Fire, Grazing, and the Prairie

Two factors in the maintenance of a prairie are grazing and fire. Grazing animals of all sizes play an extremely important role in maintaining the ecosystem. As mentioned earlier, plants that are grazed are stimulated to grow so that they can continue to collect sunlight. This triggers biological activity and nutrient exchanges. Bison, deer, and cattle compact the soil with their hooves and open up places for new seeds and new generation of plants to take root. The role of fire is prevalent in almost every ecosystem. However, few involve fire as frequently as does prairie.

Tallgrass prairie can accumulate an enormous amount of biomass in a year's time. The leaves die in the fall and the roots go dormant during the cold winter months. In the following spring, new shoots spring up. As years progress, the old dead leaf litter accumulates and creates a thick thatch over the ground. New shoots find it harder and harder to get sunlight and the ground stays cold and insulated causing a delay in plant growth in the spring. Nutrients also are locked up in plants yet to decay.

The grazers such as bison and cattle, expend more energy foraging, as they have to pick the nutritious new foliage out of the dead. As litter accumulates prairie plants actually weaken and smother. Trees and woody bushes are able to invade stressed prairies. Trees create shade as they grow and cause even further restrictions in sunlight available to plants that need full sun. Fire is nature's way of starting over. Fires are started naturally by lighting igniting flammable material. Man can start fires as well both accidentally and intentionally. The Plains Indians started fires to attract game to new grasses. They sometimes referred to fire as the "Red Buffalo." Ranchers today start fires to improve the forage for their cattle.

The benefits of fire are enormous. The tied-up nutrients that take months or years to decay are within seconds turned to ash and in a form usable to plants. Sunlight warms the blackened ground and stimulates dormant plants to sprout and grow. Grazers are able to feed, uninhibited by dead litter, further stimulating growth. Trees and shrubs with the stems and branches exposed to the intense heat are killed, allowing the ground under them to receive full sunlight once again.

The prairie has long been known for its incredible fertility. Settlers eagerly plowed the soils to plant crops of corn, wheat, sorghum, and vegetables. Today it is proudly stated that one American farmer feeds 129 people. This is testimony enough to the rich prairie soils. The domestic crops of man are various forms of grasses and therefore grow well in prairie soils. However, the exchange of nutrients, the complex organisms giving and taking cannot survive on a "monoculture" or single crop. The fertility of the soil is lost over time without anything to replace nutrients being taken out. Crops are rotated, land left to rest or fertilizers used to offset this loss. In the Flint Hills this fertility is not wasted. Even though the ground cannot be cultivated, ranchers pasture cattle on the rich prairie grasses. A steer can gain almost 2 pounds a day feeding on the nutritious bluestem grass.

The prairie is both grand and subtle. The breathtaking views and distance is what many cherish on a trip to the prairie. However it is when the observer looks into the prairie, that they will begin to understand what they have really seen. The closing thought from an anonymous author sums prairie up quite well.

Pristine Kansas prairie isn't one kind of grass, or kind of flower. It's hundreds. Meadow rose and wavy-leafed thistle. Bluestem and sunflower. Leadplant and milkweed. The variety does more than look pretty. It insures against biological calamity. In hot weather, some species wilt-others flourish. When insects and disease strike, some suffer-others thrive. Here's how the prairie bears adversity: diversity.

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