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Environmentalists fear for Alaskan caribou herd

Tuesday, September 7, 1999

By CRAIG MEDRED
SCRIPPS-McCLATCHY WESTERN SERVICE

ANCHORAGE, Alaska -- As about 8,000 subsistence hunters fan out across the Nelchina Basin for caribou, scientists are pondering what is becoming of Alaska's most hunted and most accessible caribou herd.

A couple of years ago, the Nelchina herd consisted of more than 50,000 animals and was growing. Today it has fewer than 33,000 animals and apparently is declining.

Some biologists are starting to think that hopes of maintaining a herd of 50,000 or more were too optimistic, that 50,000 is more than the summer range of the Nelchina can support. The consequences of overgrazing are evident in undersize adults and low pregnancy rates, contends Pat Valkenburg, a research biologist with the Alaska Department of Fish and Game in Fairbanks.

"They had a pretty bad summer last summer," he said.

Calves and pregnant cows were underweight going into winter. A migration to good winter range in east central Alaska helped them gain weight over the winter, a rarity for Alaska big game.

But nothing could be done about summer's undernourishment, which kept many cows from getting pregnant in the fall. Last spring, less than 50 percent of the Nelchina cows were pregnant, and in the end only about 33 of every 100 gave birth.

That, said Valkenburg, "is one of the lowest birth rates ever recorded in caribou."

Biologists had anticipated some herd shrinkage. Last year they persuaded the state Board of Game to cut the number of this year's Tier II subsistence hunting permits from 10,000 to 8,000.

That drew howls of protest from hunters accustomed to a comparatively easy supply of winter meat, but biologists now wonder if cutting 2,000 permits was enough.

Regional wildlife supervisor Jeff Hughes of Fish and Game said his agency will assess the herd in October. They'll look at summer losses to predation, as well as fall hunter kills, and decide whether the winter hunt can open Oct. 21 as scheduled.

Fall hunter kills are expected to account for the smallest of the herd's losses since calving season. Predation is the wild card.

Last year, there were 55 calves for every 100 cows in the Nelchina herd after spring calving, said area wildlife biologist Bob Tobey. By the fall, bears, wolves, eagles and accidents had killed 31 percent of them.

Going into the winter of 1998-99, the herd was down to 38 calves per 100 cows. That should have been enough to replace the adult caribou lost to hunting, predation or starvation during the winter. But by spring, the herd size was down again, dropping from the fall count of 38,000 to 33,000.

Then came the really bad news. "We were predicting a lower calf (production) rate," Tobey said. What they got was a disaster.

If predators get about the same number of calves this year, the Nelchina herd will enter winter with only about 22 calves per 100 cows -- which would continue the herd's decline.

Biologists aren't sure what to do. Like hunters, photographers and wildlife watchers, they'd like to see a big Nelchina herd roaming the wild country roughly bounded by the Glenn, Richardson and Parks highways.

With indications that the summer range is overgrazed, however, they realize that increasing the herd is a bad idea.

"Nelchina caribou have found an excellent winter range they share with the Mentasta and Fortymile herds," according to a Fish and Game publication. "But they have reached the limit of their summer range."

"We're thinking now that if we hold them at 35,000, they'll come out of this," Valkenburg said.

The herd might be most productive at a population somewhere below 35,000, but hunters have been lobbying the Board of Game to maintain the herd at 40,000 or more.

Hughes said he's not sure how big the Nelchina herd should be. Biologists have gotten mixed signals. Poor summer range is blamed for the poor calf production this year and in 1997, but there was solid calf production in 1998.

"We've just whipsawed around," Hughes said. "We've gone high, low, high, low. What can you say? They're caribou."

Fish and Game has monitored the size of the Nelchina herd for decades, but biologists have tracked spring calving success, spring and fall calf weights and summer survival for just five years.

That's a blip of time in nature, where patterns sometimes emerge in decades-long cycles. All biologists have seen so far is a lot of variation.

The Nelchina herd is thought to have numbered more than 60,000 animals in 1967; five years later it was down to about 8,000.

More than a decade of slow, steady growth in a population of 30,000 to 40,000 animals followed at the start of this decade.

Wildlife managers tried to hold the population there, but the herd size crept upward.

Some now believe that at 50,000 animals, the Nelchina caribou are again overgrazing their range.

Trying to manage any wildlife population for a steady maximum is hard to do, Hughes acknowledged. To attempt it, he said, biologists need to know more about the caribou and their ecosystem.

Next year, a new five-year research project will begin under the supervision of Layne Adams of the Alaska Biological Science Center and Bruce Dale of Fish and Game.

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