The focus of my research program is to understand the importance of spatial dynamics to communities and populations, examining ideas that are central to biodiversity maintenance and conservation.

Right now I am focusing on two questions:

1. How does spatial heterogeneity in the environment affect the invasibility of communities and the risk of extinction of resident native species? (Collaborator Brett Melbourne.) We are using models, grassland experiments and laboratory experiments.
2. How does landscape spatial structure and traits of species determine the structure and dynamics of communities?

Previously, we looked at how spatial structure (patch size and connectedness) and environmental heterogeneity affected the composition and diversity of communities. In a protist microcosm community we have been able to identify the mechanisms that allow species to coexist under different conditions. In other parts of this project we are looking at the roles of spatial structure and heterogeneity in community invasibility and ecosystem function. (Collaborators Marcel Holyoak, Valerie Offeman, Kim Preston and Quenby Lum.)

Related projects:

1. I am working with Marcel Holyoak, Richard Law and Valerie Offeman to look at the effect of species’ dispersal rates between patches on the assembly of communities. We are using experiments in protist microcosm communities and patch occupancy models, developed by Richard.
2. I have been working with Susan Harrison, Hugh Safford and Josh Viers on the determinants of diversity at local and regional scales in the flora of serpentine soils of California. Recently we have been examining the relationship between diversity and invasibility at multiple spatial scales in this system, and how the productivity of sites alters this relationship.
3. I am working with Peter Chesson to extend the Shea and Chesson (2002) explanation for the diversity-invasibility paradox.