Restoration Projects Are Fen-omenal Success
Story and Photo
by Clark Ganshirt/McGraw
The two McGraw fens that are currently undergoing restoration are absolutely flourishing. Both are growing in size and the number of native plant species.
A fen is a rare ecosystem made up of peat and driven by the presence of mineral-rich alkaline ground water. In Illinois, most are found on hillsides or slopes and are capable of supporting a great deal of biodiversity.
McGraw's fens are located on the hillside at the north end of West Lake and on the new property south of the Log Cabin, hidden near a grove of walnuts.
McGraw Vice President Clark Ganshirt launched our fen restoration in 2011. At that time, we did not own the Log Cabin fen and the West Lake fen has been overrun by invasive species such as buckthorn, shrinking its size to just a third of an acre.
The results of the restoration have been gratifying.
It is truly amazing how every year when invasive plant removal takes place, the seeds that have laid dormant in the ground for decades waste no time coming to life. In 2012 -- the first year of the West Lake fen restoration -- there were 27 native plant species. At the end of this year, the count was up to 144 and the fen is now approximately 4.5 acres - nearly 15 times larger than when restoration began, and double the size it was in 2015.
Our newer fen near the Log Cabin now boasts 65 native plant species on about an acre.
The management company hired to assist in the restoration calls the West Lake fen "of immense quality. There continues to be great potential to increase species diversity by removing non-native species and expanding this project in to other areas of the property."
The quality of a fen is measured by conducting a Floristic Quality Assessment (FQA) as defined by Swink and Wilhelm and published in Plants of Chicago Region, 1994. This method assigns a plant species a rating that reflects the fundamental conservatism that the species exhibits for natural habitats.
A native species that exhibits adaptations to a narrow spectrum of the environment is given a high rating. Conversely, an introduced species that exhibits adaptation to a broad spectrum of environmental variables is given a low rating. Utilizing this method, a Floristic Quality (FQI) and Native Mean C is derived for a given area.
Wetlands with a FQI of 20-35 are considered high quality aquatic resources and above 35 indicate "Natural Area" quality. Wetlands with Mean C values exceeding 3.5 are considered high quality aquatic resources. Both of our fens easily meet these standards - you might even say they're fen-tastic!