WEST GLACIER, Mont. (AP) -- An elaborate, two-year study has put a number for the first time on how many grizzly bears are in and around Glacier National Park: 437.
The study is the first in the United States to be based on genetic information. Researcher Kate Kendall of the U.S. Geological Survey deciphered the DNA of 2,961 hair samples from grizzlies to determine, among other things, species, gender and individual identity.
By her reckoning, there are about 332 grizzlies in Glacier's 1.2 million acres, and 437 in her study area of 2 million acres. That compares with an estimated 300 to 400 bears in the greater Yellowstone's 4 million acres.
And while it is impossible to set an exact grizzly count, she said statistical analysis of her data shows a 95 percent ''confidence interval'' that there are between 277 and 460 bears in Glacier and between 349 and 590 in the entire study area.
Kendall's estimate of 437 was developed through computer modeling, and it is higher than she expected.
''It will be very surprising to some people who thought there was a lot smaller population,'' she said.
''The bears in Glacier National Park have never been estimated with any degree of precision,'' Kendall said from her office at park headquarters. ''What's neat about this study is we were able to cover such a large area in just one year.''
The area stretched from the Whitefish range west of the park to the high plains of the Blackfeet Indian Reservation on Glacier's eastern flank.
The hair traps were the cornerstone of the study -- 128 plots with a single strand of barbed wire surrounding a pile of wood doused in a foul-smelling scent lure. Black bears and grizzly bears investigating the scent usually left a tuft of hair behind on the barbed wire.
During the summer of 1998, scores of volunteers from various agencies collected 2,382 hair samples. They were analyzed at the University of Idaho.
A second part of the study involved a different method of collecting genetic samples. By patrolling certain trails, volunteers collected scat and 579 hair samples from trees that bears regularly rubbed on.
Having two methods strengthened the validity of the study, Kendall said, because it allowed a larger segment of the population to be sampled. Similar studies in Canada relied solely on hair trapping.
The research identified 212 individual grizzly bears.
The estimate has a fairly wide margin of error, which is typical for grizzly bears, which are notoriously difficult to count.
If Kendall were to randomly repeat her sample collection, 95 percent of the time she would come up with a population estimate falling somewhere between 349 and 590 bears.
This summer, Kendall will return to the field, and the results will be compared with those from 1998 to learn more about grizzly survival rates in the wild.
Until now the park has estimated grizzly populations based on a 30-year-old study. That researcher tallied the number of bear sightings in a popular section of Glacier, tried to determine how many individual bears were among those spotted, then extrapolated for the entire area. He figured Glacier was home to 200 bears, a number the park has continued to use.
It was the best anyone could do at the time, Kendall said, but the study is flimsy and outdated data by today's standards.
Peninsula Clarion © 2016. All Rights Reserved. | Contact Us