WASHINGTON - Carson City's most famous butterfly soon could find itself under federal protection.
The Carson wandering skipper, a rare orange butterfly that nearly halted work on the Carson City freeway, and several other plant and animal species are being targeted for new government protections crafted to nurse them back to abundance.
The Interior Department is agreeing to speed up federal protections for up to 29 rare creatures and plants ranging from the Shivwits milk-vetch herb known only to Washington County, Utah, to the Tumbling Creek cavesnail relegated to a single cave in Missouri, as part of a deal with three conservation groups who say it will avert a legal challenge from them.
''This agreement won't end all the conflicts and it certainly won't save all of America's imperiled species, but it's a good start,'' said Kieran Suckling, executive director of the Center for Biological Diversity.
Under the agreement reached this week, Interior's Fish and Wildlife Service will request that three species - the cavesnail, the pygmy rabbit of Washington state whose population has dwindled to fewer than 50, and the Carson wandering skipper butterfly, found only in California and Nevada - be placed immediately on an emergency list for the endangered and threatened species.
The agency said it will make final decisions on whether to list 14 other species as endangered or threatened. It also will map critical habitats for eight more species, including the Gila chub in New Mexico and Arizona and four freshwater snails in New Mexico. The fate of the Gila chub, a small fish, already is the subject of a lawsuit.
Once found near Lompa Lane, two small populations of the Carson wandering skipper are now found only near California's Honey Lake and near Pyramid Lake. Studies in 1998 showed the proposed alignment of freeway could destroy what little was left of the skipper's Carson habitat.
Its listing as an endangered species could have stopped work on the freeway. The nickle-sized butterfly has not been sighted in Carson City since 1997.
The emergency list is not a permanent fix for endangered species, said Randi Thompson, a spokeswoman for U.S. Fish and Wildlife. The listing will buy the species eight months of protection while Fish and Wildlife personnel apply for permanent protected status.
Also, the Interior Department promised to issue findings within a year on four other species that groups have petitioned to have listed as endangered or threatened and their critical habitats defined.
''I hope this can be a model for future agreements,'' said Interior Secretary Gale Norton. Her department includes the Fish and Wildlife Service, which oversees protection programs for inland fish and land species.
The preliminary agreement would head off expected lawsuits by the Tucson, Ariz.-based Center for Biological Diversity, Southern Appalachian Biodiversity Project and the California Native Plant Society.
''All parties to this agreement ultimately want the same thing - to conserve and recover threatened and endangered species,'' said Marshall Jones, the Fish and Wildlife Service's acting director.
A final settlement must be approved by a federal judge acting on advice from Interior and Justice Department officials.
According to Fish and Wildlife, all the species for which final listing decisions are promised face significant threats. Others among them are:
-Ohlone tiger beetle of California, found only in Santa Cruz County and thinning due to urban growth and nonnative vegetation.
-Spalding's catchfly herb of Idaho, Oregon, Montana, Washington and British Columbia, Canada, a carnation dwindling because of habitat loss and trampling by livestock.
-San Diego ambrosia of southern California, a perennial threatened by highway construction and trampling by horses and humans.
-Mountain yellow-legged frog of southern California, mysteriously disappearing from 99 percent of its former mountain habitat possibly due to predation by trout introduced to the area or by air pollution.
-Coastal cutthroat trout of Washington and Oregon, nearly extinct in two rivers and facing habitat loss, hatcheries and overharvesting.
-Buena Vista Lake ornate shrew of California, of which only about 40 have been sighted, near Bakersfield; it is endangered by agriculture, altered stream use and possible selenium poisoning.
-Chiricahua leopard frog of Arizona and New Mexico, populations few and scattered and threatened by loss of wetlands and disease.
-Scaleshell mussel of Arkansas, Missouri and Oklahoma, found only in 13 streams along the Mississippi River basin and facing poor water quality, sand and gravel mining, reservoir construction and river dredging.
-Vermillion darter of Alabama, a small fish just 3 inches long and surviving in just 7.2 miles of creeks in Jefferson County due to altered stream use and pollutants.
-Golden sedge of North Carolina, limited to two counties and endangered by industrial development, mining and agriculture.
-Holmgren's milk-vetch herbs of Utah and Arizona, found in just two counties and disturbed by urban growth, off-road vehicles and livestock grazing.
-Showy stickseed herb of Washington state, the state's rarest plant, growing only in one location in Chelan County and threatened by other nonnative plants and fire suppression.
-Mississippi gopher frog found only in the state's Harrison County, but formerly seen in Alabama and Louisiana. Only 100 remain due to drought, road-building and fire suppression.