My major areas of research are population dynamics of endangered plants and invasive species. This area provides opportunities for experiments with rare species reintroduction, seed germination studies, population viability analysis with matrix models, and evaluation of habitat management techniques. Most of the projects I am involved with use ecological theory to approach applied problems in plant ecology.
I use matrix population models to examine the stochastic population dynamics of wild populations, and to compare the viability of populations of endangered species under different management practices such as grazing, timber harvest, or controlled burning. These models can also be used to pose "what if" questions to develop hypotheses for a population's response to various changes in its environment, such as decreased seed predation, grazing, reproductive failure, global warming, or even wild harvest (which occurs in medicinal plant populations). In working with matrix models, I have also used empirical data to compare different methods of stochastic modeling and examined the importance of correlations among vital rates.
My research in restoration ecology examines habitat improvement methods, invasive species control, and species reintroduction. I study habitat improvement methods such as controlled burning, mowing, herbicide applications, and livestock exclusion in various ecosystems in the Pacific Northwest, from the coast to the Willamette Valley to the arid east-side. Although my background is in endangered species management, I am also investigating noxious weeds such as Himalayan blackberry (Rubus discolor) and false brome (Brachypodium sylvaticum) and their impacts on native ecosystems. I am actively involved in reintroduction studies with seven endangered species of the Willamette Valley, as well as three other species elsewhere in the state. This research focuses on all aspects of reintroduction, from propagation through establishment, including germination and cultivation studies, comparisons of direct seeding vs. transplanting, importance of biotic and abiotic interactions, and broader issues related to inbreeding and outbreeding depression in created populations as well as strategies for successfully maintaining genetic diversity.