plant regulation

Robert Pries
Tue, 28 Jul 2009 06:06:12 PDT
 I know that passions run very high on the topic of invasive plants and I can’t restrain myself from making a few comments. At the time of the first earth day I was a doctoral candidate in plant ecology. Despite my love of the subject even at that time no one hired real plant ecologist, they just renamed engineers and so forth that were already on staff. Despite the all the progress that has been made in ecological awareness its seems finding field plant ecologist is still somewhat of a rarity in any university. I suspect that for this reason the rather limited research of Sharon Riechard has had such an impact. One should not accept the idea that 75% of all cultivated plants are potentially invasive as the common view of most plant ecologists. There are contrary views in the literature but they are not nearly as promotable in the media.

Why an alien plant can invade a new area is rather complex, it is not just the genetics of the plant, but most of our present villains where planted in such large numbers they overwhelmed the local natural system. Even so, a plant like Kudzu will not destroy everything if the local environment is not right. I can remember a hillside just south of St. Louis that was held in place by Kudzu planted by the highway department. For 40 years it did nothing other than hold the bank In the last few years with warmer winters, it has finally starting climbing the adjacent trees and become the pest we love to hate. Blaming the plant seems a bit ridiculous. 

There used to be a theory in ecology that alien plant could not successfully invade a mature well developed climax community. The thought was that unless the community was under stress it was better adapted than the alien invader. Unfortunately more and more our natural communities are under stress, whether it be air pollution, climate change, cutting, burning or protection from burning. The fact that alien plants might survive in “natural” systems is more often than not because of disturbance brought by man. They are like canaries in a coal mine. We seem to worry more about banning the messenger than addressing the causes. If we wish to continue with our assaults on nature than maybe we need the aliens in order to evolve a new local ecosystem that fits our needs. I would feel a loss not having the pristine systems but then again I am not sure I have ever really seen one. The number one threat is still habitat destruction, invasive plants are a symptom.

More information about the pbs mailing list