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COSEWIC assessment and status report on the Alkaline Wing-nerved Moss in Canada

Technical Summary

Pterygoneurum kozlovii

Alkaline wing-nerved moss
Ptérygoneure de Koslov

Range of Occurrence in Canada: BC, SK.

Extent and Area Information

Extent of occurrence (EO)(km2)
189 000 km2 (with SK); 71 000 km2 (BC only)

Specify trend in EO

Are there extreme fluctuations in EO?

Area of occupancy (AO) (km2)
Based on estimate of areas searched.
<40 km2

Specify trend in AO

Are there extreme fluctuations in AO?

Number of known or inferred current locations
13 extant as of 2002 (see Table 2)

Specify trend in #
6 extirpated(?);
13 extant of which 9 were first found  in 2002;
3 not relocated; 3 not visited
(See Table 2)

Are there extreme fluctuations in number of locations?

Specify trend in area, extent or quality of habitat?
?stable to declining

Population Information

Generation time (average age of parents in the population)

Number of mature individuals

Total population trend:
probably declining based on the loss of 1 in 4 sites

% decline over the last/next 10 years or 3 generations
about 25%

Are there extreme fluctuations in number of mature individuals?

Is the total population severely fragmented?
Yes. Locations are separated from each other by unsuitable habitat.

Specify trend in number of populations

Are there extreme fluctuations in number of populations?

List populations with number of mature individuals in each
unknown (refer to Table 3 for general comments)

Threats (actual or imminent threats to populations or habitats)

Impacts of cattle; it is not known what level of disturbance the species can withstand and continue to persist at a site.

Development, road building, off road vehicles.

Rescue Effect (immigration from an outside source)

not known in North America except in Canada

Is immigration known or possible?

Would immigrants be adapted to survive in Canada?

Is there sufficient habitat for immigrants in Canada?

Is rescue from outside populations likely?

Quantitative Analysis

Not available

Previous Status

imperiled in Mongolia

Status and Reasons for Designation

Alkaline Wing-nerved Moss
Pterygoneurum kozlovii

Status: Threatened
Alpha-numeric code: Met criteria for Endangered, B2ab(iii,iv), but designated Threatened, B2ab(iii,iv), because the species is known from several locations over a wide area, and not thought to be at imminent risk of extirpation.

Reasons for Designation: This species, restricted in North America to western Canada, is globally imperiled or rare. Canada possesses the great majority of documented locations. The species typically grows on soil among grasses and sedges along the margins of alkaline ponds and sloughs in semi-arid regions of Canada. It has been confirmed at only 13 sites from 24 reported in south central British Columbia. There is one unconfirmed site in Saskatchewan. About half of all the known sites are subject to impacts from people and domestic animals. Of the British Columbia sites, 6 have apparently been lost to urban development, highway improvement, and trampling by cattle, implying that decline in habitat quality and extent are presently impacting the species.

Applicability of Criteria

Criterion A: (Declining Total Population):
Does not meet thresholds for decline.

Criterion B: (Small Distribution, and Decline or Fluctuation):
Meets criteria for Threatened B1 (Area of Occupancy is estimated at < 40 km2). The Canadian population is severely fragmented (a), and there is a decline in the area, extent and /or quality of habitat (b iii), and number of locations (b iv).

Criterion C: (Small Total Population Size and Decline):
Information not available for total population size.

Criterion D: (Very Small Population or Restricted Distribution):
Does not meet requirements for this criterion. No population estimates.

Criterion E: (Quantitative Analysis):
Not available.