Crown High Reach

Deep within the northern Rocky Mountains, grizzly bears rest sleepily in cozy dens in the dead of winter. Meanwhile, a much smaller, bear-like creature is busy covering vast swaths of snow-blasted slopes, searching for scraps of corpses and bones of other, lesser creatures that have succumbed to the hardships of a mountain ecosystem. As the largest terrestrial member of the weasel family, wolverines are known for their stocky, muscular build and ferocious nature, character traits that come in handy when living in what 19th century naturalist George Bird Grinnell deemed the Crown of the Continent—a 10 million acre expanse of land that's one of the wildest places left in the lower-48 states.

"[The Crown] has every species of critter except for the free-roaming buffalo [and woodland caribou] that was here when Lewis and Clark came through the area, " says Gene Sentz, a conservation activist who co-founded Friends of the Rocky Mountain Front in 1977. "So it is a pretty spectacular area for wildlife habitat as well as scenery and heritage, history and so forth." ( See a slideshow of Gene's pictures ; listen to Gene talk about his work .)

A combination of U.S. Forest Service lands, national parks, tribal territories and private property, the Crown of the Continent links western Montana with southern Canada, encompassing some of the largest blocks of wilderness in the contiguous U.S., including Glacier National Park, the Bob Marshall Wilderness Complex in Montana and Waterton Lakes National Park in Alberta. As a fully functioning ecosystem, the Crown is home to nearly all of North America's large mammals, including the mountain lion, grizzly bear, lynx, gray wolf, elk and, of course, the wolverine.

In fact, the presence of wolverines in the Crown is a testament to the area's wildness.

"[The wolverine is] a species that really is a living symbol of the wilderness, " says Earthjustice attorney Tim Preso , whose work in the Northern Rockies office includes conservation and wildlife issues in the Crown. "If the place is not sufficiently wild, there will not be wolverines there." ( Listen to an interview with Tim Preso about wildlife in the Crown. )

Climate Change Consequences

In addition to a fierce attitude, the wolverine's physical attributes, like huge paws and thick, water-repellant fur, are well-suited for living in harsh, snow-capped mountains. Characteristics like these are what allow wolverines to survive sub-zero temperatures while scaling 1, 500-foot vertical climbs across ridgelines with daunting names like the Iceberg Notch. But tragically, the wolverine's very symbiosis and interdependence with its natural surroundings is also what makes it a modern-day canary in the coal mine for the impacts of climate change.

One example of how the species' interconnectedness with the Crown's ecosystem may lead to its ultimate demise is found in the female wolverine's reliance on deep snowpack for denning tunnels to raise her kits. Though some young wolverines may stay with their mothers until they reach adulthood, denning mothers will abandon these snowy hideaways if they melt early, even if the kits aren't ready to leave. In addition, a decreasing mountain snowpack caused by warmer winters simply makes it more difficult for wolverines to find suitable areas for denning.

"We think about the polar bear when we think about the poster child for climate change, and that's appropriate, but the wolverine is unfortunately in the same boat, " says Preso. "They're really dependent on areas that have maintained snow pack into the spring period and increasingly in the Rocky Mountains, that's a dwindling landscape."

Scientists believe that climate change is the single greatest threat to the wolverine, which is why in 2010 the U.S. Fish and Wildlife Service determined that wolverines warranted protection under the Endangered Species Act. The move followed a lawsuit by Earthjustice and its clients , which successfully argued that wolverines deserve protection due to their depleted numbers in the western United States and the threats posed to their habitat by climate change. Currently, fewer than 300 wolverines survive in the lower-48, and a recent study found that the breeding portion of that population amounts to just 35 individuals.

A Mountain of a Problem

Unfortunately, as the wolverine goes, so does the rest of the Crown. Though there have been many successes in preserving this ecosystem in years past, including a ban on oil and gas leasing in the Rocky Mountain Front, the Crown remains a living artifact of glacial activity, and as a result is particularly vulnerable to the changes wrought by warming climate.

Dan Fagre, a research ecologist at the Northern Rocky Mountain Science Center of the United States Geological Survey, has spent the last 15 years working to understand how climate change will affect mountain ecosystems like those found in the Crown. He says that the effects of warming are magnified by two to three times in this area's mountainous, snow-capped landscapes, a phenomenon that's mirrored in mountain ecosystems across the globe, which have warmed faster than lowland areas. ( Listen to an interview with Dan Fagre. )

The effects from this amplified warming can already be seen on the ground. One very visible impact of climate change can be found in Glacier National Park where scientists predict that climate change will melt all of the park's remaining glaciers by 2030. Though the loss of the glaciers themselves is tragic, their demise goes beyond aesthetics. For example, the survival of fish species like the bull trout, already threatened by habitat destruction and water pollution, depends on the cold, clear waters that glacier melt produces.

"I've seen just without pulling out photographs or maps each year the changes that occur [in Glacier]. Now when we go up to monitor the size of the glacier … we walk across rocks and land that has not been exposed to the atmosphere for probably 500 years, " says Fagre. "So, in a sense, we're kind of the first people to walk on that in many hundreds of years since it was covered by ice."