Human activity slowing Banff grizzly reproduction: study

CALGARY (CP) - A nine-year study coinciding with burgeoning development in and around Banff National Park has found the area's grizzly bears have the lowest reproductive rate ever recorded in North America.

The study of 71 bears between 1994 and 2002 also found that humans were responsible for more than 75 per cent of female bear deaths and 86 per cent of male deaths in the same time.

"Basically, we (need) to have 19 out of 20 adult female bears in their reproductive years survive into the next year," said Stephen Herrero, an environmental scientist at the University of Calgary and co-author of the study.

"It's a tricky balance we'll have to maintain."

Female grizzlies do not reproduce until they are about eight years old, and generally have litters of one or two cubs every four or five years. That means even the death of a single bear can have a significant impact on population trends.

The findings are to be published in the upcoming edition of Journal of Wildlife Management.

"This is definitely a wake-up call - this says we have to be very careful with mortality because these bears are going to bounce back slowly, if at all," said Herrero.

Bear habitat extends beyond Banff into Alberta's Kananaskis Country, a provincial wilderness park which has become a popular recreation spot for hikers, campers and rock climbers. That human presence is most likely to be found in areas where grizzly bears would normally have gathered berries.

Fewer berries have meant that some female grizzly bears weren't getting enough calories to reproduce.

Wildlife biologist Jon Jorgenson with Alberta Sustainable Development said the province is looking at prescribed burning programs in the backcountry, a process which would ultimately create vegetation in unpopulated areas.

"We can create sources of natural food for the bears in areas where we don't have people," Jorgenson said.

The grizzly study was supported by 55 groups including business, environmental interests, the federal and provincial government. Herrero said that was important to keep everyone who "works and plays" in the parks focused on a common goal.

"Various managers started working harder and harder to keep female grizzly bears alive," he said. "The 95 per cent survival rate that we found between 1994 and 2002 is partly testimony (to the fact) that they knew they had to keep bears alive ... because of what we were finding out about the low reproductive output."

Grete Bridgewater of Canadian Pacific Railway said it's important for all parties which use national parks to do whatever they can to avoid contact with wildlife.

"We've tried a number of things from blowing our whistles, sounding our horns and flashing the very big headlights to give a heads up to wildlife that we're coming," said Bridgewater.

But bears aren't always interested in moving and a freight train requires about two kilometres to stop. In 1999, CPR designed a vacuum truck based in Banff that can ride on the rails and pick up grain, canola and wheat that can attract bears foraging for food.

Practices adopted in the late 1980s, such as more fenced areas, keeping human garbage away from bears and relocating bruins which have become accustomed to people, are believed to have helped. Researchers believe the moves have saved at least one female grizzly a year from being killed.

Parks Canada implemented 70 km-h speed zones near the hamlet of Lake Louise to give grizzly bears a better chance to cross the busy Trans-Canada Highway. Electric fences are also being used in some campsites to keep bears away from humans.

Parks officials are also considering a 10-kilometre electric fence around the hamlet, if they can come up with a way to deal with the railway tracks and the Bow River. A feasibility study is to begin this summer.

Researchers based at the University of Calgary radiomarked and monitored grizzly bears in Alberta's Bow River Watershed between 1994 and 2002 for the study. But research for 2003 and 2004 found that more of the radiomarked bears died.

A more extensive report is expected later this spring examining the grizzly populations in Alberta's less protected Eastern Slopes. That study, which is based on the nine years of research plus the monitoring in 2003 and 2004, will include recommendations for those who set policy in Canada's wilderness areas.

The final report will also include a detailed analysis of the human related causes of bear deaths.