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Author Ruiz-Gonzalez, M.X.; Male, P.J.G.; Leroy, C.; Dejean, A.; Gryta, H.; Jargeat, P.; Quilichini, A.; Orivel, J.
Title Specific, non-nutritional association between an ascomycete fungus and Allomerus plant-ants Type Journal Article
Year 2011 Publication Biology Letters Abbreviated Journal Biol. Lett.
Volume 7 Issue 3 Pages 475-479
Keywords ant-fungus association; Cordia nodosa; Chaetothyriales; Hirtella physophora; myrmecophyte; population structure
Abstract Ant-fungus associations are well known from attine ants, whose nutrition is based on a symbiosis with basidiomycete fungi. Otherwise, only a few non-nutritional ant-fungus associations have been recorded to date. Here we focus on one of these associations involving Allomerus plant-ants that build galleried structures on their myrmecophytic hosts in order to ambush prey. We show that this association is not opportunistic because the ants select from a monophyletic group of closely related fungal haplotypes of an ascomycete species from the order Chaetothyriales that consistently grows on and has been isolated from the galleries. Both the ants' behaviour and an analysis of the genetic population structure of the ants and the fungus argue for host specificity in this interaction. The ants' behaviour reveals a major investment in manipulating, growing and cleaning the fungus. A molecular analysis of the fungus demonstrates the widespread occurrence of one haplotype and many other haplotypes with a lower occurrence, as well as significant variation in the presence of these fungal haplotypes between areas and ant species. Altogether, these results suggest that such an interaction might represent an as-yet undescribed type of specific association between ants and fungus in which the ants cultivate fungal mycelia to strengthen their hunting galleries.
Address [Leroy, Celine; Dejean, Alain; Quilichini, Angelique; Orivel, Jerome] CNRS, UMR Ecol Forets Guyane 8172, F-97379 Kourou, France, Email: jerome.orivel@ecofog.gf
Corporate Author Thesis
Publisher Royal Soc Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1744-9561 ISBN Medium
Area Expedition Conference
Notes ISI:000290515100044 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 317
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Author Vincent, G.; Molino, J.F.; Marescot, L.; Barkaoui, K.; Sabatier, D.; Freycon, V.; Roelens, J.B.
Title The relative importance of dispersal limitation and habitat preference in shaping spatial distribution of saplings in a tropical moist forest: a case study along a combination of hydromorphic and canopy disturbance gradients Type Journal Article
Year 2011 Publication Annals of Forest Science Abbreviated Journal Ann. For. Sci.
Volume 68 Issue 2 Pages 357-370
Keywords Species assemblage; Dispersal limitation; Tropical moist forest; Niche
Abstract Various processes contribute to shaping the local assemblage of species in hyperdiverse tropical forest. The relative contribution of environmental factors and dispersal limitation in determining the spatial distribution of saplings at local scale is unclear. We examined two types of environmental factors: (a) soil type reflecting drainage regime and (b) past logging damages reflecting light regime in a neotropical moist forest site. We used a logistic model to predict presence or absence of a given species in a network of elementary small plots. The effect of mapped environmental factors and a spatial correlation term were jointly estimated providing a direct measure of the relative role of habitat specialisation and dispersal limitation. At community level, dispersal limitation was the most important determinant of species absence at local scale. The two environmental factors examined played a balanced role. Different species however showed different degrees of dispersal limitation and habitat specialisation. The distribution of a large proportion of species-the majority of the most abundant species-was significantly affected by at least one environmental factor. We provide a ranking of 49 species sensitive to canopy disturbance (from shade specialist to pioneer) and 41 species affected by seasonal flooding (either positively or negatively).
Address [Vincent, Gregoire; Marescot, Lucile; Barkaoui, Karim] IRD, Unite Mixte Rech AMAP, Kourou 97387, French Guiana, Email: gregoire.vincent@ird.fr
Corporate Author Thesis
Publisher Springer France Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1286-4560 ISBN Medium
Area Expedition Conference
Notes ISI:000290448000014 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 318
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Author Brouard, O.; Le Jeune, A.H.; Leroy, C.; Cereghino, R.; Roux, O.; Pelozuelo, L.; Dejean, A.; Corbara, B.; Carrias, J.F.
Title Are Algae Relevant to the Detritus-Based Food Web in Tank-Bromeliads? Type Journal Article
Year 2011 Publication PLoS One Abbreviated Journal PLoS One
Volume 6 Issue 5 Pages e20129
Keywords
Abstract We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from similar to 10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web.
Address [Brouard, Olivier; Le Jeune, Anne-Helene; Corbara, Bruno; Carrias, Jean-Francois] Univ Clermont Ferrand, CNRS, Lab Microorganismes Genome & Environm, LMGE,UMR 6023, Aubiere, France, Email: j-francois.carrias@univ-bpclermont.fr
Corporate Author Thesis
Publisher Public Library Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000290720200066 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 319
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Author Coq, S.; Weigel, J.; Butenschoen, O.; Bonal, D.; Hattenschwiler, S.
Title Litter composition rather than plant presence affects decomposition of tropical litter mixtures Type Journal Article
Year 2011 Publication Plant and Soil Abbreviated Journal Plant Soil
Volume 343 Issue 1-2 Pages 273-286
Keywords Amazonian lowland rainforest; Belowground/aboveground interactions; Litter decomposition; Non-additive effect; Nitrogen dynamic; Plant-soil feedback
Abstract Litter decomposition is strongly controlled by litter quality, but the composition of litter mixtures and potential interactions with live plants through root activity may also influence decomposers. In a greenhouse experiment in French Guiana we studied the combined effects of the presence of tropical tree seedlings and of distinct litter composition on mass and nitrogen (N) loss from decomposing litter and on microbial biomass. Different litter mixtures decomposed for 435 days in pots filled with sand and containing an individual seedling from one of four different tree species. We found both additive and negative non-additive effects (NAE) of litter mixing on mass loss, whereas N loss showed negative and positive NAE of litter mixing. If litter from the two tree species, Platonia insignis and Goupia glabra were present, litter mixtures showed more positive and more negative NAE on N loss, respectively. Overall, decomposition, and in particular non-additive effects, were only weakly affected by the presence of tree seedlings. Litter mass loss weakly yet significantly decreased with increasing fine root biomass in presence of Goupia seedlings, but not in the presence of seedlings of any other tree species. Our results showed strong litter composition effects and also clear, mostly negative, non-additive effects on mass loss and N loss. Species identity of tree seedlings can modify litter decomposition, but these live plant effects remain quantitatively inferior to litter composition effects.
Address [Coq, Sylvain; Haettenschwiler, Stephan] CNRS, CEFE, F-34293 Montpellier 5, France, Email: sylvain.coq@gmail.com
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0032-079x ISBN Medium
Area Expedition Conference
Notes ISI:000290688000020 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 320
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Author Verbeeck, H.; Peylin, P.; Bacour, C.; Bonal, D.; Steppe, K.; Ciais, P.
Title Seasonal patterns of CO2 fluxes in Amazon forests: Fusion of eddy covariance data and the ORCHIDEE model Type Journal Article
Year 2011 Publication Journal Of Geophysical Research-Biogeosciences Abbreviated Journal J. Geophys. Res.-Biogeosci.
Volume 116 Issue 2 Pages G02018
Keywords
Abstract [1] In some regions of the Amazon, global biogeophysical models have difficulties in reproducing measured seasonal patterns of net ecosystem exchange (NEE) of carbon dioxide. The global process-based biosphere model Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) used in this study showed that a standard model parameterization produces seasonal NEE patterns that are opposite in phase to the eddy flux data of the tropical evergreen forest at the Tapajos km 67 site (Brazil), like many other global models. However, we optimized several key parameters of ORCHIDEE using eddy covariance data of the Tapajos km 67 site in order to identify the driving factors of the seasonal variations in CO2 flux in this tropical forest ecosystem. The validity of the retrieved parameter values was evaluated for two other flux tower sites in the Amazon. The different tested optimization scenarios showed that only a few parameters substantially improve the fit to NEE and latent heat data. Our results confirm that these forests have the ability to maintain high transpiration and photosynthesis during the dry season in association with a large soil depth (D-soil = 10 m) and a rooting system density that decreases almost linearly with depth (H-root = 0.1). Previous analyses of seasonal variations in eddy covariance fluxes indicated that higher GPP levels were reached in the dry season compared to the wet season. Our optimization analysis suggests that this pattern could be caused by a leaf flush at the start of the dry season increasing the photosynthetic capacity of the canopy. Nevertheless, the current model structure is not yet able to simulate such a leaf flush, and we therefore suggest improving the ORCHIDEE model by including a specific phenology module that is driven by light availability for the tropical evergreen plant functional types. In addition, our results highlight both the potential and the limitations of flux data to improve global terrestrial models. Several parameters were not identifiable, and the risk of overfitting of the model was illustrated. Nevertheless, we conclude that these models can be improved substantially by assimilating site level flux data over the tropics.
Address [Verbeeck, Hans; Steppe, Kathy] Univ Ghent, Plant Ecol Lab, Dept Appl Ecol & Environm Biol, Fac Biosci Engn, B-9000 Ghent, Belgium, Email: hans.verbeeck@ugent.be
Corporate Author Thesis
Publisher Amer Geophysical Union Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0148-0227 ISBN Medium
Area Expedition Conference
Notes ISI:000290933500002 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 321
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Author Roux, O.; Cereghino, R.; Solano, P.J.; Dejean, A.
Title Caterpillars and Fungal Pathogens: Two Co-Occurring Parasites of an Ant-Plant Mutualism Type Journal Article
Year 2011 Publication PLoS One Abbreviated Journal PLoS One
Volume 6 Issue 5 Pages e20538
Keywords
Abstract In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia) and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae) as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae) can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs) whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes), that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth.
Address [Roux, Olivier; Dejean, Alain] CNRS, Ecol Forets Guyane UMR 8172, Kourou, France, Email: olivier.roux@ird.fr
Corporate Author Thesis
Publisher Public Library Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000291097600091 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 322
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Author Hattenschwiler, S.; Fromin, N.; Barantal, S.
Title Functional diversity of terrestrial microbial decomposers and their substrates Type Journal Article
Year 2011 Publication Comptes Rendus Biologies Abbreviated Journal C. R. Biol.
Volume 334 Issue 5-6 Pages 393-402
Keywords Bacteria; Biogeochemical cycles; Decomposition; Dissimilarity; Ecosystem functioning; Functional diversity indices; Fungi; Leaf litter
Abstract The relationship between biodiversity and biogeochemical processes gained much interest in light of the rapidly decreasing biodiversity worldwide. In this article, we discuss the current status, challenges and prospects of functional concepts to plant litter diversity and microbial decomposer diversity. We also evaluate whether these concepts permit a better understanding of how biodiversity is linked to litter decomposition as a key ecosystem process influencing carbon and nutrient cycles. Based on a literature survey, we show that plant litter and microbial diversity matters for decomposition, but that considering numbers of taxonomic units appears overall as little relevant and less useful than functional diversity. However, despite easily available functional litter traits and the well-established theoretical framework for functional litter diversity, the impact of functional litter diversity on decomposition is not yet well enough explored. Defining functional diversity of microorganisms remains one of the biggest challenges for functional approaches to microbial diversity. Recent developments in microarray and metagenomics technology offer promising possibilities in the assessment of the functional structure of microbial communities. This might allow significant progress in measuring functional microbial diversity and ultimately in our ability to predict consequences of biodiversity loss in the decomposer system for biogeochemical processes. (C) 2011 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Address [Haettenschwiler, Stephan; Fromin, Nathalie; Barantal, Sandra] CNRS, CEFE, F-34293 Montpellier 5, France, Email: stephan.hattenschwiler@cefe.cnrs.fr
Corporate Author Thesis
Publisher Elsevier France-Editions Scientifiques Medicales Elsevier Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1631-0691 ISBN Medium
Area Expedition Conference
Notes ISI:000292013400008 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 323
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Author Lebrini, M.; Robert, F.; Blandinieres, P.A.; Roos, C.
Title Corrosion Inhibition by Isertia coccinea Plant Extract in Hydrochloric Acid Solution Type Journal Article
Year 2011 Publication International Journal of Electrochemical Science Abbreviated Journal Int. J. Electrochem. Sci.
Volume 6 Issue 7 Pages 2443-2460
Keywords Isertia coccinea; corrosion inhibitors; C38 steel; acidic media; adsorption
Abstract The effect of alkaloids extracted from Isertia coccinea plant (AEIC) on the corrosion of C38 steel in 1 M hydrochloric acid was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. Potentiodynamic polarization curves indicated that the extract behave as mixed-type inhibitor. The experimental data obtained from EIS method show a frequency distribution and therefore a modelling element with frequency dispersion behaviour, a constant phase element (CPE) has been used. The inhibition efficiencies of the extract calculated by three methods show the same tendency. Inhibition was found to increase with increasing concentration of the plant extract. The results obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of C38 steel in hydrochloric acid solution. The apparent activation energy of the process taking place in inhibitor presence was determined on the ground of four temperature values in the range from 25 degrees C to 55 degrees C using the data obtained by two independent methods. Theoretical fitting of different isotherms, Langmuir, Temkin and Frunkin, were tested to clarify the nature of adsorption.
Address [Lebrini, M.; Robert, F.; Blandinieres, P. A.; Roos, C.] UAG UMR ECOFOG, Lab Mat & Mol Milieu Amazonien, Cayenne 97337, French Guiana, Email: florent.robert@guyane.univ-ag.fr
Corporate Author Thesis
Publisher Electrochemical Science Group Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1452-3981 ISBN Medium
Area Expedition Conference
Notes ISI:000292331400014 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 324
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Author Baraloto, C.; Rabaud, S.; Molto, Q.; Blanc, L.; Fortunel, C.; Herault, B.; Davila, N.; Mesones, I.; Rios, M.; Valderrama, E.; Fine, P.V.A.
Title Disentangling stand and environmental correlates of aboveground biomass in Amazonian forests Type Journal Article
Year 2011 Publication Global Change Biology Abbreviated Journal Glob. Change Biol.
Volume 17 Issue 8 Pages 2677-2688
Keywords carbon stocks; climate; flooded forest; forest structure; French Guiana; Peru; REDD; soil properties; tropical rainforest; white-sand forest; wood specific gravity
Abstract Tropical forests contain an important proportion of the carbon stored in terrestrial vegetation, but estimated aboveground biomass (AGB) in tropical forests varies two-fold, with little consensus on the relative importance of climate, soil and forest structure in explaining spatial patterns. Here, we present analyses from a plot network designed to examine differences among contrasting forest habitats (terra firme, seasonally flooded, and white-sand forests) that span the gradient of climate and soil conditions of the Amazon basin. We installed 0.5-ha plots in 74 sites representing the three lowland forest habitats in both Loreto, Peru and French Guiana, and we integrated data describing climate, soil physical and chemical characteristics and stand variables, including local measures of wood specific gravity (WSG). We use a hierarchical model to separate the contributions of stand variables from climate and soil variables in explaining spatial variation in AGB. AGB differed among both habitats and regions, varying from 78 Mg ha(-1) in white-sand forest in Peru to 605 Mg ha(-1) in terra firme clay forest of French Guiana. Stand variables including tree size and basal area, and to a lesser extent WSG, were strong predictors of spatial variation in AGB. In contrast, soil and climate variables explained little overall variation in AGB, though they did co-vary to a limited extent with stand parameters that explained AGB. Our results suggest that positive feedbacks in forest structure and turnover control AGB in Amazonian forests, with richer soils (Peruvian terra firme and all seasonally flooded habitats) supporting smaller trees with lower wood density and moderate soils (French Guianan terra firme) supporting many larger trees with high wood density. The weak direct relationships we observed between soil and climate variables and AGB suggest that the most appropriate approaches to landscape scale modeling of AGB in the Amazon would be based on remote sensing methods to map stand structure.
Address [Baraloto, Christopher; Rabaud, Suzanne; Fortunel, Claire; Rios, Marcos; Valderrama, Elvis] INRA, UMR Ecol Forets Guyane, Kourou 97387, French Guiana, Email: chris.baraloto@ecofog.gf
Corporate Author Thesis
Publisher Wiley-Blackwell Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1354-1013 ISBN Medium
Area Expedition Conference
Notes ISI:000292308300013 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 325
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Author McLean, J.P.; Zhang, T.; Bardet, S.; Beauchene, J.; Thibaut, A.; Clair, B.; Thibaut, B.
Title The decreasing radial wood stiffness pattern of some tropical trees growing in the primary forest is reversed and increases when they are grown in a plantation Type Journal Article
Year 2011 Publication Annals of Forest Science Abbreviated Journal Ann. For. Sci.
Volume 68 Issue 4 Pages 681-688
Keywords Tropical trees; Growth strategy; Wood stiffness; Juvenile wood
Abstract Background This study examines the radial trend in wood stiffness of tropical rainforest trees. The objective was to determine if the type of growing environment (exposed plantation or dense primary forest) would have an effect on this radial trend. Methods The axial elastic modulus of wood samples, representing a pith to bark cross-section, of six trees from several French Guianese species (two of Eperua falcata, one of Eperua grandiflora, two of Carapa procera and one of Symphonia gloubulifera) was measured using a dynamic “forced vibration” method. Results Primary forest trees were observed to have a decrease in wood stiffness from pith to bark, whereas plantation trees, from the same genus or species, displayed a corresponding increase in wood stiffness. Juvenile wood stiffness appears to vary depending on the environment in which the tree had grown. Conclusion We suggest that the growth strategy of primary forest trees is to produce wood resistant to self-buckling so that the height of the canopy may be obtained with the maximum of efficiency. In contrast, the growth strategy of the trees growing in an exposed plantation is to produce low-stiffness wood, important to provide flexibility in wind. Further experiments to study the behaviour of more species, with more individuals per species, growing across a range of physical environments, are required.
Address [McLean, JP; Bardet, S; Clair, B; Thibaut, B] Univ Montpellier 2, LMGC, CNRS, F-34095 Montpellier, France, Email: p.mclean@auckland.ac.nz
Corporate Author Thesis
Publisher Springer France Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1286-4560 ISBN Medium
Area Expedition Conference
Notes WOS:000292553400003 Approved no
Call Number (down) EcoFoG @ webmaster @ Serial 326
Permanent link to this record