WASHINGTON (CN) - The U.S. Fish and Wildlife Service will not review the status of the wild plains bison under the Endangered Species Act because a petition to list the species as threatened does not contain enough information indicating protection may be warranted.
The agency estimates that there may be 500,000 bison in commercial herds and over 20,000 individuals in conservation herds, which are isolated to preserve their genetic stock, though only the herd at Yellowstone National Park is believed to be free of domestic cattle genes.
The agency does not consider the abundance of animals or plants considered for listing that are raised for commercial purposes because they do not contribute to the conservation of the species.
With regard to the conservation herds, the agency found that their populations are growing as fast as the habitat they depend on will allow and that the petition failed to present evidence that there are too few wild plains bison to preserve genetic diversity or that their numbers are curtailed by the current habitat conditions.
The National Park Service has been embroiled in legal challenges over its plan to slaughter bison that follow historic migration routes down from the snow-covered highlands and cross into Montana where it is feared domestic cattle will be infected by brucellosis, a disease carried by bison that can cause domestic cows to spontaneously abort calves.
The wild plains bison and its cousin the wood bison were hunted nearly to extinction by the end of the 19th century, and recovery efforts for both have been hampered by curtailment of their historic range, disease and the intermingling of genetic stock with domesticated cattle. The Endangered Species Act status of the wood bison was downgraded from "endangered to threatened" earlier this year.
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