Natural History

Bison on a native Minnesota prairie. Bison on a native Minnesota prairie.

Prairie formed in Minnesota after the last glacial episodes and once covered a little over a third of the state. Like a puzzle, prairie is a collection of pieces interacting together to create both a community and an ecosystem. Key prairie pieces include grasses, wildflowers (forbs), animals, and soil. However, climate and people have played and continue to play a significant role in how the puzzle pieces fit together.

Fire, water, heat, cold, wind, and native peoples shaped the history of prairie by defining its boundaries and adding disturbance. For instance, fire is a type of disturbance that can stunt or kill small trees that might otherwise out-compete prairie vegetation without this disturbance. Wetlands, rivers, and lakes act as a fire barrier, stopping fires and creating natural boundaries.

Any single "puzzle" piece can have a significant impact on prairie development and evolution. For example, native grazers, like bison, have a multitude of habits that change the overall prairie structure and impact wildlife use of prairie, such as:

  • Grazing: Creates height variations in vegetation and in turn benefits a variety of prairie wildlife.
  • Wallowing: Repeated rolling on the ground creates compact bowl-like depressions. Later these may fill with water creating habitat for frogs, toads, salamanders, and invertebrates.
  • Roaming: Bison can transport seeds in their fur. Their hooves disturb the ground, creating space for seeds to grow. By roaming they spread prairie grasses and wildflowers to new locations and assist with their establishment.

Humans are part of the prairie as well. Native people have a powerful connection to the land and have long coexisted with this ecosystem. For example, fires set to encourage bison grazing have helped prairie thrive. Today we must add disturbances such as fire and grazing back into the landscape to keep it healthy. People and their attitudes are a central piece of the prairie conservation puzzle.

Human intervention helped create, eliminate, and shape what we know as eastern tallgrass prairie. — H. F. Howe. 1994. Conservation Biology 8: 691-704

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