BOISE -- A rare plant that blooms in the Owyhee Desert of southwestern Idaho should be reconsidered for listing under the Endangered Species Act, according to a district court judge's ruling on Friday.

Secretary of the Interior Gale Norton relied on "improper standards" in determining that listing slickspot peppergrass under the act was not warranted, wrote District Court Judge Mikel H. Williams in his order to remand the species' fate back Norton.

In 2004, the U.S. Fish and Wildlife Service withdrew its proposal to list slickspot peppergrass under the Endangered Species Act. The state of Idaho, together with private landowners, crafted an agreement to conserve slickspot peppergrass and thereby preclude the need for listing the species under the act. When deciding not to list the plant, Fish and Wildlife officials noted the agreement should decrease risks of harm to slickspot peppergrass.

Western Watersheds filed its lawsuit saying that the Fish and Wildlife Service violated the ESA when it declined to list the species after determining that the plant had a 64 to 82 percent chance of extinction in the next 100 years, depending on implementation of the conservation agreement.

The plant grows in "slickspots," areas in a sagebrush steppe ecosystem that retain more water longer than the surrounding soil. Slickspot peppergrass can be found on 20,000 acres of land spread over Ada, Canyon, Elmore, Gem, Owyhee and Payette counties. About 91 percent of those acres belong to the Bureau of Land Management, including an allotment already wrapped up in a lawsuit between the agency and Western Watersheds in which the district court has ordered a halt to grazing.

The two court decisions argue for taking better care of the sagebrush steppe ecosystem, said Katie Fite, biodiversity director for Western Watersheds.

"The sound science is there that unless the maximum protection of the Endangered Species Act is extended to it, slickspot peppergrass will not survive," Fite said. "This pretty firmly says list this as either endangered or threatened."

Livestock are attracted to slickspot peppergrass because the plant retains moisture, Fite said. However, livestock trample and damage it.

Before deciding to withdraw its proposal to list the species, Williams wrote, the Fish and Wildlife Service "should have erred on the side of caution."

Times-News reporter Michelle Dunlop can be reached at 735-3237 or by e-mail at mdunlop@magicvalley.com.