Hydraulic and ecological restoration of the Rhône River: feed-back and lessons
Résumé
Since 2000, an ambitious ecological restoration program was carried out on the Rhône River (France). The two main restoration measures were the increase of minimum flow in by-passed sections and the floodplain channels rehabilitation. An inter-disciplinary research program was initiated since 1995 to evaluate the effects of restoration measures on both physical habitats and biological components (fish and aquatic macroinvertebrates communities). The objectives were to identify and quantify i) the main physical factors modified by restoration measures and ii) the impacts of these modifications on metrics related to aquatic communities. A predictive approach was choosen allowing the possibility to test the adequation between predictions obtained with models and observed values collected during the post-restoration monitoring. Results showed that the restoration measures increased the proportion of taxa that are fluvial specialists in by-passed channels and the beta diversity of macroinvertebrates communities within the floodplain. These results represent an important amount of knowledge usable for the management of large rivers.