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Author Stahl, C.; Freycon, V.; Fontaine, S.; Dezecache, C.; Ponchant, L.; Picon-Cochard, C.; Klumpp, K.; Soussana, J.-F.; Blanfort, V. doi  openurl
  Title Soil carbon stocks after conversion of Amazonian tropical forest to grazed pasture: importance of deep soil layers Type Journal Article
  Year 2016 Publication Regional Environmental Change Abbreviated Journal  
  Volume 16 Issue 7 Pages 2059-2069  
  Keywords  
  Abstract Recent studies suggest that carbon (C) is stored in the topsoil of pastures established after deforestation. However, little is known about the long-term capacity of tropical pastures to sequester C in different soil layers after deforestation. Deep soil layers are generally not taken into consideration or are underestimated when C storage is calculated. Here we show that in French Guiana, the C stored in the deep soil layers contributes significantly to C stocks down to a depth of 100 cm and that C is sequestered in recalcitrant soil organic matter in the soil below a depth of 20 cm. The contribution of the 50–100 cm soil layer increased from 22 to 31 % with the age of the pasture. We show that long-term C sequestration in C4 tropical pastures is linked to the development of C3 species (legumes and shrubs), which increase both inputs of N into the ecosystem and the C:N ratio of soil organic matter. The deep soil under old pastures contained more C3 carbon than the native forest. If C sequestration in the deep soil is taken into account, our results suggest that the soil C stock in pastures in Amazonia would be higher with sustainable pasture management, in particular by promoting the development of legumes already in place and by introducing new species.  
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  ISSN (down) 1436-378x ISBN Medium  
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  Call Number EcoFoG @ webmaster @ Stahl2016 Serial 721  
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Author Coq, S.; Weigel, J.; Bonal, D.; Hattenschwiler, S. url  openurl
  Title Litter mixture effects on tropical tree seedling growth – a greenhouse experiment Type Journal Article
  Year 2012 Publication Plant Biology Abbreviated Journal Plant Biol.  
  Volume 14 Issue 4 Pages 630-640  
  Keywords Amazonian lowland rain forest; Autotoxicity; Belowground/aboveground interactions; Litter decomposition; Plant nutrition; Plant-soil feedback  
  Abstract Decomposing litter provides critical nutrients for plants, particularly in nutrient-poor ecosystems such as tropical forests. We hypothesised that decomposing litter improves the performance of a variety of tropical tree seedlings, and that this litter effect varies depending on the species of litter present in litter mixtures. We addressed these hypotheses with a large pot experiment manipulating a range of different litter mixtures of contrasting quality and using seedlings of four tree species from the Amazonian forest of French Guiana. In contrast to our initial hypothesis, decomposing litter had either neutral or negative impacts on seedling growth, despite strongly different growth rates, biomass allocation patterns and leaf and root traits among tree species. Tree species varied in their responses to litter additions, which were further modified by species identity of the added litter. Our data show litter species-specific effects on growth, biomass allocation and leaf and root traits of tropical tree seedlings. These results suggest that a net nutrient release from decomposing litter does not necessarily improve tree seedling growth, even under nutrient-limiting conditions. In conclusion, litter layer composition may affect seedling establishment and recruitment success beyond litter-derived plant nutrient availability, which may contribute to tree species composition and dynamics in the studied tropical forest. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.  
  Address INRA, UMR, Écologie et Écophysiologie, Champenoux, France  
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  ISSN (down) 14358603 (Issn) ISBN Medium  
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  Notes Export Date: 27 June 2012; Source: Scopus; Coden: Pbiof; doi: 10.1111/j.1438-8677.2011.00534.x; Language of Original Document: English; Correspondence Address: Coq, S.; Laboratoire d'Ecologie Alpine (LECA), CNRS, Université Joseph Fourier, BP 53, F-38042 Grenoble, Cedex 09, France; email: sylvain.coq@gmail.com Approved no  
  Call Number EcoFoG @ webmaster @ Serial 407  
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Author Zhang, T.; Bai, S.-L.; Bardet, S.; Almeras, T.; Thibaut, B.; Beauchene, J. url  openurl
  Title Radial variations of vibrational properties of three tropical woods Type Journal Article
  Year 2011 Publication Journal of Wood Science Abbreviated Journal J. Wood Sci.  
  Volume 57 Issue 5 Pages 377-386  
  Keywords Damping coefficient; Dynamic modulus; Extractives; Microfibril angle; Tropical woods  
  Abstract The radial trends of vibrational properties, represented by the specific dynamic modulus (E′/ρ) and damping coefficient (tan δ), were investigated for three tropical rainforest hardwood species (Simarouba amara, Carapa procera, and Symphonia globulifera) using free-free flexural vibration tests. The microfibril angle (MFA) was estimated using X-ray diffraction. Consistent patterns of radial variations were observed for all studied properties. E′/ρ was found to decrease from pith to bark, which was strongly related to the increasing pith-bark trend of MFA. The variation of tan δ along the radius could be partly explained by MFA and partly by the gradient of extractives due to heartwood formation. The coupling effect of MFA and extractives could be separated through analysis of the log(tan δ) versus log(E′/ρ) diagram. For the species studied, the extractive content putatively associated with heartwood formation generally tends to decrease the wood damping coefficient. However, this weakening effect of extractives was not observed for the inner part of the heartwood, suggesting that the mechanical action of extractives was reduced during their chemical ageing. © 2011 The Japan Wood Research Society.  
  Address CIRAD, UMR Ecofog, BP 701, 97387 Kourou Cedex, Guyane Française, France  
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  ISSN (down) 14350211 (Issn) ISBN Medium  
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  Notes Export Date: 26 October 2011; Source: Scopus; Coden: Jwscf; doi: 10.1007/s10086-011-1189-7; Language of Original Document: English; Correspondence Address: Bai, S.-L.; Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871, China; email: slbai@pku.edu.cn Approved no  
  Call Number EcoFoG @ webmaster @ Serial 363  
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Author Barriault, I.; Barabe, D.; Cloutier, L.; Gibernau, M. openurl 
  Title Pollination ecology and reproductive success in Jack-in-the-pulpit (Arisaema triphyllum) in Quebec (Canada) Type Journal Article
  Year 2010 Publication Plant Biology Abbreviated Journal Plant Biol.  
  Volume 12 Issue 1 Pages 161-171  
  Keywords Araceae; bisexual inflorescence; deceptive pollination; Mycetophilidae; pollen load; Thysanoptera; visitation rates  
  Abstract Pollination ecology and reproductive success of Jack-in-the-pulpit (Arisaema triphyllum) were studied in two natural populations in Quebec, Canada. Individual A. triphyllum plants can be of three types: male, female or bisexual. In both populations studied, the presence of bisexual inflorescences was not negligible (13%), where 'female' and 'male' bisexual plants were categorised according to the relative number of stamens and ovaries. 'Male bisexual' plants produce only pollen and 'female bisexual' plants produce only fruit. Hence, A. triphyllum is a true dioecious plant, as each plant only reproduces through either the male or the female function. 'Female bisexual' plants were equivalent to female plants in terms of visitation rate by insects, fructification rate and production of berries and seeds. Neither agamospermy in female plants nor self-pollination in 'female bisexual' plants was found, thus A. triphyllum relies on insects for cross-pollination. Despite the long flowering cycle, a low visitation rate was documented: only 20-40% of inflorescences were visited, according to gender, by a mean of 1.5 insects. In this study, Mycetophilidae represented the most generically diversified and abundant family, as well as the most efficient insect pollinator, especially the genera Docosia and Mycetophila.  
  Address [Gibernau, M.] Univ Toulouse 3, Lab Evolut & Divers Biol, UMR, CNRS, F-31062 Toulouse 9, France, Email: gibernau@cict.fr  
  Corporate Author Thesis  
  Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor  
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  ISSN (down) 1435-8603 ISBN Medium  
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  Notes ISI:000272589700017 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 89  
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Author Courtois, E.A.; Stahl, C.; Van den Berge, J.; Bréchet, L.; Van Langenhove, L.; Richter, A.; Urbina, I.; Soong, J.L.; Peñuelas, J.; Janssens, I.A. url  doi
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  Title Spatial Variation of Soil CO2, CH4 and N2O Fluxes Across Topographical Positions in Tropical Forests of the Guiana Shield Type Journal Article
  Year 2018 Publication Ecosystems Abbreviated Journal  
  Volume 21 Issue 7 Pages 1445-1458  
  Keywords  
  Abstract The spatial variation of soil greenhouse gas fluxes (GHG; carbon dioxide—CO2, methane—CH4 and nitrous oxide—N2O) remains poorly understood in highly complex ecosystems such as tropical forests. We used 240 individual flux measurements of these three GHGs from different soil types, at three topographical positions and in two extreme hydric conditions in the tropical forests of the Guiana Shield (French Guiana, South America) to (1) test the effect of topographical positions on GHG fluxes and (2) identify the soil characteristics driving flux variation in these nutrient-poor tropical soils. Surprisingly, none of the three GHG flux rates differed with topographical position. CO2 effluxes covaried with soil pH, soil water content (SWC), available nitrogen and total phosphorus. The CH4 fluxes were best explained by variation in SWC, with soils acting as a sink under drier conditions and as a source under wetter conditions. Unexpectedly, our study areas were generally sinks for N2O and N2O fluxes were partly explained by total phosphorus and available nitrogen concentrations. This first study describing the spatial variation of soil fluxes of the three main GHGs measured simultaneously in forests of the Guiana Shield lays the foundation for specific studies of the processes underlying the observed patterns.  
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  ISSN (down) 1435-0629 ISBN Medium  
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  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Courtois2018 Serial 847  
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Author Yamamoto, H.; Almeras, T. doi  openurl
  Title A mathematical verification of the reinforced-matrix hypothesis using the Mori-Tanaka theory Type Journal Article
  Year 2007 Publication Journal of Wood Science Abbreviated Journal J. Wood Sci.  
  Volume 53 Issue 6 Pages 505-509  
  Keywords Engineering  
  Abstract This article presents a theoretical verification of the reinforced-matrix hypothesis derived from tensor equations, σ W = σ f + σ m and ε W = ε f = ε m (Wood Sci Technol 32:171–182, 1998; Wood Sci Technol 33:311–325, 1999; J Biomech Eng 124:432–440, 2002), using classical Mori-Tanaka theory on the micromechanics of fiber-reinforced materials (Acta Metall 21:571–574, 1973; Micromechanics — dislcation and inclusions (in Japanese), pp 141–147, 1976). The Mori-Tanaka theory was applied to a small fragment of the cell wall undergoing changes in its physical state, such as those arising from sorption of moisture, maturation of wall components, or action of an external force, to obtain ⟨σ A⟩D = ϕ·⟨σ F⟩I + (1−ϕ)·⟨σ M⟩D−I. When the constitutive equation of each constituent material was applied to the equation ⟨σ A⟩D = ϕ·⟨σ F⟩I + (1−ϕ)·⟨σ M⟩D−I, the equations σ W = σ f + σ m and ε W = ε f = ε m were derived to lend support to the concept that two main phases, the reinforcing cellulose microfibril and the lignin-hemicellulose matrix, coexist in the same domain. The constitutive equations for the cell wall fragment were obtained without recourse to additional parameters such as Eshelby’s tensor S and Hill’s averaged concentration tensors AF and AM. In our previous articles, the coexistence of two main phases and σ W = σ f + σ m and ε W = ε f =ε m had been taken as our starting point to formulate the behavior of wood fiber with multilayered cell walls. The present article provides a rational explanation for both concepts.  
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  Publisher Springer Japan Place of Publication Editor  
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  ISSN (down) 1435-0211 ISBN Medium  
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  Notes Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 215  
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Author Almeras, T.; Yoshida, M.; Okuyama, T. openurl 
  Title The generation of longitudinal maturation stress in wood is not dependent on diurnal changes in diameter of trunk Type Journal Article
  Year 2006 Publication Journal of Wood Science Abbreviated Journal J. Wood Sci.  
  Volume 52 Issue 5 Pages 452-455  
  Keywords maturation stress; growth stress; cell-wall maturation; continuous lighting; diurnal strains  
  Abstract A hypothetical mechanism for the generation of maturation stress in wood was tested experimentally. The hypothesis was that the maturation stress could partly originate in a physical mechanism related to daily changes in water pressure and associated diurnal strains. The matrix of lignin and hemicellulose, deposited in the cell wall during the night, would be put in compression by the effect of water tension during the next day. The cellulose framework, crystallizing during the day, would be put in tension by the decrease in tension at night and subsequent cell-wall swelling. This was tested on young saplings of sugi and beech. Half of the saplings were submitted to continuous lighting, which canceled diurnal strains. Saplings were tilted 40 degrees, and their uprighting movement was measured. The uprighting movement is directly due to the production of reaction wood and the concomitant development of large longitudinal maturation stress. It occurred in the continuously lighted plants at least as much as in control plants. We conclude that the generation of longitudinal maturation stress in tension or compression wood is not directly related to variations in water pressure and diurnal strains.  
  Address Nagoya Univ, Grad Sch Bioagr Sci, Lab Biomat Phys, Chikusa Ku, Nagoya, Aichi 4648601, Japan, Email: t_almeras@hotmail.com  
  Corporate Author Thesis  
  Publisher SPRINGER TOKYO Place of Publication Editor  
  Language Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN (down) 1435-0211 ISBN Medium  
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  Notes ISI:000241010600012 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 222  
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Author Fortunel, C.; Violle, C.; Rourmet, C.; Buatois, B.; Navas, M.L.; Garnier, E. openurl 
  Title Allocation strategies and seed traits are hardly affected by nitrogen supply in 18 species differing in successional status Type Journal Article
  Year 2009 Publication Perspectives in Plant Ecology Evolution and Systematics Abbreviated Journal Perspect. Plant Ecol. Evol. Syst.  
  Volume 11 Issue 4 Pages 267-283  
  Keywords Allometry; Reproductive output; Seed mass; Nitrogen concentration of organs; Succession; Nitrogen supply  
  Abstract Species performance depends on ecological strategies, revealed by suites of traits, conferring different relative ecological advantages in different environments. Although current knowledge on plant strategies along successional gradients is derived from studies conducted in situ, actually quantifying these strategies requires disentangling the effects of environmental factors from intrinsic differences between species. Here we tested whether allocation strategies and seed traits differ among successional stages and nitrogen levels. To this aim, we assessed biomass and nitrogen allocations and seed traits variations for 18 species, differing in life history and belonging to three stages of a Mediterranean old-field succession. These species were grown as monocultures in an experimental garden under limiting and non-limiting nitrogen supply. Early successional species allocated allometrically more nitrogen and proportionally more biomass to reproduction, and set more seeds than later successional species. Seed mass increased with successional status and was negatively related to seed number. Early successional species thus produced more but less-provisioned seeds, suggesting better colonization abilities. These patterns were not the sole consequence of the replacement of annuals by perennials along the successional gradient, since comparable trends were also observed within each life history. Allocation patterns were generally not altered by nitrogen supply and the higher nitrogen content in vegetative organs of plants grown under high nitrogen supply was not retranslocated from leaves to seeds during seed development. We therefore conclude that differences in plant ecological strategies in species characteristics from contrasting successional stages appear to be intrinsic properties of the studied species, and independent from environmental conditions. (c) 2009 Rubel Foundation, ETH Zurich. Published by Elsevier GmbH. All rights reserved.  
  Address [Fortunel, Claire; Violle, Cyrille; Rourmet, Catherine; Buatois, Bruno; Garnier, Eric] Ctr Ecol Fonct & Evolut, CNRS, UMR 5175, F-34293 Montpellier 5, France, Email: claire.fortunel@ecofog.gf  
  Corporate Author Thesis  
  Publisher ELSEVIER GMBH, URBAN & FISCHER VERLAG Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN (down) 1433-8319 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000271799900003 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 93  
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Author Herault, B. openurl 
  Title Reconciling niche and neutrality through the Emergent Group approach Type Journal Article
  Year 2007 Publication Perspectives in Plant Ecology Evolution and Systematics Abbreviated Journal Perspect. Plant Ecol. Evol. Syst.  
  Volume 9 Issue 2 Pages 71-78  
  Keywords Biodiversity; ecological equivalency; biological traits; neutral theory; niche differentiation; redundancy  
  Abstract Both niche and neutral theories have been suggested as potential frameworks for modelling biodiversity. Niche models assume that biological traits represent evolutionary adaptations and define individuals in terms of functional trade-offs. Neutral models assume that all individuals at a single trophic level are functionally equivalent on a per capita basis with respect to their birth, death, dispersal and speciation. The opinion of many researchers is that neutral and niche processes operate simultaneously to generate diversity without knowing how the unification of both models can be achieved. Recently, several theoretical papers have reported evidence on the evolutionary emergence of niche structures shaping the emergence of groups of similar species. In this way, an Emergent Group is defined as a set of species that have a similar functional niche owing to a convergent ecological strategy. Central to the Emergent Group concept are the assumptions of functional equivalence within and of functional divergence between Emergent Groups. Within an Emergent Group, species richness is subject to a zero-sum rule set by the balance between the rate of individual loss and of immigration. Between Emergent Groups, tradeoffs such as seed size/seedling competitivity, investment in reproductive system/investment in vegetative systems or competitive ability/predator invulnerability are cornerstones of the evolutionary divergence. Delineating Emergent Groups amounts to reaching a compromise between maximizing niche differentiation (i.e. maximizing differences in functional tradeoffs) between Emergent Groups and maximizing neutrality within Emergent Groups. Up to now, the Emergent Group concept has been mostly proposed by theoretical scientists but it should be tested by empirical ecologists. The way in which niche and neutral models could be combined provides a profitable opportunity for theoretical and empirical scientists to collaborate fruitfully. (c) 2007 Rubel Foundation, ETH Zurich. Published by Elsevier GmbH. All rights reserved.  
  Address [Herault, Bruno] Univ Antilles Guyane, UMR Ecol Forets Guyane, F-97379 Kourou, France, Email: Bruno.Herault@cirad.fr  
  Corporate Author Thesis  
  Publisher ELSEVIER GMBH, URBAN & FISCHER VERLAG Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN (down) 1433-8319 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000251685100002 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 147  
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Author Barantal, S.; Schimann, H.; Fromin, N.; Hattenschwiler, S. url  openurl
  Title Nutrient and Carbon Limitation on Decomposition in an Amazonian Moist Forest Type Journal Article
  Year 2012 Publication Ecosystems Abbreviated Journal Ecosystems  
  Volume 15 Issue 7 Pages 1039-1052  
  Keywords energy limitation; labile carbon; litter quality; nitrogen; phosphorus; priming effect; soil fauna; tropical forest  
  Abstract Tropical forests determine global biogeochemical cycles to a large extent, but control factors for key ecosystem processes such as decomposition remain poorly understood. With a full-factorial C (cellulose), N (urea), and P (phosphate) fertilization experiment, we tested the relative importance of C and nutrient limitation on litter decomposition in a mature lowland moist forest of French Guiana. Despite the previously demonstrated litter C quality control over decomposition and the very low soil P content (0. 1 mg g -1 of soil) at our study site, fertilization with C or P alone did not increase the decomposition of a wide range of litter types (N:P ratios between 20 and 80). Nitrogen fertilization alone also had no effect on decomposition. However, the combined fertilization with N and P resulted in up to 33. 5% more initial litter mass lost, with an increasing effect with wider litter N:P ratios. Soil fauna strongly stimulated litter mass loss and enhanced nutrient fertilization effects. Moreover, nutrient effects on decomposition increased with additional C fertilization in the presence of fauna. Our results suggest that increased N availability is required for a positive P effect on decomposition in the studied P-poor tropical forest. Further stimulation of decomposition by C amendment through priming indicates energy limitation of decomposers that is co-determined by nutrient availability. The demonstrated intricate control of the key resources C, N, and P on decomposition calls for an intensified research effort on multiple resource limitation on key processes in tropical forests and how they change under multiple human impacts. © 2012 Springer Science+Business Media, LLC.  
  Address UMR Ecologie des Forêts de Guyane (ECOFOG), INRA, Kourou, French Guiana  
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  ISSN (down) 14329840 (Issn) ISBN Medium  
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  Notes Export Date: 2 November 2012; Source: Scopus; Coden: Ecosf; doi: 10.1007/s10021-012-9564-9; Language of Original Document: English; Correspondence Address: Schimann, H.; UMR Ecologie des Forêts de Guyane (ECOFOG), INRA, Kourou, French Guiana; email: heidy.schimann@ecofog.gf Approved no  
  Call Number EcoFoG @ webmaster @ Serial 442  
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