Drs. Vitousek and Mueller-Dombois will conduct an integrated observational and experimental study of the regulation of ecosystem-level biogeochemistry along independent gradients of soil age, temperature, moisture, and biota in the Hawaiian Islands. Biological, geological, and climatic features combine to make the Hawaiian Islands a unique system in which many aspects of ecosystem theory can be tested experimentally. The broad range of dominant native species and the striking impact of invasions by exotic species offer the opportunity to determine unambiguously the ecosystem level consequences of population and physiological-level processes. This research is designed to determine how ecosystem dynamics are regulated during soil development and as a function of climate. Both the interactions of physiological processes with ecosystem functions and the operation of population and community processes (biological invasions, stand-level die-back) that alter ecosystem dynamics are incorporated. A modified version of the CENTURY model will be evaluated and improved using observations and experiments, and the resulting derivative models will be used in the design of further field experiments and as tools for integration and extrapolation. The results of this effort will contribute to issues of tropical biodiversity and global change. University support from Stanford and the University of Hawaii is outstanding. Drs. Vitousek and Mueller- Dombois are creative and productive researchers in the area of tropical ecosystem research.
