Conservation Status of Least Phacelia (Phacelia minutissima)

Moseley, Robert; Conservation Data Center, Idaho Dept. of Fish and Game

This report presents results of a field survey conducted by Robert Moseley to relocate known sites and find new sites of this taxon in Idaho. No plants were observed. Although not specifically stated in the report, Mr. Moseley cursorily searched the North Unit and near Pratt Butte, in Craters of the Moon National Monument as a minor part of his survey efforts in the Pioneer Mountains (R. Moseley pers. comm. with Steve Popovich, former BLM Shoshone District Botanist, currently University of Idaho NPSpecies plant database contractor, summer, 1995). Least phacelia (Phacelia minutissima) is a widely distributed, but rarely observed species, known from eight disjunct collection sites in Washington, Oregon, Idaho, and Nevada. Due to the rangewide conservation concern, it was recently added to the list of candidate plants being considered for listing as endangered or threatened under the Endangered Species Act. No systematic survey has been conducted in Idaho. To rectify this paucity of information, I conducted a field survey in the vicinity of all known Idaho sites during 1994, but was unsuccessful in relocating the old collection sites or finding new populations. Recent systematic searches and general floristic inventories in the other three states have also failed to relocate any populations. This report is the status of our knowledge of the distribution and conservation status of least phacelia throughout its range, with an emphasis on Idaho. Because no populations have been seen recently, threats to population and species viability are unknown, although the Oregon population is considered extirpated. Before useful conservation recommendations can be made for least phacelia the eight known collections sites must be relocated. This should be the immediate priority for the land-managing agencies. Once the old sites are found and habitat characteristics are better known, there is a greater chance of discovering new populations and formulating a conservation strategy.