FN Archimer Export Format PT J TI Small-scale effects of hydrodynamics on the structure of intertidal macroalgal communities: A novel approach BT AF BUREL, Thomas Schaal, Gauthier Grall, Jacques Le Duff, Michel Chapalain, Georges Schmitt, Blondie Gemin, Maxence Boucher, Olivier AR GALL, Erwan AS 1:1;2:1;3:2;4:2;5:3;6:1;7:1;8:3;9:1; FF 1:;2:;3:;4:;5:;6:;7:;8:;9:; C1 Laboratoire des Sciences de l’Environnement Marin, UMR 6539 UBO/CNRS/IRD/IFREMER, Rue Dumont d’Urville, 29280, Plouzané, Brittany, France Institut Universitaire Européen de la Mer. Observatoire du Domaine Côtier, UMS 3113. Université de Bretagne Occidentale, Rue Dumont d’Urville, 29280, Plouzané, Brittany, France Laboratoire de Génie Côtier et Environnement (LGCE), Cerema, 155 rue Pierre Bouguer, Technopôle Brest-Iroise BP 5, 29280, Plouzané, Brittany, France C2 UBO, FRANCE UBO, FRANCE CEREMA, FRANCE UM LEMAR IN WOS Cotutelle UMR copubli-france IF 2.333 TC 12 UR https://archimer.ifremer.fr/doc/00506/61769/65752.pdf LA English DT Article DE ;Macroalgal communities;Intertidal zone;Rocky shores;Wave heights;Hydrodynamics;Mini-diver;Brittany AB Wave height was used as a proxy to assess the effect of hydrodynamics on the development and structure of intertidal North-East Atlantic rocky macroalgal communities (Brittany). The characterization of hydrodynamics at small-scale (about 10 m) was performed through wave height in situ monitoring using pressure sensors. Both the diversity and the cover of the macroalgal communities were sampled in parallel. Wave heights exhibit large variations with values ranging from ca. 5 cm to 1.60 m. We show that wave height directly controls the cover of macroalgal canopies (Pearson's r between −0.62 and −0.39). In all communities, most of the fucoid covers regressed with increasing wave height values. By contrast, positive correlations were found at low shore levels between wave heights and the cover of the kelp Laminaria digitata and also of several species of Rhodophyta. Redundancy analysis points out the significant effect of wave height on the inner variability of macroalgal communities, explaining up to 19% of their upright structure and more than 15% of the distribution of canopy-forming groups. In assemblages dominated by either Pelvetia canaliculata or Fucus serratus, a significant negative correlation was also evidenced with the index of community structure (Ics), which gives an appraisal of both the structure and the development of macroalgal communities. In conclusion, this study provides a novel experimental approach helping to quantify the effects of hydrodynamics on the structure of macroalgal communities using a small-scale in situ quantification of wave heights, revealing hydrodynamics as the main environmental driver of inner structural variations in seaweed assemblages. PY 2019 PD OCT SO Estuarine Coastal And Shelf Science SN 0272-7714 PU Elsevier BV VL 226 UT 000482495700024 DI 10.1016/j.ecss.2019.106290 ID 61769 ER EF