Eastern Prairie Fringed-orchid

(Platanthera leucophaea)

Status: Endangered (COSEWIC 2016, ESA 2008)

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

Species Identification:

The Eastern Prairie Fringed-orchid is a tall, showy, perennial orchid ranging in height from 50 to 100 cm. Each plant has one flowering stalk with 10 to 40 creamy white flowers. Flowers are approximately 3 cm wide, with the prominent bottom petal (lip), consisting of 3 fringed segments. Leaves are long, oval in shape, and arranged in an alternate pattern along the stem.

Habitat and Biology:

The distribution of the Eastern Prairie Fringed-orchid is found exclusively in North America and is centered around the Great Lakes. It spans 13 states and is only found in southern Ontario in Canada. There are only 21 populations across Ontario believed to still be in existence. The four largest Ontario populations are located in Kent County (near Windsor), Bruce Peninsula National Park, Marlborough Forest (near Ottawa), and Minesing Swamp in Simcoe County, which is located in The Land Between. Almost all the Ontario populations occur in fen or prairie habitats.

This species requires full sun and low competition from trees and shrubs, occurring almost exclusively in fen or prairie habitats. The Eastern Prairie Fringed-orchid thrives in wetlands, fens, swamps, and tallgrass prairies in a range of soil types and a relatively neutral soil pH. Eastern Prairie Fringed-orchids mature and start producing flowers after three to seven years from June to July. Flowers start at the bottom of the stem opening first, with the rest following sequentially up the stalk. They are capable of remaining dormant, not producing flowers or seeds, for several years if growing conditions are not ideal. Once the flowers are in bloom, they release a fragrance at night that attracts Hawk Moths which are essential for pollination. Seed capsules are produced in late August to early September. Like many orchids, the Eastern Prairie Fringed-Orchid forms a mutually-beneficial association with fungus in soil. The fungus provides the plant with an enhanced ability to absorb water and nutrients from the soil, and in return, the plant provides sugars to the fungus that it produces through photosynthesis.

Map taken from Government of Ontario: https://www.ontario.ca/page/eastern-prairie-fringed-orchid-recovery-strategy#section-6

Threats/ Reasons for being at Risk:

1. Habitat loss and destruction: The Eastern Prairie Fringed-orchid has very specific habitat requirements, so any loss or impact to suitable habitat poses a significant threat to the species. Almost all the Canadian populations of the Eastern Prairie Fringed-orchid occur in fen or prairie habitats. However, less than 1% of the total wetland area of southern Ontario has suitable fens, and less than 0.1% of the landscape of southern Ontario is suitable wet prairie habitat. Conversion and/or drainage of suitable habitat to cropland and pasture has resulted in entire areas being rendered unsuitable for the Orchid. Fen habitats are directly linked to groundwater. Any changes or impacts to the groundwater in and around a fen as a result of human activity have the potential to impact what little suitable habitat remains for this species.

2. Competition from invasive species: Invasive plant species, specifically non-native phragmites, have the potential to outcompete all native vegetation for space and resources, rendering the habitat unsuitable for the Eastern Prairie Fringed-orchid. Competition from phragmites is a particularly strong threat to the population of the Eastern Prairie Fringed-orchid in the Minesing Swamp area of Muskoka, where this incredibly invasive, difficult to control species is outcompeting most other native species.

3. Recreational vehicles and trampling: The use of ATVs and snowmobiles on and off trails near areas where the Eastern Prairie Fringed-orchid is found have been shown to pose a threat to some of the populations. Accidental trampling as a result of walking and hiking trails near areas where the Eastern Prairie Fringed-orchid is found could pose a threat to the long term survival of the species. Damage caused by the plants being run over by these vehicles can be too great to overcome, eliminating individuals- and therefore genetic diversity from affected populations.

Photo by Sheila Collins Bourgoin: https://www.inaturalist.org/observations/131388372

Conservation and recovery strategies:

A monitoring protocol specific to the Eastern Prairie Fringed-orchid has been developed to allow for an accurate evaluation of how the various populations are changing through time. Sustained efforts are being made to monitor the known populations of the Eastern Prairie Fringed-orchid, and evaluate how they change from year to year. There have also been efforts to control phragmites populations through the direct use of pesticides and prescribed burns have resulted in positive responses from Eastern Prairie Fringed-orchid populations. The Eastern Prairie Fringed-orchid has been included as a target species in the Multi-species Action Plan for Bruce Peninsula National Park and Fathom Five National Marine Park of Canada. This action plan outlines measures to research the potential for long term conservation of the Eastern Prairie Fringed-Orchid through artificial propagation and preservation of plant tissue using freezing (cryopreservation).

Why You Should Care:

This species is listed as Endangered in Ontario, and since Ontario is the only province with this species it is the last stronghold for all of Canada. One of the four largest remaining populations of this species in Canada is located in The Land Between in the Minesing Swamp in Simcoe County.

Photo by Simon Tolzmann: https://www.inaturalist.org/observations/123119052

How can you help?

Learn how to identify the Eastern Prairie Fringed-orchid, and report any sightings to The Land Between, iNaturalist, or the Natural Heritage Information Centre with a photo and a GPS location of where it was found.
Volunteer with your local conservation group to help remove phragmites in your neighbourhood. Check out the Phrag Fighter program on The Land Between’s website! Invasive, non-native phragmites pose a significant threat to the habitat of the Eastern Prairie Fringed-orchid and many other wetland Species at Risk. Targeted, sustained removal efforts are the only way to combat this issue.
Stay on marked trails and paths to avoid disturbing wildlife.
Volunteer with local organizations, nature clubs, or Provincial parks to participate in surveys or stewardship work focused on Species at Risk.
Keep areas on your property natural, and encourage the growth and success of natural plants and wildflowers.

Quick Facts:

The flowers of the Eastern Prairie Fringed-orchid contain a pocket of nectar called a “nectar spur” that is so deep it can only be reached by very specific insects such as Hawkmoths that have mouth parts that are long enough to reach it
Like many orchids, the Eastern Prairie Fringed-orchid forms a mutually-beneficial association with fungus in soil. The fungus provides the plant with an enhanced ability to absorb water and nutrients from the soil, and in return, the plant provides sugars to the fungus that it produces through photosynthesis. This relationship is called a mycorrhizal association, and is thought to allow the Orchid seedlings to survive in the years before they emerge from underground and begin photosynthesizing
Due to its beauty and rarity, the international trade of the Eastern Prairie Fringed-orchid is heavily restricted in Canada

Photo by Julie Hall: https://www.inaturalist.org/observations/124459980

Photo by Simon Tolzmann: https://www.inaturalist.org/observations/123119046

Additional Resources:

Government of Ontario’s Eastern Prairie Fringed-orchid SAR page
Check out the information page from the North American Orchid Conservation Centre
Learn how to identify the Eastern Prairie Fringed-orchid on iNaturalist

Sources:

Government of Ontario. 2014. Eastern Prairie Fringed-orchid. Retrieved from: https://www.ontario.ca/page/eastern-prairie-fringed-orchid

Government of Ontario. 2017. Eastern Prairie Fringed-orchid Recovery Strategy. Retrieved from: https://www.ontario.ca/page/eastern-prairie-fringed-orchid-recovery-strategy#section-6

Parks Canada Agency. 2016. Multi-species Action Plan for Bruce Peninsula National Park and Fathom Five National Marine Park of Canada. Species at Risk Act Action Plan Series. Parks Canada Agency, Ottawa. v + 22 pp. https://wildlife-species.canada.ca/species-risk-registry/virtual_sara/files/plans/Ap-BpnPark-v00-2016Nov21-Eng.pdf