Change Over Time

Change Over Time

During a relatively warm, dry period some 6,000 years ago, prairie species moved well east, forming the prairie peninsula.  As the climate cooled over the next few thousand years, woody trees were favored again, leaving a complex mosaic of woodland and grassland (see Figure) throughout the region.  Only in the core of the region, where fires and drought were frequent enough, did tallgrass prairie persist in large expanses, a condition which persisted until he early American settlers arrived in the 1820s to 1850s. No doubt the large, sweeping fires were a terror to those early settlers, as was the lack of shade, large numbers of mosquitoes.  At first, the settlers mistook the open prairie as an indication that the soil was not fertile, as it would not support trees.  As they began building fire breaks and turning over the soil, they discovered just how productive it was.   In the prairie peninsula region, where the balance between prairie and woodland depended on the interplay of fire and drought, removal of fire quickly favored trees, and within a generation many of the “brush prairies” of the east become woodlands.

Introduction of the plow gave farmers a new tool for converting prairie to farmland, and between 1850 and 1910, the tallgrass prairie rapidly disappeared.  The dust bowl years showed how little farmers understood of the farm methods needed to work in this region, but introduction of greater and greater mechanized farming only increased the rate at which prairie continued to disappear, so that by the 1950s, tallgrass prairie was essentially gone, restricted to thin soil sites or wet bottoms.  Preservation efforts began only slowly.  Some farmers recognized the value of the ‘warm-season’ prairie grasses, both as a perennial cover and a nutritious source of food for cattle.  Fortunately, some of the foremost early ecologists of the nation, such as Clements, Weaver and others, began their work in tallgrass prairie, at the turn of the 19th century, leaving a rich legacy of information on the historic features of the prairie. 

Conservationists began rallying to preserve what little remained.  Aldo Leopold immortalized the prairie in his quote: “What a thousand acres of Silphiums looked like when they tickled the bellies of the buffalo is a question never again to be answered, and perhaps not even asked.” Tallgrass prairie served as one of the first North American ecosystems to become the source of wholesale restoration at the University of Wisconsin Arboretum.  University researchers, stage agencies and Heritage program staff fanned across the Midwest landscape, looking for remnants, sometimes finding only a railroad right-of-way as the major remnant in a county once dominated by tallgrass.

Prognosis for the Future

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