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Author Vincent, G.; Caron, F.; Sabatier, D.; Blanc, L.
Title (down) LiDAR shows that higher forests have more slender trees Type Journal Article
Year 2012 Publication Bois et Forets des Tropiques Abbreviated Journal Bois Forets Tropiques
Volume 66 Issue 314 Pages 51-56
Keywords Competition; Fertility; French Guiana; LiDAR; Tree allometry
Abstract High-density Airborne Laser Scanning was used to derive the Canopy Height Model (CHM) of an experimental forest site in the neotropics (Paracou, French Guiana). Individual tree heights were computed by manually segmenting tree crowns on the CHM and then extracting the local maximum canopy height. Three hundred and ninety-six (396) height estimates were matched from dominant or emergent trees with the corresponding ground records of stem diameters sampled in two plots with different mean canopy heights (28.1 m vs. 31.3 m). Tree slenderness was found to be positively and very significantly correlated with mean canopy height at the plot level. The same correlation was observed at the species population level for the three species adequately sampled. It can therefore be concluded that stratification by canopy height is to be recommended when deriving allometric relationships in order to avoid bias in Above Ground Biomass estimations.
Address CIRAD, UMR Ecofog, 97300 Kourou, France
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ISSN 0006579x (Issn) ISBN Medium
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Notes Export Date: 5 June 2013; Source: Scopus; Language of Original Document: English; Correspondence Address: IRD, UMR AMAP, 34000 Montpellier, France Approved no
Call Number EcoFoG @ webmaster @ Serial 490
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Author De Deurwaerder, H.; Hervé-Fernández, P.; Stahl, C.; Burban, B.; Petronelli, P.; Hoffman, B.; Bonal, D.; Boeckx, P.; Verbeeck, H.
Title (down) Liana and tree below-ground water competition – evidence for water resource partitioning during the dry season Type Journal Article
Year 2018 Publication Tree Physiology Abbreviated Journal
Volume 38 Issue 7 Pages 1071-1083
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Abstract To date, reasons for the increase in liana abundance and biomass in the Neotropics are still unclear. One proposed hypothesis suggests that lianas, in comparison with trees, are more adaptable to drought conditions. Moreover, previous studies have assumed that lianas have a deeper root system, which provides access to deeper soil layers, thereby making them less susceptible to drought stress. The dual stable water isotope approach (δ18O and δ2H) enables below-ground vegetation competition for water to be studied. Based on the occurrence of a natural gradient in soil water isotopic signatures, with enriched signatures in shallow soil relative to deep soil, the origin of vegetation water sources can be derived. Our study was performed on canopy trees and lianas reaching canopy level in tropical forests of French Guiana. Our results show liana xylem water isotopic signatures to be enriched in heavy isotopes in comparison with those from trees, indicating differences in water source depths and a more superficial root activity for lianas during the dry season. This enables them to efficiently capture dry season precipitation. Our study does not support the liana deep root water extraction hypothesis. Additionally, we provide new insights into water competition between tropical canopy lianas and trees. Results suggest that this competition is mitigated during the dry season due to water resource partitioning.
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Notes 10.1093/treephys/tpy002 Approved no
Call Number EcoFoG @ webmaster @ Serial 848
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Author Bekaert, E.; Robert, F.; Lippens, P.E.; Menetrier, M.
Title (down) Li-7 NMR Knight Shifts in Li-Sn Compounds: MAS NMR Measurements and Correlation with DFT Calculations Type Journal Article
Year 2010 Publication Journal of Physical Chemistry C Abbreviated Journal J. Phys. Chem. C
Volume 114 Issue 14 Pages 6749-6754
Keywords
Abstract Several Li-Sn crystalline phases, LiSn. Li7Sn3, Li5Sn7, Li13Sn5, Li7Sn2, and Li22Sn5. were prepared by ball-milling and studied by Li-7 MAS NMR spectroscopy with silica as a chiming agent to avoid field penetration limitations All phases except for LiSn exhibit exchanged NMR signals at room temperature for the various types of Li present in the unit cells. in the 10 to 100 ppm range. Electronic structure calculations based on first-principles method led to a lather good correlation between the participation of the Li 2s orbital to the density of states (DOS) at the Fermi level and the corresponding NMR Knight shift for the two Li crystallographic types in the case of LiSn, and for the weighted average of the different crystallographic types in the case of the NMR-exchanged signals for the other compounds
Address [Bekaert, Emilie; Menetrier, Michel] Univ Bordeaux, CNRS, ICMCB, F-33608 Pessac, France
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Publisher AMER CHEMICAL SOC Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
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ISSN 1932-7447 ISBN Medium
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Notes ISI:000276341700075 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 80
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Author Groc, S.; Delabie, J.H.C.; Fernández, F.; Leponce, M.; Orivel, J.; Silvestre, R.; Vasconcelos, H.L.; Dejean, A.
Title (down) Leaf-litter ant communities in a pristine Guianese rainforest: stable functional structure versus high species turnover Type Journal Article
Year 2013 Publication Myrmecological News Abbreviated Journal Myrmecol. News
Volume 19 Issue Pages 43-51
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Call Number EcoFoG @ webmaster @ Serial 523
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Author Groc, S.; Delabie, J.H.C.; Fernández, F.; Leponce, M.; Orivel, J.; Silvestre, R.; Vasconcelos, H.L.; Dejean, A.
Title (down) Leaf-litter ant communities (Hymenoptera: Formicidae) in a pristine Guianese rain-forest: Stable functional structure versus high species turnover Type Journal Article
Year 2014 Publication Myrmecological News Abbreviated Journal Myrmecological News
Volume 19 Issue Pages 43-51
Keywords Diversity gradient; Functional groups; Habitat heterogeneity; Litter-dwelling ant communities; Local scale; Pristine Amazonian rainforest; Taxonomic and functional structure
Abstract We compared the ant assemblages from four very heterogeneous habitats over a short-distance elevational gradient of vegetation (due to the presence of an inselberg) at the Nouragues Research Station, French Guiana. We focused on litter-dwelling ants, combining the use of pitfall traps and the Winkler method according to the Ants of the Leaf Litter Proto-col. This permitted us to note (1) a high leaf-litter ant diversity overall and a decreasing diversity gradient from the lowland rainforest to the top of the inselberg, and (2) differences in species density, composition and functional struc-ture. While the ant assemblages on the plateau and inselberg can be considered functionally similar and typical of an Amazonian rainforest, that of the transition forest, relatively homogenous, rather corresponded to an ant fauna typical of open areas. By contrast, the liana forest assemblage was unexpectedly richer and denser than the others, sheltering a litter-dwelling ant fauna dominated by numerous and abundant cryptic species. These taxonomical and functional dissi-milarities may reflect the influence of the environmental heterogeneity, which, through variable abiotic conditions, can contribute to maintaining a notably rich ant biodiversity in these Neotropical habitats.
Address Université de Toulouse, UPS (Ecolab), 118 route de Narbonne, 31062 Toulouse Cedex 9, France
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ISSN 19944136 (Issn) ISBN Medium
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Notes Export Date: 10 March 2014; Source: Scopus; Language of Original Document: English; Correspondence Address: Groc, S.; Instituto de Biologia, Universidade Federal de Uberlândia (UFU), 38400-902 Uberlândia, Minas Gerais, Brazil; email: groc.sarah@gmail.com Approved no
Call Number EcoFoG @ webmaster @ Serial 534
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Author Fortunel, C.; Fine, P.V.A.; Baraloto, C.
Title (down) Leaf, stem and root tissue strategies across 758 Neotropical tree species Type Journal Article
Year 2012 Publication Functional Ecology Abbreviated Journal Funct. Ecol.
Volume 26 Issue 5 Pages 1153-1161
Keywords French Guiana; Functional trade-offs; Leaf economics; Peru; Plant traits; Tropical forest; Wood economics
Abstract 1. Trade-offs among functional traits reveal major plant strategies that can give insight into species distributions and ecosystem processes. However, current identification of plant strategies lacks the integration of root structural traits together with leaf and stem traits. 2. We examined correlations among 14 traits representing leaf, stem and woody root tissues. Traits were measured on 1084 individuals representing 758 Neotropical tree species, across 13 sites representative of the environmental variation encompassed by three widespread habitats (seasonally flooded, clay terra firme and white-sand forests) at opposite ends of Amazonia (French Guiana and Peru). 3. Woody root traits were closely aligned with stem traits, but not with leaf traits. Altogether leaf, stem and woody root traits delineated two orthogonal axes of functional trade-offs: a first axis defined by leaf traits, corresponding to a 'leaf economics spectrum', and a second axis defined by covarying stem and woody root traits, corresponding to a 'wood economics spectrum'. These axes remained consistent when accounting for species evolutionary history with phylogenetically independent contrasts. 4. Despite the strong species turnover across sites, the covariation among root and stem structural traits as well as their orthogonality to leaf traits were strongly consistent across habitats and regions. 5. We conclude that root structural traits mirrored stem traits rather than leaf traits in Neotropical trees. Leaf and wood traits define an integrated whole-plant strategy in lowland South American forests that may contribute to a more complete understanding of plant responses to global changes in both correlative and modelling approaches. We suggest further meta-analyses in expanded environmental and geographic zones to determine the generality of this pattern. © 2012 The Authors. Functional Ecology © 2012 British Ecological Society.
Address Department of Biology, University of Florida, Gainesville, FL, 32611, United States
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ISSN 02698463 (Issn) ISBN Medium
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Notes Export Date: 10 October 2012; Source: Scopus; Coden: Fecoe; doi: 10.1111/j.1365-2435.2012.02020.x; Language of Original Document: English; Correspondence Address: Fortunel, C.; INRA, UMR Ecologie des Forêts de Guyane, BP 709, 97387 Kourou Cedex, France; email: claire.fortunel@ecofog.gf Approved no
Call Number EcoFoG @ webmaster @ Serial 440
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Author Fortunel, C.; Garnier, E.; Joffre, R.; Kazakou, E.; Quested, H.; Grigulis, K.; Lavorel, S.; Ansquer, P.; Castro, H.; Cruz, P.; Dolezal, J.; Eriksson, O.; Freitas, H.; Golodets, C.; Jouany, C.; Kigel, J.; Kleyer, M.; Lehsten, V.; Leps, J.; Meier, T.; Pakeman, R.; Papadimitriou, M.; Papanastasis, V.P.; Quetier, F.; Robson, M.; Sternberg, M.; Theau, J.P.; Thebault, A.; Zarovali, M.
Title (down) Leaf traits capture the effects of land use changes and climate on litter decomposability of grasslands across Europe Type Journal Article
Year 2009 Publication Ecology Abbreviated Journal Ecology
Volume 90 Issue 3 Pages 598-611
Keywords climate; community functional parameters; disturbance; leaf traits; litter decomposability; litter quality
Abstract Land use and climate changes induce shifts in plant functional diversity and community structure, thereby modifying ecosystem processes. This is particularly true for litter decomposition, an essential process in the biogeochemical cycles of carbon and nutrients. In this study, we asked whether changes in functional traits of living leaves in response to changes in land use and climate were related to rates of litter potential decomposition, hereafter denoted litter decomposability, across a range of 10 contrasting sites. To disentangle the different control factors on litter decomposition, we conducted a microcosm experiment to determine the decomposability under standard conditions of litters collected in herbaceous communities from Europe and Israel. We tested how environmental factors ( disturbance and climate) affected functional traits of living leaves and how these traits then modified litter quality and subsequent litter decomposability. Litter decomposability appeared proximately linked to initial litter quality, with particularly clear negative correlations with lignin-dependent indices ( litter lignin concentration, lignin : nitrogen ratio, and fiber component). Litter quality was directly related to community-weighted mean traits. Lignin-dependent indices of litter quality were positively correlated with community-weighted mean leaf dry matter content (LDMC), and negatively correlated with community-weighted mean leaf nitrogen concentration (LNC). Consequently, litter decomposability was correlated negatively with community-weighted mean LDMC, and positively with community-weighted mean LNC. Environmental factors ( disturbance and climate) influenced community-weighted mean traits. Plant communities experiencing less frequent or less intense disturbance exhibited higher community-weighted mean LDMC, and therefore higher litter lignin content and slower litter decomposability. LDMC therefore appears as a powerful marker of both changes in land use and of the pace of nutrient cycling across 10 contrasting sites.
Address [Fortunel, Claire; Garnier, Eric; Joffre, Richard; Kazakou, Elena] CNRS, UMR 5175, Ctr Ecol Fonct & Evolut, F-34293 Montpellier 5, France, Email: claire.fortunel@ecofog.gf
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Publisher ECOLOGICAL SOC AMER Place of Publication Editor
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0012-9658 ISBN Medium
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Notes ISI:000263776800003 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 121
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Author Haettenschwiler, S.; Coq, S.; Barantal, S.; Handa, I.T.
Title (down) Leaf traits and decomposition in tropical rainforests: revisiting some commonly held views and towards a new hypothesis Type Journal Article
Year 2011 Publication New Phytologist Abbreviated Journal New Phytol.
Volume 189 Issue 4 Pages 950-965
Keywords energy starvation; French Guiana; litter quality; mycorrhizas; nutrient cycling; nutrient limitation; phosphorus; soil fauna
Abstract Proper estimates of decomposition are essential for tropical forests, given their key role in the global carbon (C) cycle. However, the current paradigm for litter decomposition is insufficient to account for recent observations and may limit model predictions for highly diverse tropical ecosystems. In light of recent findings from a nutrient-poor Amazonian rainforest, we revisit the commonly held views that: litter traits are a mere legacy of live leaf traits; nitrogen (N) and lignin are the key litter traits controlling decomposition; and favourable climatic conditions result in rapid decomposition in tropical forests. Substantial interspecific variation in litter phosphorus (P) was found to be unrelated to variation in green leaves. Litter nutrients explained no variation in decomposition, which instead was controlled primarily by nonlignin litter C compounds at low concentrations with important soil fauna effects. Despite near-optimal climatic conditions, tropical litter decomposition proceeded more slowly than in a climatically less favourable temperate forest. We suggest that slow decomposition in the studied rainforest results from a syndrome of poor litter C quality beyond a simple lignin control, enforcing energy starvation of decomposers. We hypothesize that the litter trait syndrome in nutrient-poor tropical rainforests may have evolved to increase plant access to limiting nutrients via mycorrhizal associations.
Address [Haettenschwiler, Stephan; Coq, Sylvain; Barantal, Sandra; Handa, Ira Tanya] CNRS, CEFE, F-34293 Montpellier 5, France, Email: stephan.hattenschwiler@cefe.cnrs.fr
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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 0028-646x ISBN Medium
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Notes ISI:000286940500009 Approved no
Call Number EcoFoG @ webmaster @ Serial 296
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Author Lamarre, G.P.A.; Mendoza, I.; Fine, P.V.A.; Baraloto, C.
Title (down) Leaf synchrony and insect herbivory among tropical tree habitat specialists Type Journal Article
Year 2014 Publication Plant Ecology Abbreviated Journal Plant Ecol.
Volume 215 Issue 2 Pages 209-220
Keywords Escape; French Guiana; Herbivorous insects; Phenology; Resource availability; Time lag
Abstract Growth defense tradeoff theory predicts that plants in low-resource habitats invest more energy in defense mechanisms against natural enemies than growth, whereas plants in high-resource habitats can afford higher leaf loss rates. A less-studied defense against herbivores involves the synchrony of leaf production, which can be an effective defense strategy if leaf biomass production exceeds the capacity of consumption by insects. The aim of this study was to determine whether leaf synchrony varied across habitats with different available resources and whether insects were able to track young leaf production among tree habitat specialists in a tropical forest of French Guiana. We predicted that high-resource habitats would exhibit more synchrony in leaf production due to the low cost and investment to replace leaf tissue. We also expected closer patterns of leaf synchrony and herbivory within related species, assuming that they shared herbivores. We simultaneously monitored leaf production and herbivory rates of five pairs of tree species, each composed of a specialist of terra firme or white-sand forests within the same lineage. Our prediction was not supported by the strong interaction of habitat and lineage for leaf synchrony within individuals of the same species; although habitat specialists differed in leaf synchrony within four of five lineages, the direction of the effect was variable. All species showed short time lags for the correlation between leaf production and herbivory, suggesting that insects are tightly tracking leaf production, especially for the most synchronous species. Leaf synchrony may provide an important escape defense against herbivores, and its expression appears to be constrained by both evolutionary history and environmental factors. © 2014 Springer Science+Business Media Dordrecht.
Address Department of Biology, University of Florida, Gainesville, FL, 32611, United States
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ISSN 13850237 (Issn) ISBN Medium
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Notes Export Date: 24 February 2014; Source: Scopus; Coden: Plecf; Language of Original Document: English; Correspondence Address: Lamarre, G. P. A.; Université Antilles Guyane, UMR Ecologie des Forêts de Guyane, 97310 Kourou, French Guiana; email: greglamarre973@gmail.com; Funding Details: DEB-0743103/0743800, NSF, National Science Foundation Approved no
Call Number EcoFoG @ webmaster @ Serial 530
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Author Coste, S.; Roggy, J.C.; Imbert, P.; Born, C.; Bonal, D.; Dreyer, E.
Title (down) Leaf photosynthetic traits of 14 tropical rain forest species in relation to leaf nitrogen concentration and shade tolerance Type Journal Article
Year 2005 Publication Tree Physiology Abbreviated Journal Tree Physiol.
Volume 25 Issue 9 Pages 1127-1137
Keywords functional diversity; leaf carbon; leaf nitrogen; nitrogen-use efficiency; photosynthetic capacity; tropical rain forest
Abstract Variability of leaf traits related to photosynthesis was assessed in seedlings from 14 tree species growing in the tropical rain forest of French Guiana. Leaf photosynthetic capacity (maximum rate of carboxylation and maximum rate of electron transport) was estimated by fitting a biochemical model of photosynthesis to response curves of net CO2 assimilation rate versus intercellular CO2 mole fraction. Leaf morphology described by leaf mass per unit leaf area (LMA), density and thickness, as well as area- and mass-based nitrogen (N) and carbon (C) concentrations, were recorded on the same leaves. Large interspecific variability was detected in photosynthetic capacity as well as in leaf structure and leaf N and C concentrations. No correlation was found between leaf thickness and density. The correlations between area- and mass-based leaf N concentration and photosynthetic capacity were poor. Conversely, the species differed greatly in relative N allocation to carboxylation and bioenergetics. Principal component analysis (PCA) revealed that, of the recorded traits, only the computed fraction of total leaf N invested in photosynthesis was tightly correlated to photosynthetic capacity. We also used PCA to test to what extent species with similar shade tolerances displayed converging leaf traits related to photosynthesis. No clear-cut ranking could be detected among the shade-tolerant groups, as confirmed by a one-way ANOVA. We conclude that the large interspecific diversity in photosynthetic capacity was mostly explained by differences in the relative allocation of N to photosynthesis and not by leaf N concentration, and that leaf traits related to photosynthetic capacity did not discriminate shade-tolerance ranking of these tropical tree species.
Address CNRS Ecol Forets Guyane, INRA, ENGREF,CIRAD, Unite Mixte Rech, Kourou 97387, French Guiana, Email: roggy.j@cirad.fr
Corporate Author Thesis
Publisher HERON PUBLISHING Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0829-318X ISBN Medium
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Notes ISI:000231555200005 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 230
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