The biodiversity (invertebrates, benthic, fish, avifauna) of rivers results from the quality of the habitat of the banks. The hydrobiological quality of a river is defined by the analysis of the macrofaunal. The remarkable natural environments of the Vouge basin are studied to best preserve biological diversity. The alternation of shaded areas and light or sparse areas helps the flora to develop in the humid parts of the riverbanks of the Vouge.