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Auteur Benedetti, F.; Ayata, S.-D.; Irisson, J.-O.; Adloff, F.; Guilhaumon, F.
Titre Climate change may have minor impact on zooplankton functional diversity in the Mediterranean Sea Type Article scientifique
Année 2019 Publication Revue Abrégée Divers. Distrib.
Volume 25 Numéro 4 Pages 568-581
Mots-Clés biogeography; calanus-helgolandicus; climate change; communities; conservation; fish assemblages; framework; functional diversity; future; marine biodiversity; Mediterranean Sea; niche modelling; null model; ocean; trait; zooplankton
Résumé Aim To assess the impact of climate change on the functional diversity of marine zooplankton communities. Location The Mediterranean Sea. Methods We used the functional traits and geographic distributions of 106 copepod species to estimate the zooplankton functional diversity of Mediterranean surface assemblages for the 1965-1994 and 2069-2098 periods. Multiple environmental niche models were trained at the global scale to project the species habitat suitability in the Mediterranean Sea and assess their sensitivity to climate change predicted by several scenarios. Simultaneously, the species traits were used to compute a functional dendrogram from which we identified seven functional groups and estimated functional diversity through Faith's index. We compared the measured functional diversity to the one originated from null models to test if changes in functional diversity were solely driven by changes in species richness. Results All but three of the 106 species presented range contractions of varying intensity. A relatively low decrease of species richness (-7.42 on average) is predicted for 97% of the basin, with higher losses in the eastern regions. Relative sensitivity to climate change is not clustered in functional space and does not significantly vary across the seven copepod functional groups defined. Changes in functional diversity follow the same pattern and are not different from those that can be expected from changes in richness alone. Main conclusions Climate change is not expected to alter copepod functional traits distribution in the Mediterranean Sea, as the most and the least sensitive species are functionally redundant. Such redundancy should buffer the loss of ecosystem functions in Mediterranean zooplankton assemblages induced by climate change. Because the most negatively impacted species are affiliated to temperate regimes and share Atlantic biogeographic origins, our results are in line with the hypothesis of increasingly more tropical Mediterranean communities.
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Langue (up) English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1366-9516 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2582
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Auteur Chao, A.; Chiu, C.-H.; Villeger, S.; Sun, I.-F.; Thorn, S.; Lin, Y.-C.; Chiang, J.-M.; Sherwin, W.B.
Titre An attribute-diversity approach to functional diversity, functional beta diversity, and related (dis)similarity measures Type Article scientifique
Année 2019 Publication Revue Abrégée Ecol. Monogr.
Volume 89 Numéro 2 Pages Unsp-e01343
Mots-Clés attribute diversity; biodiversity; biological diversity; consensus; conservation; differentiation measures; diversity decomposition; evenness; framework; functional (dis)similarity; functional beta diversity; functional diversity; Hill numbers; phylogenetic diversity; quadratic entropy; similarity; species diversity; species richness; species traits; trait diversity
Résumé Based on the framework of attribute diversity (a generalization of Hill numbers of order q), we develop a class of functional diversity measures sensitive not only to species abundances but also to trait-based species-pairwise functional distances. The new method refines and improves on the conventional species-equivalent approach in three areas: (1) the conventional method often gives similar values (close to unity) to assemblages with contrasting levels of functional diversity; (2) when a distance metric is unbounded, the conventional functional diversity depends on the presence/absence of other assemblages in the study; (3) in partitioning functional gamma diversity into alpha and beta components, the conventional gamma is sometimes less than alpha. To resolve these issues, we add to the attribute-diversity framework a novel concept: tau, the threshold of functional distinctiveness between any two species; here, tau can be chosen to be any positive value. Any two species with functional distance >= tau are treated as functionally equally distinct. Our functional diversity quantifies the effective number of functionally equally distinct species (or “virtual functional groups”) with all pairwise distances at least tau for different species pairs. We advocate the use of two complementary diversity profiles (tau profile and q profile), which depict functional diversity with varying levels of tau and q, respectively. Both the conventional species-equivalent method (i.e., tau is the maximum of species-pairwise distances) and classic taxonomic diversity (i.e., tau is the minimum of non-zero species-pairwise distances) are incorporated into our proposed tau profile for an assemblage. For any type of species-pairwise distance matrices, our attribute-diversity approach allows proper diversity partitioning, with the desired property gamma >= alpha and thus avoids all the restrictions that apply to the conventional diversity decomposition. Our functional alpha and gamma are interpreted as the effective numbers of functionally equally distinct species, respectively, in an assemblage and in the pooled assemblage, while beta is the effective number of equally large assemblages with no shared species and all species in the assemblages being equally distinct. The resulting beta diversity can be transformed to obtain abundance-sensitive Sorensen- and Jaccard-type functional (dis)similarity profiles. Hypothetical and real examples are used to illustrate the framework. Online software and R codes are available to facilitate computations.
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Langue (up) English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0012-9615 ISBN Médium
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Notes WOS:000477640700001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2620
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Auteur Villeger, S.; Maire, Eva; Leprieur, F.
Titre On the risks of using dendrograms to measure functional diversity and multidimensional spaces to measure phylogenetic diversity: a comment on Sobral et al. (2016) Type Article scientifique
Année 2017 Publication Revue Abrégée Ecol. Lett.
Volume 20 Numéro 4 Pages 554-557
Mots-Clés assemblages; cophenetic distance; dendrogram; Euclidean space; functional diversity; functional space; phylogenetic diversity; reveals
Résumé Sobral et al. (Ecology Letters, 19, 2016, 1091) reported that the loss of bird functional and phylogenetic diversity due to species extinctions was not compensated by exotic species introductions. Here, we demonstrate that the reported changes in biodiversity were underestimated because of methodological pitfalls.
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Langue (up) English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1461-023x ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2116
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Auteur Loiseau, N.; Legras, G.; Kulbicki, M.; Mérigot, B.; Harmelin-Vivien, M.; Mazouni, N.; Galzin, R.; Gaertner, J.C.
Titre Multi-component β-diversity approach reveals conservation dilemma between species and functions of coral reef fishes Type Article scientifique
Année 2017 Publication Revue Abrégée J. Biogeogr.
Volume 44 Numéro 3 Pages 537-547
Mots-Clés assemblages; Beta diversity; Beta-diversity; biodiversity; climate; coral reef fish; environmental dissimilarity; functional diversity; global patterns; models; nestedness; null; partitioning; turnover; vulnerability
Résumé AimWe applied a multicomponent approach based on the decomposition of taxonomic (both presence-absence and abundance) and functional beta diversity to determine the influence of ecological factors in shaping spatial distribution diversity of coral reef fishes, and the implications for conservation decisions. LocationLagoons of ten atolls characterized by low human pressure but with contrasted geomorphology in the Tuamotu Archipelago, French Polynesia. MethodsWe computed beta diversities and their partitioning components, both at local (inter-transect, from 200m to 10km) and large (among atolls, from 22 to 350km) spatial scales. Null models were applied to test whether the observed beta diversity differed from random expectation. Multiple generalized dissimilarity models were run to test which environmental factors were the best predictors of observed beta diversities. ResultsBeta diversity was indistinguishable from randomness at both spatial scales. Species remained generally interchangeable among transects within an atoll and to some extent among atolls. However, strong deviance explained by models showed that the number of species, the number of individuals and functional traits present in transects and atolls were determined by deterministic factors (i.e. environmental factors). Modelling each beta diversity component separately also revealed partial mismatch among atolls and among species and functional dissimilarities. The influence of environmental variables strongly varied among atolls, species and functional dissimilarities. Main conclusionsBy revealing the spatial scaling of ecological factors and partial congruence among species and functional diversity, assessment of beta diversity provides insight into conservation planning. Our results support the idea that conservation planning applied to protect taxonomic diversity cannot be fully extended to functional diversity. We have addressed the dilemma of which diversity component should be favoured in conservation strategies.
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Langue (up) English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0305-0270 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2117
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Auteur Oikonomou, A.; Leprieur, F.; Leonardos, I.D.
Titre Ecomorphological diversity of freshwater fishes as a tool for conservation priority setting: a case study from a Balkan hotspot Type Article scientifique
Année 2018 Publication Revue Abrégée Environ. Biol. Fishes
Volume 101 Numéro 7 Pages 1121-1136
Mots-Clés assemblages; Balkan peninsula; communities; Conservation; Ecomorphology; environmental-factors; Freshwater fishes; functional diversity; future challenges; habitat gradients; life-history strategies; Originality; species richness; stream; traits
Résumé Biodiversity studies commonly focus on taxonomic diversity measures such as species richness and abundance. However, alternative measures based on ecomorphological traits are also critical for unveiling the processes shaping biodiversity and community assembly along environmental gradients. Our study presents the first analysis of habitat-trait-community structure in a Balkan biodiversity hotspot (Louros river, NW Greece), through the investigation of the relationships among freshwater fish assemblages' composition, morphological traits and habitat features. In order to provide a hierarchical classification of species' priority to protection measures, we highlight the most ecomorphologically distinct species using originality analysis. Our results suggest that the longitudinal changes of habitat variables (water temperature, depth, substrate, altitude) drive the local fish assemblages' structure highlighting the upstream-downstream gradient. We also present evidence for environmental filtering, establishing fish assemblages according to their ecomorphological traits. The calculation of the seven available indices of ecomorphological originality indicates that Valencia letourneuxi and Cobitis hellenica, which are endemic to Louros and threatened with extinction, exhibited the highest distinctiveness; thus their protection is of great importance. The methodological approach followed and the patterns described herein can contribute further to the application of community ecology theory to conservation, highlighting the need to use ecomorphological traits as a useful 'tool'.
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Langue (up) English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0378-1909 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2379
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