Greater short-horned lizard COSEWIC assessment and status report: chapter 11
Technical Summary
Phrynosoma hernandesi
Greater Short-horned Lizard – Grand iguane à petites cornes
Range of Occurrence in Canada:
Alberta and Saskatchewan
Extent and Area Information
Extent of occurrence (EO) (km²)
- 8830 km² : Canada
- 8110 km² : AB
- 720 km² : SK
- SK record data from Powell et al. (1998) and Saskatchewan Conservation Data Centre (2006).
- AB data from Alberta Government database, J. James (2002; 2003)
Specify trend in EO
Declining?
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km²)
- 220 km² (Canada)
- 144 km²: AB
- 76 km² : SK
- SK record data from Powell et al. (1998) and Saskatchewan Conservation Data Centre (2006).
- AB data from Alberta Government database, J. James (2002; 2003) AO calculated by creating a 2×2 kmsquare grid centred over each record within the EOO
Specify trend in AO
Declining?
Are there extreme fluctuations in AO?
Unknown
Number of known or inferred current locations
- AB: 4 locations
- SK: 2 locations
Specify trend in #
Stable
Are there extreme fluctuations in number of locations?
No
Specify trend in area, extent or quality of habitat
Declining
Population Information
Generation time (average age of parents in the population)
Estimated 3 yrs
Number of mature individuals
- Estimated AB: between 2677-16379
- SK: unknown
Total population trend:
- AB: declining
- SK: unknown/presumed stable
% decline over the last/next 10 years or 3 generations.
Unknown
Are there extreme fluctuations in number of mature individuals?
Unknown, but possible with climatic shifts
Is the total population severely fragmented?
Yes
Specify trend in number of populations
- SK: stable
- AB: declining
Are there extreme fluctuations in number of populations?
Probably not
List populations with number of mature individuals in each:
- SK: unknown
- AB: South Saskatchewan River location: 507 – 3071
- Chin Coulee location: 273 – 1653
- Manyberries Hills: 819 – 4959
- Milk River and area: 1052 - 6377
Threats (actual or imminent threats to populations or habitats)
- Natural climatic and physiological limitations: (all Canadian populations)
- Agricultural impacts: (AB: Saskatchewan River and the Forty-Mile / Chin coulee populations)
- Industrial development and roads: (AB: Manyberries Hills population).
- Urbanization: (AB: Medicine Hat population)
Rescue Effect (immigration from an outside source)
Status of outside population(s)?
- USA: Global rank S5
- Montana: Species of Concern; S3
Is immigration known or possible?
Not known and unlikely
Would immigrants be adapted to survive in Canada?
Probably
Is there sufficient habitat for immigrants in Canada?
Yes
Is rescue from outside populations likely?
Possibly, but not likely
Quantitative Analysis
Unavailable
Current Status
- COSEWIC: Special Concern 1992, Endangered 2007
- Alberta: Endangered; Saskatchewan: Vulnerable (proposed)
Status and Reasons for Designation
Status: Endangered
Alpha-numeric code: B2ab(iii)
Reasons for Designation: In Canada, this species exists in less than 10 scattered locations that are severely fragmented. Most of these populations are threatened by ongoing oil and gas development, proliferation of roads, proposed mineral development, and an increasing human presence.
Applicability of Criteria
Criterion A: (Declining Total Population): Not applicable. No appropriate long term data on population abundance.
Criterion B: (Small Distribution, and Decline or Fluctuation): The Area of Occupancy is less than 500km², there is severe fragmentation, and the habitat quality and extent are decreasing.
Criterion C: (Small Total Population Size and Decline): Meets criteria for Threatened C2a(i), as no population likely exceeds 1000 lizards.
Criterion D: (Very Small Population or Restricted Distribution): Not applicable.
Criterion E: (Quantitative Analysis): Not applicable.
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