Small- and large-scale processes including anthropogenic pressures as drivers of gastropod communities in the NE Atlantic coast: A citizen science based approach

• Published in: Science of The Total Environment
• Main Authors: Serranito, Bruno, Diméglio, Tristan, Ysnel, Frédéric, Lizé, Anne, Feunteun, Eric
• Other Authors: Centre De Recherche et d'Enseignement sur les Systèmes Côtiers (CRESCO), Muséum national d'Histoire naturelle (MNHN)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Géoarchitecture : Territoires, Urbanisation, Biodiversité, Environnement, Université de Rennes (UR)-Université de Brest (UBO), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA), University of Liverpool, Fondation de France, ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: Vertical zonation; Inorganic nitrogen; Intertidal; Macroalgae canopy; Multi-scale processes; Random Forest; Rocky-shores; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; North East Atlantic
• Online Access: https://hal.science/hal-03469236; https://hal.science/hal-03469236/document; https://hal.science/hal-03469236/file/STOTEN-D-21-14322-5-52_divis%C3%A9.pdf; https://doi.org/10.1016/j.scitotenv.2021.151600

International audience Rocky-shores are among the most threatened coastal habitats, particularly under human pressures. While rocky-shore communities have been increasingly used to evaluate local anthropogenic perturbations such as water eutrophication for instance, large-scale variability in relation to both natural and anthropogenic pressures is still overlooked. Here, using citizen science-based data, we applied a Random Forest modelling approach to assess the relative impact of both small-and large-scale processes (including natural and some anthropogenic pressures) on intertidal gastropod communities as well as taxa-specific gastropod abundances over more than 1000 km of the North-East Atlantic coast. Our model results demonstrate that small-scale conditions (i.e. within shore) are determinant in shaping gastropod communities. However, community responses are mainly driven by taxon-specific effects. Among large-scale predictors, high concentrations of inorganic nutrients and total suspended matter, as found in large river plumes, are the main drivers impacting the gastropod communities by depleting both taxon abundances and richness. According to models, the decline in abundance of the yet most prevalent taxa (Steromphala umbilicalis, Patella spp., S. pennanti and Phorcus lineatus) is expected to be between 65% and 85%, while Littorina littorea was the only taxon which may be favoured by high concentrations of inorganic nutrients and total suspended matter. Such results provide relevant insights in the context of ever-increasing needs for bioindicators of coastal ecosystems. Finally, this work sheds light on the value of a citizen science program resulting from a consultation between professional and citizen volunteers as a useful and efficient tool to investigate large-scale processes.