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Sugar
Creek Prairie and savanna with Hunter in foreground.
Ridgway photograph collection, Illinois State Museum collection |
Ecotones
Plant communities that are transitional are referred to as ecotones. Although the state’s vegetation could be differentiated into prairies and forests, these communities were not totally separate. Tallgrass prairie dominated the central part of the state with different forest types as transitional communities within and around the prairie ecosystem. Wooded ‘islands’ or groves were common on the prairie:
Examples of ecotones
In Illinois, savannas and barrens are good examples of forests that merge gradually into prairie . Each is an example of a prairie ecosystem that is transitional or integrated with a forest ecosystem.
Prairie plants dominate the understories of these types of forests. Fire maintains savannas, barrens and prairie. Fires occurred with greater frequency in the Prairie Peninsula because of the more frequent and intense drought and flat, unbroken surface of the land.
On a broader geographical scale, the oak-hickory forests (savannas) of the Prairie Peninsula in central and east central Illinois form an ecotone with the deciduous forests to the east. Sugar maple and beech and other trees that require a moderate amount of moisture dominate the eastern forests.
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Copyright© 1999 Illinois State Museum
