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Author Scotti, I.; Montaigne, W.; Cseke, K.; Traissac, S. url  openurl
  Title Life after disturbance (II): the intermediate disturbance hypothesis explains genetic variation in forest gaps dominated by Virola michelii Heckel (Myristicaceae) Type Journal Article
  Year 2015 Publication Annals of Forest Science Abbreviated Journal Annals of Forest Science  
  Volume 72 Issue 8 Pages 1035-1042  
  Keywords Amazon; Bayesian clustering; Demogenetics; Guiana shield; Parentage analysis; Regeneration; Spatial genetic structure; Tropical rainforest  
  Abstract (up) Key message: Genetic diversity appears to be unaffected by disturbance in a stand of the light-demanding Neotropical treeV. michelii. Although spatial genetic structure is modified in post-disturbance cohorts, mixing of seeds from different mother trees in canopy gaps appears to efficiently maintain genetic admixture. Context: The interplay between genetic and demographic processes has major consequences on population viability. Population size affects demographic trends, while genetic diversity insures viability by reducing risks of inbreeding depression and by maintaining adaptive potential. Yet, the consequences of increases in census size (as opposed to effective size) on genetic diversity of forest populations are poorly known. Aims: We have studied the structure of genetic diversity in populations of saplings of the light-responsive tree, Virola michelii (Myristicaceae, the nutmeg family), in two plots having undergone different levels of canopy-gap opening disturbance. This allowed us to test the “intermediate disturbance” hypothesis, which generally applies to species diversity, at the intra-specific scale. Methods: Levels and distribution of genetic diversity were compared between plots and between life stages. Sapling parentage was analysed to infer each adult tree’s contribution to regeneration. Results: Genetic diversity was higher, and spatial genetic structure was stronger in the post-disturbance than in the control seedling population. Parentage analysis suggested that a limited number of parents contributed to most of the regeneration, but that efficient mixing of their progeny may have enhanced the diversity of saplings occupying canopy gaps. Conclusion: A mixture of demo-genetic processes may contribute to maintain genetic diversity in spite of, or possibly due to, ecosystem disturbance in V. michelii. © 2015, INRA and Springer-Verlag France.  
  Address Solicaz, Guyane Technopôle, 16 bis Rue du 14 Juillet, Cayenne, French Guiana  
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  Notes Export Date: 14 December 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 642  
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Author Ghislain, B.; Alméras, T.; Prunier, J.; Clair, B. pdf  url
doi  openurl
  Title Contributions of bark and tension wood and role of the G-layer lignification in the gravitropic movements of 21 tropical tree species Type Journal Article
  Year 2019 Publication Annals of Forest Science Abbreviated Journal Ann. Forest Sci.  
  Volume 76 Issue 4 Pages 107  
  Keywords Bark; Biomechanics; G-layer; Lignification; Tension wood; Tropical rainforest; Magnoliophyta  
  Abstract (up) Key message: Gravitropic movements in angiosperm woody stems are achieved through the action of bark and/or wood motor, depending on the bark and wood fibre anatomy (with trellis structure or not; with G-layers or not). Bark motor is as efficient as wood motor to recover from tilting in young trees of 21 tropical species. Context: Angiosperm trees produce tension wood to control their orientation through changes in stem curvature. Tension wood is classified into 3 anatomical groups: with unlignified G-layer, with lignified G-layer and without G-layer. Aims: This study aimed at assessing whether this anatomical diversity reflects a diversity in efficiency of gravitropic movement. Methods: The study was conducted on tropical seedling from the three anatomical groups. Seedlings were staked and grown tilted. At the end of the experiment, changes in curvature when releasing the stem from the stake and when removing bark were measured. Three parameters were computed to compare the global efficiency of gravitropism (stem gravitropic efficiency) and the specific efficiency of motor mechanism based on wood (maturation strain of tension wood) and bark (standardized debarking curvature). Results: The maturation strain of tension wood was similar between species with unlignified and lignified G-layer. Species without G-layer exhibited low maturation strain and large debarking curvature, showing they rely on bark for gravitropism. Bark and wood achieved similar motor efficiency. Conclusion: Lignin does not affect the generation of tensile stress in the G-layer. Bark can be as efficient as wood as a motor of gravitropic movements. © 2019, The Author(s).  
  Address Laboratoire de Mécanique et Génie Civil (LMGC), Université de Montpellier, CNRS, Montpellier, 34095, France  
  Corporate Author Thesis  
  Publisher Springer Place of Publication Editor  
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  ISSN 12864560 (Issn) ISBN Medium  
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  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 900  
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Author Morel, H.; Mangenet, T.; Beauchene, J.; Ruelle, J.; Nicolini, E.; Heuret, P.; Thibaut, B. url  openurl
  Title Seasonal variations in phenological traits: leaf shedding and cambial activity in Parkia nitida Miq. and Parkia velutina Benoist (Fabaceae) in tropical rainforest Type Journal Article
  Year 2015 Publication Trees – Structure and Function Abbreviated Journal Trees – Structure and Function  
  Volume 29 Issue 4 Pages 973-984  
  Keywords Cambial activity; Climate; French Guiana; Leaf shedding pattern; Tropical rainforest  
  Abstract (up) Key message: In French Guiana, the leaf and cambium phenologies should not be considered only as exogenous-driven processes, as the dry season, but also as endogenous-driven, as tree development stage. Abstract: Studies of the periodicity of wood formation provide essential data on tree age and on factors that control tree growth. The aim of this work was to investigate cambial phenology and its relation with leaf phenology and climatic seasonality in two briefly deciduous tropical rainforest species belonging to the genus Parkia. Wood microcores were collected every 15 days from April 2009 to February 2012 from five trees of each species. The microcores were stained with cresyl violet acetate to facilitate counting the number of cells in the cambial zone, in the radial enlargement zone and wall-thickening zone. At the same time, we observed leaf shedding pattern in the crown of the same trees. In both species, cambial activity was significantly reduced during the leafless period. In P. nitida, these two concomitant events were observed during the dry season whereas in P. velutina they can occur anytime in the year with no apparent link with seasonality. In conclusion, the period of reduced cambial activity in some tropical rainforest trees may be independent of rainfall seasonality and not necessarily follow an annual cycle. It appears that leaf phenology is a good proxy to estimate cambial activity. © 2015, Springer-Verlag Berlin Heidelberg.  
  Address CNRS, UMR Laboratoire de Mécanique et Génie Civil de Montpellier, Montpellier, France  
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  Notes Export Date: 16 July 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 610  
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Author Bompy, F.; Imbert, D.; Dulormne, M. url  openurl
  Title Impact patterns of soil salinity variations on the survival rate, growth performances, and physiology of Pterocarpus officinalis seedlings Type Journal Article
  Year 2015 Publication Trees – Structure and Function Abbreviated Journal Trees – Structure and Function  
  Volume 29 Issue 1 Pages 119-128  
  Keywords Acclimation; Leaf chemical composition; Leaf gas exchange; NaCl salinity; Tropical swamp forest; Vegetative growth  
  Abstract (up) Key message: Pterocarpus officinalisis able to (1) improve its acclimation capacity if soil salinity increases slowly and (2) benefit from afreshwater episode.
Abstract: One likely effect of global change is an increase of the amplitude of salt variations in the soil of brackish coastal wetland forests. In the Antilles, such forests are dominated by the species Pterocarpus officinalis. The study aimed to determine the effect of 3 salinity levels (freshwater, moderate, and hypersalinity—i.e., 0, 10, and 30 ‰, respectively) and 3 patterns of salinity variation (fast or slow salinity increase, fluctuating salinity) on the growth and ecophysiology of P. officinalis seedlings. P. officinalis proved tolerant to 10 ‰ salinity, even if at this salt concentration the water constraint altered the plant’s water status and reduced stomatal conductance. No impact of the pattern of salinity variation was observed at 10 ‰. Seedlings were strongly affected by hypersalinity, but were able to acclimatize efficiently and to improve their performances (higher survival, total biomass, and photosynthesis) when salinity increased slowly. Young P. officinalis were also able to take advantage of a freshwater episode on the longer term, certainly through leaf desalination associated with enhanced photosynthesis and water use efficiency. Higher soil salinity and more intense dry seasons in the context of climate change could affect the stand-level regeneration potential of P. officinalis seedlings. © 2014, Springer-Verlag Berlin Heidelberg.
 
  Address UMR ECOFOG-DYNECAR, UFR des Sciences Exactes et Naturelles, Université des Antilles et de la Guyane, Pointe-à-PitreGuadeloupe (F.W.I.), France  
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  Notes Export Date: 9 April 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 595  
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Author Lehnebach, R.; Morel, H.; Bossu, J.; Le Moguédec, G.; Amusant, N.; Beauchene, J.; Nicolini, E. url  doi
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  Title Heartwood/sapwood profile and the tradeoff between trunk and crown increment in a natural forest: the case study of a tropical tree (Dicorynia guianensis Amsh., Fabaceae) Type Journal Article
  Year 2017 Publication Trees – Structure and Function Abbreviated Journal Trees – Structure and Function  
  Volume 31 Issue 1 Pages 199-214  
  Keywords Dicorynia guianensis; Growth allocation; Heartwood; Ontogeny; Sapwood; Tropical tree  
  Abstract (up) Key message: Sapwood area and the radial growth rate of the trunk follow the same pattern at breast height, with an initial increase and subsequent constant value, resulting from the increasing growth allocation toward the crown rather than tree decline. Heartwood area and heartwood volume in the trunk increase more rapidly after this shift occurs. Abstract: Sapwood (SW) and heartwood (HW) are two functionally distinct classifications of wood in perennial stems for which quantities can vary greatly in tropical trees. Numerous positive correlations have been found between the radial growth rate (RGR) and SW quantity; however, variations in the SW/HW quantities have not been studied in light of the ontogenetic variation of RGR. Wood core sampling, intensive measurements of tree structure (number of branches, stem volumes), and radial growth monitoring were performed on an abundant and highly exploited tree species in French Guiana (Dicorynia guianensis) to investigate the relationship between RGR, SW/HW quantity, tree structure, and their variations on the course of a tree’s ontogeny. SW area and RGR followed the same pattern of variation throughout tree development, both increasing first and reaching a steady state after 50 cm DBH (diameter at breast height). After this value, we observed a strong increase in both the HW area and HW volume increment, concomitant with a more rapid increase in crown volume. The stabilization of RGR for trees with DBH > 50 cm was related not to a tree’s decline but rather to an increasing wood allocation to the crown, confirming that RGR at breast height is a poor indicator of whole-tree growth for bigger individuals. We also confirmed that HW formation is an ontogenetic process managing SW quantity that is continuously and increasingly produced within the crown as the tree grows. This study highlights the effect of growth-mediated ontogenetic changes on the localization of water and carbohydrate storage within a tree, resulting from SW and HW dynamics throughout tree ontogeny. © 2016, Springer-Verlag Berlin Heidelberg.  
  Address CIRAD, UMR EcoFoG, BP701, Kourou Cedex, French Guiana  
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  Notes Export Date: 19 February 2017 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 733  
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Author Anouhe, J.-B.S.; Niamké, F.B.; Faustin, M.; Virieux, D.; Pirat, J.-L.; Adima, A.A.; Kati-Coulibaly, S.; Amusant, N. url  doi
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  Title The role of extractives in the natural durability of the heartwood of Dicorynia guianensis Amsh: new insights in antioxydant and antifungal properties Type Journal Article
  Year 2018 Publication Annals of Forest Science Abbreviated Journal Annals of Forest Science  
  Volume 75 Issue 1 Pages  
  Keywords Alkaloid; Antifungal; Antioxidant; Dicorynia guianensis; Heartwood; Natural durability; Phenols  
  Abstract (up) Key message: The natural durability of Dicorynia guianensis Amsh’s Heartwood is conferred by the high content of antioxidant phenolic compounds, especially tannins and flavonoids combined with the presence of fungistatic alkaloids. The content of phenolic compounds increases according to the natural durability classes, from durable wood (class 2) to moderately durable wood (class 3) and correlated to the antioxidant capacity.
Context: The heartwood of Dicorynia guianensis Amsh is resistant to white rot fungi decay, but the mechanism of this natural durability is not fully elucidated.
Aims: Biochemical studies were carried out in order to better understand the role of extractives in natural durability of D. guianensis.
Methods: The powders from durable and moderately durable heartwood were extracted with methanol, ethanol, and hot water. The quantity of total phenols, tannins, and flavonoids as well as antioxidant activity, evaluated by 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) were determined using colorimetric methods. Antifungal activity was assessed by using two white rot fungi. The bioactive fractions and compounds were obtained using bio-guided fractionation, HPLC isolation, MS and RMN spectroscopic analyses.
Results: Durable woods contain higher amounts of heartwood extract and antioxidant activity. Antioxidant activity was highly correlated with the content of phenolics. The purification of the most antioxidant fraction FII affords the characterization of (+)-catechin (−)-epicatechin, neoastilbin, astilbin, and isoastilbin. Alkaloid fraction FIII exhibits dose-dependent fungistatic activity against Pycnoporus sanguineus Linnaeus and Trametes versicolor Quelet.
Conclusion: Phenolic antioxidants and fungistatic alkaloids positively impact the natural durability of D. guianensis.
 
  Address AM2N, Institut Charles Gerhardt, UMR 5253, ENSCM 8 rue de l’Ecole Normale, Montpellier, France  
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  Notes Export Date: 19 February 2018 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 791  
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Author Bonal, D.; Burban, B.; Stahl, C.; Wagner, F.; Herault, B. url  openurl
  Title The response of tropical rainforests to drought—lessons from recent research and future prospects Type Journal Article
  Year 2016 Publication Annals of Forest Science Abbreviated Journal Annals of Forest Science  
  Volume 73 Issue 1 Pages 27-44  
  Keywords Carbon; Climate; Drought; Global change; Growth; Mortality; Soil; Tropical; Water  
  Abstract (up) Key message: We review the recent findings on the influence of drought on tree mortality, growth or ecosystem functioning in tropical rainforests. Drought plays a major role in shaping tropical rainforests and the response mechanisms are highly diverse and complex. The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical rainforests on the three continents. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance. Context: Tropical rainforest ecosystems are characterized by high annual rainfall. Nevertheless, rainfall regularly fluctuates during the year and seasonal soil droughts do occur. Over the past decades, a number of extreme droughts have hit tropical rainforests, not only in Amazonia but also in Asia and Africa. The influence of drought events on tree mortality and growth or on ecosystem functioning (carbon and water fluxes) in tropical rainforest ecosystems has been studied intensively, but the response mechanisms are complex. Aims: Herein, we review the recent findings related to the response of tropical forest ecosystems to seasonal and extreme droughts and the current knowledge about the future of these ecosystems. Results: This review emphasizes the progress made over recent years and the importance of the studies conducted under extreme drought conditions or in through-fall exclusion experiments in understanding the response of these ecosystems. It also points to the great diversity and complexity of the response of tropical rainforest ecosystems to drought. Conclusion: The numerous gaps identified here require the international scientific community to combine efforts in order to conduct comprehensive studies in tropical forest regions. These results are essential to simulate the future of these ecosystems under diverse climate scenarios and to predict the future of the global earth carbon balance. © 2015, INRA and Springer-Verlag France.  
  Address National Institute for Space Research (INPE), São José dos Campos, SP, Brazil  
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  Notes Export Date: 7 March 2016 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 669  
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Author Thibaut, B.; Denaud, L.; Collet, R.; Marchal, R.; Beauchene, J.; Mothe, F.; Méausoone, P.-J.; Martin, P.; Larricq, P.; Eyma, F. url  openurl
  Title Wood machining with a focus on French research in the last 50 years Type Journal Article
  Year 2016 Publication Annals of Forest Science Abbreviated Journal Annals of Forest Science  
  Volume 73 Issue 1 Pages 163-184  
  Keywords Primary conversion; Secondary processing; Surface quality; Tool wear  
  Abstract (up) Key message: Wood machining is compulsory both for timber separation and the surfacing of wooden objects. The anisotropy, cellular nature and multi-scale level organisation of wood make its cutting complicated to study. During the last 50 years, most of the wood machining subjects were covered by French teams. Context: Woodcutting is a very old technology but scientific research is scarce on the subject. In the last 50 years, much work on basic mechanisms as well as on industrial processes has been done in France. Aims: The specific nature of wood introduces strong differences between wood and metal cutting processes. The paper focuses on French teams’ contributions. Results: The basic aspects of the tool–material interaction for different basic modes in woodcutting are highlighted. In primary conversion such as sawing, veneer cutting or green wood chipping, huge progress comes from automation and the possibility of linking the process to log and product quality through new sensors. In secondary processing, much has been done on the links between the cutting process, surface qualification and the properties of these surfaces for further processing, such as gluing or coating. Tool wear depends on the cutting process, timber quality and species. Trade-offs are required in tool technology and coating technologies may improve tool life. Conclusion: A large amount of knowledge and innovation has come from 50 years of worldwide research effort, with France being particularly active in this period. The transfer of skills from metals cutting industry was often a key, but much is needed to move closer to both metal cutting sector and woodcutting skills among craftsmen. © 2015, INRA and Springer-Verlag France.  
  Address ICA, Université Paul Sabatier Toulouse III, Toulouse, France  
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  Notes Export Date: 7 March 2016 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 668  
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Author Petit, M.; Denis, T.; Rux, O.; Richard-Hansen, C.; Berzins, R. url  doi
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  Title Estimating jaguar (Panthera onca) density in a preserved coastal area of French Guiana Type Journal Article
  Year 2018 Publication Mammalia Abbreviated Journal Mammalia  
  Volume 82 Issue 2 Pages 188-192  
  Keywords camera trapping; density; French Guiana; home range; Panthera onca; spatially explicit capture recapture  
  Abstract (up) Knowledge of the jaguar population is needed in French Guiana that faces an increase of human-jaguar conflicts. We carried out a camera trap survey to assess jaguar local density and home range size in a preserved coastal area of French Guiana. We ran spatially explicit capture recapture (SECR) models. In our model, the scale parameter σ, that is linked to the home range size, was larger for males (σ=3.87±0.59 SE km) than for females (σ=2.33±0.30 SE km). The assessed jaguar density was 3.22±0.87 SE ind. 100 km â '2, which should be considered as an optimal density in a French Guiana coastal area.  
  Address Office National de la Chasse et de la Faune Sauvage, Campus Agronomique, BP316, Kourou Cedex, French Guiana  
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  Notes Export Date: 7 May 2018 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 803  
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Author Epelboin, L.; Bourhy, P.; Le Turnier, P.; Schaub, R.; Mosnier, E.; Berlioz-Arthaud, A.; Reynaud, Y.; Nacher, M.; De Thoisy, B.; Carles, G.; Richard-Hansen, C.; Demar, M.; Picardeau, M.; Djossou, F. url  doi
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  Title La leptospirose en Guyane française et sur le bouclier des Guyanes. État des connaissances en 2016 Type Journal Article
  Year 2017 Publication Bulletin de la Société de pathologie exotique Abbreviated Journal  
  Volume 110 Issue 3 Pages 165-179  
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  Abstract (up) La leptospirose est une zoonose cosmopolite causée par les bactéries du genre Leptospira. Si sa répartition est vaste sur le globe, le climat chaud et humide de la zone intertropicale est particulièrement propice à son expansion. Dans la plupart des départements et territoires français d’outremer, la leptospirose est considérée comme un problème de santé publique. En Guyane, département français situé au nord-est de la forêt amazonienne, elle est considérée comme rare. L’objectif de cette revue est de faire l’état des lieux des connaissances sur la leptospirose humaine et animale en Guyane française et dans les pays environnants. Une recherche exhaustive a été conduite, à travers la littérature médicale indexée et informelle en français, anglais, espagnol et portugais. Ainsi, respectivement dix et quatre publications ont pu être identifiées sur la leptospirose humaine et animale en Guyane, publiées entre 1940 et 1995, sous formes de cas cliniques ou de séries de cas. Les publications concernant cette maladie dans les autres pays du plateau des Guyanes, Venezuela oriental, Guyana, Suriname, et État brésilien de l’Amapá, étaient également rares voire inexistantes. En revanche, les données récentes du centre national de la leptospirose français ont montré une augmentation récente et brutale du nombre de cas dans le département, probablement en partie due à la mise en place d’outils diagnostiques tels que la sérologie IgM Elisa. Il est en fait probable que la leptospirose soit une maladie négligée dans la région, du fait de l’absence d’outils diagnostiques rapidement disponibles, de la méconnaissance des cliniciens de cette pathologie et de l’existence de nombreux autres pathogènes à présentation clinique similaire (paludisme, arboviroses, fièvre Q, toxoplasmose amazonienne). La mise en place d’études de plus grande ampleur sur la leptospirose animale et humaine est nécessaire et urgente pour connaître le véritable poids de cette maladie dans notre région.  
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  Call Number EcoFoG @ webmaster @ Epelboin2017 Serial 785  
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