The Plight of the Hungry Grizzly
The grizzly bear may soon be joining its polar bear cousin as a symbol of global warming's destructive impact. This is not encouraging news, of course, but there is one significant glimmer of hope: the U.S. Court of Appeals for the Ninth Circuit last November unanimously reasserted the animal's status as an endangered species. The court recognized that the Yellowstone grizzly population, which has been on the endangered list since 1975, is newly threatened by the decline of a primary food source, the whitebark pine, which itself faces extinction because of a warming climate.
The U.S. Fish and Wildlife Service had pushed to remove the bears from the endangered list because their numbers had rebounded. But "it's not just about numbers," says NRDC research associate Janet Barwick. "There must also be proper habitat and plentiful food sources."
The Greater Yellowstone Coalition challenged the delisting in federal court, with NRDC providing critical background related to the dire condition of whitebark pine in an amicus brief. The rapid disappearance of this crucial food source, the brief argued, poses a clear threat to grizzlies, which consume the trees' fatty, nutritious nuts. "The court agreed with us that Fish and Wildlife had not appropriately considered how much the loss of whitebark pine would affect the bear population," says Sylvia Fallon, NRDC's senior wildlife conservation scientist, who drafted the petition to list whitebark pine as endangered.
Whitebark pine faces two dire threats: from the mountain pine beetle, which is surviving at higher elevations because of warmer temperatures, and from the deadly pathogen known as blister rust, which originated in Asia but came to the United States from Europe. More than 80 percent of the tree's population in the Greater Yellowstone area have been afflicted by these scourges to a point beyond recovery, according to Fallon.
How to save the whitebark pine? Certain blister-rust resistant trees have been discovered and are being planted on affected landscapes. Volunteers from the Wyoming-based nonprofit TreeFight have been stapling small packets that release pheromones to any surviving pines; the pheromones falsely signal that a tree is already occupied by beetles, thereby preventing infestation. "We're glad that there are some restoration efforts under way, but the real issue here is climate change, so that's a tough one," Fallon says.
Whitebark pine nuts are one of several food sources for the grizzly bear, which is an omnivorous species. As the trees disappear, grizzlies must search for other food, often forcing them to lower elevations, where they are more likely to encounter humans, including hunters. As a result, grizzly mortality rates have already risen and could grow higher, particularly as the bears continue to move outside the confines of their core habitat in and around Yellowstone National Park.
"We need to ensure the bears' safety outside the park," explains Whitney Leonard, an NRDC wildlife advocate in Montana, "because bears are roaming farther to make up for that lost food source."
"Whitebark pine is an important food source. And yet grizzlies are also highly adaptable," says Andrew Wetzler, co-director of NRDC's land and wildlife program. "If we don't delist them and if we protect them from human conflict, there's reason to believe they'll recover." The prospects for whitebark pine, however, remain bleaker. "If we don't do anything to address global warming, it's very hard to see a future for this tree," Wetzler says.