The role of diversity in ecosystem functions has important implications for both the accurate prediction of ecosystem response to global change as well as the conservation of diversity. The C3 and C4 photosynthetic pathway is a fundamental physiological and ecological distinction in tropical and subtropical savannas and grasslands. Although C4 plants account for a large proportion of global terrestrial productivity, uncertainties remain regarding their response to climate variability and future climate change. C4 grasses will likely respond differently than C3 grasses to climate change and this will strongly influence future grassland and savanna ecosystem structure and function.
In this project the Working Group will focus on grasslands in the Hawaiian Islands because the extreme isolation of the islands in the middle of the Pacific make them an ideal location to study the response of terrestrial vegetation to climate variations. This research merges herbarium, climate, and satellite data over several decades to examine the spatial and temporal response of C3 and C4 grasslands to climate variability and estimate grassland productivity. Results from this project will provide new information on the functional significance of C4 photosynthesis and the role of diversity in ecosystem functions.