Pygmy pocket moss (Fissidens exilis) COSEWIC assessment and status report: chapter 8

Limiting Factors and Threats

Factors limiting the distribution and population sizes of F. exilis in Canada include climate, as Canadian populations mark the species’ northern range limit in North America. Canadian populations of F. exilis fall within a highly populated region of the country, where air and water pollution, habitat destruction, and habitat fragmentation have affected the survival of many plant species (e.g. Argus & Pryer 1990, Klinkenberg et al. 1990, Lamb & Rhynard 1994, Maycock 1963, Oldham 1990). However, over the geographic range of F. exilis, apparently suitable bare soil remains abundant, even in protected areas with unimpeded native vegetation coverage. Human activities, including recreation and conservation management, have the potential to affect the species’ survival even at protected sites (as outlined in Habitat Protection / Ownership), particularly if managers are unaware of the species’ presence. Particularities of habitat preference (such as forest age, shade characteristics), which are not well known, may help to account for the species’ apparent rarity.

Page details

Date modified: