Pearl's Fen




Fringed Gentians at Pearl's Fen

When the last glacier, the Wisconsinin, left northwest Greene County about 10,000 ago it left some things behind.   Deposits of sand and gravel that had been encompassed by the moving ice were dropped in small to large deposits called moraines, kames, eskers . The terrain of what is now Bath Township gained a series of low rolling hills from these deposits on what was otherwise a bulldozed landscape.  The gravel and sand was derived from pulverized limestone and was (and is) limey.  Meltwater and rainwater that saturated the deposits picked up the lime (calcium carbonate) and became very alkaline.  Water, after moving through them often hit something hard, bedrock, and where the rock met the air cold limey springs poured out.  Most plants are not happy to live in cold limey mud, but the exception are sedges.  These grasslike plants thrive in these harsh conditions.  Because it is so cold and harsh that bacteria and fungi don't break things down very fast.  So when the sedges died they formed organic peat.  Over time the deposits of peat can become quite deep, 6 or more feet in some places.  These wet, limey, springwater fed wetlands are now called fens.  In the Miami Valley they are a very special type of fen called a prairie fen.  These fens were invaded by prairie plants some 6,000 years ago when western prairies covered southwestern Ohio, and many of these prairie species took up residence with the sedges, rushes and other plants that had persisted there for thousands of years.

Fringed Genitians Closed



Prairie Rattlesnake Root

Fens and their unique environment have been refuges for plants and animals that now live nowhere else in the region.  They boast extraordinary biodiversity.  Unfortunately all that organic matter also made for great farmland if one can figure out how to drain the water away.  People have gotten pretty good at this and most fens are now destroyed and growing corn or soybeans.  However, some were never drained and carry on as they have for thousands of years.  One of these is Pearl's Fen.

I first encountered Pearl's Fen in 1984,  I was looking for prairie and fen remnants based on old surveyor records.  Old records showed a fen/prairie complex going west of Byron Rd.  Looking from the car there was some swampy looking ground behind some small houses along the road.  I parked at one of the houses and asked the woman if I could look around back there.  Her name was Pearl Wegiel, and she owned the land.  Her son lived next door and he had recently built a small barn for horses and let the swampy ground serve as a horse pasture.  It was October, a fine warm day and the land became increasingly wet and peaty as I walked past the horses standing in the muck.  It was a "mound" fen.  This is a fen that sticks up from the surrounding land because groundwater pressure pushes the peat up.  This strange situation results in a wetland that is higher than the drier land around it.  It was filled with all the usual plants one can find in a high quality remnant.  The biggest thrill was the fringed gentians growing from many spots the horses couldn't reach!  The downer was that the horses has eaten and stomped most of the trees, shrubs and plants to nubs, and churned up the peat into a wet black mess.  It looked pretty bad.




Pearl's Fen Heavily Grazed by Horses in October, 1984

After a few more visits I asked the Pearl and her son if they would be receptive to the installation of a fence around the fen to keep the horses out.  They were fine with it if I came up with the cost and labor of installing it.  I measured the feet of fence that would be necessary and got a price for fence and posts from a farm supply store.  I didn't have any money and knew nothing about putting up a fence.  I asked my friend Paul Knoop if he had any ideas.  He told me that the fringed gentian was the favorite plant of Marie Aull, and we should ask her for the money.  Paul and I visited Marie at her home and after explaining the situation she pulled out her checkbook.  I bought the materials had them delivered to the fen.  For the labor I recruited some of my friends from the Dayton-Montgomery County Park District to help put it up.  We had quite a time making it work.  Putting farm t-posts into peat doesn't hold things up so we had to anchor it with existing trees.  An old fence gate from a park scrap pile served as a gate.  It seemed to work though and we anxiously awaited the next growing season to see what would happen.



Fence Showing Recovery, Summer 1985

The next growing season surpassed all hopes. Native fen and prairie plants sprang up from the seedbank/roots and transformed the pasture to a garden of rare plants. Fringed gentians, prairie rattlesnake root and many others made Pearl's Fen a delight to visit.



Pearl's Fen Late Summer, 1985





High Volume Spring That Originates on Site

In October of 1984 Paul Knoop and I arranged to take some dignitaries to the fen to see the what had been achieved.  Attending were Scott Huston (Director of Miami County Park District and a great botanist), Ralph Ramey (Director of Glen Helen), Clara Weishaupt (retired botany professor from Ohio State and author of The Vascular Plants of Ohio), Sylvia Koons (Friend to Marie Aull and MetroParks volunteer, and Marie Aull (Matriarch of Miami Valley Conservation and Horticulture).  It was a delightful day with outstanding company who enjoyed themselves.


Scott Huston, Clara Weishaupt, Sylvia Koons, and Marie Aull Visit Pearl's Fen in 1985

In 1991 botanist David Dister did an intensive botanical inventory of the fen.  He spent a season finding and identifying the plants there.  He ended up finding 167 species in 54 plant families.

Over the years Mrs. Aull made many offers to buy the fen from Pearl.  She was never interested in selling but welcomed visitors.  The fen gradually changed over the years.  The rare, diminutive plants disappeared altogether, and the site became dominated by prairie grasses and shrubby cinquefoil.  By 2003 the site was completely dominated by the native cinquefoil.  I have always assumed that this was evidence that these fens undergo their own form of natural succession and that many fen species depend on periodic disturbances.In the spring of 2003 Pearl, was admitted to a nursing home.  Bob Jurick of the BW Greenway Community Land Trust was very concerned for the future of the fen.  He did not know if Pearl still had family in the neighborhood, so he went door to door and finally located Pearl's daughter.  Bob made it known that he could help find a way to protect the fen if she decided to sell it.  After some time she contacted Bob about selling.  Bob contacted me as to how to get some funding.   I approached MetroParks Board member Irv Bieser with the problem.  Irv was on the board of the Ohio Chapter of The Nature Conservancy, and he knew a a bequest left to TNC for conservation in the Dayton area.  It was more than sufficient to cover the purchase!    Terry Seidel of TNC facilitated the purchase of the fen by The Nature Conservancy in February 2003.  Tim Leiwig, Director of The Greene County Park District agreed to apply for a Clean Ohio Grant to purchase the fen from TNC.  The grant funding was received and the fen was transferred to the Greene County Park District, now called Green County Parks and Trails in June, 2004. 

The challenge now for the fen is management.  The  fen responds well to management, and likely needs it to maintain diversity.  It's current condition as a shrubland and recent invasion by Japanese Honeysuckle indicates a management plan is needed.  This fall I attended the Natural Areas Conference in Chicago and had a tour of fens in that region.  Their prescription for over abundant shrubby cinquefoil and other shrubs is fire.  They burn their fens with great results.  That sounds like what needs to be done at Pearl's, either that or bring in a herd of horses for a while!



Pearl's Fen October 2013