Wetlands are magical places where water and land embrace. The resonant trills of red-winged blackbirds, glistening wings of darting dragonflies and musky perfume rising from the black satin underfoot provide a feast for the senses.

Wetlands are a cradle of life. They are safe spawning grounds for fish, whose tiny eggs cling to an underwater forest of aquatic plants in warm, shallow pools. Waterfowl and their broods nestle in the tall grasses, reeds, sedges and cattails, and feast on the insects that thrive here. Beaver and muskrat raise their kits in snug lodges and dens carved in the muddy shoreline. Frogs perform their joyful chorus and leave behind millions of bubbly clusters of eggs. Other animals come to visit and enjoy a cool sip of water or perhaps a meal.

Like the Great Lakes, many of Ohio’s wetlands were originally sculpted by the mighty hand of mile-thick glacial ice that crept across much of the state during the most recent Ice Age, 12,000 years ago. As the glacier slowly retreated northward to present-day Canada, boulders drug by the ice carved deep holes, debris left in mounds blocked drainage outlets, and the crushing weight of the ice itself created a landscape filled with watery potholes and channels. Over time, sediments accumulated in rich, mucky beds, and plants and animals populated these areas, creating complex wetland communities.

Today, the coastal wetlands of Lake Erie are some of the state’s most expansive wetlands. Coastal marshes at Maumee Bay and East Harbor state parks are visited by more than 300 species of songbirds, shorebirds and waterfowl each year. Nearly half of the species documented are known to breed in the marshes and 120 species are considered year-round residents.

Other types of wetlands in Ohio are more isolated than the coastal marshes and add diversity to surrounding upland habitats. Tinker’s Creek State Park and the adjacent state nature preserve in Portage County provide fine examples of marsh wetlands and swamp forest. These wetland types fill in the margins of a collection of small kettle lakes created by the retreating glacier. The swamp features large pin oaks and swamp white oaks. It borders more open marsh areas with standing water skirted by cattails, willows and buttonbush. Beaver are highly active in this area, and the marshes support a heron rookery. The combination of marsh and swamp provides exceptional diversity of animal species including mink, weasels and foxes; wood ducks and warblers; salamanders, water snakes and snapping turtles.

Bog and fen wetlands are living souvenirs of earth’s most recent Ice Age. Some of the cold-climate Canadian plant species living on the fringes of the retreating glacier were able to survive the general warming trend under special environmental conditions in some areas. Portions of glacial kettle lakes at what is now Portage Lakes State Park in Summit County have aged into acidic bog wetlands harboring an assortment of Canadian plants. A bed of spongy sphagnum moss holds the chill and moisture of the ancient lake and releases acid into the water as it grows. The sphagnum moss bed supports stands of acid-tolerant tamarack, alder and swamp birch trees, as well as cranberry and gooseberry. Buck Creek State Park lies in the heart of bog and fen territory in west central Ohio. Throughout this region, spring water held in sand and gravel deposits atop ancient river beds wells up to the surface. In the Buck Creek area, the high limestone content of the gravel deposits results in alkaline conditions, forming fen wetlands which support unique plants that tolerate a high pH. Surprisingly, several species of prairie plants, which are adapted for life in harsh and dry conditions, also thrive in fen wetlands.

Buckeye Lake State Park in central Ohio surrounds what is thought to be the world’s only floating bog island. Cranberry Bog, a state nature preserve, is a 50-acre mat of sphagnum moss floating on the surface of Buckeye Lake. Extensive bog and swamp wetlands filled the valley that is now Buckeye Lake until the valley was dammed in 1830 to create a feeder reservoir for the Ohio and Erie Canal. As the boggy valley flooded, a large chunk of the valley floor broke free and rose to the surface. Most of the bog island is a mossy meadow supporting populations of large cranberry, orchids and the insect-eating pitcher plant and round-leaved sundew. Shrubs and small trees circle the edges of the island, protecting it from further erosion by the lake. Each June, a public open house is held at Cranberry Bog, featuring boat trips to the island and a guided hike on its boardwalk trail.

What was once Ohio’s greatest wetland is mostly a memory today. As the last glacier retreated, all of northwest Ohio was covered by lake waters. The shoreline of this vast lake shrank over time to the size of present-day Lake Erie, and left behind the Great Black Swamp, an enormous wetland which blanketed ten Ohio counties from the Sandusky River to the Indiana border. Tree seeds from forests to the south germinated in the rich, wet muck and grew to towering heights. In some parts of the swamp, ridges of sand from ancient beaches covered the clay of the former lake bottom, providing higher and drier places. Elk, black bear, mountain lion and even timber wolves roamed this untamed wilderness.

Native Americans developed trails along the sand ridges to travel across the vast swamp, and several Ottawa Indian villages occupied drier areas along the Maumee River. Eager to encourage further settlement, the federal government built a road through the swamp in 1827 to allow travel by wagon into northern Indiana and points west. The road was so muddy and travel so slow that many wagons could manage only one mile a day, and often had to be pulled from mud holes by teams of oxen. Early entrepreneurs seized the opportunity to make a living from the swamp, and in a short time, 35 inns were built along a 34-mile stretch of what is now State Route 20. Despite outbreaks of malaria and other hardships, persistent settlers drained the land through the 1800s and succeeded in pulling the plug on the swamp, felling the trees and exposing the rich soil for farming.

The deep and productive organic soils of northwest Ohio today are a legacy of the ancient lake muck and sticky mud that tormented pioneer farmers. An important but less obvious legacy of the wetlands created by the ancient great lakes is the natural filtering system they provide to keep the modern lakes clean. The wetland soils function like a sponge, holding water in place while the roots of wetland plants trap pollutants. Ohio’s remaining wetlands also help reduce the dangers of flooding by retaining excessive rain and snowmelt in their absorbent soils. By the same process, wetlands help keep groundwater supplies clean and plentiful by providing temporary storage and filtering the surface water as it slowly percolates into porous rock, sand and gravel underground.

Goll Woods State Nature Preserve, a 320-acre patch of old-growth forest in Fulton County, is most of what remains of the ancient Great Black Swamp. Visitors to Mary Jane Thurston, Independence Dam, Harrison Lake or Van Buren state parks in northwest Ohio can only imagine the ominous Great Black Swamp of frontier Ohio that was tamed by pioneer axes and ditches to create Ohio’s most productive agricultural land.

—Jean Backs