Bashful Bulrush (Trichophorum Planifolium)
- Assessment Summary
- Executive Summary
- COSEWIC Mandate, Membership and Definitions
- Species Information
- General Biology
- Population Size and Trends
- Limiting Factors and Threats
- Special Significance of the Species
- Evaluation and Proposed Status
- Literature Cited
- The Author
Population Sizes and Trends
This species occurs only in two areas: the wooded slopes of the Rouge River valley in Toronto and the wooded slopes adjacent to Dundas Marsh on the grounds of the RBG in Hamilton. Between 1986 and the present, all relocated sites have declined.
Crins (1986) reported a large population (his site 1a) south of Highway #401 consisting of “hundreds of flowering culms”. Varga et al., (1991) reported “several hundred clumps” in an area of several square metres. Mike Oldham, of the Natural Heritage Information Centre, Peterborough, searched unsuccessfully for this site in 1997. On 5 May 1999, the author, Steve Varga of the Ontario Ministry of Natural Resources, Aurora, Mike McMurtry, also of the Aurora office of the Ontario Ministry of Natural Resources, and Pam Fulford of the Rouge Park, Toronto, searched this area. After two hours of concerted effort we were only able to find one small clump where the large colony had previously occurred. A nearby coyote or fox den, not present in 1990, is situated very close to the remaining clump. It is likely that the digging and traffic around the den have eliminated most plants of this rare species at this site. This is a dramatic reduction to less than 1% of the population that was known as recently as 1990.
A second Rouge valley site (1b of Crins, 1986) occurred north of Highway #401, however, it has not been seen since 1981 when the single clump was first found by Steve Varga. It was not relocated by Crins (1986) nor was it found by Varga et al., (1991). Mike Oldham, of the Natural Heritage Information Centre, Peterborough, searched unsuccessfully for this population in 1997. This site may no longer be extant.
Crins (1986) lists five historic sub-populations from the RBG (four of which were found in 1984): three from the north shore of Dundas Marsh (sites 2a, 2b, and 2c) and two from the south shore of the Marsh (sites 2d and 2e). Two of the north shore sub-populations (along the Gray Doe trail) are within 100 metres of one another and the two south shore populations are also quite close together.
The present author, Tyler Smith of the RBG, and Anthony Goodban, Milton, searched the north shore Grey Doe trail area on 6 May 1999 for three hours and found only a small patch of Bashful Bulrush consisting of four clumps, each with about 10 flowering culms. This is probably site “2a” reported by Crins (1986) that had 8 small clumps with 5-30 flowering culms each in 1984. This would appear to be a 50% reduction. The three of us found no plants of this species at Crins’ (1986) site “2b” that contained several hundred flowering culms in an area of 10 m X 10 m. This site may have disappeared or it may have declined to a few plants that were missed by us in 1999. Crins (1986) reported an additional site (his 2c) on the north shore that occurred in an area of 1 m by 10 m with several hundred flowering culms. This population has not been searched for since 1984 so its status is unknown.
Tyler Smith and the present author searched the south shore area for two hours on 6 May 1999 and found only a single patch (1.5m x 1.5m) of 10 clumps, each with 10-20 flowering culms. This may be site “2d” reported by Crins (1986) that consisted of several hundred flowering culms in an area of 8 by 5 metres on both sides of a trail. This is a reduction on the order of at least 50%. Crins (1986) was not able to find site 2e (located a few hundred metres west of 2d) that was last seen by the original collector (A. Tamsalu) in 1958. The present author also looked briefly at this location without any success.
There are several historic collections made by A. Tamsalu in 1957-1958 from the north and south shores of Dundas Marsh. It is unclear if any of these old records represent localities additional to those discussed here or in Crins (1986).
Detailed site information has been provided to the Subcommittee for Vascular Plants, Mosses and Lichens (COSEWIC).
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