Nugget moss (Microbryum vlassovii) COSEWIC assessment and status report: chapter 2

COSEWIC Executive Summary

Nugget moss
Microbryum vlassovii

Species information

The Nugget Moss, Microbryum vlassovii, is one of four species previously included in Phascum in North America. It was known earlier as Phascum vlassovii. It is characterized by the strongly ornamented, sometimes bottle-shaped cells that are present on the upper surface of the leaf lamina and mid-rib, as well as hidden capsules that do not have a lid for spore release.

Distribution

Microbryum vlassovii has a disjunct distribution between western North America and western Eurasia. It is extremely rare globally and in North America, where it is known also from California. In Canada, it has been reported from two locations in south-central British Columbia.

Habitat

In British Columbia, Microbryum vlassovii is restricted to undisturbed, exposed, compact silts and clays on post-glacial lacustrine banks in semi-arid steppe and grassland environments.

Biology

Microbryum vlassovii is an inconspicuous moss that grows as individuals or small, scattered patches on compact, clay-rich soil. The production of sporophytes is common in Canadian populations, but only immature capsules have been observed to date. Spores are probably of importance only in the short-range dispersal of this species. Tuber-like structures on the rhizoids may also be of importance in the survival of this species.

Population sizes and trends

No precise information is available on population condition or trends for Microbryum vlassovii. Eight individuals in two small patches were found in the one population that was re-located during the recent survey for the species.

Limiting factors and threats

The threats to this species' habitats include road construction or maintenance, and recreational hiking.

Special significance of the species

The British Columbia populations represent two of three known locations for the species in North America, where the species is extremely rare. Lacustrine banks are also the only known habitat for a number of other rare Canadian species of mosses and lichens.

Existing protection or other status designations

No legislation, regulations, customs, or conditions currently protect this species. In British Columbia it is Red-listed, and globally is considered possibly imperilled.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal entities (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions

Wildlife Species
A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)
A wildlife species that no longer exists.

Extirpated (XT)
A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)
A wildlife species facing imminent extirpation or extinction.

Threatened (T)
A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)Footnotea
A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)Footnoteb
A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)Footnotec
A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

 

Canadian Wildlife Service

The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.

 

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