Derek Neary
Northern News Services

Fort Simpson (July 12/02) - Are there a lot of grizzlies wandering around Nahanni's Ragged Range, or just a few?

Wildlife Conservation Society biologist John Weaver is attempting to answer that question. Using 49 strands of strategically placed barbed wired, Weaver and Parks Canada conservation biologist Doug Tate collected hair samples from grizzly bears last month. They stretched the barbed wire at knee height and covered it in brush soaked with fish oil and livestock blood.

"It smells pretty rank and draws the bears in," Weaver explained while giving a public presentation at Fort Simpson's Visitor Information Centre last Thursday evening.

After setting up 49 stations over 3,200 square kilometres in Ragged Range, on the western edge of the park -- approximately 300 kilometres from Fort Simpson -- Weaver and Tate returned 20 days later and found 25 samples of grizzly bear hair.

The samples will be sent to a laboratory in Nelson, B.C. for DNA analysis. Using such sophisticated technology, there's only a one in five million chance that the bears will be misidentified, said Weaver.

By taking hair samples year after year, biologists won't necessarily be able to pinpoint the exact number of bears, but they will be able to determine whether the same bears or their offspring are returning to certain areas.

When the data on grizzly populations is compiled over a few years, Weaver said Parks Canada officials and members of the Deh Cho First Nations will have to make decisions about how to conserve the bears' habitat.

Fierce but fragile

Although grizzlies are large -- males can weigh up to 450 kilograms -- and fierce in appearance, bear populations are fragile and vulnerable to human impacts, according to Weaver, who has 30 years experience in the field. Bears may wander over a range of 2,500 square kilometres, he noted.

"In today's world we all know that space is coming more and more at a premium," he said.

Adding to the bears' vulnerability is their low reproductive rate.

Females commonly reach 10 years of age before having their first litter, often bearing only two cubs, and neither will necessarily reach adulthood.

It may be several years before a mother has another litter, Weaver said. With a lifespan of 20 to 25 years in the wild, there aren't many opportunities for grizzlies to build healthy populations, particularly north of 60, where life is tougher and the margin of safety drops.

"Bears up North are always just kind of on the edge," he said.