Smooth goosefoot (Chenopodium subglabrum) COSEWIC assessment and status report: chapter 11

Technical Summary

Chenopodium subglabrum

Smooth goosefoot: chénopode glabre

Range of Occurrence in Canada:
Alberta to Manitoba

Extent and Area Information

Extent of occurrence (EO)(km²):
82,000 km²
[ estimation based on a convex polygon of localities in and plus a separate estimation for the two locations that are disjunct and peripheral to the core range in Canada.]
Specify trend in EO:
Unknown
Are there extreme fluctuations in EO?
No
Area of occupancy (AO) (km²):
about 23 km²
[The number of 1/4 sections where C. subglabrum occurs multiplied by 0.4 ]
Specify trend in AO:
Decline
Are there extreme fluctuations in AO?
No

Number of known or inferred current locations:

  • AB: 1 extant, 8 not confirmed
  • SK: 24 extant, 2 not confirmed, 5 likely extirpated
  • MB: 2 extant
Specify trend in # :
Unknown
Are there extreme fluctuations in number of locations?
No
Specify trend in area, extent or quality of habitat :
Decline

Population Information

Generation time (average age of parents in the population):
2 months  (annual species)
Number of mature individuals:
5,200-10,000
Total population trend:
Unknown
% decline over the last/next 10 years or 3 generations.
Unknown
Are there extreme fluctuations in number of mature individuals?
Uncertain but sizeable fluctuations are documented
Is the total population severely fragmented?
No (naturally discontinuous)
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:

Fluctuates from year to year:

  • Alberta: 200-300,
  • Saskatchewan: 5,000-9,700,
  • Manitoba: 75-100

Threats (actual or imminent threats to populations or habitats)

Dune stabilization, grazing and fire control, invasive exotics, recreational activities and oil and gas exploration.

Rescue Effect (immigration from an outside source)

Status of outside population(s)?

USA:

North Dakota
S1
Montana
S1
Nebraska
S3
Wyoming
S3
Colorado, Idaho, Kansas, Nevada, Oregon,
South Dakota, Utah and Washington
SNR
Michigan
SNA
Is immigration known or possible?
Unknown
Would immigrants be adapted to survive in Canada?
Yes
Is there sufficient habitat for immigrants in Canada?
No
Is rescue from outside populations likely?
No

Quantitative Analysis

Not available

Current Status

COSEWIC
Threatened ( 2006)
Special Concern (1992)

Status and Reasons for Designation

Status:
Threatened
Alpha-numeric code:
Met criteria for Endangered, B2b(iii)c(iv), but designated Threatened due to a large number of sites scattered over a large area. Criteria met for Threatened: B2b(iii)c(iv).

Reasons for Designation:

An herbaceous annual with fluctuating populations of relatively small size. The species is restricted to areas of active sand habitats in southern Alberta, Saskatchewan and Manitoba. Current risks to the species include sand dune stabilization, invasive species, oil and gas development and recreational activities.

Applicability of Criteria

Criterion A: (Declining Total Population): Not applicable

Criterion B: (Small Distribution, and Decline or Fluctuation): Meets Endangered B2b (iii)c(iv) based on its small area of occupancy, loss in area and quality of habitat, and large fluctuations in population size.

Criterion C: (Small Total Population Size and Decline): Not applicable.   Population size >2,500 and possibly <10,000 but percent decline over 10 years is uncertain due to lack of adequate monitoring and natural population fluctuations; continuing decline could be inferred in habitat due to stabilization of habitat by invasive plants but some populations >1,000 mature plants and not all mature plants in one population.

Criterion D: (Very Small Population or Restricted Distribution): Not applicable.  Population size is too large and area of occupancy is >20km² and number of locations is >5.

Criterion E: (Quantitative Analysis): Not available.

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