Besides serving as breeding and watering sites for wildlife, potholes collect rain and flood waters, which are released slowly, helping prevent floods and erosion. Today, many areas of prairie potholes have been drained, primarily to create farmland. Fire was an important element both in forming and maintaining the prairie. In the eastern prairie, there is enough rainfall to support trees as well as grasses. Fire undoubtedly helped the tallgrass prairie from being taken over by trees.
Prairie fires destroy tree seedlings, but burn only the uppermost part of grass plants.
The roots are unharmed, and in a short time, the plant will grow again. The ashes then act as fertilizer for the grass. They recognized its value and regularly set fires in order to lure game to areas where tender new sprouts of vegetation attracted grazing animals within days after a burn. The tallgrass prairie is found in the easternmost third of the Great Plains. It receives the most rainfall, averaging 30-40 inches a year.