Classification and ordination of the alpine plant communities of Railroad Ridge, White Cloud Peaks, Idaho

Alpine vegetation of Railroad Ridge in the White Cloud Peaks, Custer County , Idaho, was investigated to ascertain native communities and describe thei r distribution with respect to important environmental factors. Percent cov er of all species and environmental information were recorded for 69 plots. Data were analyzed by TWINSPAN and CANOCO, which provided a classification and an ordination, respectively. Predominant communities are dominated by (I) Phlox pulvinata, (2) Carer elynoides, and (3) Geum rossii, and ether co mmunities of lesser importance are dominated by (4) Artemisia campestris, ( 5) Eriogonum ovalifolium and Silene acaulis, and (6) Ivesia gordonii. Altho ugh the Artemisia campestris community occupies a relatively small portion of the study area, it is noteworthy because it is a community type not prev iously known for Idaho. The community co-dominated by Eriogonum ovalifolium and Silene acaulis is also unique and has not been documented in other Ida ho alpine studies. Community distribution showed the strongest correlation with exposure, substrate type, and slope. In general, the study area suppor ts fellfield communities that are representative of alpine areas in Idaho a nd some Great Basin mountain ranges, and dense turflike communities similar to ones found throughout western North America's temperate alpine regions.