Linking geology, climate and disturbance response in California mountain environments

Abstract:

Fire, drought and insect related forest mortality are abrupt disturbances that can result in substantial loss of ecosystem biomass with consequences for both water quality and water quantity. The short-term magnitude of these responses depend strongly on the meteorology in the year following disturbance. Intermediate and long-term impacts, however, depend on post-disturbance recovery rates and potential species change, that may reflect longer-term climate drivers. In mountain environments, underlying geology shape both of these responses, through topographic influences on climate and through geologic controls on water storage and lateral redistribution. We use RHESSys, a coupled eco-hydrologic model, to quantify potential across site variation in responses to disturbance for several transects along in California mountains. At within watershed scales, we also look at how hydrologic responses to vegetation loss are influenced by subsurface geologic controls and contrast estimated disturbance effects as a function of different assumption of subsurface storage capacity and connectivity. Results highlight the tight coupling between geology and climate that influence hydrologic responses to disturbance.