%0 Journal Article %J Ecosystems %D 2019 %T Global Changes Jeopardize the Trophic Carrying Capacity and Functioning of Estuarine Ecosystems %A Chevillot, X. %A Tecchio, S. %A Chaalali, A. %A Lassalle, G. %A Selleslagh, J. %A Castelnaud, G. %A David, V. %A Guy Bachelet %A Nathalie Niquil %A Benoit Sautour %A Lobry, J. %K benthos %K carrying capacity %K demersal fish %K ecosystem function %K ecosystem health %K food limitation %K food web %K France %K Gironde Estuary %K Global change %K network analysis %K trophic environment %X At the interface between terrestrial and marine biomes, estuaries display high ecological productivity and provide goods and services to humans. Associated with many ecological functions, they are nursery, refuge, and growing areas for many species fish. These ecological functions and services depend on both their ecological production and trophic carrying capacity and the durability of food web functioning. These transitional key habitats undergo both strong anthropogenic pressures and climatic influences that impact the structure and dynamics of estuarine biodiversity. In this context, we explore, here, three decades of the Gironde estuary ecosystem history to detect the food web’s response to global changes-induced effect on biodiversity. At least two Ecological Abrupt Shifts associated with deep modifications in the biodiversity at most trophic levels have been documented for this particular ecosystem. Three food web models were thus calibrated, one for each of the three periods discriminated by the two shifts that occurred at the end of the 1980s and the beginning of the 2000s. Results highlighted that the ecotrophic efficiency estimate for subtidal macrofauna and shrimps reached the maximum possible values during the last period. This could mean that the Gironde estuary fully reached its trophic carrying capacity due to a food limitation especially for benthos demersal fish. We also observed a significant decrease in some food web indicators (such as Average Mutual Information, System Omnivory Index, and Average Path Length) usually associated with ecosystem stress, suggesting a significant impact of global change on the Gironde estuary ecosystem health and questioning the sustainability of the ecological functions associated with this ecosystem. © 2018, Springer Science+Business Media, LLC, part of Springer Nature. %B Ecosystems %I Springer New York LLC %V 22 %P 473-495 %G eng %U https://link.springer.com/article/10.1007/s10021-018-0282-9 %R 10.1007/s10021-018-0282-9 %0 Journal Article %J Journal of Sea Research %D 2017 %T Regional and latitudinal patterns of soft-bottom macrobenthic invertebrates along French coasts: Results from the RESOMAR database %A Régis K. Gallon %A Nicolas Lavesque %A Jacques Grall %A Céline Labrune %A Antoine Grémare %A Guy Bachelet %A Hugues Blanchet %A Paulo Bonifácio %A Vincent M.P. Bouchet %A Jean-Claude Dauvin %A Nicolas Desroy %A Franck Gentil %A Laurent Guerin %A Céline Houbin %A Jérôme Jourde %A Sandrine Laurand %A Michel Le Duff %A Vincent Le Garrec %A Xavier de Montaudouin %A Frédéric Olivier %A Francis Orvain %A Pierre-Guy Sauriau %A Eric Thiébaut %A Olivier Gauthier %K France %K Latitudinal pattern %K Regional pattern %K Soft-bottom %K Species richness %K Zoobenthos %X

This study aims to describe the patterns of soft bottom macrozoobenthic richness along French coasts. It is based on a collaborative database developed by the “Réseau des Stations et Observatoires Marins” (RESOMAR). We investigated patterns of species richness in sublittoral soft bottom habitats (EUNIS level 3) at two different spatial scales: 1) seaboards: English Channel, Bay of Biscay and Mediterranean Sea and 2) 0.5° latitudinal and longitudinal grid. Total observed richness, rarefaction curves and three incidence-based richness estimators (Chao2, ICE and Jacknife1) were used to compare soft bottom habitats species richness in each seaboard. Overall, the Mediterranean Sea has the highest richness and despite higher sampling effort, the English Channel hosts the lowest number of species. The distribution of species occurrence within and between seaboards was assessed for each major phylum using constrained rarefaction curves. The Mediterranean Sea hosts the highest number of exclusive species. In pairwise comparisons, it also shares a lower proportion of taxa with the Bay of Biscay (34.1%) or the English Channel (27.6%) than that shared between these two seaboards (49.7%). Latitudinal species richness patterns along the Atlantic and English Channel coasts were investigated for each major phylum using partial LOESS regression controlling for sampling effort. This showed the existence of a bell-shaped latitudinal pattern, highlighting Brittany as a hotspot for macrobenthic richness at the confluence of two biogeographic provinces.

%B Journal of Sea Research %V 130 %P 96 - 106 %G eng %U http://www.sciencedirect.com/science/article/pii/S1385110116302660 %R https://doi.org/10.1016/j.seares.2017.03.011 %0 Journal Article %J Journal of Sea Research %D 2014 %T Multiscale patterns in the diversity and organization of benthic intertidal fauna among French Atlantic estuaries %A Hugues Blanchet %A Benoît Gouillieux %A Sandrine Alizier %A Jean-Michel Amouroux %A Guy Bachelet %A Anne-Laure Barillé %A Jean-Claude Dauvin %A Xavier de Montaudouin %A Valérie Derolez %A Nicolas Desroy %A Jacques Grall %A Antoine Grémare %A Pascal Hacquebart %A Jérôme Jourde %A Céline Labrune %A Nicolas Lavesque %A Antoine Meirland %A Thiebaut Nebout %A Frédéric Olivier %A Corine Pelaprat %A Thierry Ruellet %A Pierre-Guy Sauriau %A Sébastien Thorin %K Diversity %K Estuaries %K Macrozoobenthos %K Structuring Factors %K WFD %X

Based on a parallel sampling conducted during autumn 2008, a comparative study of the intertidal benthic macrofauna among 10 estuarine systems located along the Channel and Atlantic coasts of France was performed in order to assess the level of fauna similarity among these sites and to identify possible environmental factors involved in the observed pattern at both large (among sites) and smaller (benthic assemblages) scales. More precisely this study focused on unraveling the observed pattern of intertidal benthic fauna composition and diversity observed at among-site scale by exploring both biotic and abiotic factors acting at the among- and within-site scales. Results showed a limited level of similarity at the among-site level in terms of intertidal benthic fauna composition and diversity. The observed pattern did not fit with existing transitional water classification methods based on fish or benthic assemblages developed in the frame of the European Water Framework Directive (WFD). More particularly, the coastal plain estuaries displayed higher among-site similarity compared to ria systems. These coastal plain estuaries were characterized by higher influence of river discharge, lower communication with the ocean and high suspended particulate matter levels. On the other hand, the ria-type systems were more dissimilar and different from the coastal plain estuaries. The level of similarity among estuaries was mainly linked to the relative extent of the intertidal “Scrobicularia plana–Cerastoderma edule” and “Tellina tenuis” or “Venus” communities as a possible consequence of salinity regime, suspended matter concentrations and fine particles supply with consequences on the trophic functioning, structure and organization of benthic fauna. Despite biogeographical patterns, the results also suggest that, in the context of the WFD, these estuaries should only be compared on the basis of the most common intertidal habitat occurring throughout all estuarine systems and that the \{EUNIS\} biotope classification might be used for this purpose. In addition, an original inverse relation between γ-diversity and area was shown; however, its relevance might be questioned.

%B Journal of Sea Research %V 90 %P 95 - 110 %8 07/2014 %G eng %U http://www.sciencedirect.com/science/article/pii/S1385110114000495 %R http://dx.doi.org/10.1016/j.seares.2014.02.014