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Auteur Jeanmougin, M.; Leprieur, F.; Lois, G.; Clergeau, P. url  doi
openurl 
  Titre Fine-scale urbanization affects Odonata species diversity in ponds of a megacity (Paris, France) Type Article scientifique
  Année 2014 Publication Revue Abrégée Acta Oecologica-International Journal of Ecology  
  Volume 59 Numéro Pages 26-34  
  Mots-Clés Evenness; Landscape composition; Model averaging; Ponds; Species diversity; Urban ecology; agricultural landscape; comparative biodiversity; conservation; dragonflies odonata; ecology; fresh-water habitat; patterns; richness; selection; urban  
  Résumé Current developments in urban ecology include very few studies focused on pond ecosystems, though ponds are recognized as biodiversity hotspots. Using Odonata as an indicator model, we explored changes in species composition in ponds localized along an urban gradient of a megacity (Paris, France). We then assessed the relative importance of local- and landscape-scale variables in shaping Odonata alpha-diversity patterns using a model-averaging approach. Analyses were performed for adult (A) and adult plus exuviae (AE) census data. At 26 ponds, we recorded 657 adults and 815 exuviae belonging to 17 Odonata species. The results showed that the Odonata species assemblage composition was not determined by pond localization along the urban gradient. Similarly, pond characteristics were found to be similar among urban, suburban and periurban ponds. The analyses of AE census data revealed that fine-scale urbanization (i.e., increased density of buildings surrounding ponds) negatively affects Odonata alpha-diversity. In contrast, pond localization along the urban gradient weakly explained the alpha-diversity patterns. Several local-scale variables, such as the coverage of submerged macrophytes, were found to be significant drivers of Odonata alpha-diversity. Together, these results show that the degree of urbanization around ponds must be considered instead of pond localization along the urban gradient when assessing the potential impacts of urbanization on Odonata species diversity This work also indicates the importance of exuviae sampling in understanding the response of Odonata to urbanization. (C) 2014 Elsevier Masson SAS. All rights reserved.  
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  ISSN 1146-609x ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 602  
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Auteur Boudour-Boucheker, N.; Boulo, V.; Charmantier-Daures, M.; Grousset, E.; Anger, K.; Charmantier, G.; Lorin-Nebel, C. url  doi
openurl 
  Titre Differential distribution of V-type H+-ATPase and Na+/K+-ATPase in the branchial chamber of the palaemonid shrimp Macrobrachium amazonicum Type Article scientifique
  Année 2014 Publication Revue Abrégée Cell and Tissue Research  
  Volume 357 Numéro 1 Pages 195-206  
  Mots-Clés Branchiostegite; Gills; Na+/K+-ATPase; Osmoregulation; V-type H+-ATPase; crab eriocheir-sinensis; decapoda; epithelial potential difference; fresh-water crab; gill epithelium; homarus-gammarus; ion-transport; larval development; lobster; olfersii; plasma-membrane; salinity acclimation  
  Résumé V-H+-ATPase and Na+/K+-ATPase were localized in the gills and branchiostegites of M. amazonicum and the effects of salinity on the branchial chamber ultrastructure and on the localization of transporters were investigated. Gills present septal and pillar cells. In freshwater (FW), the apical surface of pillar cells is amplified by extensive evaginations associated with mitochondria. V-H+-ATPase immunofluorescence was localized in the membranes of the apical evaginations and in clustered subapical areas of pillar cells, suggesting labeling of intracellular vesicle membranes. Na+/K+-ATPase labeling was restricted to the septal cells. No difference in immunostaining was recorded for both proteins according to salinity (FW vs. 25 PSU). In the branchiostegite, both V-H+-ATPase and Na+/K+-ATPase immunofluorescence were localized in the same cells of the internal epithelium. Immunogold revealed that V-H+-ATPase was localized in apical evaginations and in electron-dense areas throughout the inner epithelium, while Na+/K+-ATPase occurred densely along the basal infoldings of the cytoplasmic membrane. Our results suggest that morphologically different cell types within the gill lamellae may also be functionally specialized. We propose that, in FW, pillar cells expressing V-H+-ATPase absorb ions (Cl-, Na+) that are transported either directly to the hemolymph space or through a junctional complex to the septal cells, which may be responsible for active Na+ delivery to the hemolymph through Na+/K+-ATPase. This suggests a functional link between septal and pillar cells in osmoregulation. When shrimps are transferred to FW, gill and branchiostegite epithelia undergo ultrastructural changes, most probably resulting from their involvement in osmoregulatory processes.  
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  ISSN 0302-766x ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 541  
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Auteur Buisson, L.; Grenouillet, G.; Villeger, S.; Canal, J.; Laffaille, P. url  doi
openurl 
  Titre Toward a loss of functional diversity in stream fish assemblages under climate change Type Article scientifique
  Année 2013 Publication Revue Abrégée Glob. Change Biol.  
  Volume 19 Numéro 2 Pages 387-400  
  Mots-Clés assemblages; biotic homogenization; bird communities; climate change; distribution models; ecosystem; environmental-change; fresh-water biodiversity; functional traits; habitat; no-analog communities; range shifts; species; species distribution; stream fish; traits  
  Résumé The assessment of climate change impacts on biodiversity has so far been biased toward the taxonomic identification of the species likely either to benefit from climate modifications or to experience overall declines. There have still been few studies intended to correlate the characteristics of species to their sensitivity to climate change, even though it is now recognized that functional trait-based approaches are promising tools for addressing challenges related to global changes. In this study, two functional indices (originality and uniqueness) were first measured for 35 fish species occurring in French streams. They were then combined to projections of range shifts in response to climate change derived from species distribution models. We set out to investigate: (1) the relationship between the degrees of originality and uniqueness of fish species, and their projected response to future climate change; and (2) the consequences of individual responses of species for the functional diversity of fish assemblages. After accounting for phylogenetic relatedness among species, we have demonstrated that the two indices used measure two complementary facets of the position of fish species in a functional space. We have also rejected the hypothesis that the most original and/or less redundant species would necessarily experience the greatest declines in habitat suitability as a result of climate change. However, individual species range shifts could lead simultaneously both to a severe decline in the functional diversity of fish assemblages, and to an increase in the functional similarity among assemblages, supporting the hypothesis that disturbance favors communities with combination of common traits and biotic homogenization as well. Our findings therefore emphasize the importance of going beyond the simple taxonomic description of diversity to provide a better assessment of the likely future effects of environmental changes on biodiversity, thus helping to design more effective conservation and management measures.  
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  ISSN 1354-1013 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 897  
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Auteur Ben Othman, H.; Leboulanger, C.; Le Floc'h, E.; Mabrouk, H.H.; Hlaili, A.S. url  doi
openurl 
  Titre Toxicity of benz(a)anthracene and fluoranthene to marine phytoplankton in culture: Does cell size really matter? Type Article scientifique
  Année 2012 Publication Revue Abrégée J. Hazard. Mater.  
  Volume 243 Numéro Pages 204-211  
  Mots-Clés Benz(a)anthracene; Ecotoxicity; Fluoranthene; Size-sensitivity relationship; aquatic organisms; biodegradation; chlorophyll; fluorescence; food-web; fresh-water phytoplankton; in-vitro; organic pollutants; pahs; phytoplankton; polycyclic aromatic-hydrocarbons; surface sediments  
  Résumé The toxicity of benz(a)anthracene and fluoranthene (polycyclic aromatic hydrocarbons, PAHs) was evaluated on seven species of marine algae in culture belonging to pico-, nano-, and microphytoplankton, exposed to increasing concentrations of up to 2 mg L-1. The short-term (24 h) toxicity was assessed using chlorophyll a fluorescence transients, linked to photosynthetic parameters. The maximum quantum yield Fv/Fm was lower at the highest concentrations tested and the toxicity thresholds were species-dependent. For acute effects, fluoranthene was more toxic than benz(a)anthracene, with LOECs of 50.6 and 186 mu g L-1, respectively. After 72 h exposure, there was a dose-dependent decrease in cell density, fluoranthene being more toxic than benz(a)anthracene. The population endpoint at 72 h was affected to a greater extent than the photosynthetic endpoint at 24 h. EC50 was evaluated using the Hill model, and species sensitivity was negatively correlated to cell biovolume. The largest species tested, the dinoflagellate Alexandrium catenella, was almost insensitive to either PAH. The population endpoint EC50s for fluoranthene varied from 54 mu g L-1 for the picophytoplankton Picochlorum sp. to 418 mu g L-1 for the larger diatom Chaetoceros muelleri. The size/sensitivity relationship is proposed as a useful model when there is a lack of ecotoxicological data on hazardous chemicals, especially in marine microorganisms. (C) 2012 Elsevier B.V. All rights reserved.  
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  ISSN 0304-3894 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 915  
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Auteur Bouvier, T.; Venail, P.; Pommier, T.; Bouvier, C.; Barbera, C.; Mouquet, N. url  doi
openurl 
  Titre Contrasted Effects of Diversity and Immigration on Ecological Insurance in Marine Bacterioplankton Communities Type Article scientifique
  Année 2012 Publication Revue Abrégée PLoS One  
  Volume 7 Numéro 6 Pages  
  Mots-Clés 16s ribosomal-rna; bacterial communities; biodiversity; dispersal; fresh-water; gradient gel-electrophoresis; metacommunities; predictability; productivity; stability  
  Résumé The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of the predictions of the spatial and temporal aspects of the ecological insurance hypothesis. Addressing ecological insurance with bacterioplankton is of strong relevance given their central role in fundamental ecosystem processes. Our experimental set up consisted of water and bacterioplankton communities from two contrasting coastal lagoons. In order to mimic environmental fluctuations, the bacterioplankton community from one lagoon was successively transferred between tanks containing water from each of the two lagoons. We manipulated initial bacterial diversity for experimental communities and immigration during the experiment. We found that the abundance and production of bacterioplankton communities was higher and more stable (lower temporal variance) for treatments with high initial bacterial diversity. Immigration was only marginally beneficial to bacterial communities, probably because microbial communities operate at different time scales compared to the frequency of perturbation selected in this study, and of their intrinsic high physiologic plasticity. Such local “physiological insurance” may have a strong significance for the maintenance of bacterial abundance and production in the face of environmental perturbations.  
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  ISSN 1932-6203 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 499  
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