Evaluating climate change impacts on Alpine floodplain vegetation

This study aims to evaluate the long-term impacts of climate change on Alpine riparian vegetation. Special attention is given to the hydrological factors influencing the establishment, development, and retrogression of riparian vegetation. The study has been carried out in a reach of the upper course of the Drau River (Austria). Long-term effects of climate change on the local riparian vegetation were simulated using a dynamic vegetation model. The model simulates annual time steps, and provides the spatial and quantitative vegetation distribution changes over time. Climate change impacts have been estimated by performing five simulations, spanning 31 years. The first simulation was based on the reference period 1960–1990 while the remaining four were based on the sub-scenarios of the IPCC storyline A1B. Simulation results show consistent variations in both the distributions of quantitative and spatio-temporal vegetation type, primarily due to peak discharges alterations rather than to the mean spring discharges which typically influence the recruitment. Climate change scenarios forecasting an overall increase of peak discharge lead to prevailing retrogression as opposed to successional processes. Conversely, in the climate change scenarios with peak flow reduction, successional processes are dominant and vegetation is predicted to expand into the active channel.