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Auteur Manna, L.R.; Villeger, S.; Rezende, C.F.; Mazzoni, R. doi  openurl
  Titre High intraspecific variability in morphology and diet in tropical stream fish communities Type Article scientifique
  Année 2019 Publication Revue Abrégée (up) Ecol. Freshw. Fish  
  Volume 28 Numéro 1 Pages 41-52  
  Mots-Clés approach reveals; assemblages; body-size; community ecology; competition; ecology; functional diversity; functional traits; habitat use; originality; plasticity; rainforest stream; savannah stream; specialisation; specialization; traits  
  Résumé Functional diversity of fish communities has been measured according to (a) interspecific variability, assuming that intraspecific variability is negligible, or (b) morphological differences, as good descriptors of complex functions, such as diet. These two assumptions have been scarcely tested on the individual level, especially in species-rich tropical ecosystems. Here, we adapted intraspecific specialisation (ISpe) and intraspecific originality indices (IOri) to assess complementary components of intraspecific variability. Next, we applied these indices to evaluate the intra- and interspecific variability of morphological and diet traits in two contrasting Brazilian stream-dwelling fish assemblages (rainforest and savannah). We also compared correlations between morphology and diet at the individual and species level to test whether accounting for intraspecific variability increases the predictability of diet due to morphological differences. Significant contributions of intraspecific variability to differences between fish were revealed for morphology and diet. Intraspecific variability in the diet was higher than that in morphology in both assemblages. The ISpe was positively correlated to IOri in the diet of both ecosystems. The morphological-dietary relationships were significant but weak at both individual and species levels. Our findings highlight the importance of measuring individual variability and accounting for complementary components of the intraspecific variability (ISpe and IOri). Importantly, we showed that the variability in morphology does not predict diet variability at both intra- and interspecific levels. Thus, high intraspecific variability in morphology and diet challenges the use of functional traits measured at the species level to describe the functional diversity of different fish assemblages.  
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  ISSN 0906-6691 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2472  
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Auteur Courbin, N.; Besnard, A.; Peron, C.; Saraux, C.; Fort, J.; Perret, S.; Tornos, J.; Gremillet, D. doi  openurl
  Titre Short-term prey field lability constrains individual specialisation in resource selection and foraging site fidelity in a marine predator Type Article scientifique
  Année 2018 Publication Revue Abrégée (up) Ecol. Lett.  
  Volume 21 Numéro 7 Pages 1043-1054  
  Mots-Clés behavior; Behavioural consistency; Calonectris diomedea; diet; ecology; foraging site fidelity; gannets; habitat selection; mediterranean sea; models; movement; resource selection; Scopoli's shearwater; seabirds; strategies; temporal resource dynamic; Western Mediterranean  
  Résumé Spatio-temporally stable prey distributions coupled with individual foraging site fidelity are predicted to favour individual resource specialisation. Conversely, predators coping with dynamic prey distributions should diversify their individual diet and/or shift foraging areas to increase net intake. We studied individual specialisation in Scopoli's shearwaters (Calonectris diomedea) from the highly dynamic Western Mediterranean, using daily prey distributions together with resource selection, site fidelity and trophic-level analyses. As hypothesised, we found dietary diversification, low foraging site fidelity and almost no individual specialisation in resource selection. Crucially, shearwaters switched daily foraging tactics, selecting areas with contrasting prey of varying trophic levels. Overall, information use and plastic resource selection of individuals with reduced short-term foraging site fidelity allow predators to overcome prey field lability. Our study is an essential step towards a better understanding of individual responses to enhanced environmental stochasticity driven by global changes, and of pathways favouring population persistence.  
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  ISSN 1461-023x ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2380  
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Auteur van Gils, J.A.; van der Geest, M.; Jansen, E.J.; Govers, L.L.; de Fouw, J.; Piersma, T. url  openurl
  Titre Trophic cascade induced by molluscivore predator alters pore-water biogeochemistry via competitive release of prey Type Article scientifique
  Année 2012 Publication Revue Abrégée (up) Ecology  
  Volume 93 Numéro Pages 1143-1152  
  Mots-Clés Banc d'Arguin, Mauritania bivalves (Dosinia isocardia, Loripes lucinalis) facilitation growth rate hydrogen sulfide interspecific competition predation predator-exclosure experiment Red Knot, Calidris canutus canutus seagrass beds top-down effect toxicity knots calidris-canutus food webs ecological consequences habitat communities coexistence depletion bivalvia sulfide diet  
  Résumé Effects of predation may cascade down the food web. By alleviating interspecific competition among prey, predators may promote biodiversity, but the precise mechanisms of how predators alter competition have remained elusive. Here we report on a predator-exclosure experiment carried out in a tropical intertidal ecosystem, providing evidence for a three-level trophic cascade induced by predation by molluscivore Red Knots (Calidris canutus) that affects pore water biogeochemistry. In the exclosures the knots' favorite prey (Dosinia isocardia) became dominant and reduced the individual growth rate in an alternative prey (Loripes lucinalis). Dosinia, a suspension feeder, consumes suspended particulate organic matter (POM), whereas Loripes is a facultative mixotroph, partly living on metabolites produced by sulfur-oxidizing chemoautotrophic bacteria, but also consuming suspended POM. Reduced sulfide concentrations in the exclosures suggest that, without predation on Dosinia, stronger competition for suspended POM forces Loripes to rely on energy produced by endosymbiotic bacteria, thus leading to an enhanced uptake of sulfide from the surrounding pore water. As sulfide is toxic to most organisms, this competition-induced diet shift by Loripes may detoxify the environment, which in turn may facilitate other species. The inference that predators affect the toxicity of their environment via a multi-level trophic cascade is novel, but we believe it may be a general phenomenon in detritus-based ecosystems.  
  Adresse [van Gils, Jan A.; van der Geest, Matthijs; Jansen, Erik J.; de Fouw, Jimmy; Piersma, Theunis] NIOZ Royal Netherlands Inst Sea Res, Dept Marine Ecol, NL-1790 AB Den Burg, Texel, Netherlands. [Govers, Laura L.] Radboud Univ Nijmegen, Fac Sci, Inst Water & Wetland Res, Dept Environm Sci, NL-6500 GL Nijmegen, Netherlands. [Piersma, Theunis] Univ Groningen, CEES, Anim Ecol Grp, NL-9700 CC Groningen, Netherlands. van der Geest, M (reprint author), NIOZ Royal Netherlands Inst Sea Res, Dept Marine Ecol, POB 59, NL-1790 AB Den Burg, Texel, Netherlands matthijs.van.der.geest@nioz.nl  
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  ISSN 0012-9658 ISBN Médium  
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  Notes ISI Document Delivery No.: 946QK Times Cited: 0 Cited Reference Count: 60 van Gils, Jan A. van der Geest, Matthijs Jansen, Erik J. Govers, Laura L. de Fouw, Jimmy Piersma, Theunis Nwo-wotro[w.01.65.221.00] We are grateful to the staff of the Parc National du Banc d'Arguin for allowing us to work and stay in the area under their management. In 2009 we had the pleasant company of Tjisse van der Heide, Han Olff, and Erik Rosendaal, and in 2010 Brecht De Meulenaer joined us. Erik Rosendaal processed fecal samples, and Jeroen Onrust determined shell dry masses. Dick Visser redrew the figures. This work was funded by the NWO-WOTRO Integrated Programme grant W.01.65.221.00 awarded to T. Piersma. Ecological soc amer Washington Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ 722 collection 1384  
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Auteur Mazel, F.; Renaud, J.; Guilhaumon, F.; Mouillot, D.; Gravel, D.; Thuiller, W. url  doi
openurl 
  Titre Mammalian phylogenetic diversity-area relationships at a continental scale Type Article scientifique
  Année 2015 Publication Revue Abrégée (up) Ecology  
  Volume 96 Numéro 10 Pages 2814-2822  
  Mots-Clés Biodiversity; Biogeography; community ecology; conservation; conservation biogeography; habitat loss; habitat loss; null models; overestimate extinction rates; patterns; phylogenetic diversity; richness; species-area; species-area relationship; statistics; strict nested design  
  Résumé In analogy to the species-area relationship (SAR), one of the few laws in ecology, the phylogenetic diversity-area relationship (PDAR) describes the tendency of phylogenetic diversity (PD) to increase with area. Although investigating PDAR has the potential to unravel the underlying processes shaping assemblages across spatial scales and to predict PD loss through habitat reduction, it has been little investigated so far. Focusing on PD has noticeable advantages compared to species richness (SR), since PD also gives insights on processes such as speciation/extinction, assembly rules and ecosystem functioning. Here we investigate the universality and pervasiveness of the PDAR at continental scale using terrestrial mammals as study case. We define the relative robustness of PD (compared to SR) to habitat loss as the area between the standardized PDAR and standardized SAR (i.e., standardized by the diversity of the largest spatial window) divided by the area under the standardized SAR only. This metric quantifies the relative increase of PD robustness compared to SR robustness. We show that PD robustness is higher than SR robustness but that it varies among continents. We further use a null model approach to disentangle the relative effect of phylogenetic tree shape and nonrandom spatial distribution of evolutionary history on the PDAR. We find that, for most spatial scales and for all continents except Eurasia, PDARs are not different from expected by a model using only the observed SAR and the shape of the phylogenetic tree at continental scale. Interestingly, we detect a strong phylogenetic structure of the Eurasian PDAR that can be predicted by a model that specifically account for a finer biogeographical delineation of this continent. In conclusion, the relative robustness of PD to habitat loss compared to species richness is determined by the phylogenetic tree shape but also depends on the spatial structure of PD.  
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  ISSN 0012-9658 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1423  
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Auteur Christensen, V.; Coll, M.; Steenbeek, J.; Buszowski, J.; Chagaris, D.; Walters, C.J. url  doi
openurl 
  Titre Representing Variable Habitat Quality in a Spatial Food Web Model Type Article scientifique
  Année 2014 Publication Revue Abrégée (up) Ecosystems  
  Volume 17 Numéro 8 Pages 1397-1412  
  Mots-Clés Ecology; Ecopath; ecospace; Environmental Management; food web model; foraging capacity model; Geoecology/Natural Processes; habitat modeling; Hydrology/Water Resources; Plant Sciences; sampling; simulation model; species distribution model; Zoology  
  Résumé Why are marine species where they are? The scientific community is faced with an urgent need to understand aquatic ecosystem dynamics in the context of global change. This requires development of scientific tools with the capability to predict how biodiversity, natural resources, and ecosystem services will change in response to stressors such as climate change and further expansion of fishing. Species distribution models and ecosystem models are two methodologies that are being developed to further this understanding. To date, these methodologies offer limited capabilities to work jointly to produce integrated assessments that take both food web dynamics and spatial-temporal environmental variability into account. We here present a new habitat capacity model as an implementation of the spatial-temporal model Ecospace of the Ecopath with Ecosim approach. The new model offers the ability to drive foraging capacity of species from the cumulative impacts of multiple physical, oceanographic, and environmental factors such as depth, bottom type, temperature, salinity, oxygen concentrations, and so on. We use a simulation modeling procedure to evaluate sampling characteristics of the new habitat capacity model. This development bridges the gap between envelope environmental models and classic ecosystem food web models, progressing toward the ability to predict changes in marine ecosystems under scenarios of global change and explicitly taking food web direct and indirect interactions into account.  
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  ISSN 1432-9840, 1435-0629 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1196  
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