Prairies once covered about 40% of the United States.
Prairies are one of the most recently developed ecosystems in North America.
Prairies formed about 8,000 years ago.
About one percent of the North American prairies still exists.
Iowa had the largest percentage of its area covered by tallgrass prairie - 30 million acres.
In Iowa, 99.9 percent of the historic natural landscape is gone.
Over 100 plant species can occur in a prairie of less than 5 acres.
The major grasses of the tallgrass prairie are the big bluestem, the little bluestem, Indiangrass and switchgrass
These tall grasses can grow as tall as ten feet and average a height of six to eight feet.
The soil underneath the prairie is a dense tangle of roots and bulbs
Some prairie plants put out roots that extend 12 feet below the prairie surface.
Each year some of the roots die. Large quantities of organic matter are added to the soil as roots die and decompose making rich and fertile soil.
Up to 60 million bison grazed on the plains and prairies of North America when European explorers first arrived and fewer than 600 existed by 1885.
An adult male bison stands about 6 1/2 feet high at the shoulder.
A bison bull weighs up to 2,000 pounds and a cow weighs up to 1,000.
A bison can consume 30-50 pounds of feed each day.
Grazing was an integral part of the prairie ecosystem and increased the growth of prairie plants.
Prairie dogs gravitated to the patches of close-cropped grass left by grazing bison where they could watch for prowling predators.
Prior to pioneer settlement, some five billion prairie dogs in extensive colonies spread across hundreds of miles of prairie.
Saving prairie dogs means saving prairie wildlife. Other creatures have suffered due in good part to the prairie dogs' decline. For example, the burrowing owl roosts and nests in prairie dog town burrows.
Other animals such as hawks, foxes and ferrets that hunt prairie dogs, disappear when the prairie dog population diminishes.
Prairie chickens once flourished on the grasslands. As the grass disappeared, so did the prairie chicken. Today, only about 400,000 survive in the entire country, in 11 states.
Prairie fires were important to the development of the tallgrass prairie as they kept the prairie from becoming a forest.
Prairie fires can move as fast as 600 feet per minute and burn as hot as 700 degrees Fahrenheit.
Prairie fire is an important ingredient in the renewal of the prairie.
Fire does not destroy prairie grasses because they grow from the stem up rather than from the tips of the blade.