Changements environnementaux, dérives biologiques et perspectives de restauration du Rhône français après 200 ans d’influences anthropiques.

Abstract

Three main periods described the history of fluvial ecosystems of the French Rhône River during the last centuries. Direct and indirect human impacts increased during this evolution. In approximatively one century, the river passed from a braided state to a series of impounded reaches. A bibliographic review concerning the current composition, the changes, and the possible restoration of the fauna and flora communities of the floodplain of the French Rhône River was recently presented. About 300 references allowed to record nearly 3820 animal and plant species: 1052 invertebrates, 322 vertebrates, 395 algae, 2050 higher plants. The biological descriptors showed a decrease in biological diversity with the decrease of the morphological diversity and of the connectivity of the regulated hydrosystem generated by continuous anthropic interference for more than one century. The future of natural areas of the Lower Rhône is quite uncertain despite the increasing place of the nature in the socio-economical functionning of the valley. However, some recent legal tools, mainly initiated by the State and associations, let us expect a positive physical and ecological evolution of the river. A decennial programme of hydraulic and ecological restoration of the Rhône has just been launched.

Keywords

• biodiversity
• regulated river
• ecological management
• aquatic fauna
• restoration
• Rhône River