HELENA, Mont. - The black-tailed prairie dog may warrant protection under the Endangered Species Act, the U.S. Fish and Wildlife Service said this week in response to a petition by wildlife advocacy groups.

The agency said it will review the status of the black-tailed prairie dog, removed in 2004 as a candidate for listing under the species law, and expects to publish findings in a year.

"Endangered Species Act protection is likely the only way to prevent the animal's extinction," Lauren McCain of petitioner WildEarth Guardians said Tuesday.

South Dakota cattleman Mark Tubbs said prairie dogs damage grazing land, and giving them a federal shield would be a blow to livestock producers.

"They destroy the grass and they cause erosion," said Tubbs, of Edgemont, S.D. "Years ago the government called them range-destroying rodents, and that's what they are."

The burrowing prairie dog aerates the ground, the animal's waste fertilizes it and historic cohabitation with wild bison has shown that prairie dogs and cattle can coexist successfully, McCain said.

Prairie dogs merit Endangered Species Act protection no more now than they did in 2004, but their status could change nonetheless because "we have different people who will be making these decisions now," Tubbs said.

The Fish and Wildlife Service said that although its director is set to retire in January, many of the professionals working on the prairie-dog issue will be the same as before and in any case, conclusions should be driven by science, not by the composition of the staff.

Over the last 150 years the North American population of black-tailed prairie dogs has disappeared from up to 99 percent of its historic range, with plague, habitat loss, poisoning and shooting contributing to the decline, WildEarth Guardians said.

The July settlement of a lawsuit over the status of black-tailed prairie dogs required the Fish and Wildlife Service to determine whether a full status review was appropriate based on information in the petition by WildEarth Guardians, the Laramie-based Biodiversity Conservation Alliance, the Center for Native Ecosystems and Rocky Mountain Animal Defense.

Information in the petition indicates that listing the black-tailed prairie dog as threatened or endangered may be warranted because of plague, poisoning and inadequate regulations, according to a Fish and Wildlife Service notice Tuesday in the Federal Register.

Black-tailed prairie dogs are found in Colorado, Kansas, Montana, Nebraska, New Mexico, North Dakota, Oklahoma, South Dakota, Texas and Wyoming and in portions of Canada and Mexico.

In Arizona, black-tailed prairie dogs disappeared in the 1960s, largely due to poisoning. Seventy-four were placed there in October and the reintroduction of more is planned.

Wildlife that eat prairie dogs include the golden eagle, the swift fox and the endangered black-footed ferret. Other species rely on prairie dogs to varying degrees, sharing habitat with them.

Taxonomists recognize five species of prairie dog in North America. Of those, the Mexican prairie dog is classified as endangered and the Utah prairie dog as threatened. The Gunnison's prairie dog is a candidate for protection within part of its range and the white-tailed prairie dog is undergoing a status review.

If findings from the review of the black-tailed prairie dog support protection under the Endangered Species Act, then a separate, yearlong federal process would begin. Alternatively, there could be a conclusion that protection is not warranted, or that it is warranted but precluded by higher priorities.