SENSITIVITY OF ALPINE STREAM ECOSYSTEMS TO CLIMATE-CHANGE AND HUMAN IMPACTS

1. Climatic changes and water resource developments alter the relative contribution of the water sources (glacier-melt, snow-melt, rainfall run-off and springflow) to the discharge regime of alpine streams. 2. Likely changes in the magnitude and variability of a range of climatic determinants of glacier behaviour, as a result of an enhanced Greenhouse Effect, are shown to have important implications for the future hydrogeomorphological and thermal dynamics of alpine streams. 3. Zoobenthic communities typically show deterministic patterns in alpine streams due to the over-riding influence of water temperature and channel stability. These communities could act as indicators of change in the relative contribution of run-off, particularly to alterations of glacier-melt patterns. 4. A reduction of glacial meltwater, following diversion for HEP generation, is used as an example to illustrate the sensitivity of the zoobenthic communities to changes in temperature and flow regimes, and geomorphological dynamics.