COLUMBUS, Ohio Fifteen years of studying two experimental wetlands has convinced Bill Mitsch that turning the reins over to Mother Nature makes the most sense when it comes to this area of ecological restoration.
Mitsch, an environment and natural resources professor at Ohio State University, has led the effort to compare the behavior of two experimental marshes on campus one that was planted in 1994 with wetland vegetation and another that was left to colonize plant and animal life on its own.
The two wetlands now contain nearly the same number of plant species, and almost 100 more species than existed 15 years ago. When the two marshes were created, researchers planted 13 common wetland species in one marsh and left the other to develop naturally. Water from the nearby Olentangy River has been continually pumped into both marshes at rates designed to mimic water flow in a freshwater river wetland setting.
The wetlands' general similarities have persisted even after muskrats spent the winter of 2000-01 destroying most of the plants in both wetlands, either eating them or using them to build dens. Though the muskrats' favored cattails dominated the unplanted wetland at the time, bulrush grew back in the cattails' place as the marshes recovered from the animal damage. Trees also ring both wetlands, hinting at the possibility that the site could someday be transformed from a marsh into a forested wetland.
These developments suggest that as time passes, the initial conditions of the wetlands matter less than how they develop naturally on their own, Mitsch said.
"Both wetlands are examples of what we call self-design," he said. "Human beings can be involved in the beginning, but ultimately the system designs itself according to the laws of Mother Nature and Father Time." The analysis is published in the March issue of the journal BioScience.
Mitsch is a staunch proponent of factoring wetlands'
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Ohio State University