Hunting. (article from 2007)

Herds of barren-ground caribou -- which for centuries have been a crucial source of food and furs for local aboriginals -- have dropped by between 40 and 86 percent over the last 10 years. The largest single herd fell from 472,000 animals in 1986 to 128,000 in 2006 and is still declining.

...Over the past few years hunters have been allowed to kill a an average of 11,000 animals annually, a number that Case said would have to be reduced.

He also expressed concern about modern forms of transport that allow hunters to reach once inaccessible areas where in the past the caribou would have taken refuge while herd levels gradually recovered.

"They can't hide from us any more. People can either go by ice road or snowmobile or aircraft and actually find the caribou and continue to harvest...we need to be cautious about how we manage the future," Case said.

Animal rights activists say they are concerned about increased mining and oil extraction on calving grounds in Canada's mineral-rich northern region. Case said this did not seem to be a major factor in the territories.

"There has been some drilling, some seismic activity on some of the ranges but over the period that this decline occurred the activity has been very low," Case said.

"There hasn't been activity on all of the ranges yet all of the caribou herds have shown a similar decline."