Environmental and macroinvertebrate dynamics in the Lower Rhône River and a lateral dike field: a study matching two functioning descriptors

Abstract

Environmental variables and macroinvertebrate communities are studied in two sites of the Lower Rh6ne River, the main channel and a lateral, occasionally connected dike field. Environmental variables and faunistic communities allow discrimination the two compartments. The environmental and faunistic differences the two sites change over time. The physical and chemical differences are significantly correlated with water discharge of the main channel. The faunistic ones are significantly correlated with the temperature of the dike field water. The connections between the main channel and the dike field could be very important to maintain a high heterogeneity of the habitat, and for recolonization of the main channel after a perturbation.

Socio-environmental implications of process-based restoration strategies in large rivers: should we remove novel ecosystems along the Rhône (France)?

“…Alpha diversity patterns varied among the studied casiers, ranging from 13 to 42 species for phytoplankton, and from 11 to 39 taxa for macroinvertebrates. These richness values are in the same range of values measured by Franquet et al (1995) in a Lower Rhône River's groyne field during summer 1991. However, the diversity of remnant aquatic compartments was very heterogeneous, owing to the hydrological connectivity gradient observed between casiers and the main channel.…”

“…These results are consistent with Tockner et al (1998) (IDH, Connell 1978) where groyne fields that are partially connected are supposed to be partially disturbed by flow variability and may harbor more diverse benthic communities. With high biological diversity and important spatial variability, the Casiers Girardon could be considered as ecotones linking the main channel and the floodplain former channel lakes (Franquet et al 1995). In contrast to macroinvertebrates, the influence of hydrologic connectivity on phytoplankton diversity appears to be limited, probably due to the phytoplankton's rapid dynamics; this suggests that the spatial pattern of phytoplankton may be controlled by more than one constraint.…”

Functional classification of artificial alluvial ponds driven by connectivity with the river: Consequences for restoration

“…1). The former sections, called the several large European rivers during the 19th century are unique water bodies that must be taken into account in restoration plans (Franquet et al, 1995;Thorel et al, 2018). Dike fields (also called groyne fields) are fairly common infrastructures created along large rivers for flood and inundation management and to promote channel erosion for navigation.…”

Chironomid (Insecta: Diptera) Assemblages from a Gradient of Lotic and Lentic Waterbodies in River Floodplains of France: A Methodological Tool for Paleoecological Applications

“…Among the various groups of macroinvertebrates colonizing the aquatic parts of alluvial plains, Cladocera (Jacquet et al 1984;Jurasz and Amoros 1991) and Coleoptera (Castella et al 1984;Smith and Howard 2004) have been proposed as potential indicators. Chironomids also play a key role in the alluvial systems (Franquet et al 1995). They colonize all types of habitats from the main channels to the most isolated, temporary environments (Wilson 1980).…”