Thu, 24 Feb 2005
CBC News
CALGARY - Humans are the most serious threat to grizzly bears in Banff, Alta., say scientists who've found the bears aren't reproducing as successfully as before.
Stephen Herrero of the University of Calgary led a study tracing the births and deaths of 91 grizzlies living in Banff National Park and Kananaskis Country.
Banff's grizzlies are faring worse than their U.S. kin.
Herrero and his colleagues from Parks Canada and the Minnesota Department of Natural Resources captured, tagged and monitored the grizzlies from 1994 to 2002.
They found the Banff bears are reproducing more slowly than in other areas of North America because their food supply is limited in the harsh, mountain habitat.
"The more calories bears get into them, the more young they have, the earlier they have them and the shorter the period between reproductive intervals," said Herrero.
The other key finding is that bears are being killed directly and indirectly, even inside the park.
"Grizzly bears are in trouble in Alberta largely because their habitat has become so fragmented," said Nigel Douglas of the Alberta Wildlife Association. "There's been industrial activity on a huge scale."
Legal and illegal hunting is one challenge. Another part of the problem is unfenced sections of the Trans-Canada Highway. As a result, cars are hitting grizzlies.
The survival rate for female grizzlies, which rear cubs without help from males, fell from 95 per cent in 2002 to 71 per cent in 2004, the researchers found.
To sustain the population, the bears need a survival rate of at least 91 per cent, the team wrote in the January issue of the Journal of Wildlife Management.
The low birth rates and the fact that most bears die at the hands of humans reinforce the need to take more action, especially as more people head into bear country, the researchers urged.
The group will make more recommendations in the spring when it releases a final report.
CBC News
CALGARY - Humans are the most serious threat to grizzly bears in Banff, Alta., say scientists who've found the bears aren't reproducing as successfully as before.
Stephen Herrero of the University of Calgary led a study tracing the births and deaths of 91 grizzlies living in Banff National Park and Kananaskis Country.
Banff's grizzlies are faring worse than their U.S. kin.
Herrero and his colleagues from Parks Canada and the Minnesota Department of Natural Resources captured, tagged and monitored the grizzlies from 1994 to 2002.
They found the Banff bears are reproducing more slowly than in other areas of North America because their food supply is limited in the harsh, mountain habitat.
"The more calories bears get into them, the more young they have, the earlier they have them and the shorter the period between reproductive intervals," said Herrero.
The other key finding is that bears are being killed directly and indirectly, even inside the park.
"Grizzly bears are in trouble in Alberta largely because their habitat has become so fragmented," said Nigel Douglas of the Alberta Wildlife Association. "There's been industrial activity on a huge scale."
Legal and illegal hunting is one challenge. Another part of the problem is unfenced sections of the Trans-Canada Highway. As a result, cars are hitting grizzlies.
The survival rate for female grizzlies, which rear cubs without help from males, fell from 95 per cent in 2002 to 71 per cent in 2004, the researchers found.
To sustain the population, the bears need a survival rate of at least 91 per cent, the team wrote in the January issue of the Journal of Wildlife Management.
The low birth rates and the fact that most bears die at the hands of humans reinforce the need to take more action, especially as more people head into bear country, the researchers urged.
The group will make more recommendations in the spring when it releases a final report.
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