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UBC Theses and Dissertations
Interspecific associations, phenology, and environment of some alpine plant communities on Lakeview Mountain, Southern British Columbia Ratcliffe, Marilyn Jean
Three major alpine plant communities were identified on Lakeview Mountain, Cathedral Provincial Park, using multivariate analysis of percentage cover data. Communities were dominated by Kobresia myosuroides, Carex scirpoidea (with one transitional area dominated by both Kobresia myosuroides and Carex scirpoidea), or by Carex scirpoidea and Carex capitata (with Salix nivalis as an additional dominant at one site). Community composition and distribution had little relationship with aspect or with the soils and microclimatic factors measured. Phenology was recorded for vascular species during the summer of 1980. Later flowering times were observed for a number of species in Kobresia myosuroides or Carex scirpoidea/Carex capitata dominated vegetation, and plants generally flowered earlier on southern aspects. Small scale patterns in the form of significant associations between species-pairs were detected in all communities, using a plotless point-line sampling technique. Patterns were abundant at this scale, with a total of 182 significant positive associations and 103 significant negative associations recorded between different species pairs. These interspecific associations varied considerably between sampled sites in the study area, with many occurring only once. Possible association-generating mechanisms have been discussed, and characteristics of the genotype, rather than the taxonomic species, have been suggested as critical in the formation of associations. A competitive hierarchy of dominant species has also been proposed, based on interspecific association and phenological data. Soils within the study area are classified as Alpine Dystric Brunisols, and are coarse textured, strongly acidic, low in available nutrients, and high in organic matter. Climate was relatively uniform over the study area during the 1980 growing season, as were microclimatic air and soil temperature profiles and air humidity profiles. Lower soil temperatures, however, occurred beneath Kobresia myosuroides dominated vegetation.
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