I am an experimental field ecologist and my students have been working in the understorey of the Boreal Forest (southwestern Yukon, Canada) since 1990. In addition, from 1992-1999 I did collaborative research with Deborah Goldberg in the Negev Desert (Israel), and over this past few years I have (or had) students in Israel, the Garry Oak ecosystem of southern British Columbia, and the Interior forests and grasslands of British Columbia. We focus on two primary questions: (i) how are plant communities structured, and (ii) how do they function? The first question is addressed by two major sets of studies. First we are testing if the plant community is structured primarily by nutrient limitation, by herbivory, or by their interaction. Our experiments manipulate soil nutrient levels and herbivore levels, and we then monitor the consequences on individual plant species, populations, and communities. Second, we are testing hypotheses about the impacts of competition on community structure and if the magnitude of these impacts change in predictable ways along productivity gradients?
The second question is also addressed by two major sets of studies. First, we are using “functional group knock-out” experiments in which selected components of a plant community are removed and the consequent changes in community dynamics and ecosystem function monitored. Second, by simulating species loss from natural systems, in conjunction with seed and seedling additions, we can determine the effect of plant species identity on invasibility of a community, and the effect of the level of the disturbance of the community on subsequent invasion.
Click here for a recent arcticle (page 10) from the Arctic Institute of North America that features our research.
