For the animals that have roamed the great wildlands of North America over millenniums, the 49th parallel holds no distinction. There's no barbed-wire fence, no major river to ford, no mountain to separate one side of this international divide from the other.
Yet perhaps, for some creatures, the border might just as well be posted with a sign: "Enter at your own peril."
A recent spate of wolf and bear killings in western Canada has highlighted a growing concern among scientists: Animals afforded strict protection in the US are vulnerable when they wander north. The incidents underscore how southern Canada is changing. Once considered an untouched oasis for free-ranging wildlife of all kinds, development and logging are fragmenting the landscape - and increasing lethal contact between humans and beasts.
The result has been a surprising depletion of many species in the region. And with US policy at least in part guided by the notion that Canada is a near-inexhaustible reservoir of wildlife, the trend could affect American wildlife reintroductions and environmental planning for years.
It's already raising questions about a recent proposal to transplant Canadian grizzlies into the northern Rockies of Montana and Idaho. "Some areas of southwest Canada ... have been bloodbaths for US wildlife," says Louisa Willcox, who oversees the Sierra Club's Grizzly Bear Ecosystems Project.
During the mid-1990s, four dozen gray wolves - all originating from wolf packs protected in the US - were shot in southern Alberta and British Columbia. Also, in 1997, 12 grizzlies, some of them considered essential to the bears' population stability in the border region, were killed or removed from Canada's Pincher Creek drainage - just miles beyond US soil.
Besides wolves - which are viewed as vermin in Canada and can be shot on sight - and grizzlies, other species threatened by hunting and habitat destruction are wolverine, Canada lynx, bull trout, and woodland caribou. Higher latitudes of western Canada still support thriving numbers of these animals, but they're on the wane in the Canadian borderlands.
"People fly over the middle of Canada and they see mile after mile of uninhabited forest, but there is an attorney and a logging plan for every square inch," says Bart Robinson, coordinator of the Yellowstone to Yukon Conservation Initiative in Canmore, B.C.
"There are an awful lot of Canadians, too, who still think of our country as the great lone land," he says. "Not many of us are aware of what is happening in our own southern backyards."
Government wildlife officials have long argued that American animal populations are healthily connected to Canadian populations via an unbroken stretch of wildland corridors. Therefore, they've resisted placing certain species such as lynx and wolverine on the US Endangered Species List, and they have proposed taking grizzlies and wolves off the list.
But large carnivores in the northern US are becoming isolated due to the fragmentation of once-secure habitat in Canada, says Reed Noss, president of the Society for Conservation Biology.
Even parks like Banff - regarded as the Yellowstone of western Canada - have been negatively affected.
"Most Americans look to Canada as this incredible reservoir of wildlife that will be a reliable source of animals forever, but that's proving not to necessarily be the case," says conservation biologist Kevin Van Tighem, who works in Waterton Lakes National Park, a preserve adjacent to Montana's Glacier National Park.
More than 80 percent of Canada's 35 million people reside within 200 miles of the US-Canada border. Growing numbers are settling on what had previously been considered pristine land.
These areas are increasingly crisscrossed by spider-web patterns of roads and bisected by highways that prevent animals from migrating. This can "islandize" populations and make them more vulnerable to extinction.
"It's the kind of frontier mentality that resulted in America eradicating wolves and grizzlies from the West," says conservationist Michael Sawyer of the Castle-Crown Wilderness Coalition, "except we're doing it better and faster. We have two things the settlers in the States didn't have a century ago: technology and more guns."
One problem is that Canada has no equivalent of the Endangered Species Act. Earlier this year, federal lawmakers in Ottawa pressed to pass the Species at Risk Act, but the legislation fails to adequately regulate industries - such as timber, mining, and livestock - that are causing species declines, says Stephen Herrero, professor emeritus at the University of Calgary.
A second concern is that the provincial governments in Canada wield considerably more local authority than the federal government. And during the past century, critics claim, provincial ministers in British Columbia and Alberta have favored resource development over environmental protection.
For this reason, Canadian environmentalists have asked their American counterparts to make species protection part of trade negotiations. In 1998, Interior Secretary Bruce Babbitt signed an agreement with Canada that created a new framework for protecting vulnerable species along the border, but the accord carries no legal weight.
Now Canada is at a crucial crossroads, say some observers. It still has an opportunity to avoid future environmental problems by learning from mistakes made in the continental US.
"Canadians are realizing they don't have inexhaustible resources, but they have a long way to go to safeguard what they have," says Marshall Jones, assistant director for international affairs at the US Fish and Wildlife Service.
Recently, the premiers of a few provinces have pledged to address the problem. From the private sector, a few novel efforts are under way to increase ecological awareness. The Transboundary Flathead Project, for instance, aims to protect the richest pocket of grizzly bears along the Flathead River in southern British Columbia. There's also the ambitious Yellowstone to Yukon effort.
Steve Thompson, an environmental consultant with the Montana Wilderness Association and East Kootenay Environmental Society in British Columbia, says now is the time to act. "We can either try to fix the problem now when we can still deal with it, or be left with a major problem later on when it may be beyond repair," he says.
(c) Copyright 2000. The Christian Science Publishing Society