What are some catastrophic events that happened in the grasslands?

Answer 1

The Story of the catastrophic 8-year drought and great dust storms

that led to a mass exodus from the Great Plains of the U.S. The vast grasslands of the Great Plains and the Great Basin in the United States were once inhabited by many different Indian tribes and abundant wildlife. 20 million bison thundered across the plains, which the Indians depended upon for food and clothing. Some described it as "great herds of buffalo as far as you could see." Then the Homestead Act of 1862 brought 6 million settlers, and so began one of the worst environmental disasters in world history. Over the years as the settlers moved out over the plains, they brought cattle and sheep and set them to grazing in the grasslands. They slaughtered millions of bison, almost to the brink of extinction. By 1889 only 541 bison were known to be alive in the U.S. The Indians had been deprived of their main source of food. The settlers farmed the land once covered with bluestem, buffalo and grama grasses. The topsoil was plowed up and with it, the extensive root systems of the native grasses. The farmers planted grain crops such as barley and oats, and mostly wheat. Then early in the 1930's, an eight-year drought began, and a series of major wind storms swept over the Great Plains and the Southwest creating huge smothering dust storms. The soil in the grasslands had become dry and loose from plowing and the damage caused by livestock grazing. The roots of the grain crops could not hold the dry topsoil under such severe winds. Tons of loose soil was picked up and carried for hundreds of miles. Fences were buried by huge drifts and dirt had to be shoveled out of houses. The dust was so thick vision was obscured, lungs were damaged, and some people even became lost.(http://www.eco-pros.com/grasslands.htm)