Prairie Ecosystem

The interaction of three factors maintains the Prairie as a grassland:


  The periodic lack of rainfall is a very important factor in preventing the growth of trees in prairies. A drought is when the prairie receives no more than 10 inches of rain per year. In the picture below, you can see how a few trees are tenuously rooted in slight depressions where what little moisture there is gets concentrated.

photo M. Noonan


  Continuous grazing by bison, prairie dogs, and numerous other species, keeps the grass short. In a feedback cycle, the grazing also stimulates new shoots to grow which the grazing animals depend upon. As bison graze, their hoof-action also sows new seeds into the earth which helps to promote new vegetation.

photo M. Noonan


  Every three to seven years, any given area of tall grass prairie is likely to burn due to fires started naturally by lightning. This too prevents long-lived species like trees from becoming established.

photo M. Noonan is a program of Canisius College, Buffalo, NY.                                                  Web Design by Ivan Andrijevic.