Plague spurs prairie dog die-off in grasslands

An outbreak of the plague is killing off the black-tailed prairie dogs on the Comanche National Grassland in southeast Colorado, in a dramatic die-off that has raised concerns for the future of the species in one of its richest habitats.

The U.S. Forest Service, which runs the 443,750-acre grassland, said Monday that prairie dog colonies decreased from 16,000 acres in 2005 to just 3,607 this year. The plague occurs regularly among prairie dogs throughout their range, spreads quickly through colonies, and can infect pets and humans that come into contact with them, the agency said.

The news comes at a time of scrutiny on the small, plains rodent. The U.S. Fish and Wildlife Service is expected to determine, possibly as soon as today, whether the prairie dog should be protected under the Endangered Species Act.

Conservation groups, who sued to try to get the agency to reverse an earlier decision not to protect the prairie dog, say the Comanche population was one of the largest and best-documented in the state, and the die-offs indicate the species needs the federal protection.

"We're worried that the smaller the colonies get, the bigger the threat of plague is to those colonies," said Lauren McCain, desert and grasslands projects director for WildEarth Guardians, one of the groups that sued. "There's no federal protection right now for the black-tailed prairie dog. Poisoning, shooting, bulldozing for development, all those threats are allowed to continue."

The prairie dogs live throughout eastern Colorado and the Great Plains. After decades of decimation by hunters, farmers, development and the plague, a non-native disease to which the prairie dog has no resistance, the species was thought to be recovering when it was removed from consideration under the Endangered Species Act in 2004.

A 2006-07 survey by the Colorado Division of Wildlife found 329,529 acres containing prairie dog colonies, including 17,209 acres in El Paso County. Last summer, plague-ridden prairie dogs were found near Schriever Air Force Base.

State and federal officials said localized die-offs from plague are common in prairie dogs.

"Their populations wax and wane over a decade's time frame, rather than year to year or moment to moment," said Pete Gober, a Fish and Wildlife Service field supervisor overseeing the review of the prairie dog. "Just because prairie dogs are declining locally at one moment in time does not mean they will not recover or they're doing that range-wide."

Colorado allows hunting of prairie dogs, including on the national grassland, and the population drop has not changed that, said DOW spokesman Tyler Baskfield. He said entire colonies routinely die from plague in Colorado, though he was not aware of any die-offs as large as on the Comanche.

"From a biological standpoint, we understand certain areas of the population are going to be affected from time to time by the plague," he said. "On a statewide level, it really doesn't have that big an impact where we would start changing regulations."

McCain, though, said the plague outbreak should be considered regional, rather than local. And she said the threat goes beyond the prairie dog, which is still viewed as a nuisance to many plains dwellers. Owls, snakes and the endangered black-footed ferret rely on its tunnels for habitat, and many other animals feed on it.

"It's a pattern we're seeing across the Great Plains, including the national grasslands, which are some of the most important places to protect the prairie dogs," McCain said.

"We've seen it over and over again, that prairie dog populations in areas that experience plague do not reach their original levels," she said.

The Fish and Wildlife Service is studying "plague management tools," Gober said, including wide-scale spraying to control the fleas that spread the plague among prairie dogs.

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