Original paper
Changes within the Upper Rhône River macrobenthic communities after the completion of three hydroelectric schemes: anthropogenic effects or natural change?
Dolédec, S.; Dessaix, J.; Tachet, H.
Archiv für Hydrobiologie Volume 136 Number 1 (1996), p. 19 - 40
38 references
published: Feb 22, 1996
DOI: 10.1127/archiv-hydrobiol/136/1996/19
ArtNo. ESP141013601001, Price: 29.00 €
Abstract
In this paper, we study an Upper Rhône River impoundment (Brégnier-Cordon section) composed of a dam and a diversion canal. We present the ecological impact of this impoundment on the benthic invertebrate communities over 17 years (from 1975 to 1991) that shows a progressive long-term change at the five prospected sites. Before impoundment benthic communities were dominated by rheophilic species (hydropsychids) whereas after impoundment a majority of lentic and thermophilic species were collected. This long-term change in benthic invertebrate communities was partly related to the warming of water. The warming of water was attributed to the synergy between local climatic change during the study and the completion of hydroelectric schemes upstream. Due to a high degree of human impact, the diversion canal demonstrated a lower taxa richness than the other sites of the former Rhône. In the by-passed section, the level of the compensation flow was sufficient to maintain a species richness close to the normal situation, though a global change in community composition also occurred. Seasonal patterns were preserved before and after impoundment; however, after impoundment, species such as Hydra sp. blew up during spring.
Keywords
rheophilic • species richness • hydropsychids • climatic change • Upper Rhône River • Brégnier-Cordon