Wetlands are unique, important and beautiful landscapes that often go overlooked and unappreciated. Wisconsin was once home to 10 million acres of wetlands, but in the past 200 years, we’ve destroyed 50% of our wetlands. Three-fourths of Wisconsin's wildlife species rely on wetlands for survival, including a variety of threatened and endangered species such as Hine’s emerald dragonfly, a charismatic little bug with bright green eyes and amber wings.
To celebrate wetlands in all their mucky glory, let's take a look at our local wetland, Cherokee Marsh.
Before we head to the marsh, we have to figure out what exactly a wetland is. Each wetland is unique, but they share some common features. Wetlands are areas where water is present in or on the soil for all or part of the year. Some wetlands are flooded year-round, while others have water sitting just below the top of the soil, saturating the ground. The soil in wetlands, called hydric soils, are soils that are flooded or saturated with water for a long enough period to develop growth conditions unique to wetlands. Hydric soils are low in oxygen and favor water-loving — or hydrophytic — plants such as cattails, duckweed and water chestnut.
The Cherokee Marsh Conservation Park is located northeast of UW-Madison and, despite the name, is actually a 2000 acre stretch of open wet sedge meadows interspersed with fens, prairies, bogs and shallow marshes.
Sedge meadows, or wet meadows, are areas of wetlands with permanent or near-permanent water saturation. The areas are dominated by sedges, a grasslike plant with three-sided stems, thin, spiraling leaves and inconspicuous flowers (in case you ever need to tell them apart, remember that grasses are smooth, and sedges have edges). Sedge meadows were once abundant across the state, but they’re hard to find these days because many sedge meadows were drained to be more suitable for farming. Sedge meadows are home to rare birds like American Bitterns and the Northern harrier, as well as a variety of insects including the Baltimore checkerspot, a small butterfly that feeds on wild roses and milkweed.
In contrast to the saturated — but not flooded — sedge meadows, marshes are areas that are permanently or near permanently flooded, containing a layer of standing water over the soil. Marshes are home to great blue herons, minks, muskrats and threatened species of reptiles such as the plains leopard frog and Blanding's Turtle. Deeper marshes, called hemi-marshes, are rich in vegetation such as water lilies, American lotus and wild celery. This vegetation provides exceptional habitat for fishlings and endangered birds.
While marshes may be fed by streams or rivers, bogs are wetlands that only receive water from precipitation such as rain. Bogs are dominated by sphagnum moss, an ecosystem engineer that lowers the pH of its environment, which can make bogs as acidic as your favorite IPA (a pH of 3.0). These extremely nutrient-poor and acidic conditions are the perfect home for carnivorous flora like sundew and pitcher plants. These nutrient poor environments require plants to adapt new ways of getting the nutrients they need, and in the case of carnivorous plants, they thrive in these environments by eating insects.
Between bogs and marshes are fens — wetlands that are fed by groundwater that seeps out of the soil surface. Fens contain a layer of peat formed from dead plant material and are planted with herbaceous vegetation, trees and shrubs. If you’re interested, look up “fen biogeochemistry” — there are some very wacky things going on near those springs.
With all these unique ecosystems in one area, Cherokee Marsh is a crucial natural area. The marsh is an important part of Lake Mendota’s health, protecting the lake from some of the harsher effects of weather and other climatic changes. Without Cherokee Marsh, the shoreline of Lake Mendota would suffer from increased erosion due to harsher flooding, causing a downward spiral in lake health. Additionally, Cherokee Marsh acts as a nutrient sink, preventing harmful quantities of chemical fertilizer and other artificial nutrient sources from entering Lake Mendota.
In addition to providing invaluable ecosystem services, Cherokee Marsh is also a cultural site. Walking down the trails and boardwalks, you’ll eventually stumble across two conical mounds, both built around 700-1000 A.D. The original architects of these conical mounds were a pre-Ho-Chunk society called the Moundbuilders.
Want to visit Cherokee Marsh? The conservation park is open from sunrise to sunset, with 2.6 miles of boardwalk and two observation decks. It is a beautiful, easy hike for the most seasoned outdoorsman and the more casual wandered.
As always, remember to stay on the trail, as veering off could lead to you trampling delicate species or — maybe — stumbling into a giant pitcher plant, never to be seen again.