Gaspé shrew (Sorex gaspensis) COSEWIC assessment and status report: chapter 11
Technical Summary
Sorex gaspensis
Gaspé shrew – la musaraigne de Gaspé
Range of Occurrence in Canada:
Quebec, New Brunswick, Nova Scotia
Extent and Area Information
Extent of occurrence (EO) (km²) [explain source of information and calculation] :
13,089 km²; calculated using minimum convex polygon (see text).
Specify trend in EO :
None known
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km²) [explain source of information and calculation] :
128 km² calculated using 2-km² grid; 480 km² calculated using 4-km² grid.
Specify trend in AO :
None known
Are there extreme fluctuations in AO?
No
Number of known or inferred current locations :
33 (11)
Specify trend in # :
None
Are there extreme fluctuations in number of locations?
No
Specify trend in area, extent or quality of habitat :
None known
Population Information
Generation time (average age of parents in the population) :
Unknown
Number of mature individuals :
Unknown
Total population trend:
Unknown
% decline over the last/next 10 years or 3 generations.
Are there extreme fluctuations in number of mature individuals?
No
Is the total population severely fragmented?
Yes
Specify trend in number of populations:
Not known
Are there extreme fluctuations in number of populations?
Not known
List populations with number of mature individuals in each:
Not known
Threats (actual or imminent threats to populations or habitats)
None identified
Rescue Effect (immigration from an outside source)
Status of outside population(s)?
USA: S. gaspensis does not occur in USA
Is immigration known or possible?
No
Would immigrants be adapted to survive in Canada?
Does not occur outside Canada
Is there sufficient habitat for immigrants in Canada?
Yes, but habitat is naturally fragmented and isolated
Is rescue from outside populations likely?
No
Quantitative Analysis
Current Status
COSEWIC:Special Concern, April 1988; Not at Risk, April 2006
Status and Reasons for Designation
Status: Not at Risk
Alpha-numeric code: Not applicable
Reasons for Designation: It is highly likely that this shrew is more widespread and abundant than presently believed. Although the occurrence of presumed preferred habitat is restricted and isolated in the landscape, it is not at risk. The species appears to be widespread in talus habitats throughout its range. Recent information questions the taxonomic status of this shrew. Whereas it may well be a subspecies of Sorex dispar, when the original designation was made, it was considered a Canadian endemic species.
Applicability of Criteria
- Criterion A: There is no direct evidence of a declining population trend, but there are no good data on population size. Likely widespread throughout its range in Canada. May not be a distinct species but a subspecies of S. dispar.
- Criterion B: EO > 13,000 km²; AO is at least 128 km². It is likely that species is more widespread and abundant than believed.
- Criterion C: Total population size is unknown but there is no apparent threat to suitable habitat.
- Criterion D: Total population size is unknown but the species is widespread.
- Criterion E: Not available.
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