Columbian carpet moss (Bryoerythrophyllum columbianum) COSEWIC assessment and status report: chapter 2

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Species Information

Bryoerythrophyllum columbianum, the Columbian carpet moss, is one of four species of Bryoerythrophyllum in North America. It is a small, often red-brown moss that grows in small clumps or compact turfs either as pure colonies or intermixed with other mosses and lichens. Its most distinctive features are the ovate-lanceolate leaves, sharp-pointed leaf tips, and the broad, somewhat ornamented leaf mid-ribs. It is dioicous, with male and female organs on separate stems.

Distribution

This species is a western North American endemic, and, in Canada, it appears to be restricted to British Columbia. It has a rather confined distribution in the province, found at 11 confirmed locations. It has been found in the south Okanagan Valley, near Kamloops, near Spence’s Bridge, and at one site along the Fraser River in the Cariboo Region. Elsewhere it is known from Washington, Oregon and California.

Habitat

This species is restricted to soils in semi-arid steppe and grassland habitats of British Columbia. The habitats of two of the known sites for Columbian carpet moss are heavily disturbed, four are moderately disturbed, and five are relatively undisturbed.

Biology

Columbian carpet moss is a perennial that grows over soil in semi-arid shrub-steppe and grassland environments. Sporophytes have been reported only once in Canadian populations and spores are probably of limited importance in the dispersal of this species. It may disperse and colonize open soils by fragmentation of fragile leaf tips

Population Sizes and Trends

This species is uncommon or rare in seven of its known locations, and widespread but uncommon in four sites. Populations appear stable in nine sites, and two may be declining, but trends are largely unknown. 

Limiting Factors and Threats

The most important threats are agricultural practices, including grazing and development of vineyards. However, urban development, road building, hiking, and general erosion also appear to be limiting factors and threats to Columbian carpet moss.

Special Significance of the Species

This species is a western North American endemic. The British Columbia populations may represent the northern extension of its range in North America. It is probably a contributing element in a healthy biological soil crust community characteristic of shrub-steppe habitats.

Existing Protection or Other Status Designations

Most of the extant populations of this species are found on public-owned lands, either municipal or provincial, in particular crown lands. No legislation, regulations, customs, or conditions currently protect this species. Columbian carpet moss is listed as critically imperiled at the provincial level and it is Red-listed. Globally, it is ranked vulnerable.