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Hochard, S., Pinazo, C., Rochelle-Newall, E., & Pringault, O. (2012). Benthic pelagic coupling in a shallow oligotrophic ecosystem: Importance of microphytobenthos and physical forcing. Ecological Modelling, 247, 307–318.
Résumé: In coral reef lagoons, microphytobenthos (MPB) primary production can be of the same order of magnitude as coral or macroalgal production. As they are situated in oligotrophic waters, sediments receive low amount of allochtonous nutrients, and their high metabolism cannot be achieved without an efficient nutrient recycling. In oligotrophic environments nutrient exchange between sediments and the water column is considered to be low. However, physical forcing that disturbs the sediment interface may accelerate nutrient exchange. The objectives of this work were to: (i) characterize the benthic trophic status and associated nutrient diffusion fluxes as a function of terrestrial and anthropogenic influence and (ii) investigate the impact of physical forcing on the exchanges at the interface and the response of the water column. For that purpose, a multidisciplinary study was performed in the southwest lagoon of New Caledonia combining field survey, laboratory experiments and mathematical modelling. The field survey indicated that most of the lagoon sediments were autotrophic and presented negligible nutrient fluxes. This suggests an apparent decoupling between the sediment and the water column as long as diffusion is the dominant nutrient exchange mode process. This was confirmed by experimental ex situ incubations that showed bacterial production in the water column was not affected by the presence of sediment. The modelling approach showed that physical forcing, such as sediment erosion or wave driven pore water advection, might enhance the coupling between the sediment and the water column through the release of nutrients and organic matter leading to the stimulation of the bacterioplankton and phytoplankton compartments.
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Jorgensen, C., Peck, M. A., Antognarelli, F., Azzurro, E., Burrows, M. T., Cheung, W. W. L., et al. (2012). Conservation physiology of marine fishes: advancing the predictive capacity of models. Biol. Lett., 8(6), 900–903.
Résumé: At the end of May, 17 scientists involved in an EU COST Action on Conservation Physiology of Marine Fishes met in Oristano, Sardinia, to discuss how physiology can be better used in modelling tools to aid in management of marine ecosystems. Current modelling approaches incorporate physiology to different extents, ranging from no explicit consideration to detailed physiological mechanisms, and across scales from a single fish to global fishery resources. Biologists from different sub-disciplines are collaborating to rise to the challenge of projecting future changes in distribution and productivity, assessing risks for local populations, or predicting and mitigating the spread of invasive species.
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LAGABRIELLE, E., CROCHELET, E., ANDRELLO, M., SCHILL, S. R., ARNAUD-HAOND, S., ALLONCLE, N., et al. (2014). Connecting MPAs – eight challenges for science and management. Aquatic Conservation-marine And Freshwater Ecosystems, 24, 94–110.
Résumé: Connectivity is a crucial process underpinning the persistence, recovery, and productivity of marine ecosystems. The Convention on Biological Diversity, through the Aichi Target 11, has set the ambitious objective of implementing a ‘well connected system of protected areas’ by 2020. This paper identifies eight challenges toward the integration of connectivity into MPA network management and planning. A summary table lists the main recommendations in terms of method, tool, advice, or action to address each of these challenges. Authors belong to a science–management continuum including researchers, international NGO officers, and national MPA agency members. Three knowledge challenges are addressed: selecting and integrating connectivity measurement metrics; assessing the accuracy and uncertainty of connectivity measurements; and communicating and visualizing connectivity measurements. Three management challenges are described: integrating connectivity into the planning and management of MPA networks; setting quantitative connectivity targets; and implementing connectivity-based management across scales and marine jurisdictions. Finally, two paths toward a better integration of connectivity science with MPA management are proposed: setting management-driven priorities for connectivity research, bridging connectivity science, and MPA network management. There is no single method to integrate connectivity into marine spatial planning. Rather, an array of methods can be assembled according to the MPA network objectives, budget, available skills, data, and timeframe. Overall, setting up ‘boundary organizations’ should be promoted to organize complex cross-disciplinary, cross-sectoral and cross-jurisdiction interactions that are needed between scientists, managers, stakeholders and decision-makers to make informed decision regarding connectivity-based MPA planning and management.
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Lassalle, G., Gascuel, D., Loc'h, F. L., Lobry, J., Pierce, G. J., Ridoux, V., et al. (2012). An ecosystem approach for the assessment of fisheries impacts on marine top predators : the Bay of Biscay case study. Ices Journal of Marine Science, 69(6), 925–938.
Résumé: A number of marine mammal populations is currently threatened by their interactions with fisheries. The present study aimed to provide insights into the severity of potential impacts of operational and biological interactions between top predators and fisheries, in the Bay of Biscay region. Our approach was to modify an Ecopath with Ecosim (EwE) model describing the overall structure and function of the ecosystem by including landings and discards of exploited stocks and estimations of the bycatch of non-target compartments. Second, a set of ecological indices and a trophic level (TL)-based model (EcoTroph, ET) were derived from the EwE model. ET was used to simulate the effects of increasing fishing pressure on the ecosystem and, more particularly, on top predators. The Bay of Biscay was demonstrated to be not far from overexploitation at the current fishing rate, this phenomenon being particularly noticeable for the highest TLs. Within the toothed cetacean community, bottlenose dolphins appeared the most sensitive to resource depletion, whereas common dolphins and harbour porpoises were most impacted by their incidental captures in fishing gears. This study provides a methodological framework to assess the impacts of fisheries on ecosystems for which EwE, or other ecosystem models, already exist.
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Lefevre, S., McKenzie, D. J., & Nilsson, G. E. (2018). In modelling effects of global warming, invalid assumptions lead to unrealistic projections. Glob. Change Biol., 24(2), 553–556.
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