concerns. The new designation process, being taken for its first spin, extends beyond the Wyoming Game and Fish Department’s purview. If the agency’s commission decides to recommend designation to Gov. Mark Gordon, and he’s on board, the state’s chief executive would then have to appoint an “area working group” consisting of county commissioners, hunting advocates, industry reps and others.
“The area working group will make a determination and deliver that to the governor,” Brimeyer said. “He’ll either formally designate, he’ll return with some recommendations to the department — then we might do some further refinement — or he can just reject that, and it’ll stay identified.”
First, however, steps remain within Game and Fish. The agency’s commission is expected to vote on the route’s formal designation at its July meeting in Evanston.
The public has a say in the matter, too. There are also several upcoming public meetings: One in Green River on April 9, Jackson on April 10 and Pinedale on April 15.
The Sublette pronghorn migration biological risk assessment is also open to comments through May 2. Wildlife officials are looking for any and all feedback, including about the 13 bottlenecks.
“We included [bottlenecks] in the risk assessment to get a take from our public,” Brimeyer said.
Noting portions of bottlenecks that might be high-priority for a conservation easement or highlighting existing land uses are the types of information that would be especially helpful, he said.
We need to protect this corridor, forever! Human population growth, our existence, directly conflicts with wildlife. Our existence should not trump wildlife, never or we lose.
Joshua, as much as you might hate to admit it, Human Beings ARE a part of nature. Some more than others. Our “existence” is not the problem.
Wildlife habitat and migration corridors should be protected to the best of our ability to include private land owners doing what they can. But I dont see anyone removing every sign of mankind from Jackson Hole Wyoming, for example, for the benefit of elk and other local and migrating animals. A fenced mini (or not so mini) ranch owned by the former presidents and CEOs of Multi National Corps, the World Bank, etc. are as much a hinderance as any sporadic drilling site.
Again, people need to do the best they can to “co-exist”.
We are an invasive species.