Fluctuations in the extent of mangroves driven by multi-decadal changes in North Atlantic waves

• Published in: Journal of Biogeography
• Main Authors: Walcker, Romain, Anthony, Edward Jamal, Cassou, Christophe, Aller, Robert Curwood, Gardel, Antoine, Proisy, Christophe, Martinez, Jean-Michel, Fromard, François
• Other Authors: Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), CERFACS, Marine Sciences Research Center (New-York, USA), Stony Brook University SUNY (SBU), State University of New York (SUNY)-State University of New York (SUNY), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Botanique et Modélisation de l'Architecture des Plantes et des Végétations (UMR AMAP), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de la Recherche Agronomique (INRA)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut de Recherche pour le Développement (IRD France-Sud ), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), ANR-13-SENV-0002,MORDICUS,Oscillations et rétroactions climatiques aux échelles décennales : mécanismes, sensibilité et incertitudes(2013)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: Amazon; Coastal changes; Complex empirical orthogonal functions; French Guiana; Mangroves; North Atlantic Oscillation Ocean waves; Trade winds; [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics; Phylogenetics and taxonomy; [SDV.EE.ECO]Life Sciences [q-bio]/Ecology; environment/Ecosystems; [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.umontpellier.fr/hal-02095729; https://doi.org/10.1111/jbi.12580

International audience Aim : The goal of the study was to quantify changes in the extent of mangroves since the mid-twentieth century and to test the hypothesis that these changes are driven by ocean waves.Location : The pristine 300-km-long coast of French Guiana, South America.Methods : We produced time series of mangrove maps using archival remote sensing images. We retrieved significant wave heights (HS), mean wave periods (TM) and mean wave directions (θM) from the European Centre for Medium-Range Weather Forecasts reanalysis products. We used complex empirical orthogonal function (CEOF) decomposition to extract the main mode of mangrove surface area (MS) variability and singular value decomposition (SVD) to test the relationships between MS and HS, TM and θM.Results : The leading mode of variability extracted from the CEOF decomposition of MS captured approximately 78% of the total auto-covariance and revealed multi-decadal fluctuations in MS that were on the order of 10,000 ha. The SVD results indicated that the multi-decadal fluctuation in MS cross-covaried with HS, TM and θM over the North Atlantic sector, particularly in the region immediately off the French Guiana coast that is remotely forced by the North Atlantic Oscillation (NAO) during the winter season.Main conclusions : We provide evidence based on linear statistics that variations in the extent of mangroves are driven by large-scale, low-frequency changes in North Atlantic waves that are related to the NAO. Such a relationship is hypothesized to operate through wave pounding, which alters the mud substrates on which mangroves thrive and which varies with the phase of the NAO. In addition to long-term trends due to anthropogenic climate change, our results stress the importance of studying low-frequency modes of climate variability to understand changes in the extent of mangroves.