Special Places: Eco-lessons from the National Parks in Atlantic Canada

Information Sheet: Water-pennywort (Hydrocotyle umbellata)

The water-pennywort is a small herbaceous perennial, living in very special aquatic environments. It appears in only two locations in Canada, both in Nova Scotia, where it is one of the province’s rarest plants. This unique plant is found in two lakes in Kejimkujik National Park and Wilson’s Lake in Yarmouth County.

© Parks Canada / Don Pentz

The water-pennywort grows in mud, sand or gravel on lake shorelines in a narrow band below the high waterline, where it is exposed during low summer waterlevels. Natural fluctuations in water levels are important for the continued existence of the water- pennywort because flooding minimizes competition from other plants.

The water-pennywort does not flower regularly, but when it does, it produces small clusters of white flowers, anytime from late July to early September.

COSEWIC (Committee on the Status of Endangered Wildlife in Canada) designated this plant as a threatened species in Canada in 2000. Previously it was considered endangered but with warm dry summers in the last 20 years the water-pennywort has flourished and increased in numbers within Kejimkujik National Park.

Reasons for Species Loss

• Human activities such as cottage construction, shoreline dredging, beach construction or lakeshore developments have altered pennywort habitat sites.
• Recreational activities along the shorelines, such as the use of all terrain vehicles, the beaching of canoes or boats, can trample these plants and their habitat.
• Some damage to plants and their habitat occurs due to people walking through plant stands near beach areas.
• Stabilization of the water level in the lakes where the water-pennywort is found (through dams and other means) may destroy the remaining populations of this plant.

Efforts to Conserve

• The designation of all water-pennywort habitat within Kejimkujik as “Special Areas” will help to protect the plant. This designation or zoning means that development is not permitted and human use of these areas is restricted
• There is a special protection site for the water-pennywort in Yarmouth County Nova Scotia.
• Interpretation programs and on-site signs introduce the threatened plant to visitors at Kejimkujik.
• Special areas where the plant grows in Kejimkujik are roped off with signage to explain why visitors can’t walk through and damage the habitat.
• Recovery plans are being developed for the waterpennywort as well as other unique flora (pink coreopsis, redroot, sweet pepperbush) that share the common habitat requirements.

References

COSEWIC Web site: www.cosewic.gc.ca
Parks Canada Web site: www.parkscanada.gc.ca
Species at Risk Web site: www.speciesatrisk.gc.ca