Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUB-SUBSECTION II.2.2. Lake Benton-Adrian Coteau
DISCUSSION: The Bemis moraines are prominent features of this unit. Several large meltwater gorges breach the Bemis moraine, creating local areas of steeply hilly topography, and the outer scarp has been dissected by drainage downslope. To the southwest is the loess-mantled, eroded pre-Wisconsinan drift. The northern boundary is the Bemis moraine.
ELEVATION: 1,453 to 1,995 feet (443 to 608 m).
AREA: 935 square miles (2,421 sq km).
STATES: Minnesota.
CLIMATE: See subsection.
BEDROCK GEOLOGY: Bedrock is not exposed here. Glacial drift is 200 to 800 feet thick over bedrock (Olsen and Mossler 1982). Cretaceous shale, sandstone, and clay are the upper bedrock in most of the sub-subsection, but there is also upper Precambrian quartzite (Morey 1976).
LANDFORMS: Loess-capped Bemis end moraine of the Des Moines lobe. The loess is 1 to 3 feet thick.
LAKES AND STREAMS: few wetlands because of the well-developed drainage pattern.
SOILS: Cummins and Grigal (1981) map most of the sub-subsection as dry prairie soils. Soils are classified primarily as Mollisols (Borolls, Udolls, and Aquolls).
PRESETTLEMENT VEGETATION: This unit was almost entirely tallgrass prairie. Hill prairie, containing dry prairie species, is locally common on the numerous steep slopes of the sub-subsection.
NATURAL DISTURBANCE: Fire and drought.
PRESENT VEGETATION AND LAND USE: Most of the sub-subsection is now farmed; crops include corn, soybeans, oats, and flax (University of Minnesota et al. 1981a). Little or no woodland or pasture occurs here.
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| Figure 11.—Sub-subsection II.2.2: Prairie Coteau Scientific and Natural Area, Pipestone County, Minnesota. Dry hill prairie originally dominated the rolling hills of the Coteau. Conditions are drier than in much of Sections I and II, accounting for the prevalence of plants of the midgrass prairie. Minnesota Department of Natural Resources photo by E. Fuge. |
RARE PLANTS: Antennaria parvifolia (small-leaved pussytoes), Aristida purpurea var. longiseta (red three-awn), Astragalus flexuosus (slender milk-vetch), Botrychium campestre (prairie moonwort), Carex hallii (Hall's sedge), Cypripedium candidum (small white lady's-slipper), Helianthus nuttallii (Nuttall's sunflower), Platanthera praeclara (western prairie fringed orchid), Triglochin palustris (marsh arrow-grass).
RARE ANIMALS: None identified to date.
NATURAL AREAS: See subsection.
PUBLIC LAND MANAGERS: See subsection.
CONSERVATION CONCERNS: Bemis Moraine Prairies have been identified as a critical landscape for biodiversity protection.
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