The great caribou crash:
Climate change after the last Great Ice Age killed many of the large mammals of the Arctic, like the wooly mammoth and the American lion.
That may be a cautionary tale for the caribou
by Ed Struzik
Edmonton Journal
May 4, 2008
In the summer of 1996, biologist Frank Miller was flying along the coast of Bathurst Island searching for Peary caribou, an animal found only in the High Arctic of Canada, when he spied a dark spot on the sea ice.
Assuming it might be a small herd migrating to a nearby island, he instructed the pilot to go in for a closer look. Seconds later, he could see that these animals were not the caribou he was looking for. They were muskoxen, shaggy prehistoric-looking animals that survived the last Great Ice Age.
The circle of animals didn't bolt as they normally do when an aircraft hovers nearby. So Miller got the pilot to land a few hundred metres away. Even as he approached on foot, the herd didn't flinch. Try as he did to figure out why, Miller couldn't come up with an answer. As he moved closer, it dawned on him -- they were all dead.
The animals were frozen stiff and leaning against each other like statues that had been knocked over against each other by the wind.
"It was one of the most strange and gruesome things I'd ever seen as a biologist," the Edmonton-based researcher recalls.
"They were probably on their last legs and starving when they headed out across the sea ice searching for better food conditions on another island. But they didn't have the energy to get through the deep snow. So when they tried to dig down and discovered there was nothing there but sea ice, they just gave it up.
"The snow then melted and eventually hardened around their bellies. That's why some of them were still standing upright after they had died."
In the weeks that followed, Miller saw plenty of the succulent saxifrage flowers that Peary caribou feed on, but precious few animals and not a single calf at that time of year.
What he did discover with alarming regularity were the carcasses of caribou and muskoxen strewn across the tundra. By the time Miller completed his study that summer, he had counted just 300 live animals, a small fraction of what he had expected to see. When the die-off finally ended two years later, almost 98 per cent of the caribou that were on the south-central Queen Elizabeth Islands three years earlier were gone.
Overall, Peary caribou did not fare well in the last half of the 1990s. The High Arctic population is in such deep trouble now that the Committee on the Status of Endangered Species in Canada has recommended the Peary caribou remain on the endangered list.
The Peary, however, is not the only population of caribou in North America on the decline. Since the mid- to late-1980s, many of the great herds in North America have been in a free fall.
The Bathurst herd in the Central Arctic numbered 472,000 in 1986. Today, it is down to 128,000. The Cape Bathurst herd had 17,500 animals in 1992. Now there are no more than 1,800. Over in Alaska, the Yukon and Northwest Territories, the Porcupine caribou herd has declined from 178,000 animals in 1989 to the 123,000 biologists counted the last time they were able to do a comprehensive census.
In places like the south-central coast of the Canadian Arctic, there are so few animals left that arecovery may never happen.
Not only is this threatening the future of the lucrative sports hunt in the Yukon, Northwest Territories and Nunavut, it also threatens to strike at the heart and soul of Inuit, Gwich'in, Dene and Métis cultures.
In most communities, the measure of a hunter is judged by his skill in killing enough animals to feed not only his family but other members of the community who may not be healthy or old enough to go out on the land. A single caribou also saves a family $500 to $1,500 that they might otherwise have to spend on store-bought meat.
"It will have a large impact on the people because it's one of the main things you put on the dinner table," Paul Voudrach, chairman of the Tuktoyaktuk hunters and trappers' committee, said recently when a large area of caribou habitat in the western Arctic was declared off-limits to hunters.
"People tell me they don't like it, but I tell them it's their grandchildren they should be thinking about."
No one knows what exactly is going on with caribou. Climate change, overhunting, human activities and industrial development are all likely playing a role. So perhaps are contaminants that are creeping into the animals' food supply.
"But one thing that is certain," says Anne Gunn, a biologist with 30 years of caribou research behind her, "we cannot afford to dither, given the rate of changes we are unleashing across the Arctic regions. In addition to the roads, pipelines, mines and other things we have built, or plan to build on caribou habitat, global warming is already threatening the future of these animals.
Collapses in caribou populations are nothing new.
In the 1.6 million years the animals have roamed the circumpolar Arctic, there have been countless ebbs and flows in the numbers.
Back in the late 1970s, for example, there were so few animals remaining in the Qamanirjuak herd on the barrenlands of what is now west-central Nunavut that scientists were urging the Inuit to stop hunting them.
Then they watched with amazement and some disbelief as the numbers went from a low of 39,000 in 1980 to 230,000 in 1983, 260,000 in 1987 and then 496,000 the last time the animals were counted in 1994.
Part of the problem back then, as it is to a lesser extent now that survey techniques have improved, is finding enough animals to get an accurate estimate of how many caribou there are on the range. Even a good count in a year when weather and migratory animals cooperate, has a possibility of error of plus or minus 10 per cent. In other less favourable cases, it can be as high as 20 per cent.
The size of the range and the herds is simply too big to get a more accurate count economically.
Then there's always the possibility that a migration route or calving ground site has shifted before or during a census. Theoretically, that could increase the plus and minus percentages to much higher levels.
Scientists, however, have come to realize that the biggest reason for these ebbs and flows lie in a complex relationship between the caribou's ability to find food and its ability not to be food.
That relationship, Gunn suggests, is set to the rhythm of weather and climate.
Put simply, runs of cold, dry winters with less snow tend to favour caribou because there is little to slow them down and sap their energy while they're on the move or being chased by wolves. Less snow, especially the kind that is dense and hard-packed, also makes it easier for them to dig down to the vegetation they need in order to survive.
Runs of warm, wet winters, on the other hand, can be brutal for the opposite reasons. Not only is there a possibility that the snow will be deep during the long migration to the calving grounds, thawing and melting can cause some of it to ice over.
If those winters are followed by hot, dry summers that favour parasites, biting flies and fires that destroy nutritious lichen, the results can be catastrophic.
No one knows how weather can affect caribou more than Miller.
The die-off of 1996 wasn't the first time he observed a decline in the High Arctic population. He saw almost the exact scenario play itself out when he went up in 1974.
Initially, Miller was concerned that he may have missed something or done something wrong that summer. A survey 13 years earlier suggested there were as many as 26,000 animals in the High Arctic and as many as 4,000 in the area he was surveying.
Only when he searched through the meteorological records for clues to what might have happened did he come up with an explanation.
Those records showed that the freezing rain that occurred in fall of 1973 was followed by heavy snow in winter and recurring periods of thawing and freezing the following spring. As a result, much of the Queen Elizabeth Islands had been transformed into a giant, snow-covered skating rink. The ice was likely so thick in most places the animals often couldn't get through to the vegetation. Those that were successful probably spent more energy than they received.
Anne Gunn says no one should be surprised that a warmer Arctic may not be good for caribou.
Many of the large mammals of the Arctic, she notes, -- the wooly mammoth, Yukon horses, Alaskan camels, short-faced bears and American lions -- all died off during the 8,500 years the climate began warming after the last Great Ice Age ended.
Now those animals that are left are adapting to another period of warming that began 150 years ago when the Mini Ice Age ended around 1850. That natural warming is now being intensified by the emission of greenhouse gases.
Caribou, Gunn adds, likely survived that cycle of warming by dispersing and adapting to new habitats. That's why there are distinct sub-species today living in the forests, the mountains, the mainland tundra and the High Arctic.
What makes the future a potentially grim one for caribou, says Gunn, is the roads, pipelines, cutlines, mines and other human developments that are shrinking the size and the quality of the habitat these animals can move in and out from during weather events.
More important, it's encroaching on the calving grounds that are so critical for population growth.
"We still don't understand the relationship to calving grounds and caribou," says Gunn. "But everything we've learned over the years tells us that it is absolutely critical."
Weather isn't always the culprit when caribou numbers fall.
Back in 1980, when Gunn conducted a survey of caribou on Prince of Wales, Somerset and Russell islands along the south-central coast of the Arctic, she estimated a relatively healthy population of about 6,000. But when she went back 15 years later to count them again, there were so few animals left that her estimate of 100 was more hopeful than a reflection of what was actually there.
Try as she, Miller and others did in the years that followed, they had a difficult time figuring out what had happened. There was no evidence that weather was responsible. Nor was there any sign that muskoxen, which were on the rise at the time, had out-competed caribou for the limited supply of food. In fact, the diet of the muskox is quite different from that of caribou.
Unlikely as it was that the caribou moved en masse to another territory, the only other explanation was that humans hunted them down to such a low number that wolves and other natural factors prevented a recovery.
"It really could have been the sum of a lot of inconsequential things," says Gunn. "The fact is no one was monitoring the situation to see what was going on."
That wolves were part of the equation is no surprise. More than any other predator in the Arctic, wolves depend on caribou for their survival.
What makes this particular relationship an interesting one is the possibility that these wolves, which were already doing well with rising muskoxen numbers on the same range, developed a specialized means of hunting down their prey.
Inuit wildlife officer Joe Ashevak raised that prospect when he found the carcasses of 25 dead caribou strewn along a 15-kilometre stretch of the Garry River. Nine of the carcasses were located under a cliff. Like aboriginal hunters in North America, these wolves may have maximized their kills by chasing them over the edge.
Anne Gunn says there are lessons to be learned from the complacency that characterizes past management practices. The first is that more needs to be done to identify and understand the causes of declines so that conservation measures can be taken before it's too late.
Second, she says, the Inuit must also be directly involved in survey efforts and other studies so that they can buy into a strategy that might require them hunting less animals.
Not doing this in the past continues to haunt biologists and wildlife managers all across the North.
Ten years after the last major die-off of Peary caribou ended in 1998, the Inuit of the Arctic still don't believe the animal is in trouble and they continue to resist the proposal to keep the Peary on the endangered list.
Both federal and territorial government are also partly to blame. Not only do they not keep records of caribou kills in most aboriginal communities, they have also been reluctant to come up with funding to support the surveys that are needed to identify problems.
Caribou scientist Don Russell says there are other things that can be done ensure that the great caribou herds will be around in the future.
The former Canadian Wildlife Service scientist in the Yukon is now heading up CARMA, a joint effort by university scientists, government scientists and managers, industry, and community organizations to co-ordinate caribou research and monitoring throughout the world. That research, he says, could be used to identify and react to problems
before it is too late to do anything about them.
Russell is also hoping that the data CARMA collects will help wildlife managers better identify and protect those areas which provide caribou with the food they need to get through winter and those areas which cows and calves can escape to when insect harassment is at its worst.
"Here in the Yukon side of the border, we've done a pretty good job identifying and protecting those areas," he says. "We've created Ivvavik and Vuntut National parks and a special conservation area east of there under the Inuvialuit land claim.
"But the herd's calving and post-calving range in the Arctic National Wildlife Refuge in Alaska could still be opened up to oil and gas development if the energy industry gets its way. All the research that's been done indicates that this is one of the most important habitats for the herd."
Like Gunn, Russell warns that Canada cannot afford to be complacent now that industry is moving into the North to exploit oil and gas, diamonds and uranium in and around critical caribou habitat.
"We've seen continental-wide declines occur before during the First and the Second World Wars and again in the 1970s," says Russell. "But this time, for a variety of obvious reasons, the declines could be steeper and the recoveries much slower if they occur at all."
