Many member of our lab are interested in understanding the causes of rarity and invasiveness by combining a comparative, macro-evolutionary approach with species-specific demography and experimentation of ecological factors (often, interspecific interactions). Many of the worst invasive species co-occur with non-invasive, native or even rare congeners. By comparing closely related species in the same habitat, we can control for the evolutionary history of the species and for the ecological environment.

Jean Burn's research focuses on comparing traits between invasive and non-invasive plants in the Commelinaceae. This plant family is ideal for this line of research, since many species have been introduced to the southern United States; several have failed to establish whereas others have become invasive. Mickey Schutzenhofer's research compares invasive and non-native Lespedeza cuneata with its common native congeners L. virginica and L. capitata, and with its rare and federally listed congener L. leptostachya. She is conducting replicate experiments to examine whether differences in competitive ability, herbivory, and pollination explain their differences in distribution. Emily Dangremond has discovered that differences in seed predation explain the low population growth rate of the endangered species, Lupinus tidestromii, relative to its more common congeners. Kristin Powell is currently examining the breeding system, pollination ecology and competitive ability of rare, common and invasive Cirsium species. Alona Banai found that hybridization and pollen limitation affect the viability of the rare California grassland plant, Linanthus rosaceus, relative to its common congeners. Alexandra Harmon-Threatt found that exotic plant species that are not self-compatible are more likely to suffer from pollen limitation than their native congeners.