Contributors: Laboratoire d'Ecologie et de Biologie Aquatique - LEBA (Genève, Suisse); Université de Genève = University of Geneva (UNIGE); Environnement, Ville, Société (EVS); École normale supérieure de Lyon (ENS de Lyon); Université de Lyon-Université de Lyon-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE); Institut Mines-Télécom Paris (IMT)-Institut Mines-Télécom Paris (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML); Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon); Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet - Saint-Étienne (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS)-Approches Littéraires, Linguistiques et Historiques des Sources (ALLHiS); Université Jean Monnet - Saint-Étienne (UJM)-Université Jean Monnet - Saint-Étienne (UJM); Université Jean Monnet - Saint-Étienne (UJM); Ce travail a été mené grâce au programme RhônEco de suivi scientifique de la restauration hydraulique et écologique du Rhône, programme de recherche pluri‐partenaires financés dans le cadre du Plan Rhône par l’Agence de l’eau Rhône Méditerranée Corse, CNR, EDF et les Régions Auvergne‐Rhône‐Alpes et Sud PACA.; RhônEco; Observatoire Hommes-Milieux Vallée du Rhône (OHM VR); Zone Atelier Bassin du Rhône (ZABR); ANR-11-LABX-0010,DRIIHM / IRDHEI,Dispositif de recherche interdisciplinaire sur les Interactions Hommes-Milieux(2011); ANR-17-EURE-0018,H2O'LYON,School of Integrated Watershed Sciences(2017)
نبذة مختصرة : International audience ; 1. Large river floodplains are dynamic environments, where alternating low and high flows are key ecological processes shaping aquatic biota. As a result of fluctuations in flow in floodplain channels, the diversity of benthic assemblages is assumed to result from the balance between surface flow connections, which are dominant during high flows, and groundwater inputs, which are dominant during low flows. However, the relative importance of these inputs in explaining aquatic invertebrate diversity has never been tested. 2. The response of aquatic invertebrates to hydrological changes of a river flood-plain was investigated in seven braided and six braided-anastomosed flood-plain channels of the French upper Rhône River that are fed by three different processes: groundwater supply (which controls the thermal inertia of the water bodies), surface slow flow connections (i.e. diffuse overbank flows; passive overflow), and surface shear stress-related connections (i.e. condensed flows; active overflow) during high flows. 3. Generalised dissimilarity models indicated that floodplain invertebrate composition had complex relationships with the three processes considered. The relative importance of the latter appeared dependent upon the morphology of the floodplain channels. In the braided channels, the effects of shear stress-related connections were more prominent than in the anastomosed ones, for which the effects of the three processes were more similar. 4. Overall, the diversity of flow connections, that is, lateral surface water connections (both shear stress-related and slow, as defined above) and vertical connection with groundwater (inferred through thermal inertia) enhanced the species turnover at the reach scale. Thermal inertia influenced invertebrate composition when, during low flow periods, surface flow connections had limited effect. 5. Our results highlighted that the role of hydrologic connectivity upon flood-plain diversity cannot be reduced to a single process. They also ...
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