Prairies are a type of grassland, a landscape dominated by herbaceous plants, especially grasses; trees are either absent or only widely scattered on the landscape.  Grasslands occur in many regions, such as the llanos of Venezuela, the pampas of Argentina, the cerrado and campos of Brazil, the steppes of central Asia, and the grasslands of Australia.  Approximately 32 to 40% of the world's land surface is, or was, covered by grasslands.  Today, grasslands are extremely important for agriculture, and approximately 70% of the food produced for humans comes from these regions.

Source:  Photograph courtesy of Randy Schaetzl, Professor of Geography - Michigan State University  

Grasslands are the largest vegetation type in North America, covering approximately 15% of the land area.  Prairies are the grasslands found in the central part of the North American continent.  They form a more or less continuous, roughly triangular area that extends for about 2,400 miles (3,870 km) from Alberta, Saskatchewan, and Manitoba southward through the Great Plains to southern Texas and adjacent Mexico and approximately 1,000 miles (1,612 km) from western Indiana westward to the foothills of the Rocky Mountains, covering 1.4 million square miles.  Rainfall decreases from east to west, resulting in different types of prairies, with the tallgrass prairie in the wetter eastern region, mixed-grass prairie in the central Great Plains, and shortgrass prairie towards the rain shadow of the Rockies.  Today, these three prairie types largely correspond to the corn/soybean area, the wheat belt, and the western rangelands, respectively.

Source:  Photograph courtesy of Randy Schaetzl, Professor of Geography - Michigan State University  

    Michigan lies on the far eastern edge of an area called the "prairie peninsula," an eastward extension of prairies that borders deciduous forests to the north, east, and south.  This is part of the tallgrass prairie region, sometimes called the true prairie, with the landscape dominated by grasses such as big bluestem and Indian grass as well as a large number of other species of grasses and wildflowers, the latter called forbs.  The tallgrass prairie vegetation sometimes reaches a height of 10 feet or more.

Source:  Unknown

How did prairies form?
As the climate became warmer and drier, between 14,000 and 10,000 years ago, a cool mesic hardwood forest with ash, oak, elm, maple, birch, and hickory trees grew in the midwest. About 8,300 years ago, the climate became substantially warmer and drier, and within the relatively short time of 500 to 800 years, most of the forests in southwestern Michigan died out or got burned down, except along stream banks, and prairies spread over the landscape.  During the last 1,000 years the climate has become slightly cooler and wetter, making conditions more favorable to trees.  Savannas, characterized by a grassy prairie-type ground cover underneath an open tree canopy, are common in areas that border the prairies.  Scattered out on the prairie were patches of rich forests completely surrounded by prairie; these forests are called prairie groves.
    Prairies developed and were maintained under the influence of three major non-biological stresses: climate, grazing, and fire. Occurring in the central part of North America, prairies are subject to extreme ranges of temperatures, with hot summers and cold winters.  There are also great fluctuations of temperatures within growing seasons.

Source:  Unknown

During periods of drought, trees died and prairie plants took over previously forested regions.  When rainfall was abundant and fires few, the trees and forest were able to reestablish themselves.  Prairie fires, started either by lightning or by Native Americans, were commonplace before European settlement. Any given parcel of land probably burned once every one to five years. These prairie fires moved rapidly across the prairie, and damaging heat from the fire did not penetrate the soil to any great extent. Fire kills most saplings of woody species, removes thatch that aids nutrient cycling, and promotes early flowering spring species. Today fire also is beneficial to control non-native herbaceous species that can invade prairie remnants.
    A considerable portion of the above ground biomass of a prairie was consumed each year by the grazing of a wide range of browsing animals, such as bison, elk, deer, rabbits, and grasshoppers.  This grazing was an integral part of the prairie ecosystem, and therefore grasslands and ungulate mammals coevolved together.  Grazing increased growth in prairies, recycles nitrogen through urine and feces, and the trampling opens up habitat for plant species that prefer some disturbance of the soil.  Prairie plants have adapted to these stresses by largely being herbaceous perennials with underground storage/perennating structures, growing points slightly below ground level, and extensive, deep root systems.   The tender growing points of prairie plants occur an inch or so below ground and are usually not injured by prairie fires, which move rapidly across the prairie.  These underground growing points are also left unharmed by browsing animals.  During droughts, the deep roots of prairie plants are able to take up moisture from deep in the soil.
   Prairie remnants exist today in areas that have been repeatedly burned, because fire assists the grasses and eliminates woody plants that might otherwise overtop the grasses and shade them out. The best places to find prairie remnants are along old RR rights of way, which occasionally were burned as sparks and cinders were thrown out of passing trains. Prairie remnants are also observable in old cemeteries built originally on patches of prairie. The last prairie remnant in Monroe County, the Minong Prairie, is found just 13 miles north of the Ohio/Michigan state line within the Petersburg State Game Area.

Prairies in Kalamazoo County

Source:  Peters, B.C. 1970. Pioneer evaluation of the Kalamazoo County landscape. Michigan Academician 3(2): 15-25.


Today, most of Michigan's prairies have been converted to agriculture, as this image below, from Iowa, shows (with prairie in the foreground and corn in the background).

Source:  Photograph courtesy of Randy Schaetzl, Professor of Geography - Michigan State University  


Still, some areas of prairie exist in Michigan, such as this one in Middleville, in SW Michigan.  This particular prairie is located within a cemetary, and for that reason it has not been plowed or otherwise destroyed.  Like many prairies, it requires occasional fires to keep woody vegetation at bay.  The Nature Conservancy bought the cemetery and occasionally does burn it, preserving the tallgrass character of the place.

Source:  Photograph courtesy of Randy Schaetzl, Professor of Geography - Michigan State University  

Source:  Photograph courtesy of Randy Schaetzl, Professor of Geography - Michigan State University  

The first European settlers moving westward from the forests of the eastern United States encountered the prairies, which seemed like a vast ocean of grass. The wind caused waves on the surface of the shimmering grasses.  One type of wagon used by the pioneers was the "prairie schooner," a reference to a sailing vessel, further adding to the analogy of the prairie being a large inland sea of grasses.  It was easy to get lost in the prairie, especially since there were few trees or other natural features to act as landmarks.  Even when on horseback, it was often not possible to see across the prairie to the horizon. Today, many of these landscapes are in irrigated corn.  A few oaks remain as a testament to the presettlement forest vegetation that surrounded the prairies (the oak openings).

Source:  Photograph courtesy of Randy Schaetzl, Professor of Geography - Michigan State University  

Click here for some links to web sites devoted to prairies.

This material has been compiled for educational use only, and may not be reproduced without permission.  One copy may be printed for personal use.  Please contact Randall Schaetzl (soils@msu.edu) for more information or permissions.