My Research Interests and History: I received my Ph.D. in 1993 with Richard Root at Cornell University, and performed my postdoctoral studies with David Tilman at the University of Minnesota and Steve Hubbell at Princeton University. I joined the University of Pittsburgh Department of Biological Sciences in 1994.

The research in my lab continues to focus on four major areas:

1. We continue our experimental studies on the impact of herbivory on the diversity of tropical forests in Panama and Costa Rica. We have established 26 large experimental plots in 3 forests in which over 50,000 trees have been tagged, mapped, measured and monitored for 10 years. We have many collaborators on this work including faculty and graduate students at Tulane, Stanford, University of Connecticut, and the Smithsonian Tropical Research Institute.
2. We have extensive field experiments underway designed to evaluate the underlying causes of failed oak regeneration in West Virginia. We have now established more than 64 large experimental plots designed evaluate the major causes of forest change in the eastern deciduous forest. These processes include fire, canopy disturbance, and browsing.
3. We are continuing our long-term experiments at the University of Pittsburgh's Pymatuning Laboratory of Ecology on the invasive wetland plant species, purple loosestrife. In collaboration with scientists at the New Jersey Institute of Technology and the University of Georgia we are testing several of the key hypotheses associated with how exotic species can invade and dominate novel habitats.
4. As part of a new research initiative, we have surveyed 20 old-growth forests remnants across Pennsylvania to evaluate whether these systems are threatened with biodiversity collapse. Our findings show that these systems, once thought to represent examples of primeval forest, are on a successional pathway leading to near mono-dominance.