Bolander’s quillwort (Isoetes bolanderi) COSEWIC assessment and status report: chapter 13
Technical Summary
Isoetes bolanderi
Range of Occurrence in Canada: Alberta
Extent and Area Information
Extent of occurrence (EO)(km2)
[a single locality]
<< 1 km2 (2 ha)
Specify trend in EO
Decline
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km2)
[area of the single lake]
<< 1 km2 (2 ha)
Specify trend in AO
Decline
Are there extreme fluctuations in AO?
No
Number of known or inferred current locations
1
Specify trend in #
Decline
Are there extreme fluctuations in number of locations?
No
Specify trend in area, extent or quality of habitat
Stable
Population Information
Generation time (average age of parents in the population)
ca. 3-5 years
Number of mature individuals
12 000 000 ± 2 000 000
Total population trend
stable 2002-2004
% decline over the last/next 10 years or 3 generations
N/A
Are there extreme fluctuations in number of mature individuals?
No
Is the total population severely fragmented?
Yes; 1 population disjunct from USA populations
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
Summit Lake, AB
12 000 000 ± 2 000 000
Threats (actual or imminent threats to populations or habitats)
- Minor physical disturbance at present
- Potential stochastic event
Rescue Effect (immigration from an outside source)
Status of outside population(s)?
USA: N4, some states higher (S1-S3); nearest USA population ca. 30 km away, status unknown
Is immigration known or possible?
Highly unlikely
Would immigrants be adapted to survive in Canada?
Probably
Is there sufficient habitat for immigrants in Canada?
Not likely
Is rescue from outside populations likely?
No
Quantitative Analysis
[provide details on calculation, source(s) of data, models, etc] : N/A
Current Status
COSEWIC: Special Concern (1995)
Threatened (2006)
Status and Reasons for Designation
Status: Threatened
Alpha-numeric code: D2
Reasons for Designation: A small aquatic plant currently known in Canada from only one small lake in southwestern Alberta. The population has a large number of plants but is prone to being extirpated by a single, unpredictable event that could affect the entire population in a short period of time. Another population in a nearby lake has already disappeared over the past 50 years.
Applicability of Criteria
Criterion A: (Declining Total Population): Not applicable. No decline data.
Criterion B: (Small Distribution, and Decline or Fluctuation): Not applicable. Present at a single locality but continuing decline has not been shown nor can be inferred; extreme fluctuations are unknown.
Criterion C: (Small Total Population Size and Decline): Not applicable. Population is too large.
Criterion D: (Very Small Population or Restricted Distribution): Meets Threatened D2 based on the presence of a single population within a small lake of only 2 ha where the population is at risk from stochastic events, in part due to the presence of a hiking trail beside the lake.
Criterion E: (Quantitative Analysis): Not available.
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