Scientists warn caribou collapse not unlike disappearance of cod stocks

November 11, 2009 • Philip BurgessBlog

090824-Mongolia-reindeer-pic2.standardBy: Bob Weber, THE CANADIAN PRESS YELLOWKNIFE – Once, caribou wandered over the Arctic tundra in herds that took days to pass. So great were their numbers – even 20 years ago – that they were able to shake off man’s puny imprint on the great barren lands like so many flies on a rump.

“There was so much caribou all over that even our plane, our scheduled flights, couldn’t land on the airstrip,” recalled Alfonz Nitsiza of Wha Ti, a tiny aboriginal community northwest of Yellowknife.

“The caribou were on the airstrip. It was full of caribou, all our communities were.”

Today, scientists fear caribou are the new cod.

“If we want a counterpart to start looking at what may be happening with the caribou, look at the northern cod,” said Anne Gunn, a caribou biologist and former Northwest Territories researcher.

Once a gigantic bloom of life that sustained entire societies, the cod fishery was closed in 1992 after a near-total collapse of fish stocks. The subsequent bust of Newfoundland’s outport culture was nearly as complete.

Recent surveys on two major caribou herds in Canada’s North suggest the same thing may be happening there. And as scientists begin to unlock the secrets of that decline, aboriginals who still depend on the great herds to feed both body and soul are rethinking old assumptions.

“The elders are saying that there is a cycle, that caribou go away somewhere but they come back,” Nitsiza said. “This time, the caribou may not come back.”

Biologists say 15 of the world’s 23 herds are shrinking. Only six herds, generally the small ones, are growing.

“The worst is in the N.W.T.,” said Don Russell, a former Canadian Wildlife Service biologist, who now heads the Circumarctic Rangifer Monitoring and Assessment network.

The Bluenose West herd, for example, which ranges over the northwest corner of the N.W.T., was under 20,000 animals in 2006 – a quarter its size at the turn of the millennium. Nine of Canada’s 11 herds are in decline.

Concern has been building for years. But this summer, survey results carried a distinct whiff of impending catastrophe.

N.W.T. biologists estimated the Bathurst herd of the central barrens had fallen from over 120,000 animals in 2006 to 32,000 – a 75 per cent implosion representing the loss of nearly 90,000 caribou in only three years.

The news was even worse to the east, where scientists studied cow-calf pairs in the Beverly herd.

Aerial survey teams couldn’t even find enough pairs to get statistically valid data. A herd that numbered 280,000 animals only 15 years ago was simply gone.

“Collapse. I think that’s a good term,” said Ross Thompson of the Beverly-Qamanirjuaq Management Board.

Caribou herds have always fluctuated, sometimes wildly. The George River herd in Arctic Quebec grew from as few as 5,000 animals in the early 1960s to 700,000 by the 1990s (although it’s now shrinking).

But new factors are putting wobbles in the caribou cycle. Recent research is beginning to show how climate change, aboriginal hunting and industrial development may be preventing populations from recovering.

Climate change has long been suspected as being behind the recent widespread declines.

“Weather is the only thing that would operate on that big of a landscape scale,” said Jan Adamczewski, a biologist with the N.W.T. government.

The territory is warming up faster than almost anywhere else on the globe. Temperatures already show a two-degree average increase since 1948 and higher increases further north.

Research also shows that warmer conditions are allowing southern shrubs to spread north and take over from plants such as lichen. Shrubs produce more plant material, but they aren’t very good caribou food.

“On the summer range, forage biomass is increasing, but there’s some indication that forage quality is decreasing,” Adamczewski said.

Winter changes are even more significant. Warmer temperatures mean heavier, icier snow.

“The snow is not going to be so nice and fluffy and easy to kick aside when you want to dig through it to get your food,” said Gunn.

Higher temperatures also improve conditions for warble flies, biting, bloodsucking bugs that drive caribou crazy and impair their ability to breed by preventing them from building their strength.

“I’ve seen (caribou) in July and they don’t spend a lot of time feeding,” said Adamczewski. “They spend a lot of time running around and trying to get away from these things.”

Then there’s the aboriginal hunt. Once pursued on dogsled by hunters depending on skill and local knowledge, caribou are now preyed upon from snowmobiles and pickups. Their range has been invaded by roads and cutlines, their locations widely tracked and shared.

Those changes mean hunters can still fill their freezers even if there are relatively fewer caribou, said Gunn.

“You can go a lot further on a snow machine. If you find them, you can take them easily. It’s independent of abundance.”

Some say the harvest was bigger in the old days, when hunters needed to feed their dogs as well as their families. But as recently as 2007, officials estimated aboriginals were taking 11,000 animals a year – enough, perhaps, to slow the recovery of already-depressed herds.

The third wild card is industry.

Caribou decline has coincided with unprecedented northern development that includes three diamond mines, oil and gas exploration and intensive mineral prospecting. Some of that development – uranium exploration in the Thelon, for example, on the N.W.T.-Nunavut boundary – is on or adjacent to calving grounds.

Many argue those developments are pinpricks in a vast and largely untouched wilderness. Others say they already disrupt caribou movement between winter and summer ranges and calving grounds.

Little is known yet about the effect of industry on the caribou, but studies suggest the animals tend to avoid coming within about 30 kilometres of diamond mine sites.

That’s up to seven per cent of a herd’s summer range when all three mines are combined, said Gunn.

“They’re pinpricks with a zone of influence around them.”

None of these factors is suspected of being the main driver behind the collapse, but in combination it may be a different matter.

“The caribou’s world is changing,” Gunn said.

“We can measure these very strong signals of change, and we can’t say that they caused 10 per cent of the decline, but they’ve got to be playing a role.

“The interplay between them is where we run up against the limits of our knowledge. We deal in probabilities and likelihoods. We never deal with certainty.”

Adamczewski thinks back to his first field season in the North, his eyes lighting up as he describes the then-mighty Beverly herd as “a sea of animals.”

He went back last summer.

“The animals just weren’t around,” he said. “We kind of blew that one.”

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