April 6, 2006
Canada Studies Cull of its Largest Bison Herd
By Scott Haggett
CALGARY, Alberta -- Last October, a group of scientists met in the fortress-like biological sciences building of the University of Alberta's Edmonton campus to mull how best to kill all 4,500 bison in a Canadian national park.
But the buffalo, who were moved to the park from southern Alberta in the 1920s, are infected with disease that originated in the settlers' cattle -- bovine tuberculosis and brucellosis. They have been under stay of execution for nearly two decades.
That's because even though there have been no instances of the buffalo infecting domestic cattle or other bison living north and east of the massive park, the diseases are still considered a risk to Canada's beef industry.
"The disease reservoir has been there for more than 70 years," said Doug Stewart, director general of national parks for Parks Canada. "But this became topical in the 1980s when there were concerns from agricultural interests that there was potential for these to cross back into clean cattle herds ... and a threat to other bison."
The issue facing the scientists in Edmonton was whether it is possible to kill nearly every bison in a park that's bigger than the Netherlands and Luxembourg combined, and then restock the area with new animals free of the diseases that cripple the herd.
The group's answer was yes. But it would cost an estimated C$78 million ($66 million) and take two decades to complete. And, as they noted in their report, they were solving technical questions, not advocating a cull.
"The broader policy question needs to be answered by a larger group representing a wider range of interests," the report stated. "Bison are an iconic species in Canada. The subject of depopulating a free-roaming herd ... is extremely controversial.
The Canadian government had a plan in 1990 to wipe out Wood Buffalo's bison but never went forward with the scheme because, no one was certain about how the task would be accomplished, whether the herd could be replaced by healthy stock and what effect removing the beasts would have on other species in the park like wolves, caribou and moose.
The Edmonton meeting decided the plan was feasible. It would take 10 years to kill off the existing herd by rounding them up in corrals, then employing local hunters or using so-called "Judas" bison equipped with radio collars to track down stragglers.
After the existing herd is culled, the park would be repopulated with at least 1,000 disease-free bison, although the scientists said it could take another decade to return the herd to its present size.
It's a plan that has its critics, some of whom say the consequences for the park cannot be predicted. Without bison to eat the vegetation, the wildfire risk could rise, or plant diversity could be threatened without the herd to work the soil.
"We have no idea what the consequences are going to be," said Faisal Moolah, director of science at the David Suzuki Foundation in Vancouver, an environmental lobby group.
"Bison play a critical role in the ecosystem. If you're removing bison and you don't have an effective means of replacing their role, what are the unknown ecological effects going to be?"
Yet if the bison were to infect cattle, the Canadian beef industry would face additional costs. Canada's cattle herd is, for the most part, considered free of the TB and brucellosis endemic to the Wood Buffalo bison. But if the diseases spread to cattle, ranchers would need to pay for additional testing and exports could be limited.
"It doesn't affect our status but it does pose a significant risk," said Rob McNabb, assistant general manager for the Canadian Cattlemen's Association.
McNabb said Canadian beef producers could be forced create zones where cattle would be tested for brucellosis or tuberculosis if the infection spread.
In a "worst-case scenario," widespread infection would cause the loss of disease-free status for all Canadian cattle and ranchers would have to test all animals before shipment or slaughter, he added.
The Cattlemen supported the original cull proposal but McNabb said they have not considered the question since the 1990s.