Structure et fonctionnement des écosystèmes du Haut-Rhône français: 6. La macrofaune benthique du fleuve

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Summary

The benthic macroinvertebrates of the main stream were sampled by means of artificial substrates. Twelve stations were selected in a stretch of 125 km of the river and studied during one year, a sample being taken every 3 months.

More than 80 taxa are grouped around a knot of species which are constant and dominant at all seasons (Gammarus fossarum, Heptagenia sulphurea, Hydropsyche contubemalis, H. borealis…). Factorial analysis of correspondences was applied in order to display the ecological affinities between species and stations and the influence of the time of the year. Three periods only can be distinguished: spring, summer and a “cold season” (autumn + winter), each period having its own present and abundant species. As a contrast, the structure of the benthic communities is rather homogenous along the entire course studied.