14 May 2009
Yellowstone’s Grizzly Bears Face Threats on Two Fronts
The magnificent creature at the heart of the Greater Yellowstone Ecosystem now confronts two grave perils: the loss of its key food source because of rising temperatures, and increased killing by humans. A renowned grizzly expert argues that it’s time to once again protect Yellowstone’s grizzlies under the Endangered Species Act.
The Yellowstone grizzly bear population is again in serious trouble. During 2008, the bears suffered a double disaster: Grizzlies died in record numbers, and global warming dealt what could be a death blow to the bear’s most important food source.
Some 54 grizzly bears — including 37 shot by humans — were known to have died in 2008, the highest mortality ever recorded; this number probably exceeds the extensive killings of 40 years ago when Yellowstone National Park closed down its garbage dumps and bears wandered into towns and campgrounds. The Yellowstone grizzly population sharply declined in the early 1970s and, consequently, the bear was listed as threatened under the Endangered Species Act in 1975.
Related to the high mortality of 2008 was the massive die off of whitebark pine trees, whose nuts are the bear’s principal fall food. Mountain pine beetles killed the trees; the warm winters of the past decade allowed the insects to move up the mountains into the higher whitebark pine forests.
How could this record mortality have happened? In April of 2007, the Department of Interior’s U. S. Fish and Wildlife Service removed Endangered Species Act protection for the Yellowstone grizzly bear. The agency’s decision to delist suggested that all was well with the great bear.
In 2008, hunters and other humans shot bears in record numbers. People
The quality of habitat for the grizzly is eroding because of warming temperatures.
killed grizzlies because they could — sadly, a not uncommon human attitude in the American West — and since Yellowstone’s grizzlies had been removed from the protection of the ESA listing, there were virtually no penalties for shooting them. Bear management had been turned over to fish and game agencies of Wyoming, Idaho and Montana who tend to accept any hunter explanation of self-defense in grizzly country. In short, the grizzlies were easy to kill because their lives were made less valuable by delisting.
“Known” mortality is, as a rule of thumb, generally about half of actual grizzly bears dead. A hundred dead bears per year, no matter if the total number in the ecosystem is 200 or 600, means the population is crashing downhill. This is especially true for the grizzly, one of the world’s slowest-reproducing mammals.
The reason the pine nuts are not available to grizzly bears is because the whitebark trees in the Yellowstone region have succumbed to global warming. Global warming was glossed over by Fish and Wildlife when they delisted the Yellowstone grizzly. But this, too, is not rocket science. Last fall behind my Montana house on the northern flank of the Greater Yellowstone Ecosystem, far up the mountain, the forest turned red. So did the tops of all the other mountain ranges in and around nearby Yellowstone park.
You could see it from the highways. The region’s whitebark pine trees surrendered to an invasive pine beetle on a scale of death none of us thought we’d ever see. And it happened so fast — not in decades but just a few years — that it took both concerned citizens and scientists by complete surprise.
The reason the trees died is because the winters warmed up during the last seven years and the mountain pine beetle, already active in the lower lodgepole pine forest, moved up a life zone into the whitebark and killed the trees. Nature controls the beetle by freezing the larva — cold temperatures of minus 30-35 degrees Fahrenheit for about five days in winter, depending on the thickness of the tree bark. It is well documented that good whitebark cone crops decrease grizzly mortality and increase the number of bear cubs per litter.
But whitebark pine in the Yellowstone park area is nearly gone: No amount of science or management will bring the trees back in our lifetime. With whitebark pine nuts eliminated from grizzly bear diets — and this seems to be the case — grizzlies in this island ecosystem will be severely stressed. The bears could be on their way out.
What does U. S. Fish and Wildlife, which is the lead agency for the Yellowstone Grizzly Coordinating Committee and the Interagency Grizzly Bear Study Team, have to say about the dead grizzlies and dying pine trees? On April 15, 2009, these agencies gathered in Bozeman, Mont. to discuss Yellowstone grizzly mortality. They call the alarming number of dead bears in Yellowstone a “spike,” which they would reduce by recommending better hunter education, use of bear spray as a deterrent, and opening a limited grizzly bear hunt in the three adjacent states. The committee coordinator Chris Servheen admitted that the 2008 mortality was the highest that had been seen, but pointed out that today’s grizzly population is larger than that of the early 1970s.
Mortality spikes are often tied to low whitebark pine cone production and the consensus was that human-caused bear mortality will drop when the number of cones per tree bounces back. Yet when pressed (by one of the handful of non-agency people, including myself, at the meeting) about the possible role of global warming on whitebark pine, team leader Chuck Schwartz reluctantly admitted the low production of pine nuts could be the beginning of a trend.
Frankly, it doesn’t matter how many cones grow on the surviving trees when 80 percent of the whitebark forest is already dead. No one brought
The agencies seem to believe it is the inalienable right of hunters to kill grizzlies whenever they feel the need or desire to.
this up. Nor was there the whisper of a suggestion that the removal of ESA protection for the Yellowstone grizzly had anything to do with the record number of bears shot. Nobody thought of asking the public, especially elk hunters, to take responsibility for causing these encounters with grizzlies or to give up anything in terms of hunting hours or access to reduce grizzly mortality (in my opinion, getting too close to a grizzly and precipitating a charge is always the fault of the human).
The agencies seem to believe it is the inalienable right of hunters to kill grizzlies whenever they feel the need or desire to. The possibility of returning the Yellowstone grizzly to the ESA protections is unthinkable to this group.
The Department of Interior’s principal public agency responsible for protecting Yellowstone’s grizzlies is currently incapable of doing so. The Interagency Team/Committee has become an insular institution deaf to public opinion; it has pandered to state game departments who speciously argue that “socially acceptable” local views should replace the best available science to determine where grizzlies may live.
With the quality of grizzly habitat eroding due to global warming, the bears will require more public land to roam. The most important single move government could make is to relist the bear immediately, and once more afford the Yellowstone grizzly protection under the ESA. Relisting alone will reduce the record human-caused mortality; the government’s proposals will not.
Yellowstone’s grizzly bears are in trouble — people are killing them off in record numbers and global warming is burning up the food they need to survive. The Secretary of the Interior needs to instruct the U. S. Fish and Wildlife Service to withdraw its rule delisting the Yellowstone grizzly bear population.
Whether the present Interagency Team or Committee is up to this task is another question — they fought for delisting in the face of undeniable threats to the bear’s future as a species. Fresh, outside leadership is urgently needed.
ABOUT THE AUTHOR
is an American naturalist and outdoorsman and author of Grizzly Years: In Search of the American Wilderness
, a memoir of his experiences observing grizzly bears. His other books include Walking It Off: A Veteran’s Chronicle of War And Wilderness
and The Essential Grizzly: The Mingled Fates of Men and Bears
, co-authored by his wife, Andrea Peacock.