Griz DNA study results released
By CHRIS PETERSON / Hungry Horse News
From Canada to nearly Missoula, a huge swath of land along the Rocky Mountains is known as the Northern Continental Divide Ecosystem.
That ecosystem, which includes all of Glacier National Park, the Bob Marshall Wilderness Complex and millions of acres more of private and public lands, has about 765 grizzly bears, a scientist with the U.S. Geological Survey announced Tuesday.
Biologist Katherine Kendall and a small army of staffers and volunteers embarked on an ambitious DNA project in 2003-04 with the goal of counting grizzlies in an unique and non-invasive way: By capturing their hair in barbed wire.
There are two ways to accomplish this, Kendall noted. One is to create bear "traps" where barbed wired is strung in a rough square between trees. A foul juice made up of rotten fish and cows' blood is then put in the center of the square on some wood.
Bears being bears, they love the smell of rotten stuff and so they're attracted to the area. When they come to sniff the scent, they go through the barbed wire, leaving their hair, and DNA, behind.
The second method took advantage of a common bear trait — rubbing on trees. Bears have select trees in the forest they like to scratch on. By placing a small piece of barbed wired on the tree, bears that scratch leave hair behind on the wire.
All told, in the summer of 2004, they used 2,200 gallons of lure and gathered 34,000 separate bear hair samples and volunteers and staffers hiked some 18,000 miles, over the course of about two months, covering some 7.8 million acres of Montana real estate.
It took about two-and-a-half years to complete the genetic analysis. The entire project cost about $3 million and included a host of cooperating agencies from state, tribal and federal governments, as well as many private landowners and ranchers. The population estimate does have a plus and minus margin of error. On the low size, the estimate is 715 bears and on the upper end, 831 bears. Even so, that's not a lot of grizzlies, considering they're spread out over millions of acres.
The study does not mean grizzly bears in the NCDE will be taken off the Endangered Species List any time soon. It simply provides a baseline count of where grizzly bear populations were in 2004. To delist the bears, a host of criteria must still be met, including a trend monitoring study that will examine whether bear populations are increasing or decreasing.
In 2004, for example, it was a bad year for grizzly bears and human-caused female grizzly bear mortality was twice the sustainable rate, Kendall noted.
There have been bad years since then. In 2007, for example, at least 35 grizzlies were killed by humans in the NCDE.
Kendall said the one of her main concerns in sustaining grizzly bear populations in the ecosystem is the fracturing of the landscape by human development. As more humans subdivide bear habitat, the bears get into garbage and other attractants and then end up in trouble — and many times are killed.
Where grizzlies are free to roam without running into human habitation, they do pretty well. Since 1999, there has only been one human-caused grizzly mortality in Glacier National Park. The Park has strict garbage protocols and is mostly wilderness. Hunting in the park is also illegal and it's heavily patrolled by law enforcement.
There's still work to do with this study. The effort also gathered thousands of black bear samples. Kendall is currently working on a population estimate of black bears in Glacier Park. She also is working on a population estimate of grizzly bear in Glacier Park as well.