A “prairie” is a permanent grassland with few or no woody plants. Prairies are fire-dependent ecosystems. Prairies differ from old fields and meadows in that the prairies are stable and self-perpetuating, rather than being a temporary successional stage along the way to becoming a forest. The plants that occur in prairies are mainly drought-tolerant grasses and sedges (graminoids), the growing parts of which are at or below ground level and thus are unharmed by occasional wildfires. Prairie graminoids are accompanied by other herbaceous plants, generally called “forbs”* that are adapted to drought and also low nutrient levels.
*Note: A forb” is the term for any non-woody non-graminoid, i.e., what we’d normally call a “wildflower.” The use of the term “forb” is not restricted to prairies, as forbs occur in all terrestrial ecosystems.
Prairies occur world-wide, generally in the interior of continents. North American prairie is drier in the west where it borders deserts, and the type of prairie that occurs there is called “shortgrass prairie.” In the moister eastern half, adjoining deciduous forest, we have “tallgrass prairie.” Ohio is not usually thought of as a prairie state. Here are two maps from authoritative publications. Note how the Smithsonian map on the left shows us lying well outside the prairie biome, while the map from ‘Tallgrass Restoration Handbook” orrectly shows a few scattered prairie patches well within our boundaries.
Generally, where there is adequate moisture year-round, as in Ohio, trees can survive. Thus the principal vegetation type in Ohio is forest. It is believed that the prairies in Ohio, which only ever comprised about 1% of the state (and, sadly, of which only about 1% of that remains) are remnants of a time between 8,000 and 4000 years ago called the “Xerothermic Interval” when the climate was hotter and drier than it is today. At that time prairie extended eastward as a tongue-shaped band across present-day Ohio, a region called the “Prairie Peninsula.” Fires deliberately set as a game-management tool by Native Americans are believed to have helped maintain a few prairies up to the present day. Fire is still used as a management tool to maintain prairies. The principal benefit of fire is to eliminate woody vegetation, as the above-ground buds on tree saplings are susceptible to being killed by hot flames, while the grasses just laugh as the fire goes by.
In the 1950’s, Robert Gordon mapped the vegetation of Ohio during pre-settlement times, using data from the earliest land surveys. On his famous map shown below, prairie is indicated in yellow. Notice that the yellow patches are not scattered uniformly across the state, but are in discrete regions.
Prairies, having soil high in organic matter and lacking trees that would need labor-intensive removal, were well-suited for agriculture. Hence, it is primarily conversion to farmland that has caused the elimination of nearly all of the North American prairies.
In Ohio and elsewhere there are three principal types of prairie remnants: pioneer cemeteries, railroad rights-of-way, and lightly grazed areas. An example of a cemetery prairie is Smith Cemetery in Madison County: a beautiful little (1 acre) State Nature Preserve.
Railroad companies generally maintain a strip of land alongside their tracks that is untouched by the plow. Here’s one that remains after the railroad line was abandoned and dismantled in Union County, called Milford Prairie which is a Non-Dedicated State Natural Area.
Since it’s woody vegetation, including native trees, that constitute a threat to prairies, moderate animal grazing that allows grasses to remain can be a mechanical alternative to fire. In Crawford County, Daughmer Prairie Savannah State Nature Preserveis a grassland that for much of the 20th-century supported a small herd of sheep. It was purchased by the state in 1010 and soon therafter dedicated as a State Nature Preserve.
“Savanna” is the term for a grassland with scattered trees. In the tallgrass prairie region, bur oak (Quercus macrocarpa) is the tree most often seen scattered in prairies.
In Ohio we have a few regions where prairie is found, shown on the map below.
