Caribou numbers in Jasper National Park dropped 30 per cent since 2008, according to the latest Parks Canada survey of the caribou population.

In a document to be released this week, the department says that in the Maligne Lake area — considered a crucial and threatened habitat for more than a decade — just four caribou have been seen.

A federal report says Jasper's Maligne Lake caribou herd may have dropped to just four animals. (CBC)"I'm shocked that the numbers went down so fast," said Alberta naturalist Ben Gadd. "They were up at around 40 animals, which isn't a whole lot, but this is down to a tenth of that in one year."

A study in 2002 indicated the Maligne herd would be extinct in 40 years.

"That was Parks Canada's study," he said. "Now it seems like if they're really down to four animals, they could be gone in a year. And that's very serious occurrence in a world heritage site."

As early as 1992, a report for Parks Canada identified adverse effects the Maligne Lake Road was having on caribou in the park. Ever since, environmental groups have been calling for the road — used by cross-country and back-country skiers — to be closed in winter.

"Closures of any roads, particularly for a road like into the Maligne, are always difficult ones," Jasper Park superintendent Greg Fenton told CBC News on Monday. "There wasn't enough information to suggest that a permanent closure of the road, a winter closure, would actually save the population."

There was evidence enough for Ben Gadd, a Jasper naturalist.

Caribou in Jasper's back country can be stressed by skiers and dogs and become easier prey for wolves, naturalist Ben Gadd says. (CBC)"I used to ski up at Maligne Lake in the winter, like everybody did," he said. "Cross-country skiing and back-country skiing was great fun. But I quit doing that when I found out how stressed these animals were back in the mid-90s.

"By plowing the road up there for cross-country skiing, wolves were following the road up there to harass them, the skiers were going up bringing their dogs, which were often loose and running around and harassing the caribou.

"And especially in late winter, these animals are at the end of their rope, you know. They may not survive if they're chased around in the trees very much."

Fenton said the movement of caribou during the winter is not fully understood, and some Maligne caribou may have moved south.

"We do have a draft strategy," he said. "It talks about some of the threat categories or some of the stresses on caribou populations."

A ban on dogs for some areas has also been considered, he added.

But the wildlife equation is more complicated than that, Fenton said.

"It's not a matter of managing just people and wolves and caribou. It's understanding more comprehensively, as best we can, the full predator-prey relationship dynamic."

The size of the caribou population will be among the subjects at the annual planning forum for Jasper National Park, which will be held Tuesday at the Jasper Activity Centre and Thursday at the Delta Edmonton South hotel.