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Auteur Navarro, J.; Cardador, L.; Fernández, Á.M.; Bellido, J.M.; Coll, M. url  doi
openurl 
  Titre Differences in the relative roles of environment, prey availability and human activity in the spatial distribution of two marine mesopredators living in highly exploited ecosystems Type Article scientifique
  Année 2016 Publication Revue Abrégée J. Biogeogr.  
  Volume 43 Numéro 3 Pages 440-450  
  Mots-Clés deviance partitioning; elasmobranchs; environmental variables; human stressors; indicator species; marine biodiversity; Marine conservation; Mediterranean Sea; Raja asterias; Scyliorhinus canicula  
  Résumé Aim Identifying the main factors affecting the spatial distribution of marine predators is essential in order to evaluate their distribution patterns, predict the potential impact of human activities on their populations and design accurate management actions. This information is also valuable from a more general management perspective, as marine predators are often considered indicators of habitat quality. In this context, we aimed to determine the degree to which environmental features, prey availability and human activities interact and influence spatial distribution of two marine mesopredator elasmobranchs, the small-spotted catshark (Scyliorhinus canicula) and the Mediterranean starry ray (Raja asterias), living in a highly human-exploited environment. Location Mediterranean Sea. Methods With information obtained from an extended experimental survey, we investigated the relative importance of environmental variables, prey availability and human activities on the spatial distribution of the abundance, biomass and occurrence rate of these marine mesopredators using deviance partitioning analyses. Results Our results revealed that environmental variables were the most important factors explaining the spatial distribution of Mediterranean starry ray, whereas small-spotted catshark distribution was also influenced by prey availability and human factors. From a management point of view, these findings suggest that Mediterranean starry ray could be a good candidate as an indicator species of demersal environmental quality. On the other hand, the distribution of the small-spotted catshark, which responds in an interactive and complex way to environment, prey availability and particular human activities, may be misleading as an environmental indicator. Main conclusions The spatial distribution of elasmobranchs in highly human-impacted marine areas can reflect the interactive and combined effects of multiple factors. To avoid misunderstandings, attention should be paid to statistical procedures allowing the separation of pure and joint contribution of the factors driving the observed spatial patterns.  
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  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 1365-2699 ISBN Médium  
  Région Expédition Conférence  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1538  
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Auteur Loiseau, N.; Legras, G.; Gaertner, J.-C.; Verley, P.; Chabanet, P.; Mérigot, B. url  doi
openurl 
  Titre Performance of partitioning functional beta-diversity indices: Influence of functional representation and partitioning methods Type Article scientifique
  Année 2017 Publication Revue Abrégée Global Ecol. Biogeogr.  
  Volume 26 Numéro 6 Pages 753-762  
  Mots-Clés assembly rules; Beta diversity; indices; nestedness-resultant dissimilarity; partitioning; replacement; richness difference; turnover  
  Résumé Aim Two frameworks (BASVIL and PODCAR), based on two different functional representations (ordination and dendrogram), have been proposed for partitioning overall functional beta diversity into two analogous components: turnover and nestedness-resultant dissimilarity, or replacement and difference of functional richness, respectively. We compared the two frameworks by testing the influence of functional representations and partitioning methods on the measurement of overall functional beta diversity and its components. Innovation We computed beta-diversity indices from the two frameworks on a set of communities simulated according to five scenarios of assembly: random, richness gradient, pure nestedness, pure turnover and mixed turnover/loss scenarios. To disentangle the effects of the partitioning approach and those of the functional representation on measurement of functional beta diversity, we also computed PODCAR indices in multidimensional space. Main conclusions BASVIL and PODCAR frameworks led to different results for overall functional beta diversity and their analogous partitioning components. Most of the difference between the two frameworks was due to the functional representation used. The goodness-of-fit measure (mean squared deviation, mSD) to assess the quality of functional spaces showed that the one computed on the basis of the dendrogram used in PODCAR remained lower than that of the functional ordination considered in BASVIL. In addition, only functional turnover derived from the BASVIL framework is independent of difference in functional richness. Finally, BASVIL measured functional variations derived from nested phenomena while PODCAR did not allow separation of this variation derived from richness difference. However, the sensitivity of BASVIL to functionally extreme species may make it difficult to know whether variations of the nestedness-resultant dissimilarity components are due to a turnover with few extreme species or a loss in functional richness. Particular attention with regard to the properties of the two frameworks is required before drawing conclusions regarding processes that structure communities.  
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  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1466-8238 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2136  
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Auteur Pool, T.K.; Cucherousset, J.; Boulêtreau, S.; Villeger, S.; Strecker, A.L.; Grenouillet, G. url  doi
openurl 
  Titre Increased taxonomic and functional similarity does not increase the trophic similarity of communities Type Article scientifique
  Année 2016 Publication Revue Abrégée Global Ecology and Biogeography  
  Volume 25 Numéro 1 Pages 46-54  
  Mots-Clés Alpha diversity; Beta diversity; compositional similarity; functional diversity; trophic diversity  
  Résumé Aim Despite a long-standing research interest in the association between the biodiversity (i.e. taxonomic and functional composition) and trophic structure of communities, our understanding of the relationship remains limited. Community assembly theory predicts that niche partitioning will result in communities with a diverse array of functional traits, which in turn may facilitate a correspondingly diverse array of trophic interactions that define the trophic niche of those communities. The aim of our study is to test this prediction. Location North America. Methods We built a database composed of functional traits and stable isotope values (δ13C and δ15N) for 63 freshwater fish communities containing 109 species in 34 lentic and 29 lotic ecosystems. First, using linear mixed models (i.e. an alpha-diversity approach), we tested whether the taxonomic diversity of communities was positively associated with their functional diversity and if their functional diversity was positively associated with their trophic diversity. Second, we assessed the taxonomic, functional and trophic similarity of communities using multiple regression on distance matrices (MRM) and their respective ‘turnover’ and ‘nestedness-resultant’ components to test if the taxonomic similarity of communities was positively correlated with their functional similarity and if their functional similarity was positively associated with their trophic similarity (i.e. a beta-diversity approach). Results We found that the functional diversity of communities increased as their taxonomic diversity increased. Similarly, the trophic diversity of communities increased as their functional diversity increased. The pairwise taxonomic and functional similarity of communities were also positively associated, but there was a weak relationship between the functional and trophic similarities of communities. Main conclusions Our study demonstrates that communities with similar functional characteristics can have disparate food web structures, suggesting that additional site-specific factors influence community variation in trophic niche geometry. Determining the relative importance of functional characteristics and site-specific factors in shaping trophic interactions is crucial for a better understanding of how future species loss and species introductions will affect food web structure and ecosystem functioning.  
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  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1466-8238 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1540  
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Auteur Maire, Eva; Grenouillet, G.; Brosse, S.; Villeger, S. url  doi
openurl 
  Titre How many dimensions are needed to accurately assess functional diversity? A pragmatic approach for assessing the quality of functional spaces Type Article scientifique
  Année 2015 Publication Revue Abrégée Global Ecology and Biogeography  
  Volume 24 Numéro 6 Pages 728-740  
  Mots-Clés Diversity indices; functional dendrogram; functional dissimilarity; functional ecology; functional traits; multidimensional space  
  Résumé Aim Functional diversity is a key facet of biodiversity that is increasingly being measured to quantify its changes following disturbance and to understand its effects on ecosystem functioning. Assessing the functional diversity of assemblages based on species traits requires the building of a functional space (dendrogram or multidimensional space) where indices will be computed. However, there is still no consensus on the best method for measuring the quality of functional spaces. Innovation Here we propose a framework for evaluating the quality of a functional space (i.e. the extent to which it is a faithful representation of the initial functional trait values). Using simulated datasets, we analysed the influence of the number and type of functional traits used and of the number of species studied on the identity and quality of the best functional space. We also tested whether the quality of the functional space affects functional diversity patterns in local assemblages, using simulated datasets and a real study case. Main conclusions The quality of functional space strongly varied between situations. Spaces having at least four dimensions had the highest quality, while functional dendrograms and two-dimensional functional spaces always had a low quality. Importantly, we showed that using a poor-quality functional space could led to a biased assessment of functional diversity and false ecological conclusions. Therefore, we advise a pragmatic approach consisting of computing all the possible functional spaces and selecting the most parsimonious one.  
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  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 1466-8238 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection 1341  
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Auteur Albouy, C.; Delattre, V.L.; Mérigot, B.; Meynard, C.N.; Leprieur, F. url  doi
openurl 
  Titre Multifaceted biodiversity hotspots of marine mammals for conservation priorities Type Article scientifique
  Année 2017 Publication Revue Abrégée Diversity Distrib  
  Volume 23 Numéro 6 Pages 615-626  
  Mots-Clés conservation; Functional diversity; marine mammals; phylogenetic diversity  
  Résumé Aim Identifying the multifaceted biodiversity hotspots for marine mammals and their spatial overlap with human threats at the global scale. Location World-wide. Methods We compiled a functional trait database for 121 species of marine mammals characterized by 14 functional traits grouped into five categories. We estimated marine mammal species richness (SR) as well as functional (FD) and phylogenetic diversity (PD) per grid cell (1° × 1°) using the FRic index (a measure of trait diversity as the volume of functional space occupied by the species present in an assemblage) and the PD index (the amount of evolutionary history represented by a set of species), respectively. Finally, we assessed the spatial congruence of these three facets of biodiversity hotspots (defined as 2.5% and 5% of the highest values of SR, FD and PD) with human threats at the global scale. Results We showed that the FRic index was weakly correlated with both SR and the PD index. Specifically, SR and FRic displayed a triangular relationship, that is, increasing variability in FRic along the species richness gradient. We also observed a striking lack of spatial congruence (<0.1%) between current human threats and the distribution of the multiple facets of biodiversity hotspots. Main Conclusions We highlighted that functional diversity calculated using the FRic index is weakly associated with the species richness of marine mammals world-wide. This is one of the most endangered vertebrate groups playing a key ecological role in marine ecosystems. This finding calls for caution when using only species richness as a benchmark for defining marine mammal biodiversity hotspots. The very low level of spatial congruence between hotspots of current threats and those of the multiple facets of marine mammal biodiversity suggests that current biodiversity patterns for this group have already been greatly affected by their history of exploitation.  
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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 1472-4642 ISBN Médium  
  Région Expédition Conférence  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2125  
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