COSEWIC assessment and update status report on the American Columbo in Canada
- Assessment Summary
- Executive Summary
- COSEWIC History, Mandate, Membership and Definitions
- Lists of Figures and Tables
- Species Information
- Population Sizes and Trends
- Limiting Factors and Threats
- Special Significance of the Species
- Existing Protection or Other Status Designations
- Technical Summary
- Acknowledgements and Authorities Contacted and Information Sources
- Biographical Summary of Report Writers and Collections Examined
Range of Occurrence in Canada: Ontario
Extent and Area Information
Estimates based on all 22 historical populations and 12 current populations.
2000 km2 at present based on extant populations
Estimate based on 12 extant populations with a maximum extent of 1 ha each
Threats (actual or imminent threats to populations or habitats)
- Sites are highly disrupted by the presence of several invasive exotic plants.
- Habitat disturbance, in the form of trails, dumping, and logging are also of concern.
- Potential loss of three populations is anticipated due to development activities.
Rescue Effect (immigration from an outside source)
USA: Widespread but not abundant in the USA, rare (S2) in NY, nearest state to Canadian populations
(Inadequate data for quantitative analysis)
COSEWIC: Special Concern (1993)
Additional Sources of Information: A literature search using Frasera caroliniensis, Swertia caroliniensis, American Columbo, Inuit Knowledge, Indigenous Knowledge, Traditional Knowledge, Aboriginal Knowledge, Native Knowledge and Indian Knowledge as keywords produced no results.
Status and Reasons for Designation
Reasons for Designation: A long-lived perennial with 11 to 12 extant Canadian populations. These are fragmented and restricted geographically to a highly agricultural and urbanized region that is subject to continuing habitat loss and degradation. Populations consist primarily of vegetative rosettes with only a few flowering plants produced in a given year. The spread of invasive plants within its habitat is a major threat to the persistence of the species. Further losses of populations due to site development are anticipated.
Applicability of Criteria
Criterion A: (Declining Total Population):
Not applicable. Although a 41% decline based on the loss of 9 of 22 populations has been documented, 7 of these losses were historic and most likely well beyond the 10 years or 3 generation timeframe.
Criterion B: (Small Distribution, and Decline or Fluctuation):
Meets Endangered B1 ab (ii, iii, iv, v) +2ab(ii, iii, iv, v) due to the small Extent of Occurrence and Area of Occupancy that fall below critical values, the presence of 11-12 extant populations that are highly fragmented and the continued decline in quality of habitat. This can be inferred due the presence of sites in a highly agricultural and urbanized region that has been subjected to extensive ongoing losses in forested habitats and the presence of a series of invasive plants within its habitat. Two populations have seemingly also been lost since 1989 and future losses due to site development are inferred at three other localities.
Criterion C: (Small Total Population Size and Decline):
Meets Endangered C2a(i). The total number of rosettes counted, as of 2005, was about 4200 but the majority of rosettes likely represent vegetative plants that are not mature and not ready to flower. As of 2005, an incomplete inventory from 6 of the 12 extant sites yielded only 70 flowering plants at 4 sites with the largest number at a single site being 24. It is unlikely that a single population would have more than 250 mature (flowering) plants.
Criterion D: (Very Small Population or Restricted Distribution):
Meets Threatened D2 due to the very small area of occupancy comprising <1 km2 from which can be inferred that stochastic events could impact the populations. The populations also occur within a highly urbanized region where habitat degradation and loss can be expected to continue. Site development at three localities may also result in population losses.
Criterion E: (Quantitative Analysis):
- Date Modified: