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Auteur Leruste, A.; Villeger, S.; Malet, N.; De Wit, R.; Bec, B. doi  openurl
  Titre Complementarity of the multidimensional functional and the taxonomic approaches to study phytoplankton communities in three Mediterranean coastal lagoons of different trophic status Type Article scientifique
  Année (down) 2018 Publication Revue Abrégée Hydrobiologia  
  Volume 815 Numéro 1 Pages 207-227  
  Mots-Clés classification; Classification; disturbance; diversity; ecology; Functional entity; Functional traits; lake phytoplankton; marine-phytoplankton; patterns; size; synechococcus; Taxonomic diversity; traits  
  Résumé We used the individual-based multidimensional functional diversity and the taxonomic approaches in a complementary way to describe phytoplankton communities in three coastal lagoons with different eutrophication status in the South of France. We sampled communities during three seasons, i.e., in autumn, spring, and summer. Using classical taxonomy, 107 taxa/morphotypes were identified in the nine communities. The individual-based functional approach allowed grouping these individuals into 20 functional entities according to their values for 5 traits related to trophic adaptations (cell size, mobility, trophic regime, coloniality, and pelagic/benthic life). Some species (e.g., Prorocentrum micans) emerged in multiple functional entities, showing the importance to consider intraspecific variability. The functional description of phytoplankton communities better reflected the hydrological functioning and the different eutrophication status of the lagoons than the taxonomic approach. Specific functional adaptations were identified in the nine communities. For example, phytoplankton organisms with heterotrophic and potentially mixotrophic abilities occurred when the availability of inorganic nutrient decreased, or when organic matter and small preys were potentially the main nutrient resources. The limitation has also favored small cells highly competitive for nutrients. Using functional indices together with taxonomic description has also helped revealing important aspects of community assembly, such as competitive exclusion in summer.  
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  ISSN 0018-8158 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2322  
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Auteur Legras, G.; Loiseau, N.; Gaertner, J.-C. doi  openurl
  Titre Functional richness: Overview of indices and underlying concepts Type Article scientifique
  Année (down) 2018 Publication Revue Abrégée Acta Oecol.-Int. J. Ecol.  
  Volume 87 Numéro Pages 34-44  
  Mots-Clés biodiversity; community composition; diversity indexes; ecology; ecosystem processes; fish communities; Functional richness indices; Guidelines; Index properties; intraspecific trait variation; Limitations; phylogenetic diversity; species richness; variability  
  Résumé Functional richness, currently defined as the amount of niche space occupied by the species within a community, is one of the three major components of functional diversity. Different indices have been developed in order to quantify this component. However, the range of indices available for assessing functional richness, often mathematically complex and based on different rationales, can cause confusion for field ecologists and lead to misinterpretation of the results obtained. In this context, we have provided the first study exclusively focused on the comparison of the definitions, advantages and drawbacks of a large set of functional richness indices. The first part of this work is focused on four indices (FDP&G, FRic, TOP and N-hypervolumes indices) that are currently the most commonly used for assessing functional richness. We have completed our study by including recently developed indices that enable us to take into account the intraspecific trait variability (i.e. FRim index and TDP framework), because there is currently a growing scientific consensus regarding the necessity of including this aspect in the assessment of the functional diversity of communities. We demonstrate that although authors have argued that their index describes the functional richness, each of them describes only part of it, and this part may strongly differ from one index to another. Rather than advocating the general use of a single index and/or systematically avoiding others, our study highlights the need for selecting indices in close relation with the context, the available data and the aims of each study. Such a strategy is an essential preliminary step for preventing misunderstanding and artefactual controversies. Along these lines, we propose some guidelines to help users in selecting the most appropriate indices according both to the facet of functional richness on which they wish to focus and to the characteristics of the available data.  
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  ISSN 1146-609x ISBN Médium  
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Auteur Bettarel, Y.; Halary, S.; Auguet, J.-C.; Mai, T.C.; Bui, N.V.; Bouvier, T.; Got, P.; Bouvier, C.; Monteil-Bouchard, S.; Christelle, D. doi  openurl
  Titre Corallivory and the microbial debacle in two branching scleractinians Type Article scientifique
  Année (down) 2018 Publication Revue Abrégée Isme J.  
  Volume 12 Numéro 4 Pages 1109-1126  
  Mots-Clés brown band disease; coral-associated bacteria; diversity; drupella-cornus; great-barrier-reef; network analysis; red-sea; search tool; viral communities; viruses  
  Résumé The grazing activity by specific marine organisms represents a growing threat to the survival of many scleractinian species. For example, the recent proliferation of the corallivorous gastropod Drupella now constitutes a critical case in all South-East Asian waters. If the damaging effects caused by this marine snail on coral polyps are relatively well known, the indirect incidence of predation on coral microbial associates is still obscure and might also potentially impair coral health. In this study, we compared the main ecological traits of coral-associated bacterial and viral communities living in the mucus layer of Acropora formosa and Acropora millepora, of healthy and predated individuals (i.e., colonized by Drupella rugosa), in the Bay of Van Phong (Vietnam). Our results show a substantial impact of the gastropod on a variety of microbiological markers. Colonized corals harbored much more abundant and active epibiotic bacteria whose community composition shifted toward more pathogenic taxa (belonging to the Vibrionales, Clostridiales, Campylobacterales, and Alteromonadales orders), together with their specific phages. Viral epibionts were also greatly influenced by Drupella corallivory with spectacular modifications in their concentrations, life strategies, genotype richness, and diversity. Novel and abundant circular Rep-encoding ssDNA viruses (CRESS-DNA viruses) were detected and characterized in grazed corals and we propose that their occurrence may serve as indicator of the coral health status. Finally, our results reveal that corallivory can cause severe dysbiosis by altering virus-bacteria interactions in the mucus layer, and ultimately favoring the development of local opportunistic infections.  
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  ISSN 1751-7362 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2325  
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Auteur Miloslavich, P.; Bax, N.J.; Simmons, S.E.; Klein, E.; Appeltans, W.; Aburto‐Oropeza, O.; Garcia, M.A.; Batten, S.D.; Benedetti‐Cecchi, L.; Checkley, D.M.; Chiba, S.; Duffy, J.E.; Dunn, D.C.; Fischer, A.; Gunn, J.; Kudela, R.; Marsac, F.; Muller‐Karger, F.E.; Obura, D.; Shin, Y.-J. url  doi
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  Titre Essential ocean variables for global sustained observations of biodiversity and ecosystem changes Type Article scientifique
  Année (down) 2018 Publication Revue Abrégée Global Change Biology  
  Volume 24 Numéro 6 Pages 2416-2433  
  Mots-Clés driver-pressure-state-impact-response; essential ocean variables; framework for ocean observing; global ocean observing system; marine biodiversity changes; Marine Biodiversity Observation Network; ocean change  
  Résumé Sustained observations of marine biodiversity and ecosystems focused on specific conservation and management problems are needed around the world to effectively mitigate or manage changes resulting from anthropogenic pressures. These observations, while complex and expensive, are required by the international scientific, governance and policy communities to provide baselines against which the effects of human pressures and climate change may be measured and reported, and resources allocated to implement solutions. To identify biological and ecological essential ocean variables (EOVs) for implementation within a global ocean observing system that is relevant for science, informs society, and technologically feasible, we used a driver-pressure-state-impact-response (DPSIR) model. We (1) examined relevant international agreements to identify societal drivers and pressures on marine resources and ecosystems, (2) evaluated the temporal and spatial scales of variables measured by 100+ observing programs, and (3) analysed the impact and scalability of these variables and how they contribute to address societal and scientific issues. EOVs were related to the status of ecosystem components (phytoplankton and zooplankton biomass and diversity, and abundance and distribution of fish, marine turtles, birds and mammals), and to the extent and health of ecosystems (cover and composition of hard coral, seagrass, mangrove and macroalgal canopy). Benthic invertebrate abundance and distribution and microbe diversity and biomass were identified as emerging EOVs to be developed based on emerging requirements and new technologies. The temporal scale at which any shifts in biological systems will be detected will vary across the EOVs, the properties being monitored and the length of the existing time-series. Global implementation to deliver useful products will require collaboration of the scientific and policy sectors and a significant commitment to improve human and infrastructure capacity across the globe, including the development of new, more automated observing technologies, and encouraging the application of international standards and best practices.  
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  ISSN 1365-2486 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2336  
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Auteur Milner-Gulland, E.J.; Garcia, S.; Arlidge, W.; Bull, J.; Charles, A.; Dagorn, L.; Fordham, S.; Zivin, J.G.; Hall, M.; Shrader, J.; Vestergaard, N.; Wilcox, C.; Squires, D. doi  openurl
  Titre Translating the terrestrial mitigation hierarchy to marine megafauna by-catch Type Article scientifique
  Année (down) 2018 Publication Revue Abrégée Fish. Fish.  
  Volume 19 Numéro 3 Pages 547-561  
  Mots-Clés albatrosses; artisanal fisheries; biodiversity offsets; biodiversity offsetting; circle hooks; conservation; economic incentives; fisheries bycatch; fishing effort; harbor porpoise; leatherback turtle; no net loss; seabird bycatch; sharks and rays; turtles  
  Résumé In terrestrial and coastal systems, the mitigation hierarchy is widely and increasingly used to guide actions to ensure that no net loss of biodiversity ensues from development. We develop a conceptual model which applies this approach to the mitigation of marine megafauna by-catch in fisheries, going from defining an overarching goal with an associated quantitative target, through avoidance, minimization, remediation to offsetting. We demonstrate the framework's utility as a tool for structuring thinking and exposing uncertainties. We draw comparisons between debates ongoing in terrestrial situations and in by-catch mitigation, to show how insights from each could inform the other; these are the hierarchical nature of mitigation, out-of-kind offsets, research as an offset, incentivizing implementation of mitigation measures, societal limits and uncertainty. We explore how economic incentives could be used throughout the hierarchy to improve the achievement of by-catch goals. We conclude by highlighting the importance of clear agreed goals, of thinking beyond single species and individual jurisdictions to account for complex interactions and policy leakage, of taking uncertainty explicitly into account and of thinking creatively about approaches to by-catch mitigation in order to improve outcomes for conservation and fishers. We suggest that the framework set out here could be helpful in supporting efforts to improve by-catch mitigation efforts and highlight the need for a full empirical application to substantiate this.  
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  ISSN 1467-2960 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2337  
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