Exotics Research
The invasion of alien species into natural ecosystems has been shown to negatively affect species diversity and ecosystem function. A framework for predicting the invasibility of an area and the capability of an alien plant to spread in natural systems is necessary for determining the magnitude and nature of environmental impact. Microstegium vimineum (Trin.) A. Camus is an invasive exotic grass that is colonizing numerous habitats because of its tolerance to various light and nutrient resources. It was hypothesized that this alien species may compensate for low light levels by spreading into nutrient rich soil which is typical for its floodplain habitat. This grass was also thought to accellerate stolon production or vegetative biomass to increase spread in low light conditions, rather than expending energy on sexual reproductive bodies. The plasticity of the plant modules involved in spread and the resource allocation of M. vimineum was examined under different light and nutrient levels using a balanced field and greenhouse study. The results from this experiment show that shading alters resource allocation patterns, but does not limit the overall invasibility due to the plastic use of the available resources. Plants grown in nutrient stressed environments greatly reduced reproductive spread; conversely, altering the amount of available light for plants did not moderate distribution. M. vimineum seems to be taking advantage of an unutilized nutrient resource under the canopy to continue plant spread success. Investigations of resource drift within invasive exotic plants allow ecologists to govern and forecast both the present and future effects of these plants.
A greenhouse experiment examining shading and nutrient effects on resource allocation.  
  A field experiment examining shading effects on resource allocation.
  Shading treatments in the greenhouse were matched with those in the field.
A field experiment examining competition effects on Microstegium growth and reproduction.. Undergraduate Chris Henson
  Publications from this research:

Claridge, Kevin & S. B. Franklin. 2002. Compensation and plasticity in an invasive plant species. Biological Invasions 4:339-447. PDF

Kevin Claridge. 2000. Effects of light and nutrients on resource allocation in Microstegium vimineum. M.S. Thesis, UM.

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