River seen by ecologists

Abstract

Today, the scientific knowledge of French water streams is still poor. Research studies are usually focused on the Rhine-Rhône-Loire-Garonne, etc... rivers and, globally, medium size and rural water streams are not studied very much. This lack of knowledge is an handicap for a coherent approach that must prepare a development phase. This document gives the opinions of a scientist specialized in water streams, using the example of a complex fluvial landscape, related to the medium Rhône and located in an area of the valley whose fringes are still very populated. This part of the river looks like a mosaic of interconnected pieces, where transfers of water, nutrients and living organism occur, each playing a role in the functioning of the whole system. The hydrosystem is considered in the three spatial dimensions: upstream/downstream and downstream/upstream interconnections, transverse : lateral interconnections with annex environments and vertical : ground waters/underground waters inteconnections. In this document, the author demonstrates the functional solidarity of all the structures that make up a river landscape, and reminds that this hydrosystem represents a very reactive entity, from its source to its confluence. He invites us to be humble and reminds us that a water stream is an extraordinary piece of machinery whose devastating strength must never be underestimated.