Eastern prairie fringed orchid recovery efforts continue in Illinois
January 18, 2018
Eastern prairie fringed orchids in Illinois. Photo by USFWS.
The eastern prairie fringed orchid, listed as threatened under the Endangered Species Act, depends on its annual seed set to maintain its population. Year after year, the species’ population at the Lone Grove Forest Preserve in Kane County, Illinois, lacked viable seed production even though flowering plants were abundant. Viable seed set occurs when flowers are cross-pollinated. Successful seed production is measured by how many plump (rather than skinny) seed capsules are formed. Plump capsules contain a higher number of seeds, and a higher percentage of those seeds are viable. The skinny seed capsules often contain no seeds at all, or if they do contain any seed, they’re few in number and many are not viable. Another challenge facing these orchids is that their natural pollinators may not be present in enough numbers for successful cross-pollination.
Fortunately in July of 2017, an enthusiastic group tackled this problem onsite during the orchid’s bloom period by cross-pollinating flowers by hand. This group included the two long-time (and hard-working) orchid volunteer monitors from the site, as well as staff from the Kane County Forest Preserve District, Fermilab and our Chicago Ecological Services Field Office. Using pollen collected from a nearby population of eastern prairie fringed orchids, the group hand-pollinated one-third of the flowers on half of the plants. The group also collected pollen from these plants to cross-pollinate at the nearby population where pollen was initially removed. Subsequent monitoring after seed production revealed that their efforts were a success, showing a large increase in the number of plump pods versus skinny pods.
In other recovery news, biologists from the Chicago Field Office worked together with staff from the McHenry County Conservation District to distribute eastern prairie fringed orchid seed capsules on appropriate habitat at Hackmatack National Wildlife Refuge. The seeds were collected from two existing healthy populations from both McHenry County Conservation District land and from Cook County Forest Preserve land. This is a long-term project as it typically takes from 5 to 9 years for the first blooming plants to appear. Augmentation of this year’s seed will take place for the next 5 years as long as enough seed is available from nearby populations.
Things are looking up for the eastern prairie fringed orchid. Although overall 2017 numbers were down by about 750 from 2016’s record-breaking year, Illinois recorded 1,186 blooming plants, and some some sites recorded their highest numbers since counts began in 1991.
DuPage County Forest Preserve District staff member Scott Kobal counts the number of flowers on an eastern prairie fringed orchid. Photo by USFWS.