As the name implies, wetlands have water at or just above the surface of the soil for much if not all of the year. Known for a distinctive set of plants, wetlands support a wide variety of animals, and provide essential services such as flood and stormwater abatement and water quality management. The Lakeshore Nature Preserve has two major natural wetlands—one on Picnic Point and one on the western edge of University Bay—as well as a wetland restoration, the Class of 1918 Marsh.
Preserve marshes are mostly classified as “emergent aquatic” freshwater wetlands, named for the kinds of plants (cattails, pickerel weed, reeds) that dominate them. Such marshes usually extend along a lake shoreline and follow the slope of the land into the basin from the shore to deep water. The shallower and longer the slope, the more extensive the marsh is.
The emergent aquatic plants that create the marshes are rooted under water, but their erect stems, leaves, and flowers extend well above the water surface for much of the year. This part-aquatic, part-aerial existence has led to some interesting adaptations. One problem the emergents face is how to get oxygen to their waterlogged roots.
Cattails (pictured) solve this problem with leaves and stems made up of specialized spongy tissues containing tubes that carry oxygen to all parts of the plants. Many a hero in adventure stories has used the hollow stems of reeds, adapted for the same purpose, to use as a breathing tube while hiding under water.
The emergent aquatic plants are usually found towards the upland edge of a marsh, and, depending on the steepness of the slope, can form large, densely packed single-species mats.
Floating leaf aquatics
Especially in the deeper portions of the marshes, the emergents are joined by three additional sets of plants. The first of these are the water lilies, or floating-leaved aquatics. These plants send up sets of flat, saucer-shaped leaves that, as their name implies, rest just on the surface of the water. The circular shape helps keep the leaves from being torn apart by wind and waves, and serves as a platform for the display of the large, spectacular flowers.
Submerged aquatic plants
Here you will also find the familiar “pond weeds” or submergent aquatic plants. Their delicate stems and leaves stay beneath the water, often forming large patches. The only parts of the plants that emerge above the surface are the flowers, leading botanists to believe that their ancestors evolved on land and then moved into the water.
Finally, the marshes are home to the tiny duckweeds, a type of plant known as a floater. Duckweeds are among the smallest of plants, smaller even than a dime, with much reduced leaves and roots. What they lack in size, though, they make up for in numbers, sometimes forming colonies that turn the surface of the water a bright green.
The marshes in the Lakeshore Nature Preserve support many kinds of migrating and some resident waterfowl (ducks and geese), numerous red-winged blackbirds, and even in recent years a few sandhill cranes. Muskrats, frogs and turtles are also very visible residents of these communities.
University Bay, Triangle, and Class of 1918 Marshes
Before 1900, both University Bay Marsh and the area occupied by the Class of 1918 Marsh were part of an extensive wetland extending well inland of University Bay Drive and east of Wingra Creek Woods, including the small area known as Triangle Marsh. The wetlands were mostly drained, leaving only the lakeshore remnants, and not until 1969 was restoration begun on part of the drained inland area that became Class of 1918 Marsh.
All three marshes—Class of 1918, Triangle, and University Bay Marshes—suffer from excessive drainage of runoff from roads, parking lots, and fields. Management of upland runoff is one of the major challenges for management of these wetlands into the future.
Picnic Point Marsh
The wetland on Picnic Point was also historically an emergent aquatic marsh, but in recent years has become a wooded swamp, with a well-developed tree canopy, and an understory that includes a variety of herbaceous species.
Picnic Point Marsh has had a varied history linked to variation in the level of Lake Mendota. To return it to an emergent aquatic marsh would require a major restoration effort, but it also has value as our only example of a swamp within the boundaries of the Preserve.
Read an article by Roma Lenehan on “University Bay: Preservation and Change”