Serpentine Alpine Community
Stonewall Pass, in the eastern Trinity Alps Wilderness, at the western edge of the Trinity Ultramafic Sheet. The gray mountains in the background are not ultramafic. Photo by Shauna Hee.
Shasta-Trinity National Forest botanists on the serpentine alpine summit of Mt. Eddy, the highest peak in the Klamath-Siskiyou bioregion. Mt. Shasta, a southern Cascade Range volcano, is in the background. Photo by Hugh D. Safford.
Peridotite soils dominate the terrain on the steeper soils found in alpine communities, although serpentinite soils can also be present. Alpine communities are relatively uncommon and by definition found only at the highest elevations of western North America; serpentine soils in alpine associations are even less common. These areas are characterized by the absence of trees and the presence of low growing shrubs or subshrubs, and cold-tolerant herbaceous species. Elevations of alpine serpentine habitat in the Klamath-Siskiyou region range from 8,000 to the highest peak in the Klamath-Siskiyou region, Mt. Eddy, at 9,025 feet. Some of the Klamath-Siskiyou alpine environments were glaciated as recently as 7,000 years ago. Alpine landforms include boulder fields and fell-fields, talus slopes, rocky ridges, moraines, and snow basins.
The absence of trees and spotty presence of low-growing, compact plants, interspersed with areas free of vegetation, characterize the serpentine alpine plant community. Only a handful of plant species can survive the short growing season and bitterly cold temperatures combined with harsh soil chemistry, relative to more moderate habitats, but the species that do exist are the hardiest of the Klamath Range and often the loveliest. Buckwheats are one of the most common shrub genera seen at alpine elevations, including the very rare Trinity buckwheat (Eriogonum alpinum) and Mt. Eddy buckwheat (Eriogonum umbellatum var. humistratum), but common juniper (Juniperus communis var. saxatilis) may also be present. Herbaceous plants include Siskiyou milkvetch (Astragalus whitneyi var. siskiyouensis), quill-leaf lewisia (Lewisia leana), cobwebby Indian paintbrush (Castilleja arachnoidea), and mountain jewelflower (Streptanthus tortuosus var. orbiculatus). Annual species such as staining collomia (Collomia tinctoria) and Johnston’s knotweed (Polygonum douglasii ssp. johnstonii) germinate from seed, grow, and set seed in as little as three months each year.
Eriogonum alpinum: note how the color of the leaves precisely matches the color of the serpentine rock pavement. Photo by Sydney Carothers.
Collomia tinctoria on reddish peridotite. Photo by Julie Kierstead Nelson.
It is common to encounter rare species in the alpine habitats because of the Klamath Ranges’ high degree of serpentine endemism. There are fewer threats than in habitats closer to urban areas and most disturbances are natural occurrences. Recreational use does cause some damage to these habitats. Climate change looms as a particularly intractable threat to the continued existence of these cold-adapted plants on their alpine sky islands. Other rare plants you might encounter are golden draba (Draba aureola), Mason’s sky pilot (Polemonium chartaceum), crested potentilla (Potentilla cristae), Copeland’s speedwell (Veronica copelandii), Mt. Eddy draba (Draba carnosula), and Siskiyou fireweed (Epilobium siskiyouense).
Our thanks to CalPhotos and its many contributors for many of the pictures in this photo gallery.
Resources and References
- Safford, H. D., J. H. Viers, and S. P. Harrison. 2005. Madrono 52(4): 222-257.
- Alexander, Earl B., R. G. Coleman, T. Keeler-Wolf, and S. P. Harrison. 2007. Serpentine Geoecology of Western North America. Oxford University Press, 512 p.