September 3, 2008

Plague Fought on Rodents’ Behalf


INTERIOR, S.D. -- On the grasslands a few miles from the pinnacles and spires of Badlands National Park, federal wildlife officials have been waging a war since spring to save one of the country's largest colonies of endangered black-footed ferrets.

The deadly disease sylvatic plague was discovered in May in a huge prairie dog town in the Conata Basin. The black-tailed prairie dog is the main prey of ferrets, and the disease quickly killed up to a third of the area's 290 ferrets along with prairie dogs.

The disease stopped spreading with the arrival of summer's hot, dry weather, but it poses a serious threat to efforts to establish stable populations of one of the country's rarest mammals, said Scott Larson of the U.S. Fish and Wildlife Service in Pierre.

The plague, which is carried by fleas, is the biggest danger to ferrets in the Conata Basin and other places that still have ferrets, said Larson, who is coordinating ferret conservation efforts among five federal agencies.

"It has the capacity to take out more ferret habitat than anything we've run up against, and do it in such a short order," he said. "For ferrets, it's the most challenging issue we face."

The ferrets were once considered extinct. But a colony was discovered in Wyoming in 1981, and a captive-breeding program increased their numbers. Ferrets have since been reintroduced at 17 sites in South Dakota, Wyoming, Montana, Colorado, Utah, Kansas and New Mexico, said Nancy Warren, the leader of the endangered species program in the Rocky Mountain Region of the U.S. Forest Service.

Larson said reintroduction efforts failed in some places, and plague has hit most of the ferret colonies to some degree.

Establishing many reintroduction sites helps protect the overall ferret population from being wiped out by plague, he said.

Representatives of federal agencies and some conservation groups have taken a double-barreled approach to try to stop the spread of plague and save prairie dogs and ferrets in the 20-mile-long Conata Basin, a portion of the Buffalo Gap National Grasslands just south of the Badlands in southwestern South Dakota.

This summer, a crew of four has buzzed across the prairie on all- terrain vehicles, pausing frequently to spray white insecticide dust into prairie dog burrows to kill fleas.

After dark, another crew moved into the area during part of the summer to shine spotlights across the grasslands, trap ferrets and vaccinate them against the plague.

Officials want to dust about 11,000 acres with insecticide by this fall, and they have covered about two-thirds of that area so far. More than 60 ferrets have been vaccinated, including 15 that have already received the desired two doses.

Of the 25,000 acres of prairie dog habitat managed for ferrets in the basin, the plague had spread to about 9,700 acres before its growth halted in August. Officials expect that the plague might start spreading again this fall or next spring.

Warren said it's too early to tell whether the insecticide will save the ferrets.

"We're learning as we go. We really don't know the answer to that yet," she said. "We're hopeful with the dusting, which is something new we're doing now, we'll be able to at least contain the extent of this plague."

The basin also has been the focus of controversy as the Forest Service tries to balance the protection of prairie dogs and ferrets with the needs of ranchers whose cattle graze on leased sections of the national grasslands.

Prairie dogs once were routinely poisoned as pests. However, they expanded rapidly in the region, moving from federal land to private ranches, during an extended drought. Poisoning on federal land was halted while officials considered whether the rodents should be protected under the Endangered Species Act. The Fish and Wildlife Service decided in 2004 not to protect prairie dogs, but it is reconsidering that.

Jonathan Proctor, the Great Plains representative for Defenders of Wildlife, a conservation group, said the Conata Basin is the last remaining large complex of black-tailed prairie dogs on the Great Plains. Prairie dogs must be protected because they are important not only to ferrets, but also to hawks, burrowing owls and many other species, he said.

"Even with the loss of almost 10,000 acres of prairie dogs, Conata Basin still remains the largest and most important prairie dog complex on federal lands in the Great Plains. It's worth all these efforts to save it," he said.

But Shirley Kudma, who ranches in the basin with her husband, Donald, said the prevalence of plague confirms the predictions of ranchers overrun by prairie dogs in the past decade. They argued that more should have been done to limit the spread of prairie dogs because the hungry rodents strip the ground of grass, leaving little for cattle.

"Nature took care of it, didn't it?" she said. "There's the plague and the prairie dogs, and that's nature taking care of the expansion."

Ranchers don't want to wipe out prairie dogs, she said.

"I think we want to get along," she said. "We want to be able to survive just the same as the prairie dogs want to survive. We don't want to annihilate them. We don't. Just get them under control so they're not sick. Give the ferrets something healthy to eat."

About 5 to 15 people are infected by plague in the United States each year, but it can be cured with antibiotics if treatment is prompt.

Fish & Wildlife Service:

Originally published by CHET BROKAW Associated Press.

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