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Auteur Rossi, F.; Gribsholt, B.; Gazeau, F.; Di Santo, V.; Middelburg, J.J. url  doi
openurl 
  Titre Complex Effects of Ecosystem Engineer Loss on Benthic Ecosystem Response to Detrital Macroalgae Type Article scientifique
  Année 2013 Publication (up) Revue Abrégée PLoS One  
  Volume 8 Numéro 6 Pages  
  Mots-Clés Community structure; assemblages; biodiversity; carbon flow; diversity; experiment; field; impact; marine-sediments; species richness; stability  
  Résumé Ecosystem engineers change abiotic conditions, community assembly and ecosystem functioning. Consequently, their loss may modify thresholds of ecosystem response to disturbance and undermine ecosystem stability. This study investigates how loss of the bioturbating lugworm Arenicola marina modifies the response to macroalgal detrital enrichment of sediment biogeochemical properties, microphytobenthos and macrofauna assemblages. A field manipulative experiment was done on an intertidal sandflat (Oosterschelde estuary, The Netherlands). Lugworms were deliberately excluded from 1x m sediment plots and different amounts of detrital Ulva (0, 200 or 600 g Wet Weight) were added twice. Sediment biogeochemistry changes were evaluated through benthic respiration, sediment organic carbon content and porewater inorganic carbon as well as detrital macroalgae remaining in the sediment one month after enrichment. Microalgal biomass and macrofauna composition were measured at the same time. Macroalgal carbon mineralization and transfer to the benthic consumers were also investigated during decomposition at low enrichment level (200 g WW). The interaction between lugworm exclusion and detrital enrichment did not modify sediment organic carbon or benthic respiration. Weak but significant changes were instead found for porewater inorganic carbon and microalgal biomass. Lugworm exclusion caused an increase of porewater carbon and a decrease of microalgal biomass, while detrital enrichment drove these values back to values typical of lugworm-dominated sediments. Lugworm exclusion also decreased the amount of macroalgae remaining into the sediment and accelerated detrital carbon mineralization and CO2 release to the water column. Eventually, the interaction between lugworm exclusion and detrital enrichment affected macrofauna abundance and diversity, which collapsed at high level of enrichment only when the lugworms were present. This study reveals that in nature the role of this ecosystem engineer may be variable and sometimes have no or even negative effects on stability, conversely to what it should be expected based on current research knowledge.  
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  Volume de collection Numéro de collection Edition  
  ISSN 1932-6203 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 513  
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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 (up) 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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  Volume de collection Numéro de collection Edition  
  ISSN 1365-2699 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1538  
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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 (up) 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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  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 Colin, N.; Villeger, S.; Wilkes, M.; de Sostoa, A.; Maceda-Veiga, A. doi  openurl
  Titre Functional diversity measures revealed impacts of non-native species and habitat degradation on species-poor freshwater fish assemblages Type Article scientifique
  Année 2018 Publication (up) Revue Abrégée Sci. Total Environ.  
  Volume 625 Numéro Pages 861-871  
  Mots-Clés biodiversity; ecosystems; community; life-history traits; Non-native species; 4th-corner problem; Functional diversity; Fish assemblages; Biomonitoring; ecological quality; flow regime; Human disturbance; mediterranean rivers; Mediterranean rivers; stream; traits-environment relationships  
  Résumé Trail-based ecology has been developed for decades lo infer ecosystem responses to stressors based on the functional structure of communities, yet its value in species-poor systems is largely unknown. Here, we used an extensive clataset in a Spanish region highly prone to non-native fish invasions (15 catchments, N 389 sites) to assess for the first time how species-poor communities respond to large-scale environmental gradients using a taxonomic and functional trait-based approach in riverine fish. We examined total species richness and three functional trait-based indices available when many sites have <= 3 species (specialization, FSpe; onginaliy, FOri and entropy, FEnt). We assessed the responses of these taxonomic and functional indices along gradients of altitude, water pollution, physical habitat degradation and non-native fish biomass. Whilst species richness was relatively sensitive to spatial effects, functional diversity indices were responsive across natural and anthropogenic gradients. All four diversity measures declined with altitude but this decline was modulated by physical habitat degradation (richness, FSpe and FEnt) and the non-native total fish biomass ratio (FSpe and FOri) in ways that varied between indices. Furthermore, FSpe and FOri were significantly correlated with Total Nitrogen. Non-native fish were a major component of the taxonomic and functional structure of fish communities, raising concerns about potential misdiagnosis between invaded and environmentally-degraded river reaches. Such misdiagnosis was evident in a regional fish index widely used in official monitoring programs. We recommend the application of FSpe and FOri to extensive clatasets from monitoring programs in order to generate valuable cross-system information about the impacts of non-native species and habitat degradation, even in species-poor systems. Scoring non-native species apart from habitat degradation in the indices used to determine ecosystem health is essential to develop better management strategies. (C) 2013 Elsevier B.V. All rights reserved.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0048-9697 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2309  
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Auteur Si, X.; Baselga, A.; Leprieur, F.; Song, X.; Ding, P. url  doi
openurl 
  Titre Selective extinction drives taxonomic and functional alpha and beta diversities in island bird assemblages Type Article scientifique
  Année 2016 Publication (up) Revue Abrégée J Anim Ecol  
  Volume 85 Numéro 2 Pages 409-418  
  Mots-Clés Beta diversity; community assembly; dispersal; diversity–area relationship; environmental filtering; functional trait; island biogeography; nestedness; null model; turnover  
  Résumé * Taxonomic diversity considers all species being equally different from each other and thus disregards species’ different ecological functions. Exploring taxonomic and functional aspects of biodiversity simultaneously can better understand the processes of community assembly. * We analysed taxonomic and functional alpha and beta diversities of breeding bird assemblages on land-bridge islands in the Thousand Island Lake, China. Given the high dispersal ability of most birds at this spatial scale (several kilometres), we predicted (i) selective extinction driving alpha and beta diversities after the creation of land-bridge islands of varying area and (ii) low taxonomic and functional beta diversities that were not correlated to spatial distance. * Breeding birds were surveyed on 37 islands annually from 2007 to 2014. We decomposed beta diversity of breeding birds into spatial turnover and nestedness-resultant components, and related taxonomic and functional diversities to island area and isolation using power regression models (for alpha diversity) and multiple regression models on distance matrices (for beta diversity). We then ran simulations to assess the strength of the correlations between taxonomic and functional diversities. * Results revealed that both taxonomic and functional alpha diversities increased with island area. The taxonomic nestedness-resultant and turnover components increased and decreased with difference in area, respectively, but functional counterparts did not. Isolation played a minor role in explaining alpha- and beta-diversity patterns. By partitioning beta diversity, we found low levels of overall taxonomic and functional beta diversities. The functional nestedness-resultant component dominated overall functional beta diversity, whereas taxonomic turnover was the dominant component for taxonomic beta diversity. The simulation showed that functional alpha and beta diversities were significantly correlated with taxonomic diversities, and the observed values of correlations were significantly different from null expectations of random extinction. * Our assessment of island bird assemblages validated the predictions of no distance effects and low beta diversity due to pervasive dispersal events among islands and also suggested that selective extinction drives taxonomic and functional alpha and beta diversities. The contrasting turnover and nestedness-resultant components of taxonomic and functional beta diversities demonstrate the importance of considering the multifaceted nature of biodiversity when examining community assembly.  
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  Éditeur de collection Titre de collection Titre de collection Abrégé  
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  ISSN 1365-2656 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1543  
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