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Auteur Ben Gharbia, H.; Yahia, O.K.-D.; Cecchi, P.; Masseret, E.; Amzil, Z.; Herve, F.; Rovillon, G.; Nouri, H.; M’Rabet, C.; Couet, D.; Triki, H.Z.; Laabir, M.
Titre (up) New insights on the species-specific allelopathic interactions between macrophytes and marine HAB dinoflagellates Type Article scientifique
Année 2017 Publication Revue Abrégée Plos One
Volume 12 Numéro 11 Pages e0187963
Mots-Clés Dinoflagellates; Lagoons; Leaves; marine ecosystems; Phenols; Photosynthesis; Phytoplankton; Toxins
Résumé Macrophytes are known to release allelochemicals that have the ability to inhibit the proliferation of their competitors. Here, we investigated the effects of the fresh leaves of two magnoliophytes (Zostera noltei and Cymodocea nodosa) and thalli of the macroalgae Ulva rigida on three HAB-forming benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima, and Coolia monotis). The effects of C. nodosa and U. rigida were also tested against the neurotoxic planktonic dinoflagellate Alexandrium pacificum Litaker sp. nov (former Alexandrium catenella). Co-culture experiments were conducted under controlled laboratory conditions and potential allelopathic effects of the macrophytes on the growth, photosynthesis and toxin production of the targeted dinoflagellates were evaluated. Results showed that U. rigida had the strongest algicidal effect and that the planktonic A. pacificum was the most vulnerable species. Benthic dinoflagellates seemed more tolerant to potential allelochemicals produced by macrophytes. Depending on the dinoflagellate/macrophyte pairs and the weight of leaves/thalli tested, the studied physiological processes were moderately to heavily altered. Our results suggest that the allelopathic activity of the macrophytes could influence the development of HAB species.
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ISSN 1932-6203 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2242
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Auteur Henckel, L.; Meynard, C.N.; Devictor, V.; Mouquet, N.; Bretagnolle, V.
Titre (up) On the relative importance of space and environment in farmland bird community assembly Type Article scientifique
Année 2019 Publication Revue Abrégée PLoS One
Volume 14 Numéro 3 Pages e0213360
Mots-Clés beta diversity; dispersal; ecology; habitat; landscape; metacommunity structure; model; patterns; scale; skylarks alauda arvensis
Résumé The relative contribution of ecological processes in shaping metacommunity dynamics in heavily managed landscapes is still unclear. Here we used two complementary approaches to disentangle the role of environment and spatial effect in farmland bird community assembly in an intensive agro-ecosystem. We hypothesized that the interaction between habitat patches and dispersal should play a major role in such unstable and unpredictable environments. First, we used a metacommunity patterns analysis to characterize species co-occurrences and identify the main drivers of community assembly; secondly, variation partitioning was used to disentangle environmental and geographical factors (such as dispersal limitation) on community structure and composition. We used high spatial resolution data on bird community structure and composition distributed among 260 plots in an agricultural landscape. Species were partitioned into functional classes, and point count stations were classified according to landscape characteristics before applying metacommunity and partitioning analyses within each. Overall we could explain around 20% of the variance in species composition in our system, revealing that stochasticity remains very important at this scale. However, this proportion varies depending on the scale of analysis, and reveals potentially important contributions of environmental filtering and dispersal. These conclusions are further reinforced when the analysis was deconstructed by bird functional classes or by landscape habitat classes, underlining trait-related filters, thus reinforcing the idea that wooded areas in these agroecosystems may represent important sources for a specific group of bird species. Our analysis shows that deconstructing the species assemblages into separate functional groups and types of landscapes, along with a combination of analysis strategies, can help in understanding the mechanisms driving community assembly.
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Langue English Langue du Résumé Titre Original
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ISSN 1932-6203 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2548
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Auteur Strauß, A.; Guilhaumon, F.; Randrianiaina, R.D.; Valero, K.C.W.; Vences, M.; Glos, J.
Titre (up) Opposing Patterns of Seasonal Change in Functional and Phylogenetic Diversity of Tadpole Assemblages Type Article scientifique
Année 2016 Publication Revue Abrégée Plos One
Volume 11 Numéro 3 Pages e0151744
Mots-Clés Animal phylogenetics; Ecological metrics; Frogs; Phylogenetics; Polynomials; Seasons; species diversity; Tadpoles
Résumé Assemblages that are exposed to recurring temporal environmental changes can show changes in their ecological properties. These can be expressed by differences in diversity and assembly rules. Both can be identified using two measures of diversity: functional (FD) and phylogenetic diversity (PD). Frog communities are understudied in this regard, especially during the tadpole life stage. We utilised tadpole assemblages from Madagascan rainforest streams to test predictions of seasonal changes on diversity and assemblage composition and on diversity measures. From the warm-wet to the cool-dry season, species richness (SR) of tadpole assemblages decreased. Also FD and PD decreased, but FD less and PD more than expected by chance. During the dry season, tadpole assemblages were characterised by functional redundancy (among assemblages—with increasing SR), high FD (compared to a null model), and low PD (phylogenetic clustering; compared to a null model). Although mutually contradictory at first glance, these results indicate competition as tadpole community assembly driving force. This is true during the limiting cool-dry season but not during the more suitable warm-wet season. We thereby show that assembly rules can strongly depend on season, that comparing FD and PD can reveal such forces, that FD and PD are not interchangeable, and that conclusions on assembly rules based on FD alone are critical.
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1562
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Auteur Van Colen, C.; Rossi, F.; Montserrat, F.; Andersson, M.G.I.; Gribsholt, B.; Herman, P.M.J.; Degraer, S.; Vincx, M.; Ysebaert, T.; Middelburg, J.J.
Titre (up) Organism-Sediment Interactions Govern Post-Hypoxia Recovery of Ecosystem Functioning Type Article scientifique
Année 2012 Publication Revue Abrégée Plos One
Volume 7 Numéro 11 Pages
Mots-Clés
Résumé <p>Hypoxia represents one of the major causes of biodiversity and ecosystem functioning loss for coastal waters. Since eutrophication-induced hypoxic events are becoming increasingly frequent and intense, understanding the response of ecosystems to hypoxia is of primary importance to understand and predict the stability of ecosystem functioning. Such ecological stability may greatly depend on the recovery patterns of communities and the return time of the system properties associated to these patterns. Here, we have examined how the reassembly of a benthic community contributed to the recovery of ecosystem functioning following experimentally-induced hypoxia in a tidal flat. We demonstrate that organism-sediment interactions that depend on organism size and relate to mobility traits and sediment reworking capacities are generally more important than recovering species richness to set the return time of the measured sediment processes and properties. Specifically, increasing macrofauna bioturbation potential during community reassembly significantly contributed to the recovery of sediment processes and properties such as denitrification, bedload sediment transport, primary production and deep pore water ammonium concentration. Such bioturbation potential was due to the replacement of the small-sized organisms that recolonised at early stages by large-sized bioturbating organisms, which had a disproportionately stronger influence on sediment. This study suggests that the complete recovery of organism-sediment interactions is a necessary condition for ecosystem functioning recovery, and that such process requires long periods after disturbance due to the slow growth of juveniles into adult stages involved in these interactions. Consequently, repeated episodes of disturbance at intervals smaller than the time needed for the system to fully recover organism-sediment interactions may greatly impair the resilience of ecosystem functioning.</p>
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 753
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Auteur Bertrand, A.; Chaigneau, A.; Peraltilla, S.; Ledesma, J.; Graco, M.; Monetti, F.; Chavez, F.P.
Titre (up) Oxygen: A Fundamental Property Regulating Pelagic Ecosystem Structure in the Coastal Southeastern Tropical Pacific Type Article scientifique
Année 2011 Publication Revue Abrégée PLoS ONE
Volume 6 Numéro 12 Pages
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Editeur Lieu de Publication Éditeur Slomp, C.P.
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Numéro d'Appel LL @ pixluser @ collection 119
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