HABITAT REQUIREMENTS FOR ERIGERON-KACHINENSIS, A RARE ENDEMIC OF THE COLORADO PLATEAU

Erigeron kachinensis is a rare endemic of the Colorado Plateau in sout heastern Utah. This perennial composite grows in small, isolated popul ations at seeps and alcoves arising along canyon walls in Cedar Mesa S andstone substrates. Characteristics of six Erigeron kachinensis sites in Natural Bridges National Monument, San Juan County, Utah, were stu died to determine habitat requirements for this species. Sites were an alyzed with respect to geology, soil chemistry, physical properties, a nd vegetational characteristics. The alcoves studied were very saline, often with soil surfaces covered with a white crust of salt. Living c over was enhanced by perennially moist soils, diminished amounts of so lar radiation, soil salinity, and above-average amounts of available s oil phosphorus. Kachina daisy vegetative growth appears to be favored by these same abiotic factors. The most commonly associated plant spec ies on E. kachinensis sites were Aquilegia micrantha, Calamagrostis sc opulorum, Zigadenus vaginatus, and Erigeron kachinensis. These species and the daisy accounted for more than 75% of the total living cover i n the alcoves studied. A principal components analysis procedure was d eveloped for evaluating site suitability for Erigeron kachinensis. Thi s daisy has been successfully introduced to a site selected using that model.