Slender collomia (Collomia tenella) COSEWIC assessment and status report: chapter 12

Technical Summary

Collomia tenella

Slender Collomia – collomia délicat

Range of Occurrence in Canada:

British Columbia

Extent and Area Information

Extent of occurrence (EO)(km²)

Based on area of the single site. ≤1 (56 )

Specify trend in EO:

Unknown

Are there extreme fluctuations in EO?

Unknown

Area of occupancy (AO) (km²)

Based on an approximation of habitats occupied. ≤1 (56 m²)

Specify trend in AO:

Unknown

Are there extreme fluctuations in AO?

Unknown

Number of known or inferred current locations:

1

Specify trend in #:

Unknown

Are there extreme fluctuations in number of locations?

Unknown

Specify trend in area, extent or quality of habitat:

Unknown

Population Information

Generation time (average age of parents in the population):

1 year

Number of mature individuals:

0-127

Total population trend:

fluctuating numbers of plants

% decline over the last/next 10 years or 3 generations.

N/A

Are there extreme fluctuations in number of mature individuals?

Yes

Is the total population severely fragmented?

1 population known and considerably disjunct from nearest site in WA state

Specify trend in number of populations:

Unknown

Are there extreme fluctuations in number of populations?

Unknown

List populations with number of mature individuals in each:

Princeton, Stevenson Lake area - 127 individuals

Threats (actual or imminent threats to populations or habitats)

  • Development - roads, housing, sand removal
  • Introduced species encroachment

Rescue Effect (immigration from an outside source)

Status of outside population(s)?

USA: Unknown status in 4 jurisdictions (WA, OR, ID & NV) and imperiled in WY and UT.

Is immigration known or possible?

Unknown

Would immigrants be adapted to survive in Canada?

Unknown

Is there sufficient habitat for immigrants in Canada?

Unknown

Is rescue from outside populations likely?

Unlikely

Quantitative Analysis

N/A

Current Status

COSEWIC: Endangered

Status and Reasons for Designation

Status: Endangered

Alpha-numeric code: Met criteria for Endangered, B1ac(iv)+2ac(iv); D1.

Reasons for Designation: An annual herb present at a single sandy site near Princeton, British Columbia. The population fluctuates widely from year to year. At risk to stochastic events, roadside development, sand removal, and invasion by alien species.

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