Prairie Restoration Management - Art or Science?
by Don Gardner
Expect Continuous Change
A prairie ecosystem is never static but continually changes. When native prairie was disturbed—possibly by trampling bison, or flooding, or drought—the resulting open area was invaded by pioneering species that establish quickly, such as black-eyed Susan, yellow coneflower, and nodding wild rye. These and other such species promptly establish cover on exposed soil and are the first step in a long series of successional changes. The same will occur on a prairie restoration.
Then come the tall grasses, which were so impressive and prevalent that early settlers applied that name to central Illinois prairie: grasses such as big bluestem and Indian grass. In my restoration experience, these grasses on present day restorations give the added benefit of displacing many non-native species. Over time, the big grasses are partially displaced by hemiparasitic species such as wood betony, possibly due to chemical allelopathic interactions among roots, possibly by depletion of certain soil nutrients, or due to factors not yet known.
In the presence of a generous supply of seed, conservative prairie species such as leadplant, downy gentian, prairie dropseed, and many others make their successional appearance in increasing numbers. Areas that exhibit slower development can be enriched with additional seed. This can be applied by drilling or overseeding by hand broadcasting following the late-winter burn, which gives time for spring rains to incorporate the seed into the soil. Alternatively, or if available seed is limited, small amounts can be scratched in on the open areas that develop between tussocks of the tall grasses. This is especially applicable to spring forbs such as shooting star, wood betony, prairie phlox, and prairie violet. Seed can be introduced during the fall of the same year when it was collected. The area between the vigorous tussocks of Indian grass or big bluestem would seem to be an inhospitable location to introduce such seemingly fragile spring ephemerals. However, the seeds and their resulting plants are much tougher than they appear and have evolved over the millennia in just such niches.
