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Auteur (up) Moullec, F.; Velez, L.; Verley, P.; Barrier, N.; Ulses, C.; Carbonara, P.; Esteban, A.; Follesa, C.; Gristina, M.; Jadaud, A.; Ligas, A.; Díaz, E.L.; Maiorano, P.; Peristeraki, P.; Spedicato, M.T.; Thasitis, I.; Valls, M.; Guilhaumon, F.; Shin, Y.-J.
Titre Capturing the big picture of Mediterranean marine biodiversity with an end-to-end model of climate and fishing impacts Type Article scientifique
Année 2019 Publication Revue Abrégée Progress in Oceanography
Volume 178 Numéro Pages 102179
Mots-Clés Ecosystem model; Ecosystem Approach to Fisheries Management; Eco3M-S model; Global change; NEMOMED model; OSMOSE model
Résumé The Mediterranean Sea is one of the main hotspots of marine biodiversity in the world. The combined pressures of fishing activity and climate change have also made it a hotspot of global change amidst increasing concern about the worsening status of exploited marine species. To anticipate the impacts of global changes in the Mediterranean Sea, more integrated modelling approaches are needed, which can then help policymakers prioritize management actions and formulate strategies to mitigate impacts and adapt to changes. The aim of this study was to develop a holistic model of marine biodiversity in the Mediterranean Sea with an explicit representation of the spatial, multispecies dynamics of exploited resources subject to the combined influence of climate variability and fishing pressure. To this end, we used the individual-based OSMOSE model (Object-oriented Simulator of Marine ecOSystEms), including 100 marine species (fish, cephalopods and crustaceans) representing about 95% of the total declared catch, at a high spatial resolution (400 km2) and a large spatial scale (the entire Mediterranean basin) – the first time such a resolution and scale have been modelled. We then combined OSMOSE with the NEMOMED 12 physical model and the Eco3M-S biogeochemical low trophic level model to build the end-to-end model, OSMOSE-MED. We fitted OSMOSE-MED model with observed or estimated biomass and commercial catch data using a likelihood approach and an evolutionary optimization algorithm. The outputs of OSMOSE-MED were then verified against observed biomass and catch data, and compared with independent datasets (MEDITS data, diet composition and trophic levels). The model results – at different hierarchical levels, from individuals to the scale of the ecosystem – were consistent with current knowledge of the structure, functioning and dynamics of the ecosystems in the Mediterranean Sea. While the model could be further improved in future iterations, all the modelling steps – the comprehensive representation of key ecological processes and feedback, the selective parameterization of the model, and the comparison with observed data in the validation process – strengthened the predictive performance of OSMOSE-MED and thus its relevance as an impact model to explore the future of marine biodiversity under scenarios of global change. It is a promising tool to support ecosystem-based fishery management in the Mediterranean Sea.
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Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0079-6611 ISBN Médium
Région Expédition Conférence
Notes WOS:000496861900020 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2667
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Auteur (up) Ouisse, V.; Marchand-Jouravleff, I.; Fiandrino, A.; Feunteun, E.; Ysnel, F.
Titre Swinging boat moorings: Spatial heterogeneous damage to eelgrass beds in a tidal ecosystem Type Article scientifique
Année 2020 Publication Revue Abrégée Estuarine, Coastal and Shelf Science
Volume 235 Numéro Pages 106581
Mots-Clés Anthropogenic disturbances; Boat mooring; Modeling approach; SCUBA-Diving; Seagrass ecology
Résumé Seagrass meadows are currently known to be subjected to huge physical disturbances including boat moorings in shallow bays. We aimed to identify the impact of permanent swing mooring on the fast-growing seagrass Zostera marina in a mega-tidal area. Coupling the hydrodynamic MARS3D model to simulate mooring chain movements and in situ measurements of plant traits, we analyzed the structural responses of the eelgrass bed to scraping disturbance in the western English Channel (France). A comparison of the results with a reference site without any permanent swing boat mooring showed a significant impact on eelgrass structure (shoot density, leaf size, leaf dry weight), depending on the direction and distance from the mooring. Zostera marina was absent close to the mooring fixation point in three out of the four directions we evaluated. Beyond 5 m, the canopy height remained lower than in the reference site, most likely due to regular disturbances by mooring chains. Conversely, shoot density beyond 5 m was higher than in the reference site. This adaptive response counter-balanced the decrease in canopy height at these distances. The fluctuations of the structure of the eelgrass cover (number of shoots, leaf length) at a small spatial scale was clearly in accordance with the scraping intensity simulated by the MARS3D model. The tidal currents coupled to tidal amplitude variability imply a small-scale heterogeneous effect of permanent mooring on the benthic compartment, previously undetected by an aerial survey. The present results highlight the interest of coupling approaches so as to understand how physical pressure influences fast-growing species traits. The resulting important modifications could imply a more functional impact such as biodiversity loss and carbon sequestration, which is beyond the scope of the present paper.
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Editeur Lieu de Publication Éditeur
Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0272-7714 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2719
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Auteur (up) Pennino, M.G.; Bellido, J.M.; Conesa, D.; Coll, M.; Tortosa-Ausina, E.
Titre The analysis of convergence in ecological indicators: An application to the Mediterranean fisheries Type Article scientifique
Année 2017 Publication Revue Abrégée Ecological Indicators
Volume 78 Numéro Supplement C Pages 449-457
Mots-Clés Convergence analysis; ecological indicators; Ecosystem Approach to Fisheries Management; Mediterranean Sea; Non-parametric density estimation; Transition probability matrix
Résumé Ecological indicators are increasingly used to examine the evolution of natural ecosystems and the impacts of human activities. Assessing their trends to develop comparative analyses is essential. We introduce the analysis of convergence, a novel approach to evaluate the dynamic and trends of ecological indicators and predict their behavior in the long-term. Specifically, we use a non-parametric estimation of Gaussian kernel density functions and transition probability matrix integrated in the R software. We validate the performance of our methodology through a practical application to three different ecological indicators to study whether Mediterranean countries converge towards similar fisheries practices. We focus on how distributions evolve over time for the Marine Trophic Index, the Fishing in Balance Index and the Expansion Factor during 1950–2010. Results show that Mediterranean countries persist in their fishery behaviors throughout the time series, although a tendency towards similar negative effects on the ecosystem is apparent in the long-term. This methodology can be easily reproduced with different indicators and/or ecosystems in order to analyze ecosystem dynamics.
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Langue Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1470-160x ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2226
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Auteur (up) Poussin, J.-C.; Renaudin, L.; Adogoba, D.; Sanon, A.; Tazen, F.; Dogbe, W.; Fusillier, J.-L.; Barbier, B.; Cecchi, P.
Titre Performance of small reservoir irrigated schemes in the Upper Volta basin: Case studies in Burkina Faso and Ghana Type Article scientifique
Année 2015 Publication Revue Abrégée Water Resources and Rural Development
Volume Numéro Pages 50-65
Mots-Clés Irrigated crops; Iwrm; Participatory approach; Sub Saharan Africa
Résumé A major direct use of water from West African small reservoirs is irrigation. Analyzing the performances of irrigated agriculture is therefore a useful way to measure the impact of small reservoirs on food security and livelihoods of local communities. The aim of this study was to assess the performance of two such irrigated schemes in the Upper Volta basin (one in Burkina Faso and the other in Ghana) through participatory methods, to jointly identify major constraints, and to discuss possible solutions with local communities. The agronomic and economic performance of irrigated agriculture at both sites were far from satisfactory, due to the lack of maintenance of the small reservoirs and irrigation schemes, sub-optimal crop management, and poor product marketing. These issues were analyzed with the farmers across differing sub-schemes and cropping systems and some solutions were envisaged. Our assessment showed that farmers often had difficulty obtaining quality agricultural inputs and marketing their products. The poor performance of irrigated crops, due to poor condition of hydraulic infrastructures, poor agronomic management, and organizational failure provided only limited incomes for local households. Nevertheless, the existence and the many uses of small reservoirs improved food security and created indirect activities that also enhanced livelihoods. The local authorities generally considered preserving water to be a priority in small reservoir management, but the degradation of irrigation schemes could happen quickly and result in scheme failures, thus reducing indirect economic activities and causing under utilization or even abandonment of the small reservoir, unless appropriate measures are taken.
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Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Managing Rainwater and Small Reservoirs in Sub-Saharan Africa Titre de collection Abrégé
Volume de collection 6 Numéro de collection Edition
ISSN 2212-6082 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1443
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Auteur (up) ROA PASCUALI, L.; Demarcq, H.; Nieblas, A.-E.
Titre Detection of mesoscale thermal fronts from 4km data using smoothing techniques: Gradient-based fronts classification and basin scale application Type Article scientifique
Année 2015 Publication Remote Sensing of Environment Revue Abrégée
Volume 164 Numéro Pages 225-237
Mots-Clés Mesoscale thermal fronts; Preliminary smoothing; Sea surface temperature; 4 km resolution; Gradient intensity classification; Expert-based approach; Detection efficiency; Indian Ocean
Résumé In order to optimize frontal detection in sea surface temperature fields at 4 km resolution, a combined statistical and expert-based approach is applied to test different spatial smoothing of the data prior to the detection process. Fronts are usually detected at 1 km resolution using the histogram-based, single image edge detection (SIED) algorithm developed by Cayula and Cornillon in 1992, with a standard preliminary smoothing using a median filter and a 3 × 3 pixel kernel. Here, detections are performed in three study regions (off Morocco, the Mozambique Channel, and north-western Australia) and across the Indian Ocean basin using the combination of multiple windows (CMW) method developed by Nieto, Demarcq and McClatchie in 2012 which improves on the original Cayula and Cornillon algorithm. Detections at 4 km and 1 km of resolution are compared. Fronts are divided in two intensity classes (“weak” and “strong”) according to their thermal gradient. A preliminary smoothing is applied prior to the detection using different convolutions: three type of filters (median, average and Gaussian) combined with four kernel sizes (3 × 3, 5 × 5, 7 × 7, and 9 × 9 pixels) and three detection window sizes (16 × 16, 24 × 24 and 32 × 32 pixels) to test the effect of these smoothing combinations on reducing the background noise of the data and therefore on improving the frontal detection. The performance of the combinations on 4 km data are evaluated using two criteria: detection efficiency and front length. We find that the optimal combination of preliminary smoothing parameters in enhancing detection efficiency and preserving front length includes a median filter, a 16 × 16 pixel window size, and a 5 × 5 pixel kernel for strong fronts and a 7 × 7 pixel kernel for weak fronts. Results show an improvement in detection performance (from largest to smallest window size) of 71% for strong fronts and 120% for weak fronts. Despite the small window used (16 × 16 pixels), the length of the fronts has been preserved relative to that found with 1 km data. This optimal preliminary smoothing and the CMW detection algorithm on 4 km sea surface temperature data are then used to describe the spatial distribution of the monthly frequencies of occurrence for both strong and weak fronts across the Indian Ocean basin. In general strong fronts are observed in coastal areas whereas weak fronts, with some seasonal exceptions, are mainly located in the open ocean. This study shows that adequate noise reduction done by a preliminary smoothing of the data considerably improves the frontal detection efficiency as well as the global quality of the results. Consequently, the use of 4 km data enables frontal detections similar to 1 km data (using a standard median 3 × 3 convolution) in terms of detectability, length and location. This method, using 4 km data is easily applicable to large regions or at the global scale with far less constraints of data manipulation and processing time relative to 1 km data.
Adresse Institut Français pour Recherche et Exploitation de la Mer (IFREMER), UMR MARBEC (IRD/Ifremer/Université de Montpellier/CNRS), Station Ifremer Avenue Jean Monnet, CS 30171, 34203 Sète CEDEX, France
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Editeur Elsevier BV Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0034-4257 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ 37998 collection 1230
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