Report on the conservation status of Phacelia inconspicua in Idaho.

Moseley, Robert

Obscure phacelia (Phacelia inconspicua) is a small, desert annual known only from five sites in Pershing County, Nevada, and southern Butte County, Idaho. A status inventory for obscure phacelia in Idaho, was conducted by the Idaho Natural Heritage Program during June 1989, in the portion of the eastern Snake River Plain known as the Big Desert. Ten populations of obscure phacelia were found in Idaho, comprising less than 33 acres. Over 10,000 individuals were observed in June 1989. Nine populations occur at Big Southern Butte, ranging in size from one to six acres with several hundred to approximately 2000 individuals each. One population occurs at Pratt Butte, less than 0.5 acre in size and containing approximately 500 individuals. Most suitable-appearing habitat within the Big Desert was searched during June 1989, with only the two sites mentioned above found. All populations occur on lands administered by the Big Butte Resource Area, Idaho Falls District, Bureau of Land Management. Although known populations are few and occur in locally rare habitats, all appear stable. No significant threats to population viability were observed, although a heavily used cattle watering area occurs within 30 m of the Pratt Butte population. It is recommended that obscure phacelia remain a category 2 candidate until its conservation status in Nevada is determined. The U.S. Fish and Wildlife Service should enter into a Conservation Agreement with the BLM for management and protection of the known populations in Idaho.