DISSERTATION RESEARCH: Determining how environmental heterogeneity and species traits interact to affect species invasion and coexistence over large spatio-temporal scales

Biological invasions pose one of the greatest threats to global biodiversity and have profound economic impacts. However, predicting whether invasions will cause extinctions of native species or if natives can persist in the face of invasion remains challenging because these outcomes depend on both characteristics of the species involved and characteristics of the environment. This project seeks to explain patterns observed in two large-scale, long-term data sets in the heavily invaded California grasslands. The investigators will determine how similar are invasive plant species observed in field plots in terms of their phylogenetic relatedness, country of origin, and ecological traits. Spatial variation in the abiotic environment, especially soil characteristics, will also be measured in these field plots. Together, this information will be analyzed to determine the relative importance of environmental variation versus invasive species traits in contributing to local extinctions of native species.

This project has important implications to land management; it will inform efforts directed at restoration and maintenance of native species diversity. The research will be conducted within the University of California Natural Reserve System, thus its data and findings will be explicitly available to all reserve system managers and the public through the reserve system's online research database and outreach publications. Furthermore, the investigators will provide seminars and tours of field plots to reserve visitors. This project supports the thesis research of a doctoral student and will provide opportunities for involvement of undergraduates in field research.