Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION V.2.3. Galena-Platteville
DISCUSSION: Sub-subsection is defined by the dominance of tallgrass prairie, which occurs on broad, gently rolling portions of the till plain (ground moraine) or on outwash.
ELEVATION: 580 to 1,095 feet (177 to 334 m).
AREA: 1,054 square miles (2,727 sq km).
STATES: Wisconsin.
CLIMATE: See subsection.
BEDROCK GEOLOGY: Drift thickness over bedrock is generally less than 50 feet (Trotta and Cotter 1973). The largest area of prairie in the west, in Dane and Columbia Counties, is located on the broad Galena-Platteville and Prairie du Chien cuestas of Ordovician dolomite (Finley 1976, Morey et al. 1982). In the southeast along Lake Michigan, the large prairies occur on the broad, gently sloping Niagaran cuesta of Silurian dolomite.
LANDFORMS: The landform where tallgrass prairie vegetation dominates is typically ground moraine, but prairie also occupies some outwash channels as well as the rolling recessional end moraines near Lake Michigan in southeastern Wisconsin.
LAKES AND STREAMS: No lakes within the prairies. Several small rivers cross the prairie near Lake Michigan, including the Root, Des Plaines, and Pike.
SOILS: Soils are silt loam at the surface, derived from loess; subsoils are generally calcareous loam (till) or calcareous sand and gravel outwash (Hole and Germain 1994). The loess cap is typically about 2 feet thick. Prairie soils had a thick (6 to 12 inches), dark, surface horizon that resulted from the deep penetration and eventual decomposition of prairie grasses. Prairie soils were classified as Typic Argiudolls (Hole 1976, Hole and Germain 1994).
PRESETTLEMENT VEGETATION: Within the tallgrass prairie were areas of bur oak savanna. Wetlands were generally not extensive, but consisted of either wet prairie or sedge meadow (Hole and Germain 1994, Finley 1976).
NATURAL DISTURBANCE: Fire was important for maintaining tallgrass prairie. Native American land management with fire may have been partially responsible for maintaining the prairies. Winnebago villages were near Lake Mendota and other lakes and streams in Dane and Columbia Counties from at least 1810, and several Potawatomi villages were in the prairie region along Lake Michigan from approximately the same date (Tanner 1986).
PRESENT VEGETATION AND LAND USE: The entire sub-subsection is intensively farmed. Only small areas of wet or wet mesic prairies persist.
RARE PLANT COMMUNITIES: Tallgrass prairie, including mesic prairie, wet mesic prairie, and wet prairie. Fens also occur at the foot of calcareous slopes.
RARE PLANTS: Asclepias sullivantii (prairie milkweed), Aster furcatus (forked aster), Lespedeza leptostachya (prairie bush clover), Liatris spicata (marsh blazing star), Platanthera leucophaea (prairie white-fringed orchid). Near the Lake Michigan shoreline, Fimbristylis puberula (chestnut sedge), Phlox glaberrima ssp. interior (smooth phlox), Solidago ohioensis (Ohio goldenrod).
RARE ANIMALS: Papaipema silphii (silphium borer moth), Podiceps grisegena (red-necked grebe), Sterna forsteri (Forster's tern).
NATURAL AREAS: State Natural Areas: Ripon Prairie, Chiwaukee Prairie, Audubon Goose Pond, Renak-Polak Beech Maple Woods; The Nature Conservancy Preserves: Chiwaukee Prairie.
PUBLIC LAND MANAGERS: National Wildlife Refuges: Horicon.
CONSERVATION CONCERNS: Of the extensive original tallgrass prairies and oak openings, only small preserves remain. The landscape is heavily disturbed and severely fragmented.
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