Assessing the ecological effects of low-intensity marine aggregate extraction in a strong-hydrodynamic, coarse environment context: A case study of the GIE GMO site (English channel)

Abstract

Marine aggregate extraction represents an opportunity to face the depletion of terrestrial aggregate resources. The environmental effects of this activity have been assessed in several studies, leading to the formulation of recommendations to mitigate its effects. This study investigates its environmental impacts in a coarse, high-current environment with low-intensity extraction, a unique scenario not extensively studied before. Employing multivariate analyses and a trophic group approach, it examines complex responses at both species and community levels. Results indicate a decline in biodiversity, promoting the establishment of r-selected species, particularly filter feeders. Although site restoration timelines remain uncertain, initial indications suggest rapid recovery (2-3 years) for this site. The study also discusses methodological challenges in sampling these low-intensity dredged sites and emphasizes the need for new indices tailored to this pressure and coarse sediments under strong hydrodynamics. These insights offer valuable directions for future research.

Keywords: Benthos; Diversity; Ecological indices; Environmental effects; Marine aggregate; Trophic groups.