ECOLOGICAL ASPECTS OF THE RESTORATION STRATEGY FOR A RIVER-FLOODPLAINSYSTEM ON THE DANUBE RIVER IN AUSTRIA

The key factors determining the ecology of large rivers and their adja cent floodplains are extent, duration and dynamics of the hydrological connectivity between the two compartments, both via surface how and g roundwater how. This hydrological connectivity has been strongly reduc ed in all large European rivers due to regulation and damming. The pre sent paper discusses the scientific background in planning a restorati on strategy for the free-flowing stretch of the Danube in Austria. As a first step in this conservation strategy which is within the framewo rk of the 'Alluvium Zone National Park', a large-scale pilot project h as been developed to restore the hydrological and ecological integrity of the river-floodplain system. In order to assess the progress towar ds the project's ecological objectives, various limnological variables (functional descriptors) are to be monitored.