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The tallgrass prairie ecosystem is dominated by grasses. The most notable of these are Big Bluestem, Indiangrass, Little Bluestem, and Switch Grass. The relatively low annual precipitation combined with the cold winters and hot summers creates conditions that favor this grassland biome. Konza Prairie Biological Station, located about six miles southwest of Manhattan, Kansas, is part of the Flint Hills region, the largest contiguous area of unplowed, native tallgrass prairie in North America. The Flint Hills stretch from near the Nebraska border south into northeastern Oklahoma. Most tallgrass prairie ecosystems have been plowed and are currently in agricultural use. Less than 4% of the original tallgrass prairie remains. Before the arrival of European settlers the naturally occurring prairies of North America were maintained as a result of grazing by large herds of bison, occasional fires from lightening strikes and fires set by Native American Indians. These fires could damage non-grass species of plants, such as woody shrubs and forbs. The underground root system of most prairie grasses is not destroyed by these fires so the above-ground parts grow back readily. One of the effects of fire and regular grazing on grasses is increased growth and nutritional value. Read more about grazing from Science Adventure Trail 8: Bison. The presence of a variety of non-grass species on the prairie indicates the condition of the ecosystem. Too many annual forbs and woody shrubs are undesirable. Yet, a variety of plants is necessary to keep a grassland healthy. Some grasses, forbs, and woody plants are not native to the tallgrass prairie and can be quite aggressive in competing with the native plants. EFFECT OF FIRE ON PLANT DIVERSITY PURPOSE: Sampling the kinds of plants present on Konza Prairie or other native prairies helps researchers determine the diversity of plant life. The kinds and numbers of plant species indicate the relative health of the prairie. Comparing fire treatments from one area to another also can determine what is the best burn program for maintaining a healthy and diverse grassland ecosystem. Comparing restored prairies to native, unplowed prairie is helpful in understanding the nature and function of a prairie ecosystem. METHODS: Teams of at least two students are assigned to an area to be sampled. Each of these plots is characterized by its location or a specific grazing or burn treatment (annual, biennial, unburned, etc.). Equipped with a sampling frame that encompasses a known area, the students randomly place the frame inside the test plot. Each team identifies, counts, and records the number of each kind of plant (grass, forb, or woody shrub) inside the sampling frame. This procedure is repeated during a second sample within the same test plot. Averages of several samples and comparisons of these averages allow students to interpret the meaning of the data they have collected. |
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