Relict grassland in northern Saskatchewan : a phytogeographic study in the Clearwater River Valley
Johnson, Rodney Harvey
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The main purpose of this research was to characterize the vegetation of the open slopes along the lower Saskatchewan reach of the Clearwater River. Examination of the species that constitute a representative site and the environmental conditions within which they exist was essential to the prediction of vegetation status and continued site occupation. An hypothesis was put forward on the origin of these communities and various methods to measure environmental parameters were used to determine the present site conditions. Many plants of the community were found to be displaced in Saskatchewan flora range and outside their normal climatic region. Most notable species are Anemone cylindrica A. Gray, Artemisia frigida Willd., Aster conspicuus Lindl., A. laevis L., Penstemon gracilis Nutt. and Stipa curtiseta (Hitchc.) Barkworth. Near the steppe study site, Abiesbalsamea (L.) Mill. exists as an isolated population in well protected spring-sapping zones. Calamagrostis purpurascens R. Br., a northern resident found previously as far south as the Cluff Lake area, represents a southern range extension. The data collected suggest recent advancement of footslope overstory but that maximum upslope movement may have been reached. The grassland species present are explained as being a relict community of previously widespread steppe origin.