9412224 Rundel The structure and dynamics of riparian ecosystems in the chaparral region of Southern California have not been studied in any detail. Trees and woody shrubs are the dominant component of plant cover in these ecosystems, but a high diversity of herbaceous riparian species are also present. The recent extensive fires in Southern California heavily impacted this reparian zone over large areas, with both direct effects on plant cover and woody debris and longer term effects on debris flow and runoff. This proposal investigates a series of hypothesis relating chaparral fire to: 1) changes in woody debris and consequent impacts on sediment flow; 2) mortality of riparian trees; 3) seedling establishment for riparian trees; and, 4) nutrient loss and movement through riparian systems.