Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION V.2.4. Kettle Moraine
DISCUSSION: Sub-subsection V.2.4 is a narrow band of ice-disintegration topography, formed as an interlobate area between the Green Bay and Lake Michigan lobes of the Wisconsin Glaciation (Clayton et al. 1991). The band of irregular sand and gravel ridges begins east of Lake Winnebago and continues south into Illinois, becoming less prominent in Kenosha, Racine, and southern Walworth Counties.
ELEVATION: 918 to 1,195 feet (280 to 364 m).
AREA: 226 square miles (585 sq km).
STATES: Wisconsin.
CLIMATE: See subsection.
BEDROCK GEOLOGY: The Kettle moraine is underlain by Silurian-age dolomite for the northeastern two-thirds of its length and by Ordovician dolomite for the southwestern third, beginning in Waukesha County (Ostrom 1981, Morey et al. 1982). Glacial drift thickness over bedrock ranges from less than 50 feet to 400 feet (Trotta and Cotter 1973).
LANDFORMS: The Kettle moraine is steep ice-disintegration topography, with numerous kettle lakes on steep ridges of fluvial sand and gravel.
LAKES AND STREAMS: Many kettle lakes within or at the edge of this narrow sub-subsection.
SOILS: Typic Hapludalfs are most common (Hole 1976). Outwash sands and gravels are overlain by loess, generally less than 20 inches thick.
PRESETTLEMENT VEGETATION: At the southern edge, bur oak openings and white oak-black oak forests, with small inclusions of wet prairie, sedge meadow, and marsh, were the dominant vegetation (Finley 1976). Farther to the north, where strings of kettle lakes and steep moraines created fire barriers, sugar maple-basswood forests were largely unbroken on the landscape, except where conifer swamps occupied small wetlands.
NATURAL DISTURBANCE: Fire in areas dominated by oak savannas and forests.
PRESENT VEGETATION AND LAND USE: Heavy development and recreational pressures threaten.
RARE PLANT COMMUNITIES: Fens are common, as indicated from the number of State Natural Areas named for their fens; also oak openings and tallgrass prairies.
RARE PLANTS: Besseya bullii (kitten-tails), Cypripedium candidum (white lady's-slipper), Lithospermum latifolium (American gromwell), Platanthera leucophaea (prairie white-fringed orchid), Scirpus cespitosus (tussock bulrush).
RARE ANIMALS: Oarisma poweshiek (Poweshiek skipper), Papaipema beeriana (liatris borer moth), Calephelis muticum (swamp metalmark), Regina septemvittata (queen snake), Wilsonia citrina (hooded warbler).
NATURAL AREAS: Wisconsin: State Natural Areas: Scuppernong Prairie, Haskell Noyes Memorial Woods, Milwaukee River and Swamp, Spring Lake, Kewaskum Maple-Oak Woods, Ottawa Lake Fen, Kettle Moraine Fen and Low Prairie, Eagle Oak Opening, Young Prairie, Milwaukee River Floodplain Forest, Kettle Hole Woods, Crooked Lake Wetlands, Butter Lake and Flynn Springs, Milwaukee River Tamarack Lowlands, Johnson Hill Kame, Kettle Moraine Red Oaks, Bluff Creek, Kettle Moraine Oak Openings, Cliff Messenger Dry Prairie and Savanna Preserve, Clover Valley Fen and Peat Lake; The Nature Conservancy Preserves: Lulu Lake Preserve.
PUBLIC LAND MANAGERS: Kettle Moraine State Forest.
CONSERVATION CONCERNS: Several preserves protect fens, prairies, and adjacent oak-dominated upland areas. Recreational and residential development around the numerous kettle lakes may severely limit natural area management and expansion of natural areas in many areas. The Kettle moraine is considered a critical landscape for many uncommon or rare species characteristic of southern Wisconsin, especially vertebrates, but also invertebrates, plants, and aquatic organisms. This is the most intact landscape in southeastern Wisconsin.
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