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COSEWIC Assessment and Status Report on the Columbian Carpet Moss in Canada


Habitat Requirements

Bryoerythrophyllum columbianum is restricted to soils in semi-arid shrub-steppe and grassland environments, characterized by dry, hot summers and cool to cold, moderately wet winters. Across its North American range, ithas been found growing on soil over acid rock, on sandy soil, in grassland steppe, or on ledges and bluffs near rivers (Zander 2000).

In British Columbia, this species is found in the Bunchgrass Biogeoclimatic Zone, which is restricted to a number of narrow valleys in the south-central part of the province. Common plants in this zone are bluebunch wheatgrass (Agropyron spicatum), needlegrass (Stipa comata), big sage (Artemisia tridentata), and antelope brush (Purshia tridentata, in the southern portions of the Okanagan Valley). Within the Bunchgrass Zone, it has been found on a variety of soil types, including compact silts, silt-loams, and sandy loams, where it appears to be a minor component of some biological soil crusts, important contributors to the health of arid land ecosystems (Belnap et al. 2001, Evans and Johansen 1999). Common crust associates include lichens, Cladonia cariosa, Acarospora schleicheri, and Psora spp, and mosses, in particular Tortula atrovirens, Didymodon vinealis, Syntrichia ruralis, Pseudocrossidium obtusulum, and Ceratodon purpureus. It also has been found on thin soil over an outcrop face (Collection 5), growing with a species of Grimmia, although this is an unusual habitat for this species.


Table 2 (Column C) lists habitat trends and conditions for each of the 11 known populations, along with conditions for some of the reported but unconfirmed locations of Bryoerythrophyllum columbianum in British Columbia. Two of the known locations are heavily disturbed, four are moderately disturbed, and five are relatively undisturbed. Most sites appear to be relatively stable, but site monitoring is necessary in order to confirm this.

Table 2: Habitat and Population Characteristics of Bryoerythrophyllum columbianum Collection Sites in British Columbia
Collection Site
( * = confirmed
and Threats
and Trend
and Trend
1B (C)B – C, B??
2?A (E) FA – B, B?Gmp
6*D EA – B, BB, BGm?
7AB, A - B?Gp
8 and 10*?D EA, BA, BGm
9*?D EA, BB, BGm
11*C E FB, BA, CGp
12*A FB, BB, BGp
13*EA – B, AB, B (?A)P
14*AB – C, BA, BGp
15*A (F)B – C, BB, BGp
16*D EC, BC, CGp?
17*E FC, ?AA, B (?A)Gm
18*E FA – B, BC, BGm

Notes (in all cases, ‘?’ refers to ‘unknown’ or ‘uncertain’, and a letter in brackets refers to ‘minor importance’):
1. With respect to Column B: A refers to grazing impacts, B refers to vineyard, C refers to urban development, D refers to road building, E refers to human impacts such as hiking, and F refers to general erosion.
2. With respect to Column C: Habitat Condition: A refers to relatively undisturbed, B refers to moderately disturbed, C refers to heavily disturbed; Habitat Trend: A refers to improving, B refers to stable, C refers to degrading.
3. With respect to Column D: Population Size: ‘A’ means widespread in area surveyed, ‘B’ means uncommon across site, and ‘C’ rare across site; Population Trend: A refers to improving, B refers to stable, C refers to declining.
4. With respect to Column E: P refers to private ownership and G refers to government ownership, either municipal (m) or provincial (p, usually crown land).


Most of our extant populations of Bryoerythrophyllum columbianum are found on public-owned lands, either municipal or provincial, in particular crown lands. At Collection Site 1, it may be present in an ecological research area that is found along Inkaneep Road north of Osoyoos, but was not seen there during the survey. At Collection Site 2 near Spences Bridge, there is a sign near the site that restricts entry to the waterfalls area at the municipal site, but B. columbianum, if it is still present here, is probably more common in the shrub-steppe nearby where access is allowed. Some protection appears available at Collection Site 7 (Churn Creek Provincial Park in the Cariboo) and at Collection Sites 8, 9, and 10 (apparently this part of the Valleyview area in Kamloops is a municipal recreational park, and dogs are regularly walked at this location).