Field Survey for Three Rare Plant Species in the Raft River Mountains, Utah

摘要

This report summarizes our surveys for three rare plant species endemic to the Great Basin region of the Intermountain West. Grouse Creek rockcress (Arabis falcatoria), Cottams cinquefoil (Potentilla cottamii), and rock violet (Viola lithion) are all on the U.S. Forest Service, Region 4 Sensitive plant list. Fewer than ten occurrences have been documented for each of these species. Sawtooth National Forest land in the Raft River Mountains of northwestern Utah is known to support several Cottams cinquefoil occurrences. It is also reported to have one or two occurrences of Grouse Creek rockcress. Rock violet has never been documented from the Sawtooth NF, but occurs in close proximity to Cottams cinquefoil at a site in Nevada, and the two species habitat requirements overlap to a large degree. In a cooperative project with the Sawtooth National Forest, the Idaho Conservation Data Center conducted a field survey for these three rare plant species in the Raft River Mountains in 2003. Two new occurrences of Cottams cinquefoil were discovered, including a possible new elevational low. In addition, updated conservation information was collected at two previously documented Cottams cinquefoil occurrences. A third previously documented occurrence was not relocated. Grouse Creek rockcress and rock violet were not found and potential habitat for these two species appears to be limited on Sawtooth National Forest land.