Bolander’s quillwort (Isoetes bolanderi) COSEWIC assessment and status report: chapter 6

Distribution

Global Range

Isoetes bolanderi is endemic to western North America, occurring in the Rocky Mountains and the Coast, Cascade and Sierra Nevada mountains of the United States and adjacent Canada (Figure 2). It is known today throughout its historical range.


Figure 2: Global Range of Isoetes bolanderi

Figure 2: Global range of Isoetes bolanderi


Canadian Range

Isoetes bolanderi is currently known in Canada only from Waterton Lakes National Park in southwestern Alberta (Figure 3). It was first collected by A.E. Porsild and A.J. Breitung in 1946 from the Carthew Lakes area of Waterton Lakes National Park. They identified it as I. echinospora and the specimen was unreported by subsequent investigators, including Breitung's own report (Breitung 1957) on the flora of Waterton Lakes National Park, until included as I. echinospora in Cody and Britton (1989). The identification was revised to I. bolanderi during the original COSEWIC report on this species (Brunton 1994).


Figure 3: Canadian Location of Isoetes bolanderi

Figure 3: Canadian location of Isoetes bolanderi

The Carthew Lakes area was searched unsuccessfully for I. bolanderi in 1995, 1996, 2002 and 2003 by Peter Achuff. The unusually high elevation of the Carthew Lakes site and absence of any subsequent I. bolanderi reports from there raised questions as to the legitimacy of the original 1946 discovery. An examination of Canadian Museum of Nature archives determined, however, that the collectors were indeed at that site on that day (Brunton 2002). The Carthew Lakes population is now considered extirpated since recent, thorough searches have failed to find it. The cause of the extirpation is not apparent but can be regarded as a stochastic event that befell a small population even though in a strict protected area.

A second population of Isoetes bolanderi was discovered by Breitung on 14 August 1953 at Summit Lake, Waterton Lakes National Park, 3.5 km southwest of Porsild and Breitung's original Carthew Lakes site. This population has been widely reported since (e.g. Breitung 1957, Kuijt 1982, Achuff 1997).

Isoetes bolanderi is known today in Canada only from the Summit Lake population. The nearest known population is in the USA at Dutch Lakes in Glacier National Park, Montana, about 30 km southwest of Summit Lake (Lesica 2002).

The close similarity of Isoetes bolanderi to I. howellii has resulted in three erroneous reports of I. bolanderi in British Columbia, all of which have been re-identified as I. howellii:

1) "... abundant in a marshy pond on the Indian Reservation at Kamloops ... partly in and partly out of the water ... " (Macoun 1890).

The ephemeral sage-flats pool in which the Macoun collection was apparently taken (50o 41'N, 120o 15'W, 200 m W of Highway 5, 400 m N of South Thompson River, Kamloops Indian Reserve 1) has been severely impacted by in-filling, habitat alteration by Typha latifolia and sewage run-off from an adjacent trailer park. No Isoetes was apparent in August 1992 (D. Brunton, pers. obs.). The Macoun report was regarded as I. bolanderi by Taylor (1970) and Scoggan (1978). Macoun's collection (in pools on the Indian Reserve, Kamloops. John Macoun s.n., 24 July 1889 [CAN5536; CAN 5535]) has been revised to I. howellii (Cody and Britton 1989).

2) "... quite common in Shushwap [sic] Lake at Sicamous ..." (Macoun 1890).

The report is repeated and mapped by Taylor (1970) and Scoggan (1978). No subsequent reports of Isoetes bolanderi from the Sicamous area or elsewhere in interior British Columbia are known. Macoun's collection (In the water near the railway bridge, Shushwap [sic] Lake, Sicamous, John Macoun s.n., 17 July 1889, CAN 5534) has been revised to I. howellii (Cody and Britton 1989).

3) 49o 01.5 N'  114o 03.5 W'; 50 m W of Akamina Pass Trail, 120 m W of Alberta border, Akamina - Kishinena Recreation Area, East Kootenay Region.

This is the basis for recent reports of Isoetes bolanderi occurring in British Columbia (e.g. Straley et al. 1985, Argus and Pryer 1990, Taylor et al. 1993, Ceska 2000). Plants from this population were first collected 24 August 1976 by D. Polster as I. echinospora (UV 94753) - fide R.T. Ogilvie. Additional material, obtained in August 1981 by A. Polster for cytological investigations by A. Ceska and D.M. Britton, was identified as atypical I. bolanderi (cf. Kuijt 1982). Subsequently, this population has been determined to be I. howellii (Brunton 1994, Douglas et al. 1998, Ceska 2000) and was still extant in 2004 (P. Achuff, pers. obs.).

Since the Carthew Lakes population is extirpated, the current Extent of Occurrence and Area of Occupancy consist solely of the Summit Lake location, which is about 2 ha.

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