Species Profile

Pygmy Pocket Moss

Scientific Name: Fissidens exilis
Taxonomy Group: Mosses
Range: British Columbia, Ontario, Quebec, Nova Scotia
Last COSEWIC Assessment: April 2016
Last COSEWIC Designation: Not at Risk
SARA Status: Schedule 1, Special Concern


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Quick Links: | Description | Distribution and Population | Habitat | Biology | National Recovery Program | Documents

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Description

Pygmy Pocket Moss (Fissidens exilis) is an ephemeral moss, periodically producing minute (up to 2 mm), 4- to 8-leaved plants from a mat of undifferentiated green filaments, or “protonemata”, persisting between periods of reproductive activity on and in the surface soil layer. It can be identified using microscopic features of the leafy plants (gametophores), but the protonemata, which persist between periods of reproductive activity, cannot be visually identified by any means. Spore-filled capsules, supported on 2 – 9 mm stalks, are attached to the apex of each successfully fertilized, mature plant. Pygmy Pocket Moss is most likely to be detected when capsules are present, especially in large colonies.

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Distribution and Population

Pygmy Pocket Moss is known from Europe, Asia, Africa, the West Indies, New Zealand and North America. Some authors speculate that it may have been introduced to the last three of these, but conclusive evidence is lacking. Pygmy Pocket Moss was first discovered in North America in 1947, in Cleveland, Ohio, and it is known from at least fifteen eastern US states, as well as from the Canadian provinces of Nova Scotia, Quebec, Ontario, and British Columbia. Some experts believe the species may be introduced in British Columbia. Search effort for Pygmy Pocket Moss requires specific, intensive approaches that address challenges associated with ephemeral mosses, which can be visually recognized under only certain, sporadic conditions. These measures have not been undertaken, and most known subpopulations were opportunistically discovered.

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Habitat

In North America, most Pygmy Pocket Moss has been found largely on bare, moist, at least partly shaded, clay-based soil or loam. It has been collected on the forested banks of streams and ravines, floodplains, bluffs, beaches, roadsides, trails and other environments where bare soil is exposed. Habitat patches are transient and may be unpredictable, resulting from a variety of natural and human-related phenomena. No broad trends in the preferred habitat of Pygmy Pocket Moss are known.

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Biology

Pygmy Pocket Moss is ephemeral and exhibits a “fugitive” life history strategy: the life and reproductive cycles of its leafy plants are short (less than a year), not seasonally dependent, and driven largely by abiotic factors. Reduced size allows such species to reach maturity sooner than larger mosses with more protracted developmental processes. It expends relatively high reproductive effort, with virtually every tiny plant producing a spore-filled capsule, and its small spores (less than 20 um) are characteristic of species with longevity in the spore bank. These traits equip plants to complete their life cycles in transient, early-successional environments, and avoid stress during periods of habitat unsuitability by persisting in forms (spores and underground filaments) that are less vulnerable to unfavourable conditions. Spores are dispersed from less than 1 cm above the substrate, and most collections of this moss have been made from at least partly sheltered environments, so long-distance spore dispersal may be very infrequent. Dispersal of moss- or spore-laden soil via a range of possible biotic and abiotic vectors may be important.

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Some threats can be inferred with reference to the general biology of mosses and the habitats in which Pygmy Pocket Moss has been collected, but no research has demonstrated any specific threats to this species. Some human activities that routinely threaten other plant species may have a neutral or beneficial effect on this species, which relies on localized soil disturbance.

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Documents

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.

11 record(s) found.

COSEWIC Status Reports

  • COSEWIC Assessment and Status Report on the Pygmy Pocket Moss Fissidens exilis in Canada (2016)

    Pygmy Pocket Moss (Fissidens exilis) is an ephemeral moss, periodically producing minute (up to 2 mm), 4- to 8-leaved plants from a mat of undifferentiated green filaments, or “protonemata”, persisting between periods of reproductive activity on and in the surface soil layer. It can be identified using microscopic features of the leafy plants (gametophores), but the protonemata, which persist between periods of reproductive activity, cannot be visually identified by any means. Spore-filled capsules, supported on 2 – 9 mm stalks, are attached to the apex of each successfully fertilized, mature plant. Pygmy Pocket Moss is most likely to be detected when capsules are present, especially in large colonies.

COSEWIC Assessments

Response Statements

  • Response Statement - Pygmy Pocket Moss (2017)

    This species has a very large extent of Canadian occurrence, occurring on both Pacific and Atlantic coasts, and in central Canada. Despite low detectability that confounds attempts to quantify population sizes and trends, the number of known occurrences has increased from 7 to 21 since 2005, and it is expected that more occurrences will be documented with ongoing search effort.  Although it is found in some densely populated regions of Canada, including southern Ontario, no declines or direct imminent threats are known for this species. Localized soil disturbance is required for suitable habitat, such that some kinds of human disturbance may actually benefit the species. Although data are lacking in many aspects of its biology, ecology, distribution, and abundance, no evidence suggests that this species is at risk in Canada.
  • Response Statements - Pygmy Pocket Moss (2005)

    A moss with a limited distribution in eastern North America, but which is widespread in Europe. Few populations have been documented in Canada, primarily in Ontario where it occurs in heavily populated and developed areas where natural habitats are widely known to be at serious risk. Although cryptic in habit, the species often grows with other small species that have well documented ranges. The species prefers woodlands, where it is usually found on bare clay or disturbed soil. Most locations are in areas benefiting from some level of conservation protection.

Management Plans

  • Management Plan for the Pygmy Pocket Moss (Fissidens exilis) in Canada (2016)

    The Minister of the Environment is the competent minister under SARA for the Pygmy Pocket Moss and has prepared this management plan as per section 65 of SARA. To the extent possible, it has been prepared in cooperation with the British Columbia, Ontario, Quebec and Nova Scotia governments.

Orders

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2005 (2005)

    2005 Annual Report to the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.

Consultation Documents

  • Consultation on Amending the List of Species Under the Species At Risk Act: November 2005 (2005)

    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 - January 2017 (2017)

    The Government of Canada is committed to preventing the disappearance of wildlife species at risk from our lands. As part of its strategy for realizing that commitment, on June 5, 2003, the Government of Canada proclaimed the Species at Risk Act (SARA). Attached to the Act is Schedule 1, the list of the species provided for under SARA, also called the List of Wildlife Species at Risk. Extirpated, Endangered and Threatened species on Schedule 1 benefit from the protection afforded by the prohibitions and from recovery planning requirements under SARA. Special Concern species benefit from its management planning requirements. Schedule 1 has grown from the original 233 to 521 wildlife species at risk. In 2016, on the recommendation of the Minister of the Environment, the Governor in Council approved listing proposals for 44 wildlife species. It is proposed that 23 species be added to Schedule 1, 18 be reclassified or have a change made to how they are defined (two wildlife species are being split into four), one species  be removed from Schedule 1, and another two species not be added. Listing proposals were published in Canada Gazette, part I for a 30-day public comment period and final listing decisions for all 44 species are expected in the first half of 2017.Please submit your comments byMay 11, 2017, for terrestrial species undergoing normal consultationsand byOctober 11, 2017, for terrestrial species undergoing extended consultations.For a description of the consultation paths these species will undergo, please see:Species at Risk Public Registry website The COSEWIC Summaries of Terrestrial Species Eligible for Addition or Reclassification on Schedule 1 - January 2017

Recovery Document Posting Plans

  • Environment and Climate Change Canada's Three-Year Recovery Document Posting Plan (2016)

    Environment and Climate Change Canada’s Three-Year Recovery Document Posting Plan identifies the species for which recovery documents will be posted each fiscal year starting in 2014-2015. Posting this three year plan on the Species at Risk Public Registry is intended to provide transparency to partners, stakeholders, and the public about Environment and Climate Change Canada’s plan to develop and post these proposed recovery strategies and management plans. However, both the number of documents and the particular species that are posted in a given year may change slightly due to a variety of circumstances. Last update March 31, 2017