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Auteur Leclerc, C.; Villeger, S.; Marino, C.; Bellard, C. doi  openurl
  Titre Global changes threaten functional and taxonomic diversity of insular species worldwide Type Article scientifique
  Année 2020 Publication Revue Abrégée Divers. Distrib.  
  Volume 26 Numéro 4 Pages 402-414  
  Mots-Clés biodiversity; birds; conservation; dimensions; extinction risk; functional specialization; functional originality; functional richness; islands; mammals; redundancy; species traits; trait; vulnerability  
  Résumé Aim The assessment of biodiversity patterns under global changes is currently biased towards taxonomic diversity, thus overlooking the ecological and functional aspects of species. Here, we characterized both taxonomic and functional diversity of insular biodiversity threatened by multiple threats. Location Worldwide islands (n = 4,348). Methods We analysed the relative importance of eleven major threats, including biological invasions or climate change, on 2,756 insular endemic mammals and birds. Species were functionally described using five ecological traits related to diet, habitat and body mass. We computed complementary taxonomic and functional diversity indices (richness, specialization, originality and vulnerability) of species pools affected by each threatening process to investigate relationships between diversity dimensions and threats. We also determined whether species-specific traits are associated with specific threats. Results On average, 8% of insular endemic species at risk of extinction are impacted by threats, while 20% of their functional richness is affected. However, a marked disparity in functional richness values associated with each threat can be highlighted. In particular, cultivation and wildlife exploitation are the greatest threats to insular endemic species. Moreover, each threat may contribute to the loss of at least 10% of functional diversity, because it affects threatened species that support unique and extreme functions. Finally, we found complex patterns of species-specific traits associated with particular threats that is not explain by the threatening processes (directly affecting survival or modifying habitat). For instance, cultivation threatens very large mammals, while urbanization threatens very small mammals. Main conclusions These findings reinforce the importance of exploring the vulnerability of biodiversity facets in the face of multiple threats. Anthropogenic pressures may result in a loss of unique functions within insular ecosystems, which provides important insights into the understanding of threatening processes at a global scale.  
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  ISSN 1366-9516 ISBN Médium  
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  Notes WOS:000511022100001 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2738  
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Auteur McLean, M.; Auber, A.; Graham, N.A.J.; Houk, P.; Villeger, S.; Violle, C.; Thuiller, W.; Wilson, S.K.; Mouillot, D. doi  openurl
  Titre Trait structure and redundancy determine sensitivity to disturbance in marine fish communities Type Article scientifique
  Année 2019 Publication Revue Abrégée Glob. Change Biol.  
  Volume 25 Numéro 10 Pages 3424-3437  
  Mots-Clés biodiversity; climate change; climate-change; coral reefs; coral-reef fish; diversity stability; ecological traits; ecosystem functioning; ecosystem productivity; egg buoyancy; English Channel; functional diversity; functional redundancy; north-sea; regime shifts; response diversity; vulnerability  
  Résumé Trait diversity is believed to influence ecosystem dynamics through links between organismal traits and ecosystem processes. Theory predicts that key traits and high trait redundancy-large species richness and abundance supporting the same traits-can buffer communities against environmental disturbances. While experiments and data from simple ecological systems lend support, large-scale evidence from diverse, natural systems under major disturbance is lacking. Here, using long-term data from both temperate (English Channel) and tropical (Seychelles Islands) fishes, we show that sensitivity to disturbance depends on communities' initial trait structure and initial trait redundancy. In both ecosystems, we found that increasing dominance by climatically vulnerable traits (e.g., small, fast-growing pelagics/corallivores) rendered fish communities more sensitive to environmental change, while communities with higher trait redundancy were more resistant. To our knowledge, this is the first study demonstrating the influence of trait structure and redundancy on community sensitivity over large temporal and spatial scales in natural systems. Our results exemplify a consistent link between biological structure and community sensitivity that may be transferable across ecosystems and taxa and could help anticipate future disturbance impacts on biodiversity and ecosystem functioning.  
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  ISSN 1354-1013 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2652  
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Auteur Carvalho, P.G.; Jupiter, S.D.; Januchowski-Hartley, F.A.; Goetze, J.; Claudet, J.; Weeks, R.; Humphries, A.; White, C. doi  openurl
  Titre Optimized fishing through periodically harvested closures Type Article scientifique
  Année 2019 Publication Revue Abrégée J. Appl. Ecol.  
  Volume 56 Numéro 8 Pages 1927-1936  
  Mots-Clés bioeconomic model; conservation; coral-reef fishes; fish behaviour; fisheries management; management; marine protected areas; marine reserves; new-zealand; outcomes; periodically harvested closures; population dynamics; vulnerability; yield  
  Résumé Periodically harvested closures are a widespread, centuries-old form of fisheries management that protects fish between pulse harvests and can generate high harvest efficiency by reducing fish wariness of fishing gear. However, the ability for periodic closures to also support high fisheries yields and healthy marine ecosystems is uncertain, despite increased promotion of periodic closures for managing fisheries and conserving ecosystems in the Indo-Pacific. We developed a bioeconomic fisheries model that considers changes in fish wariness, based on empirical field research, and quantified the extent to which periodic closures can simultaneously maximize harvest efficiency, fisheries yield and conservation of fish stocks. We found that periodic closures with a harvest schedule represented by closure for one to a few years between a single pulse harvest event can generate equivalent fisheries yield and stock abundance levels and greater harvest efficiency than achievable under conventional fisheries management with or without a permanent closure. Optimality of periodic closures at maximizing the triple objective of high harvest efficiency, high fisheries yield, and high stock abundance was robust to fish life history traits and to all but extreme levels of overfishing. With moderate overfishing, there emerged a trade-off between periodic closures that maximized harvest efficiency and no-take permanent closures that maximized yield; however, the gain in harvest efficiency outweighed the loss in yield for periodic closures when compared with permanent closures. Only with extreme overfishing, where fishing under nonspatial management would reduce the stock to <= 18% of its unfished level, was the harvest efficiency benefit too small for periodic closures to best meet the triple objective compared with permanent closures. Synthesis and applications. We show that periodically harvested closures can, in most cases, simultaneously maximize harvest efficiency, fisheries yield, and fish stock conservation beyond that achievable by no-take permanent closures or nonspatial management. Our results also provide design guidance, indicating that short closure periods between pulse harvest events are most appropriate for well-managed fisheries or areas with large periodic closures, whereas longer closure periods are more appropriate for small periodic closure areas and overfished systems.  
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  ISSN 0021-8901 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2619  
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Auteur Su, G.; Villeger, S.; Brosse, S. doi  openurl
  Titre Morphological diversity of freshwater fishes differs between realms, but morphologically extreme species are widespread Type Article scientifique
  Année 2019 Publication Revue Abrégée Glob. Ecol. Biogeogr.  
  Volume 28 Numéro 2 Pages 211-221  
  Mots-Clés diet; ecology; patterns; vulnerability; richness; freshwater fish; functional diversity; extinction risk; traits; biogeographical realms; functional redundancy; functional vulnerability; mismatch; morphological traits; morphologically extreme species; rivers  
  Résumé Aim The aim was to analyse the morphological diversity of the world freshwater fish fauna. We tested to which extent the distributions of morphological traits are supported by extreme morphologies and how those extreme morphologies are distributed among realms and affect the functional vulnerability. We also analysed the contribution of between- and within-order morphological variability to the morphological differences between realms. Major taxa studied Freshwater fish. Location Global. Time period 1960s-2010s. Methods We used a global database of freshwater fishes from the six realms. Ten morphological traits were measured on 9,150 species, that is, 75% of the ca. 13,000 freshwater fish species. A principal components analysis was conducted to combine the 10 traits into a multidimensional space. We used Kolmogorov-Smirnov tests to compare the difference in morphological diversity between the six realms and between and within the major fish orders. We then identified the morphologically extreme species and quantified their contributions to the morphological range to assess the functional vulnerability and redundancy of fish faunas in the six biogeographical realms for freshwater ecosystems. Results We report a strong morphological variability among freshwater fishes of the world, with significant morphological differences among realm fish faunas, caused by an interplay between taxonomic composition of the realm faunas and morphological differences within orders among the realms. Morphologically extreme species accounted for a large percentage of the filling of the global morphological space and are distributed throughout the world. Main conclusions Fish morphological diversity is largely supported by a few species with extreme trait combinations, indicating that functional vulnerability exists throughout the world. Our results suggest that more attention should be paid to these morphologically extreme species and that they should be protected to ensure the sustainability of functions they support.  
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  ISSN 1466-822x ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 2528  
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Auteur Olivier, D.; Loiseau, N.; Petatan-Ramirez, D.; Trujillo Milian, O.; Suarez-Castillo, A.N.; Torre, J.; Munguia-Vega, A.; Reyes-Bonilla, H. doi  openurl
  Titre Functional-biogeography of the reef fishes of the islands of the Gulf of California: Integrating functional divergence into marine conservation Type Article scientifique
  Année 2018 Publication Revue Abrégée Glob. Ecol. Conserv.  
  Volume 16 Numéro Pages e00506  
  Mots-Clés biodiversity; communities; diversity; species richness; Biodiversity; vulnerability; framework; ecosystem function; redundancy; Functional traits; Biologically important area; Marine protected area; regionalization; rocky reefs; Sea of Cortez; Tropical Eastern Pacific  
  Résumé The Gulf of California (GC) is a semi-closed sea in the Tropical Eastern Pacific and is recognised as a highly diverse marine ecosystem. Despite this status, this region is still poorly studied in comparison to other marine hotspots. To start filling this gap, we attempt to provide a global overview of reef-fish diversity around the numerous islands of the region. We evaluated species richness, the abundance and biomass, and the functional diversity of the fish assemblages for the major islands of the GC. We first highlight that the southwestern part of the central GC is the hotspot of reef-fishes diversity within the GC, in terms of species richness, functional diversity, and fish abundance. We then found out an important functional divergence between fish assemblages of northern and southern regions. The fish biomass of each region is dominated by different species, characterised by different ecological traits (the opposite of functional convergence). This functional divergence may be explained by an important oceanographic heterogeneity along the latitudinal axis of the GC. The northern part shows larger climate fluctuations while the southern part is more tropical and climatically stable. Such functional divergence is a biodiversity facet to take into account when determining the sites to focus conservation action. In the GC, this criterion allows the importance of some sites to be highlighted to preserve the legacy of the reef-fishes, despite their lower diversity levels. (C) 2018 The Authors. Published by Elsevier B.V.  
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