Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUBSECTION V.3. Lake Winnebago Clay Plain
DISCUSSION: Subsection is an extension of the more expansive lake plain north of the tension zone in Subsection VIII.1, but much of the flat to undulating landscape is also ground moraine that has been reworked by proglacial lake waters (Lineback et al. 1983, Farrand et al. 1984). Unlike Subsection VIII.1, its silty soils are Alfisols rather than Spodosols.
SUB-SUBSECTIONS: None.
ELEVATION: 748 to 1,070 feet (228 to 326 m).
AREA: 1,165 square miles (3,018 sq km).
STATES: Wisconsin.
CLIMATE: Growing season ranges from 143 to 150 days (Wisconsin Agricultural Statistics Service 1987). Average annual precipitation is 30 to 32 inches, and average annual snowfall ranges from 40 inches in the south to approximately 48 inches in the north (Wendland et al. 1992). Extreme minimum temperature ranges from approximately -30½F along Lake Michigan to -35½F farther inland (Reinke et al. 1993).
BEDROCK GEOLOGY: Subsection is underlain by Ordovician dolomite, with some limestone and shale (Ostrom 1981). Depth to bedrock ranges from less than 50 feet to 200 feet (Trotta and Cotter 1973).
LANDFORMS: Flat till plain and lake plain are prevalent. Much of the till plain has been reworked by proglacial lake waters.
SOILS: Soils are red clays, containing parent material both from local dolomite and reworked, northern lacustrine deposits. Portions of the red, clay soils are derived from iron formations in the Precambrian bedrock farther to the north (Hole 1976). Soils are more carbonate rich than those farther to the north because of the underlying dolomite of the subsection. Tills low in pebbles and cobbles have been mistaken for lacustrine deposits in the area north and west of Lake Winnebago. The most common soil of the subsection is silty clay loam to clay loam in texture. It has almost equal parts of sand, silt, and clay; gravel, primarily dolomite, makes up 10 to 20 percent of the coarse fraction. Soils are classified as Alfisols.
PRESETTLEMENT VEGETATION: Sugar maple-basswood forest covered most of the landscape; bur oak openings were present in the southwest, where fire probably originated farther to the southwest on the ground moraine of Sub-subsections V.2.2 or V.2.3 (Finley 1976). These oak openings extended to the north of Lake Winneconne and Lake Butte des Morts on rolling ground moraine, and they may have persisted partially as a result of Native American land management with fire. There were Mosouakie villages and later Winnebago villages along Lakes Winnebago, Winneconne, and Butte des Morts, and along the Fox River from before 1600 to 1830 (Tanner 1986). These lakes were along the major trade route from the Wisconsin River, with a portage connecting to the Fox River and Green Bay. Swamp forest grew in the wet depressions of the ground moraine. Two large wetland areas consisted of wet meadow, wet prairie, and lowland shrubs (Finley 1976), one surrounding Lake Poygan and the other along the Fox River. East of Lake Winnebago, along the North Branch of the Manitowoc River, there was also a large area of lowland hardwoods.
NATURAL DISTURBANCE: Fire was probably important at the southern edge. Large windthrows were noted within the northern part (Cottam and Loucks 1984).
PRESENT VEGETATION AND LAND USE: Much of the subsection has been converted to agriculture, often requiring some ditching to improve drainage conditions on the flat landscape.
RARE PLANT COMMUNITIES: Wet-mesic prairie. Oak savanna occurred here historically.
RARE PLANTS: Platanthera leucophaea (prairie white-fringed orchid) and a single historic record for Plantago cordata (heart-leaved plantain).
RARE ANIMALS: Acipenser fulvescens (lake sturgeon), Sterna forsteri (Forster's tern).
NATURAL AREAS: State Natural Areas: Oshkosh-Larsen Trail Prairies, Hortonville Bog, and High Cliff Escarpment.
PUBLIC LAND MANAGERS:
CONSERVATION CONCERNS: Winnebago Pool (includes Lakes Winnebago, Poygan, and Butte des Morts) is especially important for lake sturgeon, Forster's tern, and other aquatic species. A comprehensive management plan has been strongly recommended for these lakes.
Previous Section -- Sub-subsection V.2.4. Kettle Moraine
Return to Contents
Next Section -- Subsection V.4. Rock River Hill Country
