Fate of Yellowstone grizzly bears tied to moths
ravalliriepublic.com
A grizzly bear sow and her twin yearling cubs forage for food above
a moth site July 31 in the Shoshone National Forest near
Meeteetse, Wyo.
a moth site July 31 in the Shoshone National Forest near
Meeteetse, Wyo.
OUTSIDE OF MEETEETSE, Wyo. — High above the trees, in the rocky slopes of the Absarokas, one-calorie morsels scurried from the light. They crawled under rocks and in dark shadows.
The army cutworm moths come from as far as Kansas and Nebraska where farmers curse them as an agricultural pest. In the Absarokas, they're something very different: one of several key ingredients to the survival of the grizzly bear.
One day in late July, Cody science teacher Dale Ditolla watched as nine bears gathered in the talus of a mountain bowl, miles outside of Meeteetse.
The bears looked like dogs in search of buried bones. They lifted and heaved stones the size of frying pans between their legs, sending them tumbling down the mountainside. Their salad plate-sized paws swiped at scampering moths.
Counting multiple grizzlies at this site is a relatively new trend. Few lived in this part of Wyoming 30 years ago.
"It's amazing to me that a bear can live up here and survive and put on weight," Ditolla said.
The greater Yellowstone ecosystem's bears are hardy, making a living in the West's harshest conditions.
Their expansion into new regions comes as grizzlies may once again face removal from the endangered species list. Researchers already know grizzlies eat nearly everything from ants to fish to elk to snowmobile seats. What researchers don't know, and what keeps grizzlies on the list, is what key foods the bears need to survive.
King of the omnivores
A bear's diet generally varies by season. In the greater Yellowstone ecosystem, they eat big game, elk calves and cutthroat trout in the early summer; anything from moths to berries to grass in the summer; and a whitebark pine cone's fatty nuts in the fall, said Gary Beauvais, director of the Wyoming Natural Diversity Database, a research institute at the University of Wyoming specializing in sensitive species.
Cutthroat trout used to be a spring staple. Invasive lake trout drastically cut down the number of cutthroats, which may mean grizzlies are switching to eating more elk calves, he said.
But it is the future of the whitebark pine that keeps bears on the endangered species list.
Whitebark pine nuts give grizzlies a critical meal as they start to fatten up for hibernation. Researchers using radio collars found bears will spend weeks in whitebark pine forests looking for nuts and cones, Beauvais said.
That was until white pine blister rust and the mountain pine beetle devastated swaths of forest.
The U.S. Fish and Wildlife Service removed grizzlies from the endangered species list in 2007, but a federal judge put them back on the list in 2009, citing several concerns including the future of whitebark pine. An appeals court dismissed some of the concerns in 2011, but upheld the whitebark pine ruling. The U.S. Fish and Wildlife Service needed to know more about the tree's decline before grizzlies could be removed, the appeals court ruled.
Nut production on whitebark pine trees naturally cycles. During bad years, bears tend to move out of the high country looking for food. Game and Fish officials have already alerted hunters and backpackers about the possibility of more conflicts because production is limited this fall.
Conservationists worry about how grizzlies will behave with the tree's permanent loss, said Chris Colligan, wildlife program manager for the Greater Yellowstone Coalition, a Yellowstone-based conservation group that was involved in the 2009 relisting of grizzly bears.
"The concern is the increasing conflicts with humans that may be in part due to the loss of the primary food source," he said.
More conflicts mean more grizzly deaths.
The Interagency Grizzly Bear Study Team, a group of federal and state researchers, may have an answer by the end of October. They're also looking at such effects on grizzlies as changes in body fat or reproduction.
Officials with the Fish and Wildlife Service will then disseminate the team's information and decide whether it will propose a delisting, said Chris Servheen, the service's grizzly bear coordinator.
The feds hope to make a decision by early 2014, he said.
After a possible delisting
If grizzlies do come off the list, the federal government and states have a plan in place for their management, Servheen said.
"Delisting doesn't mean we throw our hands up and say, 'We're done, you do whatever you want now,'" he said. "I don't know what's going to happen in the future, but I do know we do have a system in place to respond to those changes if and when they occur."
Those changes include issues like a decline in whitebark pine or cutthroat trout.
The agreement also says only a certain number of bears can die each year from anything, including car accidents, natural death or hunting. If more than the allowed number dies for a certain number of years, bears could go back on the endangered species list, he said.
Unlike the gray wolf, which is managed individually by each state, Wyoming, Idaho and Montana would all work together to maintain one bear population.
Wyoming hunting season quotas would need to consider bear deaths in other states, said Brian Nesvik, chief of the Wyoming Game and Fish Department's wildlife division.
"All states would have the same skin in the game, and if any of the three states' management plan didn't support maintaining a population, all would suffer," he said.
Wyoming officials may discuss a grizzly bear hunting season if bears are delisted, but nothing has been decided, and it would be a slow and deliberate process, Nesvik said.
The season would be different than Wyoming's controversial wolf season, which started in 2012 with a goal of reducing the animal's population. Grizzlies give birth less frequently than wolves and have far fewer young.
Game and Fish officials believe allowing hunting could create advocates for the grizzly among sportsmen. It gives the public an opportunity to appreciate bears not just for their intrinsic natural value, but also for sport, said Dan Thompson, large carnivore section supervisor for the department.
Colligan, the wildlife program manager for the Greater Yellowstone Coalition, wants to maintain a level of public interest in grizzlies that doesn't exist with wolves. But he sees other avenues.
"People care about bears in a different way. We need to keep that," he said. "For us it leads to us reducing the conflicts that give bears a negative image. We need to find creative ways and find ways to partner with land management agencies to try and improve those conditions."
Artificial borders
Some animals in the United States will likely never leave the endangered species list. The Kendall Warm Springs dace, a fish with a natural habitat in about 300 yards of stream north of Pinedale, will probably always be protected because its home range is so tiny. The California condor also may never leave the list because of its limited numbers and slow reproductive rate, said Beauvais, the director of the Wyoming Natural Diversity Database.
Some species left the list long ago because they became extinct.
Grizzly bears are different. Their rebound is hailed as one of the great conservation success stories. Many people, managers and conservationists alike, agree one day grizzlies could be delisted in the greater Yellowstone ecosystem.
Unlike species such as the dace, managers aren't trying to preserve or improve the only habitat in which bears can live. Wildlife managers are trying to preserve the only place people will let grizzlies live, Beauvais said.
And conservationists worry if Yellowstone grizzlies cannot reach other isolated populations such as those in northern Montana, their recent successes will be short-term, Colligan said.
The Yellowstone ecosystem is an island with limited genetic diversity. Their ultimate survival may depend on each population's ability to reach the other, he said.
Historically, bears lived nearly everywhere. They wandered in the tundra, prairies, deserts and forests across the northern hemisphere, Beauvais said.
The Yellowstone ecosystem is, in fact, not ideal grizzly habitat.
"Grizzly bears live where we let them live," Beauvais said. "If you were to ask the grizzly bear, the Yellowstone plateau is pretty marginal habitat. They'd rather be out by the Missouri River eating winter kill bison and plums."
Whitebark pine and cutthroat trout weren't the key to grizzly bear survival worldwide. Grizzlies in the Black Hills, for example, never saw a whitebark pine tree or ate a cutthroat trout.
Even fewer lapped army cutworm moths from rocks in Wyoming's steepest terrain. But in the absence of a spot on the Missouri eating plums and bison, Yellowstone's grizzlies will continue to fill their bellies with moths, plants, elk and ants.
It remains to be seen if that will be enough.
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