RENO, Nev. (AP) - The U.S. Fish and Wildlife Service has rejected a request by a conservation group to protect four Nevada butterfly subspecies under the Endangered Species Act.

The agency announced Friday that a thorough review determined such a listing was not warranted for the Baking Powder Flat blue butterfly, the bleached sandhill skipper, the Steptoe Valley crescentspot and the White River Valley skipper.

Agency officials say a 12-month review determined the four butterfly subspecies found in eastern Nevada are not threatened by factors such as livestock grazing, off-highway vehicles, and mining and energy development.

The review was in response to a 2010 petition from WildEarth Guardians requesting that 10 subspecies of Great Basin butterflies in Nevada and California be listed as threatened or endangered.

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