Global climate change and invasion by non-native species are considered among the most important physical and biological drivers, respectively, of future changes and extinctions in ecological communities. These drivers can interact in complex ways, yet relatively little research has been done on their combined effects in a single ecosystem. Cattle, deer, and elk were introduced to Santa Rosa Island, part of the Channel Islands National Park, more than a century ago, but were removed from the island beginning in 1998. Long-term data sets from Santa Rosa Island will be used to develop statistical and population models for five rare plant species and quantify how they have responded to both climatic variation and the removal of invasive herbivores. A parallel analysis will be used to determine effects of these factors on the composition of island plant communities. Comparing responses for both individual populations and communities will test how well predictions for a few well-studied species can be extrapolated to larger communities. The project also will assess whether species responses are correlated with their life histories, an approach which could be used to improve predictions about which species are at risk.
The results of this work will contribute to more informed conservation management, especially for the Channel Islands National Park, which supports 75 endemic plant species. The project will also enable continued collection of valuable long-term data sets that will be accessible for use by other researchers. This study will support mentorship and training of undergraduate students by creating 2-4 summer research and senior thesis opportunities each year. The data will also contribute to development of course materials for teaching quantitative skills, to be made available on the web and in educational journals. Finally, the project will involve substantial public education and outreach efforts.
