Vegetation communities and plant distributions and their relationships with parent materials in the forest-tundra of northwestern Canada

Vegetation data from 95 sites and chemical and textural data for parent materials from 98 sites in subarctic northwestern Canada were analyzed by ordination, classification, and statistical techniques A discontinuity in plant species occurrence, vegetation communities, and parent materials takes place near the southeast/northwest boundary north of Great Slave Lake Till parent materials in the forest-tundra show regional differences in nutrient concentration and texture that correlate with the local bedrock Northwestern tills, as a group, are markedly richer in nutrients and finer-textured than Shield tills, with much higher levels of cation exchange capacity, nitrogen, potassium, calcium, magnesium, hydrogen, and organic carbon, and more silt and clay than Shield tills Plant species occurrence and vegetation community composition show strong relationships with soil pH, moisture, texture, and latitude The northwest is characterized by calciphilic white spruce. Dryas , legume, and bryophyte communities, and high species diversity, on basic loamy Cryosols The southeast is characterized by acidophiles and widespread generalist black spruce, ericad, and lichen communities, and low species diversity, on acidic loamy sand and sandy loam Brunisols