Hill’s thistle (Cirsium hillii) COSEWIC assessment and status report: chapter 10

Existing Protection or Other Status

Global heritage status rank: G3 (Vulnerable - Vulnerable globally either because very rare and local throughout its range, found only in a restricted range (even if abundant at some locations), or because of other factors making it vulnerable to extinction or elimination. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals (assigned 26 December 1997) (NatureServe 2001).

Global heritage status rank reasons: Scattered populations in remnant prairie or similar communities. Despite its extreme rarity in Iowa, Indiana, and to some extent Illinois, there are numerous records of viable populations within the remainder of its range, including Ontario, Michigan, Wisconsin, and Minnesota. Additional populations are likely to be found through ongoing inventory. Presently, there are approximately 141 viable populations rangewide. On the other hand, Hill's thistle remains vulnerable to continued decline in many portions of its range if no managing strategies are determined and implemented (Penskar, 1997; NatureServe 2001).

National rank (US): N3 (Vulnerable in the nation either because rare and uncommon, or found only in a restricted range (even if abundant at some locations), or because of other factors making it vulnerable to extirpation. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals (assigned 17 December 1994; NatureServe 2001).

US & Canada State/Province heritage status ranks: S1 (Critically imperiled) in Illinois, Indiana, and Iowa; S3 (Vulnerable) in Michigan, Minnesota, Wisconsin and Ontario (NatureServe 2001).

National rank (Canada): N3 (Vulnerable in the nation either because rare and uncommon, or found only in a restricted range (even if abundant at some locations), or because of other factors making it vulnerable to extirpation. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals (assigned 8 November 1996; NatureServe 2001).

Ontario rank: S3 (Vulnerable in the province either because rare and uncommon, or found only in a restricted range (even if abundant at some locations), or because of other factors making it vulnerable to extirpation. Typically 21 to 100 occurrences or between 3,000 and 10,000 individuals (assigned 18 October 1994; NHIC 2001).

OMNR Designation: None

Ontariogeneral status: Sensitive (assigned 19 April 2000, NHIC 2001)

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