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Riverbank erosion is an essential morphodynamic process for the improvement of river health and the ecohydrogeomorphological functioning of alluvial rivers. Lateral channel dynamics and sediment supply caused by bank erosion largely create and maintain heterogeneous in-channel habitats for fauna and aquatic or riparian plant species. However, humans very early started to stabilize riverbanks in order to favour navigation or to prevent valuable land and infrastructures close to the channel from eroding. During the 20th century, bank protection works such as riprap considerably increased and blocked lateral channel erosion, causing a loss of local sediment supply, which in turn resulted in a decrease in local bedload transport and channel incision. The aim of the article is to evaluate to what extent riprap removal may be an efficient restoration measure in terms of the reactivation of bank erosion and the replenishment of the local bedload in gravel-bed floodplain rivers with a sufficient amount of freedom space. An experimental in situ restoration approach was chosen. First, riprap was removed at two geomorphologically contrasting sites on the Allier River, France. Second, bank retreat was monitored, and the volumes eroded were quantified using photogrammetric and LiDAR surveys. Third, in the case of post-restoration bank erosion, grain size and morphological channel evolution analyses were carried out. Our results suggested that the removal of riprap is an effective measure for certain but not all channelized floodplain reaches. The geomorphological and sedimentary contexts are two criteria that should be considered when selecting sites for restoration. Thus, this study helps river managers to better target the criteria to be taken into account for the selection of sites with high potential for the restoration of lateral channel dynamics. [ABSTRACT FROM AUTHOR]

Feedback between hydrogeomorphological processes and riparian plants drives landscape dynamics and vegetation succession in river corridors. We describe the consequences of biogeomorphological feedback on the formation and dynamics of vegetated fluvial landforms based on observations from the channelized Isère River in France. The channel was laterally confined with embankments and mostly straightened. From the beginning of the 1970s to the end of the 1990s, alternate bars were progressively but heavily colonized by vegetation. This context presented an exceptional opportunity to analyse temporal adjustments between fluvial landforms and vegetation succession from bare gravel bars to mature upland forest as the consequence of biogeomorphological interactions. Based on a GIS analysis of aerial photographs (between 1948 and 1996), we show that the spatiotemporal organization of vegetated bars within the river channel observed in 1996 resulted from a bioconstruction and biostabilization effect of vegetation and interactions between bars of varying age, size and mobility. Field measurements in 1996 reflected how a strong positive feedback between sedimentary dynamics and riparian vegetation succession resulted in the construction of the vegetated bars. A highly significant statistical association of geomorphological and vegetation variables (RV of co‐inertia analysis = 0.41, p < 0.001) explained 95% of the variability in just one axis, supporting the existence of very strong feedback between geomorphological changes (i.e. the transformation of small bare alternate bars to fluvial landforms covered by mature upland forest, and vegetation succession). Such dynamics reflect the fluvial biogeomorphological successions model, as described by the authors earlier. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The development of the Neolithic way of life in the western Mediterranean during the sixth millennium cal. BC is the consequence of the spread of populations from the Near East after successive stages of cultural remodelling. Despite the clear contribution of the Near Eastern and Aegean Neolithic to the economic and technical changes that happened to the west, little is known here about their symbolic legacies, because of the scarcity of representations and ritual evidences associated to the earliest western Neolithic contexts. Excavations at the rock shelter of Pendimoun (southeastern France) yielded the first anthropomorphic stone sculpture from the western Mediterranean Neolithic (early sixth millennium cal. BC). Using both carving and painting techniques, it represents a realistic-looking human face and is a unique example within the western Mediterranean and European frameworks. After describing the shaping and colouring details of the mask, the authors here deal with its possible social significances and cultural connections. [ABSTRACT FROM PUBLISHER]