Regional Landscape Ecosystems of Michigan, Minnesota, and Wisconsin
SUBSECTION VI.2. Kalamazoo Interlobate
DISCUSSION: This subsection is the southern portion of an interlobate area between three glacial lobes, which formed approximately 13,000 to 16,000 years B.P. The entire interlobate area is more than 150 miles long. This flat plain was the northernmost extension of the "Prairie Peninsula," as described by Transeau (1935).
SUB-SUBSECTIONS: Battle Creek Outwash Plain (VI.2.1), Cassopolis Ice-Contact Ridges (VI.2.2).
ELEVATION: 750 to 1,280 feet (229 to 390 m).
AREA: 3,511 square miles (9,096 sq km).
STATES: Michigan.
CLIMATE: Average growing season ranges from approximately 140 days at the north edge of the subsection to more than 160 days in the southwest (Eichenlaub et al. 1990). Average annual precipitation ranges from 32 inches in the north to 38 inches in the southwest. Average snowfall ranges from 50 inches in the east to more than 60 inches in the southwest near Lake Michigan. Extreme minimum temperature ranges from -22½F in the south to -30½F in the extreme north.
BEDROCK GEOLOGY: The subsection is entirely underlain by Mississippian (Paleozoic) shale (Dorr and Eschman 1984, Milstein 1987). Glacial drift is shallow in the east where there are local exposures of shale, but it is as much as 350 feet thick in the west and southwest (Akers 1938).
LANDFORMS: The center of the subsection (Sub-subsection VI.2.1) consists of a broad outwash plain that contains numerous small lakes and small "islands" of ground moraine. The edges of the subsection consist of steep, narrow bands of end moraine, and the center of the subsection is steep ice-contact topography; these moraines and ice-contact topography are Sub-subsection VI.2.2. See sub-subsections.
LAKES AND STREAMS: Kettle lakes are numerous on both the pitted outwash of Sub-subsection VI.2.1 and on the end moraines and ice-contact ridges of Sub-subsection VI.2.2. Many small kettles contain bogs or swamp forest. Streams are quite numerous on the outwash of Sub-subsection VI.2.1. The largest streams are the Kalamazoo and St. Joseph Rivers.
SOILS: The most common soil textures are sand and sandy loam. Soils are primarily Alfisols and Histosols, with Mollisols (Aquolls and Udolls) in the prairies of the southwest. Soils are classified by the Soil Conservation Service (1967) as gently sloping Hapludalf plus Argiudolls.
PRESETTLEMENT VEGETATION: This subsection contained the only extensive areas of tallgrass prairie found in Michigan (Brewer et al. 1984, Hodler et al. 1981). Tallgrass prairie was restricted to flat outwash deposits, especially where streams or wetlands did not provide fire barriers. Oak savannas were primarily on broad, rolling "islands" of end moraine. Oak forest was also common throughout, especially in the more dissected ice-contact topography and on the steep end moraine to the north.
NATURAL DISTURBANCE: Early settlers reported fire to be a widely used Native American management tool; the extent of natural fire is not known. Without fire, all the oak openings have closed in to become closed-canopy oak forests.
PRESENT VEGETATION AND LAND USE: All of the upland prairie and most of the upland forests have been converted to agriculture. Forest remains on the steeper end moraines and ice-contact topography. Residential development is encroaching on many of the remaining upland forests. The subsection now supports closed-canopy oak forests due to fire suppression. The oak ecosystems of this and adjacent subsections were classified and described by Archambault et al. (1990), and the ecological species groups of their groundflora were described and classified (Archambault et al. 1989).
RARE PLANT COMMUNITIES: Tallgrass prairie was originally quite extensive, but prairie lands were among the first farmed in Michigan. Tallgrass prairie persists as small fragments along railroad rights-of-way; small fragments of wet prairie also persist. Oak savannas have been either destroyed by agriculture or heavily degraded by fire suppression.
RARE PLANTS: See sub-subsections.
RARE ANIMALS: See sub-subsections.
NATURAL AREAS: See sub-subsections.
PUBLIC LAND MANAGERS: See sub-subsections.
CONSERVATION CONCERNS: Development pressures are high; residential development threatens almost all lakes and mature forests. Similarly, residential development is heavy at the southwestern end of the subsection. The greatest potential for protecting and managing a large natural tract of this landscape is probably in Calhoun, St. Joseph, or Cass Counties. Few preserves adequately represent both the wetlands and uplands of this subsection.
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