. The Canadian field-naturalist. 300 The Canadian Fdeld-Naturalist Vol. 113 Table 1. Location of Castilleja levisecta populations in Canada. Collection Site Last Observation Collector Population (number of plants/area) Cedar Hill (Victoria) 1887 J. Macoun Extirpated South Wellington 1898 J. Fletcher Extirpated Foul Bay (Victoria) 1918 W. C. Carter Extirpated Sidney 1927 V. Goddard Extirpated Lost Lake (Victoria) 1945 G. Hardy Extirpated Dallas Road Cliffs (Victoria) 1969 L. J. Clark Extirpated Beacon Hill (Victoria) 1991 T. C. Brayshaw Extripated Trial Island (Victoria) 1992 G. W. Douglas 2560
. The Canadian field-naturalist. 300 The Canadian Fdeld-Naturalist Vol. 113 Table 1. Location of Castilleja levisecta populations in Canada. Collection Site Last Observation Collector Population (number of plants/area) Cedar Hill (Victoria) 1887 J. Macoun Extirpated South Wellington 1898 J. Fletcher Extirpated Foul Bay (Victoria) 1918 W. C. Carter Extirpated Sidney 1927 V. Goddard Extirpated Lost Lake (Victoria) 1945 G. Hardy Extirpated Dallas Road Cliffs (Victoria) 1969 L. J. Clark Extirpated Beacon Hill (Victoria) 1991 T. C. Brayshaw Extripated Trial Island (Victoria) 1992 G. W. Douglas 2560/4900 m^ Alpha Islet (Victoria) 1994 S. Cannings 1000/100 m- Population Size and Trends Castilleja levisecta has been observed at nine sites in Canada on southern Vancouver Island or adjacent islands (Table 1, Figure 2). Populations at seven of these sites are now considered extirpated. The popu- lation at Beacon Hill consisted of three plants in 1991. Although the site has been visited every year since then, not a single plant has been located thus the plant is probably extirpated at this site. The pop- ulations on Alpha Islet (1000 plants over 100 m^ in 1994) and Trial Island (2560 plants over 4900 m^ recorded in 1992) remained stable during 1992 to 1996. Limiting Factors In the past, the most direct threat to populations of C. levisecta was that of habitat destruction. Grass- dominated meadows occur on gentle slopes near the most climatically-favourable coastal areas of British Columbia and have been subjected to extensive agri- cultural and residential development. Although the two known Canadian populations occur in protected Ecological Reserves, recreational use of the islands could affect the species. Competition from aggres- sive introduced species is probably the most direct threat. There is also the possibility of a marine oil disaster affecting the islands, since they are located on one of the most busy oil traffic lanes in the world. Special Significance of the Spec
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