Points of Interest:
- Hike along scenic Coonville Creek on the Mooner’s hiking trail.
- Look for plants more common to the Great Lakes states.
- See colorful orangethroat and rainbow darters and southern redbelly dace in Coonville Creek, a State Outstanding Resource Waters.
Natural Features Description: Coonville Creek is a high-quality Ozark headwater creek that flows for two miles through the natural area. Much of the creek in the natural area flows over Cambrian age dolomite bedrock. The creek has a well-sustained base flow due to the numerous seeps and small springs along its course. Along the upper reaches of Coonville Creek are unique and fragile wetlands known as fens.
Fens are wetlands created when calcareous groundwater seeps out to the soil surface. Ozark fens such as these are typically dominated by herbaceous plants and are kept open by both saturated soils and historically, occasional wildfires. The fens along Coonville Creek are created by groundwater moving down through dolomite formations and hitting a resistant layer, likely sandstone, along which the water then runs horizontally and seeps out onto the lower slopes along the valley.
Although small, fens are botanically rich and often support plant and insect species that are restricted to these unique wetlands. Coonville Creek’s fens include plant species considered “glacial relicts.” That is, they are species that were common in Missouri 10,000 years ago when glaciers covered the upper midwest. In the intervening thousands of years Missouri’s climate has gotten warmer and drier. The glacial relict species were able to persist in fens and along spring branches where cool groundwater provides appropriate habitat conditions. Other glacial relict species in Missouri persist on cool, moist north facing bluffs. At Coonville Creek’s fens, glacial relicts include interior sedge, marsh fern, and swamp thistle. Visitors to the area may spot the swamp metalmark, a butterfly species that is highly associated with fens and whose larvae feed primarily on swamp thistle. Although small, fens are hot spots of botanical and insect diversity.
This natural area is within St. Francois State Park. Because fens are a fragile habitat easily marred by foot traffic visitors are urged to stay on the Mooner’s hiking trail that traverses the natural area. From Bonne Terre, travel north on Highway 67 for three miles from the Highway 47/67 intersection. The park entrance is off Highway 67. Enter the park and travel a third of a mile to the state park office. Inquire at the visitor center about accessing this natural area.