ABSTRACT: Serpentine soils and vegetation of northwestern North America.

CGRG Bibliography of Canadian Geomorphology
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Abstract

Ultramafic rocks with serpentine soils are widely distributed in accreted terranes southwest of the Rocky Mountain trench-Tintina fault zone and in Alaska-type bodies of British Columbia and Southeast Alaska. Although the areas of serpentine soils are small, many of them have vegetation that is distinctly different than that on adjacent soils. Soil classes in the World Reference Base and Canadian (in parentheses) systems are predominantly Cambisols (mostly Eutric Brunisols, but with Dystric and Humo-Ferric Brunisols where tephra or glacial drift have been deposited over the serpentine materials). Regosols (Orthic Regosols), Phaeozems (Mellanic Brunisols), and Luvisols (Gray Brown Luvisols) are also represented by serpentine soils. The most distinctive feature of the serpentine soils, other than the serpentine minerals inherited from the parent materials, is low exchangeable Ca/Mg ratios. This is the soil property that has the greatest effect on serpentine plantdistributions. The common serpentine plant communities are alpine tundra, savanna, and forest. Most of the forests are coniferous (for example; white spruce, subalpine fir, and Douglas-fir), but paper birch (Betula papyrifera) is common toward the north and aspen (Populus tremuloides) is a successional species, along with lodgepole pine (P. contorta). Shrub species and herbs differ from north to south, although some shrubs such as low juniper (J. communis) are widespread on serpentine. Some of the more common genera of grass and sedges, from coldest to warmest, are Arctagrostis, Carex (C. bigelovii), Festuca (F. altaica), Calamagrostis, Pseudroegnaria (P. spicata), and Poa (P. secunda). Bryophytes and lichens are common ground cover toward the north and near the Pacific Coast.

Bibliography of Canadian Geomorphology