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Auteur Canard, E.F.; Mouquet, N.; Mouillot, D.; Stanko, M.; Miklisova, D.; Gravel, D. url  doi
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  Titre Empirical Evaluation of Neutral Interactions in Host-Parasite Networks Type Article scientifique
  Année 2014 Publication Revue Abrégée American Naturalist  
  Volume 183 Numéro 4 Pages 468-479  
  Mots-Clés abundance; animal mutualistic networks; community; dissimilarity; effort; food-web structure; geographical variation; host-parasite network; network structure; neutrality; null model; phylogenetic signal; reconciling niche; sampling; scale-dependence; species abundance distribution  
  Résumé While niche-based processes have been invoked extensively to explain the structure of interaction networks, recent studies propose that neutrality could also be of great importance. Under the neutral hypothesis, network structure would simply emerge from random encounters between individuals and thus would be directly linked to species abundance. We investigated the impact of species abundance distributions on qualitative and quantitative metrics of 113 host-parasite networks. We analyzed the concordance between neutral expectations and empirical observations at interaction, species, and network levels. We found that species abundance accurately predicts network metrics at all levels. Despite host-parasite systems being constrained by physiology and immunology, our results suggest that neutrality could also explain, at least partially, their structure. We hypothesize that trait matching would determine potential interactions between species, while abundance would determine their realization.  
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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 0003-0147 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 573  
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Auteur Coll, M.; Steenbeek, J.; Sole, J.; Palomera, I.; Christensen, V. doi  openurl
  Titre Modelling the cumulative spatial-temporal effects of environmental drivers and fishing in a NW Mediterranean marine ecosystem Type Article scientifique
  Année 2016 Publication Revue Abrégée Ecol. Model.  
  Volume 331 Numéro Pages 100-114  
  Mots-Clés acoustic estimation; anchovy engraulis-encrasicolus; climate-change; Cumulative effects; Ecopath with Ecosim; environment; european hake; exploited ecosystems; fishing; food-web model; food webs; hake merluccius-merluccius; protected areas; south catalan sea; trawling disturbance  
  Résumé To realistically predict spatial-temporal dynamics of species in marine ecosystems it is essential to consider environmental conditions in conjunction with human activities and food web dynamics. In this study, we used Ecospace, the spatial-temporal dynamic module of Ecopath with Ecosim (EwE) food web model, to drive a spatially explicit marine food web model representing the Southern Catalan Sea (NW Mediterranean) with various environmental drivers and with fishing. We then evaluated the individual and joint effects of environmental conditions and fishing in various compartments of the food web. First we used a previously developed EwE model fitted to time series of data from 1978 to 2010 as a baseline configuration. The model included 40 functional groups and four fishing fleets. We first ran the original Ecospace spatial-temporal dynamic model using the original habitat configuration, in addition to fishing, and we predicted species distributions and abundances. Afterwards, we ran the new habitat foraging capacity model using the most important environmental drivers linked with the Ebro River delta dynamics (salinity, temperature, and primary production), in addition to depth, substrate and fishing, and we compared results with those from the original implementation of Ecospace. Three commercial species, European hake (Merluccius merluccius), anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus), were used to analyse results. Species distributions more closely matched the empirical information available from the study area when using the new habitat capacity model. Results suggested that the historical impacts of fishing and environmental conditions on the biomass and distributions of hake, anchovy and sardine were not additive, but mainly cumulative with a synergistic or antagonistic effect. Fishing had the highest impact on spatial modelling results while the spatial distribution of primary producers and depth followed in importance. This study contributes to the development of more reliable predictions of regional change in marine ecosystems of the Mediterranean Sea. (C) 2016 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 0304-3800 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1643  
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Auteur Deininger, A.; Faithfull, C.L.; Lange, K.; Bayer, T.; Vidussi, F.; Liess, A. doi  openurl
  Titre Simulated terrestrial runoff triggered a phytoplankton succession and changed seston stoichiometry in coastal lagoon mesocosms Type Article scientifique
  Année 2016 Publication Revue Abrégée Mar. Environ. Res.  
  Volume 119 Numéro Pages 40-50  
  Mots-Clés climate change; communities; community composition; Diatoms; dynamics; ecosystems; events; food-web; growth; Mediterranean; Mesocosm; Phytoplankton; plankton; productivity; river flash-flood; schelde; soil; Stoichiometry; Thau lagoon  
  Résumé Climate change scenarios predict intensified terrestrial storm runoff, providing coastal ecosystems with large nutrient pulses and increased turbidity, with unknown consequences for the phytoplankton community. We conducted a 12-day mesocosm experiment in the Mediterranean Thau Lagoon (France), adding soil (simulated runoff) and fish (different food webs) in a 2 x 2 full factorial design and monitored phytoplankton composition, shade adaptation and stoichiometry. Diatoms (Chaetoceros) increased fourfold immediately after soil addition, prymnesiophytes and dinoflagellates peaked after six- and 12 days, respectively. Soil induced no phytoplanlcton shade adaptation. Fish reduced the positive soil effect on dinoflagellates (Scripsiella, Glenodinium), and diatom abundance in general. Phytoplankton community composition drove seston stoichiometry. In conclusion, pulsed terrestrial runoff can cause rapid, low quality (high carbon: nutrient) diatom blooms. However, bloom duration may be short and reduced in magnitude by fish. Thus, climate change may shift shallow coastal ecosystems towards famine or feast dynamics. (C) 2016 Elsevier Ltd. 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 0141-1136 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2063  
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Auteur Galiana, N.; Lurgi, M.; Claramunt-Lopez, B.; Fortin, M.-J.; Leroux, S.; Cazelles, K.; Gravel, D.; Montoya, J.M. doi  openurl
  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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  Volume de collection Numéro de collection Edition  
  ISSN 2397-334x ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2339  
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Auteur Meddeb, M.; Grami, B.; Chaalali, A.; Haraldsson, M.; Niquil, N.; Pringault, O.; Sakka Hlaili, A. url  doi
openurl 
  Titre Plankton food-web functioning in anthropogenically impacted coastal waters (SW Mediterranean Sea): an ecological network analysis Type Article scientifique
  Année 2018 Publication Revue Abrégée Progress in Oceanography  
  Volume Numéro Pages  
  Mots-Clés Ecological Network Analysis; Food-web modelling; Mediterranean coastal waters; plankton ecology  
  Résumé The study is the first attempt to (i) model spring food webs in three SW Mediterranean ecosystems which are under different anthropogenic pressures and (ii) to project the consequence of this stress on their function. Linear inverse models were built using the Monte Carlo method coupled with Markov Chains to characterize the food-web status of the Lagoon, the Channel (inshore waters under high eutrophication and chemical contamination) and the Bay of Bizerte (offshore waters under less anthropogenic pressure). Ecological network analysis was used for the description of structural and functional properties of each food web and for inter-ecosystem comparisons. Our results showed that more carbon was produced by phytoplankton in the inshore waters (966–1234 mg C m-2 d-1) compared to the Bay (727 mg C m-2 d-1). The total ecosystem carbon inputs into the three food webs was supported by high primary production, which was mainly due to >10µm algae. However, the three carbon pathways were characterized by low detritivory and a high herbivory which was mainly assigned to protozooplankton. This latter was efficient in channelling biogenic carbon. In the Lagoon and the Channel, foods webs acted almost as a multivorous structure with a tendency towards herbivorous one, whereas in the Bay the herbivorous pathway was more dominant. Ecological indices revealed that the Lagoon and the Channel food webs/systems had high total system throughput and thus were more active than the Bay. The Bay food web, which had a high relative ascendency value, was more organized and specialized. This inter–ecosystem difference could be due to the varying levels of anthropogenic impact among sites. Indeed, the low value of Finn’s cycling index indicated that the three systems are disturbed, but the Lagoon and the Channel, with low average path lengths, appeared to be more stressed, as both sites have undergone higher chemical pollution and nutrient loading. This study shows that ecosystem models combined with ecological indices provide a powerful approach to detect change in environmental status and anthropogenic impacts.  
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  ISSN 0079-6611 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2292  
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