Southern California is global biodiversity hotspot, and has experienced high levels of habitat-loss due to land-use change and development. Remaining intact ecosystems are threatened by a suite of global changes including climate change, invasion by exotic species, and potentially accelerated fire regimes. Along with collaborators from SDSU and the U.S. Forest Service, we have undertaken experiments in local ecosystems to investigate whether invasion alters ecosystem responses to shifting rainfall patterns associated with climate change. We've found that exotic species respond much more strongly than native species to high pulses of rainfall, and could alter ecosystem carbon storage through feedbacks associated with shifting species composition. We are currently parameterizing a Dynamic Global Vegetation Model for the region to scale-up from these local-experiments to predict regional carbon-cycle responses to climate change. (#27866)