Brook spike-primrose (Epilobium torreyi) COSEWIC assessment and status report: chapter 11

Technical Summary

Epilobium torreyi

brook spike-primrose – épilobe de Torrey

Range of Occurrence in Canada:

British Columbia

Extent and Area Information

Extent of occurrence (EO) (km²)
<<1 km² if still extant
Specify trend in EO
Decline:  Craigflower Meadow population seemingly disappeared between 1993 and 2001.
McTavish Road population seemingly disappeared between 1966 and 2001.
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km²):
unknown if still present in seed bank
Specify trend in AO:
decline
Are there extreme fluctuations in AO?
No
Number of known or inferred current locations:
2 possibly extirpated
Specify trend in #:
decline – now presumed extirpated
Are there extreme fluctuations in number of locations?
No
Specify trend in area, extent or quality of habitat:
Declining in extent as a result of urban and rural development. Declining in quality as a result of human activity and invasive species.

Population Information

Generation time (average age of parents in the population):
seven months
Number of mature individuals:
0
Total population trend:
decline and now presumed extirpated
% decline over the last/next 10 years or 3 generations.
possibly 100%
Are there extreme fluctuations in number of mature individuals?
Not applicable (n/a)
Is the total population severely fragmented?
n/a  all presumed extirpated
Specify trend in number of populations:
decline
Are there extreme fluctuations in number of populations?
No
List populations with number of mature individuals in each:
both presumed extirpated

Threats (actual or imminent threats to populations or habitats)

  • Existing threats: habitat loss through urban and rural development; habitat deterioration due to human activities and invasive species

Rescue Effect (immigration from an outside source)

Status of outside population(s)?
USA: healthy but disjunct
Is immigration known or possible?
Not without assistance
Would immigrants be adapted to survive in Canada?
Possibly
Is there sufficient habitat for immigrants in Canada?
Little remaining
Is rescue from outside populations likely?
No

Quantitative Analysis

n/a

Current Status

COSEWIC: Endangered (2006)

Status and Reasons for Designation

Status: Endangered

Alpha-numeric code: D1

Reasons for Designation: Although no plants have been seen at the two known sites after intensive directed surveys, there is still the possibility that some seeds may remain in the soil seed bank given the relatively short period of time since the last observation of plants in 1993, or that previously overlooked populations may be found.

Applicability of Criteria

  • Criterion A: (Declining Total Population): n/a
  • Criterion B: (Small Distribution, and Decline or Fluctuation): n/a
  • Criterion C: (Small Total Population Size and Decline): n/a
  • Criterion D: (Very Small Population or Restricted Distribution): Although the species is seemingly recently extirpated in Canada, there is the possibility that there is a sufficient number of seeds in the soil seed bank that some could germinate and develop into mature plants, thereby meeting a status of Endangered if conditions improved.
  • Criterion E: (Quantitative Analysis): n/a

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