"This raises an important question for the National Park Service: Is it okay for a species to go extinct in a national park?" Weber asks.
National Parks aren't designated to protect wildlife, but today they've become reservoirs of biodiversity," said Kim Berger, an Idaho-based biologist with WCS who is studying the pronghorn and their predators. "Part of what we hope to do in the parks is preserve intact ecosystems. Loss of the pronghorn would compromise that ecosystem."
Protecting Corridors
To protect the pronghorn, biologists must preserve their migration routes. The animals summer high in the mountains within the national park. But once fall comes, they must move to lower elevation areas that receive less snow in order to survive. Those that are trapped in the park over the winter usually perish.
These animals are movers," said Franz Camenzind, executive director if the Jackson Hole Conservation Alliance. Their survival strategy is to outrun predators—which they can't do in deep snow."
"If they lose that migration route, they will go extinct," said Steven Cain, acting chief of science and resource management for Grand Teton National Park. "There's a high premium on protecting that route."
Over the last few years, biologists have identified problem areas. New subdivision development, more roadways, and booming oil and gas development are either blocking the historic migration route or creating bottlenecks.
Fences pose a huge problem for the antelope—they will crawl under, but few will leap them. In some places, pronghorns must walk down the street through newly-built residential areas south of Bridger-Teton National Forest. "We're changing their habitat faster than (the pronghorn) can change," Camenzind says.
Coyotes and Wolves
To track the fate of young antelope, Berger and her biologist husband, Joel Berger, radio collared 38 fawns last summer. "We had about 85 percent mortality," said Berger. When they recovered the carcasses, they found that most were killed by coyotes.
The coyote predation may come partly from an ecological domino effect that scientists call the "mesapredator release hypothesis."
By the 1930's, Berger explains, the area's top predator, the gray wolf, was gone from the region. That allowed the coyote to move in and take over their niche. Wolves tend to eat larger prey, like elk—but coyotes prey on young antelope.
In a celebrated program, wolves were reintroduced to Yellowstone in 1995. They are now recolonizing Grand Teton National Park.
Will they push coyotes back and ease pressure on pronghorns?" questions Weber. For the next two years, the Bergers will try to answer that question by studying wolves and coyotes—and how their ecological reorganization affects the pronghorn.
Preserving an Ecosystem
Other factors may also be speeding the pronghorns decline, including disease as well as changes in habitat and climate.
The scientists want to develop a management plan that keeps the pronghorn migration corridor open—which will require cooperation of federal, state and local agencies and private landowners.
Besides preserving this unique migratory event—one of only 29 such migrations which are imperiled worldwide—Berger hopes her research will help protect the web of life that thrives in that corner of Wyoming.
"This is one of the last intact temperate ecosystems," said Berger. "There are very few places left where you have a full assemblage of mammals. We want it to survive."
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