|Looking east across the western fen opening backed by a glacial esker|
Gallagher Fen is home to some of the best prairie fen habitat left in Ohio, as well as nice examples of bur oak savanna and mature upland oak/hickory forest. Much like the area's numerous other fen openings and complexes, Gallagher Fen owes its existence and future to the continued flow and percolation of cold, alkaline groundwater to the surface. Following the last glacial event around 10-12,000 years ago, this region of Ohio's old waterways and river valleys were left full of glacial till and were subsequently filled with meltwater. These ancient, saturated subterranean river valleys are what we call aquifers and are the lifeblood for west central Ohio's fens to this day.
|Standing in the western fen meadow looking east across the marl meadow, backed by bur oak savanna on the esker|
The glaciers didn't just influence the hydrology of Gallagher Fen but the topography and geology as well. What appears to be a hill at the back of the western fen meadow pictured above is actually a long, winding ridge of stratified gravel and sand called an esker. Eskers, such as the one found here are formed during a glacier's recession as gushing meltwater from in/under the ice sheet deposits the rocky debris along its course.
|Aerial photograph of Gallagher Fen with the glacial esker outlined in brown|
The aerial photograph above shows the preserve's two fen openings and also highlights the glacial esker that forms the northern backbone for the west and east fen meadows. The 55 degree, calcium-carbonate laden groundwater seeps from the base of the esker and flows down into the bowl-like fen meadows where other small rivulets come together to form a spring-fed stream that drains out the bottoms of both openings.
|Bur oak savanna perched on the esker above the eastern fen meadow|
Perched above the cold, saturated fen openings on the slopes and crest of the gravel esker is the curious habitat of a bur oak savanna. The rocky, shallow, fast-draining soils atop the esker created an ideal situation for prairie plants and their accompanying bur, white, and post oaks to occur and persist. My newly-minted winter experience allowed a better appreciation and observation of the gnarled, venerable oaks rising above the beige sea of desiccated and dispersed seed heads underneath. These trees have undoubtedly seen their fair share of winters thaw into spring.
|Queen-of-the-prairie blooming in the fen meadows against a bur oak background|
Summer is hands down the best time to experience our alkaline prairie fen environments and it's not hard to surmise why. From early June into September their mucky meadows are alive with wildflowers, grasses, and sedges all going about their reproductive duties, completely oblivious to their Homo sapiens observers and admirers.
As my boots sank into the marl and muck of the deadened sedge meadows during my winter escape into Gallagher, I realized I had a unique opportunity on this isolated occasion to compare and contrast this spectacular ecosystem between the two extremes of summer and winter. So upon my return home, I did my best to find opposite season photographs of the same corresponding capture and I came away rather pleased with the results that you can see below.
|Looking west atop the west fen meadow's esker among the summer prairie wildflowers|
One of the best views in the 200+ acre preserve is located atop the esker looking west across the western fen meadow. The bowl-like depression of the meadow is more evident from this vantage point and allows you to immerse yourself in a medley of purple coneflower (Echinacea purpurea), grey-headed coneflower (Ratibida pinnata), and whorled rosinweed (Silphium trifoliatum) come July. Other botanical oddities and rarities like the state-threatened prairie thimbleweed (Anemone cylindracea) and the state-endangered prairie violet (Viola pedatifida) occur along the gravel-ridden slopes of the bur oak savanna as well.
|View of the perched bur oak savanna in the east fen meadow|
It's not everyday you can visit a spot in Ohio, or many other places where two unique and equally fascinating habitats of such variety and contrast like fens and savannas merge. The sludgy, saturated soils of the fen meadow support fen Indian plantain (Arnoglossum platagineum), sticky tofieldia (Triantha glutinosa), wand-lily (Zigadenus elegans), Indian grass (Sorghastrum nutans), queen-of-the-prairie (Filipendula rubra), nodding ladies'-tresses (Spiranthes cernua), and Ohio goldenrod (Oligoneuron ohioense) right up to the base of the esker and its groundwater seeps.
|The stark contrast of the prairie dock in the western fen meadow and marl bed.|
Perhaps the most impressive floral display to be found at Gallagher is the annual summer flaunting of prairie dock (Silphium terebinthinaceum) in the western fen meadow's marl bed. Hundreds, if not thousands of flowering stems rise over your head and are adorned with golden yellow stars that shine in the July and August sun. It's truly a sight to behold and take in with your own eyes. It's hard to believe so much green, life, and growth pictured on the left turns to ashes come winter, only to come back to life in the waxing temperatures and sunlight of summer.
You may be wondering how a plant species so adapted to dry, barren-like soil and habitat conditions like the prairie dock could survive, let alone thrive in the saturated muck of a marl bed. This odd occurrence is due to the fact that plants have a hard time absorbing water and nutrients from the very chilled water of the fen meadow and thus react as if living in a more dry, drought-prone environment. This is why so many of our fen complexes in west central Ohio have a strong prairie association in them, hailing back to the influence of the prairie peninsula some 4-8,000 years ago during a period of a warmer/drier climate.
|Looking east out across the western fen opening and its spring-fed channels|
If looking west across the western fen meadow from atop the esker is one of Gallagher's best spectacles, then the same must be said for the reciprocal of that view. The great expanse of sedge meadow, raised hummocks scattered among the rivulets, and mucky marl bed are home to dozens of intriguing and rare plants such as grass of parnassus (Parnassia glauca), twigrush (Cladium mariscoides), blue-leaved willow (Salix myricoides), Carex flava, C. viridula, C. sterilis, C. buxbaumii, tufted hairgrass (Deschampsia cespitosa), Kalm's lobelia (Lobelia kalmii), round-leaved sundew (Drosera rotundifolia), low nutrush (Scleria verticillata), horned bladderwort (Utricularia cornuta), and Canadian burnet (Sanguisorba canadensis) for starters. An advantage to my mid-December visit was being able to see the esker much more clearly and defined at the back of the fen meadow. Lush growth and greenery block the view most other times of the year.
Realistically, I could do a whole series of posts dedicated to the beauty and biological diversity of this gem of a nature preserve but this at least gives you a beginner's look at what an incredible and mesmerizing site Gallagher Fen is. Despite some confusion, this preserve is indeed open to the public nowadays and I could not encourage you to get out and immerse yourself in its wonders more, regardless of the time of year. Which is something I can officially say with validity after my winter excursion into its depths!