Flooded jellyskin (Leptogium rivulare) COSEWIC assessment and status report: chapter 12
Technical Summary
Leptogium rivulare
Flooded jellyskin – Leptoge des terrains inondés
Range of Occurrence in Canada:
ON, MB
Extent and Area Information
Extent of occurrence (EO) (km²)
Three currently known sites in Ontario only: 130 km²
All four currently known sites (Ontario and Manitoba): 107,000 km²
Specify trend in EO
stable
Are there extreme fluctuations in EO?
no
Area of occupancy (AO) (km²)
0.2-0.3 km² (2-3 hectares of lowland forest)
Specify trend in AO
stable
Are there extreme fluctuations in AO?
no
Number of known or inferred current locations
4
Specify trend in #
unknown
Are there extreme fluctuations in number of locations?
no
Specify trend in area, extent or quality of habitat
stable
Population Information
Generation time (average age of parents in the population)
3-4? years
Number of mature individuals
10's of thousands
Total population trend:
stable
% decline over the last/next 10 years or 3 generations.
not applicable
Are there extreme fluctuations in number of mature individuals?
unknown
Is the total population severely fragmented?
yes
Specify trend in number of populations
not applicable
Are there extreme fluctuations in number of populations?
unknown
List populations with number of mature individuals in each:
Threats (actual or imminent threats to populations or habitats)
- Habitat reduction resulting from climatic change;
- substrate loss through invasive alien pests and disease;
- habitat loss from urban development
Rescue Effect (immigration from an outside source)
Status of outside population(s)?
Restricted to Canada in North America
Is immigration known or possible?
No
Would immigrants be adapted to survive in Canada?
Yes
Is there sufficient habitat for immigrants in Canada?
Yes
Is rescue from outside populations likely?
No
Quantitative Analysis
Not applicable
Other status
Not applicable
Status and Reasons for Designation
Status: Threatened
Alpha-numeric code: D2
Reasons for Designation: This is a globally rare species currently known in Canada from only 4 locations, all in Ontario and Manitoba. The species has very restricted habitat requirements, found primarily at the margins of seasonal (vernal) pools, where it grows on rocks and at the base of living deciduous trees between the seasonal high and low water marks. It is vulnerable to changes in normal patterns of annual flooding, as well as to death of host trees. Major threats to the largest populations include urban development and recreational activity.
Applicability of Criteria
Criterion A (Declining Total Population): does not meet thresholds for decline
Criterion B (Small Distribution, and Decline or Fluctuation): meets some criteria for Endangered (area of occupancy < 500km², severely fragmented populations) but does not meet decline criteria.
Criterion C (Small Total Population Size and Decline): does not meet threshold for small population size (population estimate > 10,000)
Criterion D (Very Small Population or Restricted Distribution): does not meet threshold for Endangered, small population (population estimate > 10,000), but does meet criteria for Threatened, area of occupancy < 20km² and small number of locations (<5)
Criterion E (Quantitative Analysis): not applicable
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