Weather, wolves threaten caribou

Since 1988, state's woodland caribou population has fallen from 1,900 to 300

Posted: Sunday, July 21, 2002

FAIRBANKS - Alaska's only woodland caribou herd is on the brink of extinction and there isn't much biologists can do to save it because the herd resides in a national park and preserve.

Since 1988, the Chisana Caribou Herd has declined from about 1,900 animals to just 300 due to a domino-like effect of severe winters followed by a major drought and now anchored by hungry wolves.

The animals summer in Alaska and winter in Canada, ranging across the Alaska-Yukon border in the Nutzotin Mountains south of the Alaska Highway.

Today the herd is decrepit. Most of the animals are classified as "old gummers," a term used by wildlife biologists to describe the condition of the animals' teeth, or lack thereof.

Old age and wolves are killing more caribou than the herd can annually produce, resulting in a downward spiral that shows no sign of stopping.

"Ecologically it's one of the most astonishing things I've ever seen," said Yukon Territory wildlife biologist Rick Farnell, who has spent 24 years working for the Yukon's Department of the Environment. "You would think they would have some kind of built-in defense mechanism that would prevent something like this from happening but that isn't the case."

Alaska caribou expert Craig Gardner, a wildlife biologist with the state Department of Fish and Game, called the Chisana herd's decline "impressive." "Nobody has ever seen a herd disappear," he said.

But that's precisely what may happen if something isn't done, biologists said. The herd has reached a point where it needs human help if it is to survive. Who will provide that help, however, is the question because the Chisana herd splits its time between Alaska and Canada.

The herd calves in 13.2-million acre Wrangell-St. Elias National Park and Preserve, and it is on the calving grounds where wolves are killing practically all the newborn calves.

"This herd wouldn't be in this situation if it wasn't on preserve land," Gardner said. "The Yukon side would have done something and if it was on state land it gives you a little more flexibility" in managing the herd.

The National Park Service, meanwhile, says there isn't much it can do, given its mandate to manage "natural and healthy" wildlife populations, according to the Alaska National Interest Lands Conservation Act, which created the park 22 years ago.

"We're constrained in doing manipulative wildlife management for anything other than federally listed threatened and endangered species," said Mason Reid, the preserve's lone wildlife biologist.

The park service can't kill wolves, and biologists say wolves are the problem.

"We've looked at everything," said Farnell, the Yukon biologist. "There's nothing wrong with the habitat. There's no disease or parasites. There's physically nothing wrong with the animals. Everything points to neo-natal predation."

While pregnancy rates in the herd are high - 80 percent to 100 percent - the number of calves in the herd is almost negligible. Plenty of calves are born but only a few survive. The herd hasn't had a successful calf crop since 1990.

While there are several woodland caribou herds in the Yukon Territory and British Columbia, the Chisana herd is the only woodland herd in Alaska. That was confirmed by a DNA study by Farnell in 1999, which shows the Chisana herd is genetically distinct from other herds in Alaska and the Yukon.

Woodland caribou are bigger-bodied and have different antler configurations than barren-ground caribou that inhabit the rest of Alaska. Rather than a distinctive "shovel" protruding from the bottom of their antlers, as barren ground caribou are noted for, woodland caribou grow spikes and tines, making their antlers look almost like a deer's.

Biologists recently met in Tok to discuss ways to help save the herd. Some of the options included a captive breeding program to save the gene pool, small-scale wolf sterilization to reduce predation, and capturing semen from some bulls to store in a semen bank in order to preserve the herd's DNA.

Another alternative, and the one that has been met with the least resistance, is capturing cows on their home range. Cows could be "captured" and kept in corrals in the Yukon Territory through the calving season, Farnell said.

The caribou would be kept in the cloth pens for calving and would remain there until their calves are large enough to elude predators, probably for a month or two. The technique has been used on a small scale in Alaska and has proved successful, biologists said.

Trending this week:


© 2018. All Rights Reserved.  | Contact Us