. The Canadian field-naturalist. Natural history. Vancouver Island Nanaimo Wellington Port ^^.adysmith Albemi mr-. Figure 2. Distribution of Aster curtus in British Columbia, (o firmed sites, # - recently confirmed sites) extirpated sites, â - uncon- ranging from 125 to 300 m2. Individual plant stems were fairly high, considering the limited areas cov- ered, ranging from 200 to 1200 stems/site. Only two of the sites (Mount Tzuhalem and Uplands Park) have been observed with respect to colony trends. During a three-year time period the lat- ter colonies maintained their size and stem numbers wit
. The Canadian field-naturalist. Natural history. Vancouver Island Nanaimo Wellington Port ^^.adysmith Albemi mr-. Figure 2. Distribution of Aster curtus in British Columbia, (o firmed sites, # - recently confirmed sites) extirpated sites, â - uncon- ranging from 125 to 300 m2. Individual plant stems were fairly high, considering the limited areas cov- ered, ranging from 200 to 1200 stems/site. Only two of the sites (Mount Tzuhalem and Uplands Park) have been observed with respect to colony trends. During a three-year time period the lat- ter colonies maintained their size and stem numbers within 10% of their maximums. A slight decrease at Mt. Tzuhalem was due mainly to the efforts of mem- bers of a local natural history society who, during a Cytisus scoparius removal program, piled and burned the shrub on a sizeable Aster curtus colony. Limiting Factors The major threat to Aster curtus is habitat destruction. This is of particular concern in the grass-dominated meadows often associated with the Quercus garryana-Bromus communities that are limited to the southeastern side of Vancouver Island and some of the Gulf Islands. Both types of vegetation are believed to have been much more common before colonization by European settlers. Their destruction has continued to the present resulting in the elimination of almost all sites occurring outside parks or ecological reserves. Historically, Quercus garryana commu- nities and grass-dominated meadows have always been heavily influenced by human (1972) believed that without human interference some of these stands would have eventually been replaced by Douglas-fir Pseudotsuga menziesii Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ottawa Field-Naturalists' Club. Ottawa, Ottawa Field-Naturalists' Club
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