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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 (down) 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 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 (down) 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 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 (down) 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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  Call Number EcoFoG @ webmaster @ Serial 900  
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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 (down) 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 Leclerc, T.; Vimal, R.; Troispoux, V.; Périgon, S.; Scotti, I. url  openurl
  Title Life after disturbance (I): changes in the spatial genetic structure of Jacaranda copaia (Aubl.) D. Don (Bignonianceae) after logging in an intensively studied plot in French Guiana Type Journal Article
  Year 2015 Publication Annals of Forest Science Abbreviated Journal Annals of Forest Science  
  Volume 72 Issue 5 Pages 509-516  
  Keywords Amazon; Bayesian clustering; Demogenetics; Guiana shield; Parentage analysis; Regeneration; Spatial genetic structure; Tropical rainforest  
  Abstract (down) Key message: Forest disturbance affects the within-population distribution of genetic diversity, but not its overall levels, in a tropical pioneer tree species. In particular, clumps of related saplings with impoverished diversity are found in canopy gaps but not under forest cover. Context: Forest disturbances can have long-term consequences on the genetic structure of tree populations, because they can alter the demographic properties of the regeneration process and favour some subpopulations/genotypes, both by stochastic processes and by selection. Intermediate disturbances tend to favour species diversity, at least in highly diverse communities, but their effect on intra-specific diversity is unknown. Aims: In this study, we have looked at the genetic consequences of forest disturbance in a stand of the long-lived Neotropical pioneer species, Jacaranda copaia. Methods: The study site was experimentally logged in 1984, and the canopy gaps generated by the logging were mapped. Seedlings of J. copaia colonised the gaps, as expected, at a higher density than in the surrounding forest. In 2006, we exhaustively sampled all saplings and adult trees available in a 25-ha area. The samples were genotyped at nine microsatellite loci, and the distribution of genetic diversity was inspected by analyses of spatial autocorrelation, automated Bayesian assignment and comparisons of diversity between cohorts by bootstrap (RaBoT). Results: Spatial autocorrelation was found to extend farther in post-disturbance saplings than in the undisturbed population (100 m and beyond versus less than 50 m), and divergent clumps (F<inf>ST</inf> = 0.05) of related genotypes were found; genetic diversity was found to be impoverished in each clump relative to the global population at about half of the loci. Conclusion: Overall, our results suggest that forest disturbance has changed the patterns of distribution of genetic diversity, with potential consequences on long-term population viability. © 2015, INRA and Springer-Verlag France.  
  Address INRA, URFM « Ecologie des Forêts Méditerranéennes », Domaine de Saint-Paul, Avignon, France  
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  Notes Export Date: 16 July 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 611  
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Author Ziegler, C.; Coste, S.; Stahl, C.; Delzon, S.; Levionnois, S.; Cazal, J.; Cochard, H.; Esquivel-Muelbert, A.; Goret, J.-Y.; Heuret, P.; Jaouen, G.; Santiago, L.S.; Bonal, D. url  doi
openurl 
  Title Large hydraulic safety margins protect Neotropical canopy rainforest tree species against hydraulic failure during drought Type Journal Article
  Year 2019 Publication Annals of Forest Science Abbreviated Journal Ann. Forest Sci.  
  Volume 76 Issue 4 Pages 115  
  Keywords Amazon rainforest; Embolism resistance; Hydraulic safety margins; Turgor loss point; Water potential  
  Abstract (down) Key message: Abundant Neotropical canopy-tree species are more resistant to drought-induced branch embolism than what is currently admitted. Large hydraulic safety margins protect them from hydraulic failure under actual drought conditions. Context: Xylem vulnerability to embolism, which is associated to survival under extreme drought conditions, is being increasingly studied in the tropics, but data on the risk of hydraulic failure for lowland Neotropical rainforest canopy-tree species, thought to be highly vulnerable, are lacking. Aims: The purpose of this study was to gain more knowledge on species drought-resistance characteristics in branches and leaves and the risk of hydraulic failure of abundant rainforest canopy-tree species during the dry season. Methods: We first assessed the range of branch xylem vulnerability to embolism using the flow-centrifuge technique on 1-m-long sun-exposed branches and evaluated hydraulic safety margins with leaf turgor loss point and midday water potential during normal- and severe-intensity dry seasons for a large set of Amazonian rainforest canopy-tree species. Results: Tree species exhibited a broad range of embolism resistance, with the pressure threshold inducing 50% loss of branch hydraulic conductivity varying from − 1.86 to − 7.63 MPa. Conversely, we found low variability in leaf turgor loss point and dry season midday leaf water potential, and mostly large, positive hydraulic safety margins. Conclusions: Rainforest canopy-tree species growing under elevated mean annual precipitation can have high resistance to embolism and are more resistant than what was previously thought. Thanks to early leaf turgor loss and high embolism resistance, most species have a low risk of hydraulic failure and are well able to withstand normal and even severe dry seasons. © 2019, The Author(s).  
  Address Smithsonian Tropical Research Institute, Balboa, Ancon, Panama  
  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 901  
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Author Foucaud, J.; Rey, O.; Robert, S.; Crespin, L.; Orivel, J.; Facon, B.; Loiseau, A.; Jourdan, H.; Kenne, M.; Masse, P.S.M.; Tindo, M.; Vonshak, M.; Estoup, A. pdf  url
openurl 
  Title Thermotolerance adaptation to human-modified habitats occurs in the native range of the invasive ant Wasmannia auropunctata before long-distance dispersal Type Journal Article
  Year 2013 Publication Evolutionary Applications Abbreviated Journal Evol. Appl.  
  Volume 6 Issue 4 Pages 721-734  
  Keywords Adaptation; Heat shock; Invasive species; Natural selection and contemporary evolution; Thermotolerance  
  Abstract (down) Key evolutionary events associated with invasion success are traditionally thought to occur in the introduced, rather than the native range of species. In the invasive ant Wasmannia auropunctata, however, a shift in reproductive system has been demonstrated within the native range, from the sexual non-dominant populations of natural habitats to the clonal dominant populations of human-modified habitats. Because abiotic conditions of human- modified habitats are hotter and dryer, we performed lab experiments on workers from a set of native and introduced populations, to investigate whether these ecological and genetic transitions were accompanied by a change in thermotolerance and whether such changes occurred before establishment in the introduced range. Thermotolerance levels were higher in native populations from human-modified habitats than in native populations from natural habitats, but were similar in native and introduced populations from human-modified habitats. Differences in thermotolerance could not be accounted for by differences in body size. A scenario based on local adaptation in the native range before introduction in remote areas represents the most parsimonious hypothesis to account for the observed phenotypic pattern. These findings highlight the importance of human land use in explaining major contemporary evolutionary changes. © 2013 The Authors.  
  Address Department of Biology, Stanford University, Stanford, CA, United States  
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  Notes Export Date: 5 June 2013; Source: Scopus; :doi 10.1111/eva.12058; Language of Original Document: English; Correspondence Address: Foucaud, J.; INRA, UMR1062 CBGP, Montpellier, France; email: foucaud@supagro.inra.fr Approved no  
  Call Number EcoFoG @ webmaster @ Serial 488  
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Author Dejean, A.; Corbara, B. url  openurl
  Title Reactions by army ant workers to nestmates having had contact with sympatric ant species Type Journal Article
  Year 2014 Publication Comptes Rendus Biologies Abbreviated Journal C. R. Biol.  
  Volume 337 Issue 11 Pages 642-645  
  Keywords Army ants Antipredation Colony-mate recognition Eciton Transferring cuticular compounds; Eciton; Formicidae  
  Abstract (down) It was recently shown that Pheidole megacephala colonies (an invasive species originating from Africa) counterattack when raided by the army ant, Eciton burchellii. The subsequent contact permits Pheidole cuticular compounds (that constitute the “colony odour”) to be transferred onto the raiding Eciton, which are then not recognised by their colony-mates and killed. Using a simple method for transferring cuticular compounds, we tested if this phenomenon occurs for Neotropical ants. Eciton workers rubbed with ants from four sympatric species were released among their colony-mates. Individuals rubbed with Solenopsis saevissima or Camponotus blandus workers were attacked, but not those rubbed with Atta sexdens, Pheidole fallax or with colony-mates (control lot). So, the chemicals of certain sympatric ant species, but not others, trigger intra-colonial aggressiveness in Eciton. We conclude that prey-ant chemicals might have played a role in the evolution of army ant predatory behaviour, likely influencing prey specialization in certain cases.  
  Address Clermont Université, Université Blaise-Pascal, LMGE, BP 10448Clermont-Ferrand, France  
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  Publisher Elsevier Masson SAS Place of Publication Editor  
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  ISSN 16310691 (Issn) ISBN Medium  
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  Notes Export Date: 12 November 2014; Coden: Crboc; Correspondence Address: Dejean, A.; CNRS, É Cologie des Forêts de Guyane, UMR-CNRS 8172, BP 316, France Approved no  
  Call Number EcoFoG @ webmaster @ Serial 566  
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Author Vleminckx, Jason ; Fortunel, Claire ; Valverde-Barrantes, Oscar ; Paine, C.E. Timothy ; Engel, Julien ; Petronelli, Pascal ; Dourdain, Aurélie K. ; Guevara, Juan ; Béroujon, Solène ; Baraloto, Christophier doi  openurl
  Title Resolving whole-plant economics from leaf, stem and root traits of 1467 Amazonian tree species Type Journal Article
  Year 2021 Publication Oikos Abbreviated Journal  
  Volume 130 Issue 7 Pages 1193-1208  
  Keywords  
  Abstract (down) It remains unclear how evolutionary and ecological processes have shaped the wide variety of plant life strategies, especially in highly diverse ecosystems like tropical forests. Some evidence suggests that species have diversified across a gradient of ecological strategies, with different plant tissues converging to optimize resource use across environmental gradients. Alternative hypotheses propose that species have diversified following independent selection on different tissues, resulting in a decoupling of trait syndromes across organs. To shed light on the subject, we assembled an unprecedented dataset combining 19 leaf, stem and root traits for 1467 tropical tree species inventoried across 71 0.1-ha plots spanning broad environmental gradients in French Guiana. Nearly 50% of the overall functional heterogeneity was expressed along four orthogonal dimensions, after accounting for phylogenetic dependences among species. The first dimension related to fine root functioning, while the second and third dimensions depicted two decoupled leaf economics spectra, and the fourth dimension encompassed a wood economics spectrum. Traits involved in orthogonal functional strategies, five leaf traits in particular but also trunk bark thickness, were consistently associated with a same gradient of soil texture and nutrient availability. Root traits did not show any significant association with edaphic variation, possibly because of the prevailing influence of other factors (mycorrhizal symbiosis, phylogenetic constraints). Our study emphasises the existence of multiple functional dimensions that allow tropical tree species to optimize their performance in a given environment, bringing new insights into the debate around the presence of a whole plant economic spectrum in tropical forest tree communities. It also emphasizes the key role that soil heterogeneity plays in shaping tree species assembly. The extent to which different organs are decoupled and respond to environmental gradients may also help to improve our predictions of species distribution changes in responses to habitat modification and environmental changes.  
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  Call Number EcoFoG @ webmaster @ Serial 1030  
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Author Christensen-Dalsgaard, K.K.; Fournier, M.; Ennos, A.R.; Barfod, A.S. openurl 
  Title Changes in vessel anatomy in response to mechanical loading in six species of tropical trees Type Journal Article
  Year 2007 Publication New Phytologist Abbreviated Journal New Phytol.  
  Volume 176 Issue 3 Pages 610-622  
  Keywords hydraulic architecture; hydraulic-mechanical trade-off; mechanical adaptation; rooting morphology; tropical trees; vascular anatomy  
  Abstract (down) It is well known that trees adapt their supportive tissues to changes in loading conditions, yet little is known about how the vascular anatomy is modified in this process. We investigated this by comparing more and less mechanically loaded sections in six species of tropical trees with two different rooting morphologies. We measured the strain, vessel size, frequency and area fraction and from this calculated the specific conductivity, then measured the conductivity, modulus of elasticity and yield stress. The smallest vessels and the lowest vessel frequency were found in the parts of the trees subjected to the greatest stresses or strains. The specific conductivity varied up to two orders of magnitude between mechanically loaded and mechanically unimportant parts of the root system. A trade-off between conductivity and stiffness or strength was revealed, which suggests that anatomical alterations occur in response to mechanical strain. By contrast, between-tree comparisons showed that average anatomical features for the whole tree seemed more closely related to their ecological strategy.  
  Address Univ Manchester, Fac Life Sci, Manchester M60 1QD, Lancs, England, Email: karen@cd-mail.dk  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING Place of Publication Editor  
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  ISSN 0028-646X ISBN Medium  
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  Notes ISI:000250275000013 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 156  
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