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Auteur Legras, G.; Loiseau, N.; Gaertner, J.-C.
Titre Functional richness: Overview of indices and underlying concepts Type Article scientifique
Année 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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Volume de collection Numéro de collection Edition
ISSN 1146-609x ISBN Médium
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Numéro d'Appel (up) MARBEC @ alain.herve @ collection 2323
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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.
Titre Corallivory and the microbial debacle in two branching scleractinians Type Article scientifique
Année 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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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1751-7362 ISBN Médium
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Numéro d'Appel (up) MARBEC @ alain.herve @ collection 2325
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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.
Titre Translating the terrestrial mitigation hierarchy to marine megafauna by-catch Type Article scientifique
Année 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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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1467-2960 ISBN Médium
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Numéro d'Appel (up) MARBEC @ alain.herve @ collection 2337
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Auteur Galiana, N.; Lurgi, M.; Claramunt-Lopez, B.; Fortin, M.-J.; Leroux, S.; Cazelles, K.; Gravel, D.; Montoya, J.M.
Titre The spatial scaling of species interaction networks Type Article scientifique
Année 2018 Publication Revue Abrégée Nat. Ecol. Evol.
Volume 2 Numéro 5 Pages 782-790
Mots-Clés area relationships; biodiversity; competition; diversity; ecological networks; extinction; food-web structure; habitat loss; source-sink metacommunities; trophic interactions
Résumé Species-area relationships (SARs) are pivotal to understand the distribution of biodiversity across spatial scales. We know little, however, about how the network of biotic interactions in which biodiversity is embedded changes with spatial extent. Here we develop a new theoretical framework that enables us to explore how different assembly mechanisms and theoretical models affect multiple properties of ecological networks across space. We present a number of testable predictions on network-area relationships (NARs) for multi-trophic communities. Network structure changes as area increases because of the existence of different SARs across trophic levels, the preferential selection of generalist species at small spatial extents and the effect of dispersal limitation promoting beta-diversity. Developing an understanding of NARs will complement the growing body of knowledge on SARs with potential applications in conservation ecology. Specifically, combined with further empirical evidence, NARs can generate predictions of potential effects on ecological communities of habitat loss and fragmentation in a changing world.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 2397-334x ISBN Médium
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Numéro d'Appel (up) MARBEC @ alain.herve @ collection 2339
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Auteur Cowart, D.A.; Durand, L.; Cambon-Bonavita, M.-A.; Arnaud-Haond, S.
Titre Investigation of bacterial communities within the digestive organs of the hydrothermal vent shrimp Rimicaris exoculata provide insights into holobiont geographic clustering Type Article scientifique
Année 2017 Publication Revue Abrégée PLoS One
Volume 12 Numéro 3 Pages e0172543
Mots-Clés alignment; chamber; deposits; diversity; Ecology; microbial community; mid-atlantic ridge; population; sequence data; sp nov.
Résumé Prokaryotic communities forming symbiotic relationships with the vent shrimp, Rimicaris exoculata, are well studied components of hydrothermal ecosystems at the Mid-Atlantic Ridge (MAR). Despite the tight link between host and symbiont, the observed lack of spatial genetic structure seen in R. exoculata contrasts with the geographic differentiation detected in specific bacterial ectosymbionts. The geographic clustering of bacterial lineages within a seemingly panmictic host suggests either the presence of finer scale restriction to gene flow not yet detected in the host, horizontal transmission (environmental selection) of its endosymbionts as a consequence of unique vent geochemistry, or vertically transmitted endosymbionts that exhibit genetic differentiation. To identify which hypothesis best fits, we tested whether bacterial assemblages exhibit differentiation across sites or host populations by performing a 16S rRNA metabarcoding survey on R. exoculata digestive prokaryote samples (n = 31) taken from three geochemically distinct vents across MAR: Rainbow, Trans-Atlantic Geotraverse (TAG) and Logatchev. Analysis of communities across two organs (digestive tract, stomach), three molt colors (white, red, black) and three life stages (eggs, juveniles, adults) also provided insights into symbiont transmission mode. Examining both whole communities and operational taxonomic units (OTUs) confirmed the presence of three main epibionts: Epsilonproteobacteria, Mollicutes and Deferribacteres. With these findings, we identified a clear pattern of geographic segregation by vent in OTUs assigned to Epsilonproteobacteria. Additionally, we detected evidence for differentiation among all communities associated to vents and life stages. Overall, results suggest a combination of environmental selection and vertical inheritance of some of the symbiotic lineages.
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Langue English Langue du Résumé Titre Original
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ISSN 1932-6203 ISBN Médium
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Numéro d'Appel (up) MARBEC @ alain.herve @ collection 2085
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