ABSTRACT
The two typologies are two modes of perception of a water course: an upstream-downstream gradient or a mosaic of microhabitats. Two upstream-downstream typologies have contributed significantly to progress made in the ecology of running waters in Europe: that of M. Huet and that of J. lilies and L. Botosaneanu. Huet’s typology refers to certain morphodynamic factors and to fish, which are highly mobile and have a wide ecological tolerance, lilies and Botosaneanu’s zonation is based on morphodynamic factors, temperature, and benthic invertebrates, which are seen as better biological indicators than fish. The morphodynamic factors are those of Huet’s zonation, that is, slope-width, complemented by flow, depth, order of drainage, and temperature. Lilies and Botosaneanu looked for nodas, which are discontinuities in the morphodynamic factors due to abrupt changes in flow and bed width at the confluents of streams of similar size. These nodas are observed particularly in canopy massifs or plateaux of Hercynian Europe.
