Cliff paintbrush (Castilleja rupicola) COSEWIC assessment and status report: chapter 9

Population sizes and trends

A total of 15 historic and extant populations have been documented. Three recently surveyed populations are found in the Skagit River valley in southwestern British Columbia (Figure 3; Table 1). Eleven other records of the species are known from both the Skagit and Chilliwack River valleys from 1901 to 1999 (Table 1). A 1912 collection is also known from Mount Brunswick in the southern Coast Mountains. All of the latter 12 collections have virtually no information on population sizes. The recently confirmed populations, observed in 2003, cover an extent of occurrence (EO) of about 90 km2 with the EO of all known sites totalling <1000 km2 (Figure 3). Their area of occupancy ranges from one to five m2 each and consist of one to three plants.

It is likely that the 9 populations reported in 1984, and thereafter, are extant since none of the sites is at risk. Two of these locations (Finlayson Peak and Whitworth Peak) were revisited in 2003 but the populations were not relocated. This is probably due to the rareness of the plants on the high ridges and the difficulty in finding plants in rugged terrain when present in very low numbers.

Short- and long-term trends for these populations are unknown but can be expected to vary depending on the plant’s life span, which, unfortunately, is unknown for this perennial herb. Also, since the plant apparently only occurs in small numbers, the success of seed germination and seedling survival will play a major role in these trends.

 

Table 1. Locations and population sizes for Castilleja rupicola in southwestern British Columbia.
Collection Site Last observation Collector Number of plants/area (m2)
Tomyhoi Peak, CRVFootnote a 1901 (historic record) Macoun Unknown
Mount Brunswick, Coast Mtn. Range 1912 (historic record) Perry Unknown
Mount Cheam, CRV 1954 (historic record) Brayshaw Unknown
Church Mountain, CRV 1984 Ceska “few plants”
Mount McGuire, CRV 1984 Ceska “few plants”
Mount Liumchen, CRV 1984 Ceska “few plants”
Thompson Peak, CRV 1984 Ceska “few plants”
Mount Lindeman, CRV 1984 Ceska “few plants”
Finlayson Peak, SVPPFootnote b 1988 Ceska “few plants”
Whitworth Peak, SVPP 1988 Ceska “few plants”
Klesilkwas Mountain, CRV/SVPP 1992 Ceska “few plants”
Foley Peak, CRV 1999 Lomer “few plants”
Silvertip Mountain, SRVFootnote c 2003 Lomer 2/2 m2
Mt. Brice, SVPP 2003 Douglas & Smith 3/5 m2
Marmot Mountain, SRV 2003 Douglas & Smith 1/1 m2

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