DOES THE RHINE STILL HAVE CHARACTERISTICS OF A RIVER ECOSYSTEM - THE LONGITUDINAL DISTRIBUTION OF MACROINVERTEBRATES

A structural and functional analysis of macroinvertebrate taxa was mad e in order to relate species richness and functional feeding groups to hydrological, physico-chemical, nutritional and habitat characteristi cs of the main channel transects of the entire river Rhine. Species di versity was highest in the upstream parts, Hochrhein and Oberrhein, an d lowest in the Mittelrhein, which might be related to the greater var iety of habitats and of nutritional resources and the lower degree of pollution in the upstream sections. The relative contributions of the macroinvertebrate species over the various functional feeding groups w as remarkably constant with collector species dominating the species c omposition in all river sections, suggesting an overall importance of FPOM as macroinvertebrate food in the sections studied. The relative s hare of shredder species suggests the importance of the input of CPOM in the entire river from tributaries, riparian and floodplain vegetati on.