Columbian carpet moss (Bryoerythrophyllum columbianum) COSEWIC assessment and status report: chapter 14

Technical Summary

Bryoerythrophyllum columbianum

Columbian carpet moss
Érythrophylle du Columbia

Range of Occurrence in Canada: BC

Extent and Area Information

Extent of occurrence (EO)( km2 )
> 20 000 km2

Specify trend in EO

stable to declining

Are there extreme fluctuations in EO ?


Area of occupancy (AO) ( km2 )

> 20 km2 , based on area of Bunchgrass and Purshia communities in which species was found.

Specify trend in AO


Are there extreme fluctuations in AO ?


Number of known or inferred current locations

11 recently confirmed of 18 known/reported

Specify trend in #

1 possibly lost

Are there extreme fluctuations in number of locations?


Specify trend in area, extent or quality of habitat

stable to declining depending on habitat type ( e.g. , Purshia ecosystem is declining) (refer to Table 1 )

Population Information

Generation time (average age of parents in the population)
perennial, likely several years

Number of mature individuals


Total population trend:

?declining – possible loss of 1 population

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

Are there extreme fluctuations in number of mature individuals?


Is the total population severely fragmented?


Specify trend in number of populations

?declining, based on loss of 1 population

Are there extreme fluctuations in number of populations?


List populations with number of mature individuals in each:

unknown # of mature individuals (refer to Table 1 )

Threats (actual or imminent threats to populations or habitats)

Grazing impacts, vineyard and urban development, road construction, human impacts such as hiking, camping, and general erosion (refer to Table 1)

Rescue Effect (immigration from an outside source)

Status of outside population(s)?
USA: especially common in south-central Washington

Is immigration known or possible?

not likely. Spores seldom produced in this species

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 Applicable

Other Status

NatureServe: imperiled to secure (G2G4)

Status and Reasons for Designation

Status: Special Concern
Alpha-numeric code: Not applicable

Reasons for Designation: This is a western North American endemic species. It is a small perennial species and in Canada has a restricted distribution in the shrub-steppe in semi-arid regions of British Columbia where recent surveys have confirmed its presence from 11 sites. The species is never abundant in sites where it is found and extensive surveys have provided few new locations. At least one population is believed to have been lost to cultivation (vineyard) or to stochastic events. Threats include agriculture (especially vineyards), impact by grazing animals, urban development, road improvements, and human recreational impacts. Based on known occurrences, the species appears to have a very restricted distribution. However the species is patchily distributed at low densities in large habitats not all of which have been censused.

Applicability of Criteria

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

Criterion B (Small Distribution, and Decline or Fluctuation):
Does not meet any criterion for ‘a’ (known from 11 sites) or ‘c’ (no fluctuation)

Criterion C (Small Total Population Size and Decline):
no data – number of mature individuals not known.

Criterion D (Very Small Population or Restricted Distribution):
Does not meet criterion: Number of sites > 5 (11 confirmed), and area of occupancy likely > 20 km2

Criterion E (Quantitative Analysis):
not applicable.


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