Monday, May 12, 2014

May-apples in prairies?


May is the season for may-apples (Podophyllum peltatum), and clones are now popping up all over the place. According to Curtis and others, this is a species which is found primarily in forests, occasionally also in closed savannas. It is a classic "spring ephemeral", completing its life cycle in early spring before leaves fully develop and the canopy becomes closed.

It was interesting to me that this "forest" species can also be found occasionally in prairies. The photo here was taken in the South Unit of Black Earth Rettenmund Prairie. How do we explain its ability to grow there?

The explanation is encompassed in the history of the site. The area where this small clone is present was originally prairie but had become invaded by honeysuckle in the early 1960s. Restoration of this area did not occur until about 40 years later. Presumably during the years of "neglect" may-apple became established under the shade of the honeysuckle.

How many years will this small clone hold on? Or will it even expand, or eventually be replaced by conventional prairie plants? According to my experience at Pleasant Valley Conservancy, such clones may remain, or even expand, for at least 16 years.

This phenomenon is a good example of a legacy effect, and hence of considerable interest in restoration ecology. Researchers now recognize that: “site history is embedded in the structure and function of all ecosystems, that environmental history is an integral part of ecological science, and that historical perspectives inform policy development and the management of systems…” (Foster, David; Swanson, Frederick; Aber, John; Burke, Ingrid; Brokaw, Nicholas; Tilman, David; and Knapp, Alan. 2003. The importance of land-use legacies to ecology and conservation. BioScience 53: 77-88.)
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