Flooded Jellyskin

(Leptogium rivulare)

Status: Threatened (ESA 2007, COSEWIC 2004)

Table of Contents:

Species Identification
Habitat and Biology
Threats/Reasons for Being at Risk
Conservation and Recovery Strategies
Why You Should Care
How You Can Help

Photo by Samuel Brinker: https://www.inaturalist.org/observations/52692205

Species Identification:

The Flooded Jellyskin is a small, leafy cyanolichen, which is a lichen composed of cyanobacteria, as opposed to an algae or a fungus. It is about 4 cm in diameter, with a papery texture and bluish-grey in colour when dry. When wet, the Flooded Jellyskin becomes jelly-like and somewhat see-through, and it has many reddish-brown, circular reproductive structures.

Habitat and Biology:

Their range spans Eastern North America as well as much of Europe. However, while it has a large range it is rarely found. There are three Canadian subpopulations of Flooded Jellyskin ranging from Manitoba to eastern Quebec with the south-central Ontario population being the largest. Flooded Jellyskin can be found in The Land Between north of Peterborough, and west of Ottawa. It is also found northeast of Sudbury.

Map taken from Government of Canada: https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/cosewic-assessments-status-reports/flooded-jellyskin-2015.html#_11_1

Photo by Samuel Brinker: https://www.inaturalist.org/observations/52692205

Flooded Jellyskin is primarily found in forested areas of seasonal flooding with clean water, minimal sediment, and high availability of calcium. It is most frequently found growing on Green and Black Ash trees, but has also been found growing on Maple, Elm, and Willow. The trees must be alive as Flooded Jellyskin attaches to bark and cannot attach to bare wood. To reproduce, fungal spores are released by circular reproductive structures and transported by wind and water. The spores that are produced are exclusively fungal spores. As such, in order for the lichen to persist into the next generation, the fungal spore must land in an area that contains the cyanolichen it requires to form the relationship that becomes the Flooded Jellyskin. It takes approximately 10 to 20 years for this lichen to successfully reproduce.

Threats/ Reasons for being at Risk:

1. Emerald Ash Borer: Flooded Jellyskin is commonly found growing on Green and Black Ash Trees, both of which are affected by the Emerald Ash Borer. 20 of the 76 known populations of Flooded Jellyskin are found in forests dominated by Ash trees. The Emerald Ash Borer is spreading quickly through Canadian Ash trees, with mass mortalities expected in the next 60 years. The mass casualties of these trees has the potential to render large areas of previously suitable, Ash-dominated tree stands unsuitable for the growth of the Flooded Jellyskin.

2. Climate change: Climate change has the potential to alter the flooding regime in Flooded Jellyskin habitat, rendering a habitat no longer suitable. The Flooded Jellyskin relies on regular seasonal flooding for optimal growth and to promote the growth of its preferred growth strata such as Ash and Maple trees. Drought brought on by climate change can have significant impacts and change forest dynamics.

3. Dams: The installation of dams near Flooded Jellyskin habitat have the potential to alter the seasonal flooding regime, rendering the habitat no longer suitable for the lichen, or eliminating it completely. Dams control flooding which is essential for the Flooded Jellyskin to survive.

4. Water course/ water quality alteration: Any other activities, human or otherwise, that have the potential to alter the natural water course and impact the seasonal flooding of Flooded Jellyskin habitat have the potential to negatively impact the species. Flooded Jellyskin requires flooding with clean water that is low in sediment to survive. Activities such as urban development or natural resource extraction that result in an increase in erosion, can negatively affect the water quality and therefore the species itself.

Photo by Wasyl Bakowsky: https://www.inaturalist.org/observations/20131170

Conservation and recovery strategies:

Preservation of Ash trees allows for the preservation of an important habitat for the Flooded Jellyskin. Multiple innovative traps and lures have been developed by scientists and forestry companies that allow for early detection of the Emerald Ash Borer. Parasitic wasps have also been cultivated and used as a natural form of pest control for the Emerald Ash Borer. Alternative pesticides have been explored, including spores of pathogenic fungi. The spores are applied to the Emerald Ash Borer when it enters a trap, and are subsequently transferred to other individuals during mating. Seeds of hardy individuals are being collected to be used to re-establish decimated populations that have been impacted by the Emerald Ash Borer or from harvesting. Early detection allows actions to be taken before the pest has a chance to become established in its host Ash trees.

Why You Should Care:

Flooded Jellyskin is both globally and historically a rare species
Ontario is home to some of the largest and strongest populations of Flooded Jellyskin in the world, so we have a responsibility to protect this species
Flooded Jellyskin is of particular scientific interest because of its adaptations to unusual habitat

Photo by Colin Chapman-Lam: https://www.inaturalist.org/observations/7909088

How can you help?

Learn how to identify Flooded Jellyskin and submit observations online to The Land Between and/or to iNaturalist.
Protect ash trees on your property to allow habitat for the Flooded Jellyskin. There have already been reported occurrences of the Emerald Ash Borer in The Land Between.
Educate yourself in how to identify trees potentially infected by Emerald Ash Borers.
Volunteer with local organizations to participate in surveys or stewardship programs that protect Species at Risk.

Additional Resources:

Learn to identify the Flooded Jellyskin on iNaturalist
COSEWIC 2015 Assessment and Report on the Flooded Jellyskin in Canada

Sources:

COSEWIC. 2015. COSEWIC assessment and status report on the Flooded Jellyskin Leptogium rivulare in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. xii + 48 pp. https://registrelep.gc.ca/default.asp?lang=En&n=1AAA604E-1