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Author Urbina, Ifigenia ; Grau, Oriol ; Sardans, Jordi ; Margalef, Olga ; Peguero, Guillermo ; Asensio, Dolores ; Llusia, Joan ; Ogaya, Roma ; Gargallo-Garriga, Albert ; Van Langenhove, Leandro ; Verryckt, Lore T. ; Courtois, Elodie A. ; Stahl, Clement ; Soong, Jennifer L. ; Chave, Jérome ; Hérault, Bruno ; Janssens, Ivan A. ; Sayer, Emma ; Penuelas, Josep
Title High foliar K and P resorption efficiencies in old-growth tropical forests growing on nutrient-poor soils Type Journal Article
Year 2021 Publication Ecology and Evolution Abbreviated Journal
Volume 11 Issue 13 Pages 8969-8982
Keywords
Abstract (down) Resorption is the active withdrawal of nutrients before leaf abscission. This mechanism represents an important strategy to maintain efficient nutrient cycling; however, resorption is poorly characterized in old-growth tropical forests growing in nutrient-poor soils. We investigated nutrient resorption from leaves in 39 tree species in two tropical forests on the Guiana Shield, French Guiana, to investigate whether resorption efficiencies varied with soil nutrient, seasonality, and species traits. The stocks of P in leaves, litter, and soil were low at both sites, indicating potential P limitation of the forests. Accordingly, mean resorption efficiencies were higher for P (35.9%) and potassium (K; 44.6%) than for nitrogen (N; 10.3%). K resorption was higher in the wet (70.2%) than in the dry (41.7%) season. P resorption increased slightly with decreasing total soil P; and N and P resorptions were positively related to their foliar concentrations. We conclude that nutrient resorption is a key plant nutrition strategy in these old-growth tropical forests, that trees with high foliar nutrient concentration reabsorb more nutrient, and that nutrients resorption in leaves, except P, are quite decoupled from nutrients in the soil. Seasonality and biochemical limitation played a role in the resorption of nutrients in leaves, but species-specific requirements obscured general tendencies at stand and ecosystem level.
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Publisher Wiley Place of Publication Editor
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Call Number EcoFoG @ webmaster @ Serial 1011
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Author Falkowski, M.; Jahn-Oyac, A.; Ferrero, E.; Issaly, J.; Eparvier, V.; Girod, R.; Rodrigues, A.M.S.; Stien, D.; Houel, E.; Dusfour, I.
Title Assessment of A Simple Compound-Saving Method to Study Insecticidal Activity of Natural Extracts and Pure Compounds Against Mosquito Larvae Type Journal Article
Year 2016 Publication Journal of the American Mosquito Control Association Abbreviated Journal Journal of the American Mosquito Control Association
Volume 32 Issue 4 Pages 337-340
Keywords Mosquitoes; natural insecticides; screening method
Abstract (down) Research on natural insecticides has intensified with the spread of resistance to chemicals among insects, particularly disease vectors. To evaluate compounds, the World Health Organization (WHO) has published standardized procedures. However, those may be excessively compound-consuming when it comes to assessing the activity of natural extracts and pure compounds isolated in limited amount. As part of our work on the discovery of new mosquito larvicides from Amazonian plants, we developed a compound-saving assay in 5-ml glass tubes instead of WHO larval 100-ml cups. Comparing activity of synthetic and natural chemicals validated the glass tube assay. Raw data, lethal doses that kill 50% (LD50) and 90% (LD90) at 24 and 48 h, were highly correlated (0.68 < R2 < 0.96, P < 0.001, Pearson test) between cups and tubes. It was also established that 10 tubes (N = 50 larvae) provided the same level of sensitivity as 20 tubes (N = 100). This method proved suitable for rapid screening of natural extracts and molecules, identifying active compounds using 10 times less material than in the WHO protocol. © 2016 by The American Mosquito Control Association, Inc.
Address Sorbonne Universites, UPMC, Universite Paris 06, CNRS, Laboratoire de Biodiversite et Biotechnologies Microbiennes (USR 3579, LBBM), Observatoire Oceanologique, avenue de Fontaul e, Banyuls/Mer-sur-mer, France
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Notes Export Date: 3 March 2017 Approved no
Call Number EcoFoG @ webmaster @ Serial 740
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Author Rodrigues, A.M.S.; Theodoro, P.N.E.T.; Eparvier, V.; Basset, C.; Silva, M.R.R.; Beauchene, J.; Espindola, L.S.; Stien, D.
Title Search for Antifungal Compounds from the Wood of Durable Tropical Trees Type Journal Article
Year 2010 Publication Journal of Natural Products Abbreviated Journal J. Nat. Prod.
Volume 73 Issue 10 Pages 1706-1707
Keywords
Abstract (down) Research on antifungal compounds from the durable wood from French Guiana Amazonian forest trees highlights the correlation between the activity of their extracts against wood-rotting fungi and human pathogens. The fractionation of an ethyl acetate extract of Sextonia rubra wood led to the isolation of rubrenolide (1) and rubrynolide (2). The potential of compounds 1 and 2 is described through the evaluation of their activity against 16 pathogenic fungi and their cytotoxicity toward NIH-3T3 mammalian fibroblast cells.
Address [Rodrigues, Alice M. S.; Eparvier, Veronique; Basset, Charlie; Espindola, Laila S.; Stien, Didier] Univ Antilles Guyane, CNRS, UMR ECOFOG, F-97300 Cayenne, France, Email: darvenne@unb.br
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Publisher AMER CHEMICAL SOC Place of Publication Editor
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ISSN 0163-3864 ISBN Medium
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Notes ISI:000283288900015 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 25
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Author Molto, Q.; Rossi, V.; Blanc, L.
Title Error propagation in biomass estimation in tropical forests Type Journal Article
Year 2013 Publication Methods in Ecology and Evolution Abbreviated Journal
Volume 4 Issue 2 Pages 175-183
Keywords Bayesian framework; Modelling; Redd; Uncertainty propagation
Abstract (down) Reliable above-ground biomass (AGB) estimates are required for studies of carbon fluxes and stocks. However, there is a huge lack of knowledge concerning the precision of AGB estimates and the sources of this uncertainty. At the tree level, the tree height is predicted using the tree diameter at breast height (DBH) and a height sub-model. The wood-specific gravity (WSG) is predicted with taxonomic information and a WSG sub-model. The tree mass is predicted using the predicted height, the predicted WSG and the biomass sub-model. Our models were inferred with Bayesian methods and the uncertainty propagated with a Monte Carlo scheme. The uncertainties in the predictions of tree height, tree WSG and tree mass were neglected sequentially to quantify their contributions to the uncertainty in AGB. The study was conducted in French Guiana where long-term research on forest ecosystems provided an outstanding data collection on tree height, tree dynamics, tree mass and species WSG. We found that the uncertainty in the AGB estimates was found to derive primarily from the biomass sub-model. The models used to predict the tree heights and WSG contributed negligible uncertainty to the final estimate. Considering our results, a poor knowledge of WSG and the height-diameter relationship does not increase the uncertainty in AGB estimates. However, it could lead to bias. Therefore, models and databases should be used with care. This study provides a methodological framework that can be broadly used by foresters and plant ecologist. It provides the accurate confidence intervals associated with forest AGB estimates made from inventory data. When estimating region-scale AGB values (through spatial interpolation, spatial modelling or satellite signal treatment), the uncertainty of the forest AGB value in the reference forest plots has to be taken in account. We believe that in the light of the Reducing Emissions from Deforestation and Degradation debate, our method is a crucial step in monitoring carbon stocks and their spatio-temporal evolution. © 2012 The Authors. Methods in Ecology and Evolution © 2012 British Ecological Society.
Address CIRAD, UMR 'Ecologie des Forêts de Guyane', Kourou Cedex, 97 379, France
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Notes Export Date: 21 February 2013; Source: Scopus Approved no
Call Number EcoFoG @ webmaster @ Serial 470
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Author Roux, O.; Vantaux, A.; Petitclerc, F.; Orivel, J.; Dejean, A.; Billen, J.
Title Structural adaptations and mechanism of reflex bleeding in the larvae of the myrmecophilous ladybird Diomus thoracicus Type Journal Article
Year 2017 Publication Arthropod Structure and Development Abbreviated Journal Arthropod Structure and Development
Volume 46 Issue 4 Pages 529-536
Keywords 3D reconstruction; Coccinellidae; Myrmecophagous insect; Reflex bleeding; Ultrastructure
Abstract (down) Reflex bleeding is an effective defensive mechanism against predators. When attacked, some insects emit hemolymph, which coagulates, quickly entangling their aggressor. Bleeding occurs at weak intersegmental membranes or through dedicated organs, which can be associated or not with glandular cells. Here, we describe the behavior and morphological structures involved in reflex bleeding in the larvae of the ladybird, Diomus thoracicus, which are intranidal parasites of the ant Wasmannia auropunctata. The larvae are tolerated by the ants thanks to odor mimicry, but some rare aggressive ant behaviors were observed that trigger reflex bleeding both at a pair of thoracic tubercles and a pair of posterodorsal abdominal humps. No glandular structure was found in association with these emission points, which suggests that the material emitted was hemolymph only. A 3D reconstruction suggested that reflex bleeding seems to be controlled by muscles whose contraction increases the internal hydrostatic pressure and pushes the hemolymph into a funnel-like structure with an opening to the outside. In D. thoracicus, the morphological structures involved in reflex bleeding are among the most complex and prominent described to date. © 2017 Elsevier Ltd
Address KU Leuven, Zoological Institute, Naamsestraat 59, box 2466, Leuven, Belgium
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Notes Export Date: 18 December 2017 Approved no
Call Number EcoFoG @ webmaster @ Serial 778
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Author Rockwell, C.; Kainer, K.A.; Marcondes, N.; Baraloto, C.
Title Ecological limitations of reduced-impact logging at the smallholder scale Type Journal Article
Year 2007 Publication Forest Ecology and Management Abbreviated Journal For. Ecol. Manage.
Volume 238 Issue 1-3 Pages 365-374
Keywords community forest management; forest inventories; liana cutting; sustained yield; timber management; tropical forest conservation
Abstract (down) Reduced-impact logging (RIL) has many demonstrated benefits to the industrial logging operations for which they were developed. It is less clear whether these gains remain consistent in smallholder forest systems that increasingly play an important role in global conservation and that target a broader suite of outputs in their management schemes. We evaluate potential ecological consequences of five RIL components (pre-harvest inventories, harvest intensity, cutting cycles, skid trail planning, and liana cutting) when applied to small-scale operations in the Brazilian Amazon and provide suggestions for modifications to RIL guidelines for smallholder systems. Rapid assessment inventories of the entire landholding should be a part of crop tree selection to minimize inbreeding and recruitment failure. Additionally, while community-based taxonomists accurately identify species to common names, botanical samples must be verified with herbarium specimens to avoid market and ecological problems when multiple species share a single common name. We advocate that smallholder managers move beyond an emphasis on RIL guidelines, while still incorporating its basic tenets into practical application. Based on our analysis, this would include evaluating benefits of particular RIL components and assessing potential advantages that smallholders have over industrial operations. We suggest incorporating anthropogenically-generated forest patches of varying sizes and successional stages into a more formalized management system, incorporating and expanding on traditional ecological knowledge acquired over generations, and integrating enrichment plantings and tending of regeneration. (c) 2006 Published by Elsevier B.V.
Address Univ Florida, Sch Forest Resources & Conservat, Gainesville, FL 32611 USA, Email: crockwel@ufl.edu
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Publisher ELSEVIER SCIENCE BV Place of Publication Editor
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ISSN 0378-1127 ISBN Medium
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Notes ISI:000243761700033 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 220
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Author Sist, P.; Sheil, D.; Kartawinata, K.; Priyadi, H.
Title Reduced-impact logging in Indonesian Borneo: some results confirming the need for new silvicultural prescriptions Type Journal Article
Year 2003 Publication Forest Ecology and Management Abbreviated Journal For. Ecol. Manage.
Volume 179 Issue 1-3 Pages 415-427
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Abstract (down) Reduced-impact logging (RIL) and conventional techniques (CNV) were compared in a mixed dipterocarp hill forest in East Kalimantan in three blocks of about 100 ha each. Damage was evaluated using pre- and post-harvesting assessments in 24 one-hectare sample plots. RIL techniques nearly halved the number of trees destroyed (36 vs 60 trees/ha). RIL's main benefit was in the reduction of skidding damage (9.5% of the original tree population in RIL vs 25% in CNV). Before logging, mean canopy openness in CNV (three plots only) and RIL (9 plots) was similar (3.6 and 3.1%) and not significantly different (x(2) = 2.73, P = 0.254). After logging, the mean canopy openness was 19.2% in CNV (n = 9 plots) and 13.3% in RIL (n = 8 plots), and the distributions of the canopy class in RIL and CNV significantly different x(2) = 43.56, P < 0.001). CNV plots showed a higher proportion of measurements in the most open class greater than or equal to30% than in RIL. At a larger scale, the area of skidtrail per unit timber volume extracted was halved in the RIL compartment (15 m(2) vs 27 m(2) m(-3) for CNV). However, under high felling intensity (>8 trees/ha), both stand damage and canopy disturbance in RIL approached those recorded in CNV under low or moderate felling regime. Over this felling intensity threshold the effectiveness of RIL in reducing tree damage is limited. In mixed dipterocarp forest where harvestable timber density generally exceeds 10 trees/ha, a minimum diameter felling limit is clearly insufficient to keep extraction rates below 8 trees/ha. Based on these new results and previous studies in Borneo, we suggest three silvicultural rules: (1) to keep a minimum distance between stumps of ca. 40 m, (2) to ensure only single tree gaps using directional felling, (3) to harvest only stems with 60-100 cm dbh. Foresters, policy makers and certifiers should consider these as criteria for sustainable forest management. We emphasise the need to expand harvesting studies to look at impacts and trade-offs across larger forest landscapes, to expand RIL beyond silvicultural concepts and to include the maintenance of other forest goods and services. (C) 2002 Elsevier Science B.V. All rights reserved.
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Notes WOS:000183836300033 Approved no
Call Number EcoFoG @ webmaster @ Serial 311
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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.
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
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Abstract (down) 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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Call Number EcoFoG @ webmaster @ Stahl2016 Serial 721
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Author Lehnebach, R.; Doumerc, L.; Clair, B.; Alméras, T.
Title Mechanical stress in the inner bark of 15 tropical tree species and the relationship with anatomical structure Type Journal Article
Year 2020 Publication Botany Abbreviated Journal Bot.
Volume 98 Issue 1 Pages 1-8
Keywords Bark anatomical structure; Mechanical stress; Sclereids; Secondary phloem; Tree biomechanics; Tropical species
Abstract (down) Recent studies have shown that the inner bark is implicated in the postural control of inclined tree stems through the interaction between wood radial growth and tangential expansion of a trellis fiber network in bark. Assessing the taxonomic extent of this mechanism requires a screening of the diversity in bark anatomy and mechanical stress. The mechanical state of bark was measured in 15 tropical tree species from various botanical families on vertical mature trees, and related to the anatomical structure of the bark. Significant tensile or compressive longitudinal stresses were observed in the stems of most species. Tensile longitudinal stress was observed in various botanical families and was always associated with fibers arranged in a trellis-like structure and strong dilatation of rays. The highest tensile stress was recorded in species with gelatinous fibers forming a treillis. Compressive stress was typically associated with a large amount of sclereids in the bark, supporting the differentiation of sclereids as a potential origin of the generation of longitudinal compressive stresses in bark. In species exhibiting both a fibrous trellis structure and a significant amount of sclereids, the sign of longitudinal stress may depend on the balance between these two mechanisms.
Address Faculty of Bioscience Engineering, Laboratory of Wood Technology, Woodlab, Coupure Links 653, Gent, B-9000, Belgium
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Notes Cited By :1; Export Date: 20 January 2020; Correspondence Address: Lehnebach, R.; Laboratoire de Mécanique et Génie Civil (LMGC), Université de Montpellier, CNRS, 860 rue de St. Priest, France; email: lehnebach.romain@hotmail.fr Approved no
Call Number EcoFoG @ webmaster @ Serial 913
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Author Siefert, A.; Violle, C.; Chalmandrier, L.; Albert, C.H.; Taudiere, A.; Fajardo, A.; Aarssen, L.W.; Baraloto, C.; Carlucci, M.B.; Cianciaruso, M.V.; de L. Dantas, V.; de Bello, F.; Duarte, L.D.S.; Fonseca, C.R.; Freschet, G.T.; Gaucherand, S.; Gross, N.; Hikosaka, K.; Jackson, B.; Jung, V.; Kamiyama, C.; Katabuchi, M.; Kembel, S.W.; Kichenin, E.; Kraft, N.J.B.; Lagerström, A.; Bagousse-Pinguet, Y.L.; Li, Y.; Mason, N.; Messier, J.; Nakashizuka, T.; Overton, J.M.; Peltzer, D.A.; Pérez-Ramos, I.M.; Pillar, V.D.; Prentice, H.C.; Richardson, S.; Sasaki, T.; Schamp, B.S.; Schöb, C.; Shipley, B.; Sundqvist, M.; Sykes, M.T.; Vandewalle, M.; Wardle, D.A.
Title A global meta-analysis of the relative extent of intraspecific trait variation in plant communities Type Journal Article
Year 2015 Publication Ecology Letters Abbreviated Journal Ecology Letters
Volume 18 Issue 12 Pages 1406-1419
Keywords Community ecology; Functional diversity; Interspecific variation; Intraspecific variability; Leaf trait; Plant functional trait; Trait-based ecology
Abstract (down) Recent studies have shown that accounting for intraspecific trait variation (ITV) may better address major questions in community ecology. However, a general picture of the relative extent of ITV compared to interspecific trait variation in plant communities is still missing. Here, we conducted a meta-analysis of the relative extent of ITV within and among plant communities worldwide, using a data set encompassing 629 communities (plots) and 36 functional traits. Overall, ITV accounted for 25% of the total trait variation within communities and 32% of the total trait variation among communities on average. The relative extent of ITV tended to be greater for whole-plant (e.g. plant height) vs. organ-level traits and for leaf chemical (e.g. leaf N and P concentration) vs. leaf morphological (e.g. leaf area and thickness) traits. The relative amount of ITV decreased with increasing species richness and spatial extent, but did not vary with plant growth form or climate. These results highlight global patterns in the relative importance of ITV in plant communities, providing practical guidelines for when researchers should include ITV in trait-based community and ecosystem studies. © 2015 John Wiley & Sons Ltd/CNRS.
Address Department of Physical Geography and Ecosystem Science, Lund University, Sölvegatan 12, Lund, Sweden
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Notes Export Date: 16 November 2015 Approved no
Call Number EcoFoG @ webmaster @ Serial 637
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