This two-year award will support dissertation research on the effects of rapidly rising CO2 concentrations on terrestrial ecosystems by Cathlyn Stylinski at San Diego State University in cooperation with Dr. Franco Miglietta at the CNR Institute of Agrometeorology and Environmental Analysis for Agriculture in Florence, Italy. The main objective of the research is to investigate the long-term effects of elevated CO2 on gas exchange, water relations, and distribution patterns of evergreen and winter-deciduous oak species. The dissertation project will take place in an enriched mixed oak forest community in Tuscany, Italy, where a natural CO2 spring has enriched CO2 concentrations for centuries or longer. CO2 springs provide an opportunity to compare effects from naturally enriched communities to those from previous short-term manipulations using seedlings and saplings in controlled environments and to observe changes over different times scales and spatial scales. The research will benefit from the work of the Italian institute on Italian CO2 springs and from the Principal Investigator's work on the effects of elevated CO2 and climate change on Mediterranean-type ecosystems in such areas as California, South Africa, Australia, Chile, and the Mediterranean Basin.