Species Profile

Margined Streamside Moss

Scientific Name: Scouleria marginata
Taxonomy Group: Mosses
Range: British Columbia
Last COSEWIC Assessment: May 2012
Last COSEWIC Designation: Endangered
SARA Status: Schedule 1, Endangered

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Quick Links: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | Recovery Team | National Recovery Program | Documents

Image of Margined Streamside Moss

Margined Streamside Moss Photo 1
Margined Streamside Moss Photo 2



The Margined Streamside Moss is a relatively large, cushion-forming moss that grows in dark green or yellowish-brown to blackish tufts. Its stems are frequently branched and range in length from 6 to 10 cm. The leaves are lance-shaped, 2.5 to 4 mm long, and about 1 mm wide.


Distribution and Population

Globally, the Margined Streamside Moss is restricted to the Pacific Northwest in North America. The only population known to occur in Canada is in the Kootenay region of British Columbia near the border with the United States. There is no information on the population size or trends of the Canadian population. The Margined Streamside Moss has not been found at the site since the original discovery. As the area has been heavily disturbed, it is possible that the species is now extirpated from this location.



Margined Streamside Moss grows on rocks, particularly granite, in streams. It may be exposed or submerged, and is found at a range of elevations. The population found in southern British Columbia was on wet rocks at an elevation of 1300 m. In the United States, it is usually mixed with the more common Scouleria aquatica and requires clean water and cool temperatures.



Little is known about the biology of the Margined Streamside Moss. It is dioicous: the male and female reproductive units are on separate plants — and it apparently does not reproduce vegetatively. The dioicous nature is known to limit the production of spores (the reproductive body from which a new plant arises) in many species of moss. Without spore production, it is impossible for a species to spread. When spores are produced, they are likely dispersed by water or possibly wind. The Margined Streamside Moss is often found with the closely related Scouleria aquatica. The two species apparently have similar habitat requirements, and the Margined Streamside Moss may get out-competed in some areas. This may partially account for the restricted range of the Margined Streamside Moss.



Flooding, cattle usage, and sedimentation threaten the Margined Streamside Moss. In particular, deposits of silt on boulders in the streams interfere with the establishment of the moss.



Federal Protection

The Margined Streamside Moss is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.


Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Margined Streamside Moss (Scouleria marginata) in Canada
Status Final posting on SAR registry


Recovery Team

BC Bryophyte Recovery Team

  • Brenda Costanzo - Chair/Contact - Government of BC
    Phone: 250-387-9611  Fax: 250-356-9145  Send Email


Recovery Progress and Activities

Summary of Progress to Date The draft recovery strategy has been completed. The species was not relocated during an inventory completed during the summer of 2005.


PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

12 record(s) found.

COSEWIC Status Reports

  • COSEWIC assessment and status report on the margined streamside moss Scouleria marginata in Canada (2002)

    Scouleria marginata is a relatively large, acrocarpous moss in the moss family Scouleriaceae. Only one other species of Scouleria is found in North America, Scouleria aquatica. It has a broader range than S. marginata. Although very similar and possibly indistinguishable in the field macroscopically, the two species can be readily separated through microscopic features of the leaf and sporophyte.

COSEWIC Assessments

Response Statements

  • Response Statement - Margined Streamside Moss (2013)

    This large, showy moss occurs just above water’s edge along small montane streams. A rare western North American endemic, it is known in Canada from a single occurrence in southern British Columbia. Although the species has not been found in recent surveys, it may be present in nearby watersheds.
  • Response Statements - Margined Streamside Moss (2004)

    A response statement is a communications document that identifies how the Minister of the Environment intends to respond to the assessment of a wildlife species by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The document provides a start to the listing and recovery process for those species identified as being at risk, and provides timelines for action to the extent possible.

Recovery Strategies

  • Recovery Strategy for the Margined Streamside Moss (Scouleria marginata) in Canada (2008)

    The margined streamside moss was listed on Schedule 1 of the Species at Risk Act (SARA) as Endangered in June 2003. SARA section 37 requires the competent minister to prepare a recovery strategy for all listed extirpated, endangered or threatened species. SARA section 44 allows the Minister to adopt all or part of an existing plan for the species if it meets the requirements under SARA for content (sub-sections 41(1) or (2)). The British Columbia Ministry of Environment led the development of this recovery strategy for the species in cooperation with Environment Canada, Canadian Wildlife Service – Pacific and Yukon Region. The strategy meets SARA requirements in terms of content and process (Sections 39-41). In the spirit of cooperation of the Accord, the Government of British Columbia has given permission to the Government of Canada to adopt the Recovery Strategy for the Margined Streamside Moss (Scouleria marginata Britt) in British Columbia (Appendix 1) under Section 44 of the Species at Risk Act. Environment Canada has included an addition which completes SARA requirements for this recovery strategy, and excludes the section on Socio-Economic Considerations which is not required by the Act. Due to technical difficulties, the comment period for this proposed Recovery Strategy was extended until March 25, 2008.


  • Order Acknowledging Receipt of the Assessments Done Pursuant to Subsection 23(1) of the Species at Risk Act (2004)

    This Order acknowledges receipt by the Governor in Council of the assessments of the status of wildlife species done pursuant to subsection 23(1) of the Species at Risk Act (SARA) by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The purpose of SARA is to prevent wildlife species from being extirpated or becoming extinct, to provide for the recovery of wildlife species that are extirpated, endangered or threatened as a result of human activity and to manage species of special concern to prevent them from becoming endangered or threatened.
  • Order Amending Schedules 1 to 3 to the Species at Risk Act (2005)

    Schedule 1, the List of Wildlife Species at Risk of the Species at Risk Act (SARA), is amended by Order of the Governor in Council (GIC), on the recommendation of the Minister of the Environment, by the addition of 73 species. This Order is based on scientific assessments by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and follows consultations with provincial and territorial governments, Aboriginal peoples, stakeholders and the public, and analysis of costs and benefits to Canadians.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2003 (2003)

    May 2003 Annual Report to the Canadian Endangered Species Conservation Council by the Committee on the Status of Endangered Wildlife in Canada.
  • COSEWIC Annual Report - 2011-2012 (2012)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to “assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species”. COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (September 1, 2011 to September 30, 2012) from November 21 to 25, 2011 and from April 29 to May 4, 2012. On February 3, 2012, an Emergency Assessment Subcommittee of COSEWIC also assessed the status of the Tri-colored Bat (Perimyotis subflavus), the Little Brown Myotis (Myotis lucifugus), and the Northern Myotis (Myotis septentrionalis). During the current reporting period COSEWIC assessed the status or reviewed the classification of 67 wildlife species. For species already found on Schedule 1 of SARA, the classification of 32 species was reviewed by COSEWIC and the status of the wildlife species was confirmed to be in the same category (extirpated - no longer found in the wild in Canada but occurring elsewhere, endangered, threatened or of special concern). The wildlife species assessment results for the 2011-2012 reporting period include the following: Extinct: 1 Extirpated: 4 Endangered: 29 Threatened: 10 Special Concern: 15 Data Deficient: 2 Not at Risk: 6 Total: 67 Of the 67 wildlife species examined, COSEWIC reviewed the classification of 49 species that had been previously assessed. The review of classification for 26 of those species resulted in a confirmation of the same status as the previous assessment (see Table 1a).

Consultation Documents

  • Consultation on Amending the List of Species Under the Species At Risk Act: March 2004 (2004)

    The Government of Canada proclaimed the Species at Risk Act (SARA) on June 5, 2003 as part of its strategy for the protection of wildlife species at risk. Attached to the Act is Schedule 1, the list of the species that receive protection under SARA, hereinafter referred to as the 'SARA list'. Canadians are invited to comment on whether all or some of the species included in this document should be added to the SARA list.
  • Consultation on Amending the List of Species under the Species at Risk Act: Terrestrial Species – December 2012 (2013)

    As part of its strategy for protecting wildlife species at risk, the Government of Canada proclaimed the Species at Risk Act (SARA) on June 5, 2003. Attached to the Act is Schedule 1, the list of the species that receive protection under SARA, also called the List of Wildlife Species at Risk. Please submit your comments by March 4, 2013, for terrestrial species undergoing normal consultations and by October 4, 2013, for terrestrial species undergoing extended consultations. Consultation paths.