Indiana Biological Survey
Aquatic Research Center
Division of Fishes Projects
Northern Indiana Till Plain Ecoregion
The Northern Indiana Till Plain (NITP) consists of extensive crop and livestock production. It is distinguished from other adjacent ecorgions by the natural forest cover, a high percent of urbanization, and extensive quarrying. The broad, nearly flat to rolling glaciated plain includes deeply mantled glacial till and outwash, sand and gravel beach ridges and flats, belts of morainal hills, and bog kettle depressions. Elevations range between from less than a meter to 179.6 m along the shores of the Great Lakes to over 334 m on some moraines. Streams are sluggish and are bordered by riverine wetlands throughout the 25,800 square miles of the ecoregion. Perennial streams include drainage ditches and channelized streams with a density of one half mile per square mile. Lakes are common in some areas; however, many depressions are filled with peat deposits or dark mineral soils. Precipitation occurs mainly during the growing season and averages from 35-46 inches annually.Both perennial and intermittent streams are common in the NITP. Intermittent streams comprise between 10-15% of the streams. Constructed drainage ditches and channelized streams further assist in soil drainage in flat, poorly drained areas. Stream density is about one half mile per square mile in the typical areas of the NITP.
The NITP is managed for cropland, livestock, forest and woodland, and urban uses. Crops are primarily corn, other feed grains, soybeans, and hay for livestock. Emphasis on livestock includes the dairy cattle, but beef cattle, swine, sheep, and poultry are also important. About 25% of the ecoregion is urbanized.
Most of the soils were developed under the influence of deciduous forest vegetation. The soils are derived from loamy glacial drift and till. Hapladalfs and Ochraqualf’s are the dominant soil groups, while poorly drained soils include Argiaquolls, Haplaquolls, Haplaquepts, and Psammaquents. Udipsamments form on better drained outwash plains. Mediprists and other organic soils can be found on depressions.
The natural vegetation of the area consists of diverse hardwood forests, predominantly oak and hickory. A significant amount of white oak, red oak, black oak, bitternut hickory, shagbark hickory, sugar maple, and beech exists. This vegetation is not common in the mixed forest to the north or on the poorly drained lake plain to the south and east. Wet sites include red maple, white oak, American elm, and basswoods. White ash, red maple, quaking aspen, and black cherry grow along river and stream corridors.
Indiana Biological Survey - Aquatic Research Center
6440 S. Fairfax Rd., Bloomington, IN 47401
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