Résilience écologique de la macrofaune benthique sur un ancien site d’extraction de granulats marins

Faced with the multiple anthropogenic pressures, it has become increasingly urgent to investigate the recovery processes of disturbed marine ecosystems in order to implement appropriate management measures. The present study examines the resilience of a former marine aggregate extraction site that was intensively exploited until 2017. Five years after dredging cessation, extraction pits—up to 8 meters below the average seabed level—remain clearly visible. These depressions act as traps for fine particles, which accumulate in the deepest part of the site. The habitat, originally characterized by coarse sands, is now muddy and shows no signs of recovery. The slopes of the pits alternate between medium to coarse sands and gravels. It experiences episodic avalanche and natural processes such as sand dune migration. The spatial heterogeneity of the habitats, resulting from the intensity of the extraction, affects both the structural and functional diversity of the benthic macrofauna. The latter exhibits spatial divergence, and ecological trajectory analyses reveal no evidence of recovery. The site may have switch to a new ecological state. Given the extent of habitat alteration, a return to the reference conditions seems unlikely. Monitoring planned for 2027 will help confirm this hypothesis.