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Author Staudt, K.; Serafimovich, A.; Siebicke, L.; Pyles, R.D.; Falge, E. url  openurl
  Title Vertical structure of evapotranspiration at a forest site (a case study) Type Journal Article
  Year 2011 Publication Agricultural and Forest Meteorology Abbreviated Journal Agric. For. Meterol.  
  Volume 151 Issue 6 Pages 709-729  
  Keywords Eddy-covariance; Evapotranspiration; In-canopy profiles; Model; Picea abies L.; Sap flux; coniferous forest; ecosystem modeling; eddy covariance; evapotranspiration; forest canopy; sap flow; Fichtelgebirge; Germany; Picea abies  
  Abstract The components of ecosystem evapotranspiration of a Norway spruce forest (Picea abies L.) as well as the vertical structure of canopy evapotranspiration were analyzed with a combination of measurements and models for a case study of 5 days in September 2007. Eddy-covariance and sap flux measurements were performed at several heights within the canopy at the FLUXNET site Waldstein-Weidenbrunnen (DE-Bay) in the Fichtelgebirge mountains in Germany. Within and above canopy fluxes were simulated with two stand-scale models, the 1D multilayer model ACASA that includes a third-order turbulence closure and the 3D model STANDFLUX. The soil and understory evapotranspiration captured with the eddy-covariance system in the trunk space constituted 10% of ecosystem evapotranspiration measured with the eddy-covariance system above the canopy. A comparison of transpiration measured with the sap flux technique and inferred from below and above canopy eddy-covariance systems revealed higher estimates from eddy-covariance measurements than for sap flux measurements. The relative influences of possible sources of this mismatch, such as the assumption of negligible contribution of evaporation from intercepted water, and differences between the eddy-covariance flux footprint and the area used for scaling sap flux measurements, were discussed. Ecosystem evapotranspiration as well as canopy transpiration simulated with the two models captured the dynamics of the measurements well, but slightly underestimated eddy-covariance values. Profile measurements and models also gave us the chance to assess in-canopy profiles of canopy evapotranspiration and the contributions of in-canopy layers. For daytime and a coupled or partly coupled canopy, mean simulated profiles of both models agreed well with eddy-covariance measurements, with a similar performance of the ACASA and the STANDFLUX model. Both models underestimated profiles for nighttime and decoupled conditions. During daytime, the upper half of the canopy contributed approximately 80% to canopy evapotranspiration, whereas during nighttime the contribution shifted to lower parts of the canopy. © 2010 Elsevier B.V.  
  Address (up) Max Planck Institute for Chemistry, Biogeochemistry Department, Joh.-J.-Becherweg 27, 55128 Mainz, Germany  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 01681923 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Cited By (since 1996): 3; Export Date: 21 October 2011; Source: Scopus; Coden: Afmee; doi: 10.1016/j.agrformet.2010.10.009; Language of Original Document: English; Correspondence Address: Staudt, K.; University of Bayreuth, Department of Micrometeorology, 95440 Bayreuth, Germany; email: katharina.staudt@uni-bayreuth.de Approved no  
  Call Number EcoFoG @ webmaster @ Serial 349  
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Author Esquivel-Muelbert, A.; Baker, T.R.; Dexter, K.G.; Lewis, S.L.; Brienen, R.J.W.; Feldpausch, T.R.; Lloyd, J.; Monteagudo-Mendoza, A.; Arroyo, L.; Álvarez-Dávila, E.; Higuchi, N.; Marimon, B.S.; Marimon-Junior, B.H.; Silveira, M.; Vilanova, E.; Gloor, E.; Malhi, Y.; Chave, J.; Barlow, J.; Bonal, D.; Davila Cardozo, N.; Erwin, T.; Fauset, S.; Hérault, B.; Laurance, S.; Poorter, L.; Qie, L.; Stahl, C.; Sullivan, M.J.P.; ter Steege, H.; Vos, V.A.; Zuidema, P.A.; Almeida, E.; Almeida de Oliveira, E.; Andrade, A.; Vieira, S.A.; Aragão, L.; Araujo-Murakami, A.; Arets, E.; Aymard C, G.A.; Baraloto, C.; Camargo, P.B.; Barroso, J.G.; Bongers, F.; Boot, R.; Camargo, J.L.; Castro, W.; Chama Moscoso, V.; Comiskey, J.; Cornejo Valverde, F.; Lola da Costa, A.C.; del Aguila Pasquel, J.; Di Fiore, A.; Fernanda Duque, L.; Elias, F.; Engel, J.; Flores Llampazo, G.; Galbraith, D.; Herrera Fernández, R.; Honorio Coronado, E.; Hubau, W.; Jimenez-Rojas, E.; Lima, A.J.N.; Umetsu, R.K.; Laurance, W.; Lopez-Gonzalez, G.; Lovejoy, T.; Aurelio Melo Cruz, O.; Morandi, P.S.; Neill, D.; Núñez Vargas, P.; Pallqui Camacho, N.C.; Parada Gutierrez, A.; Pardo, G.; Peacock, J.; Peña-Claros, M.; Peñuela-Mora, M.C.; Petronelli, P.; Pickavance, G.C.; Pitman, N.; Prieto, A.; Quesada, C.; Ramírez-Angulo, H.; Réjou-Méchain, M.; Restrepo Correa, Z.; Roopsind, A.; Rudas, A.; Salomão, R.; Silva, N.; Silva Espejo, J.; Singh, J.; Stropp, J.; Terborgh, J.; Thomas, R.; Toledo, M.; Torres-Lezama, A.; Valenzuela Gamarra, L.; van de Meer, P.J.; van der Heijden, G.; van der Hout, P.; Vasquez Martinez, R.; Vela, C.; Vieira, I.C.G.; Phillips, O.L. pdf  url
doi  openurl
  Title Compositional response of Amazon forests to climate change Type Journal Article
  Year 2019 Publication Global Change Biology Abbreviated Journal Global Change Biol.  
  Volume 25 Issue 1 Pages 39-56  
  Keywords bioclimatic niches; climate change; compositional shifts; functional traits; temporal trends; tropical forests; bioclimatology; climate change; floristics; lowland environment; niche; temporal variation; tropical forest; Amazonia; carbon dioxide; water; biodiversity; Brazil; classification; climate change; ecosystem; forest; physiology; season; tree; tropic climate; Biodiversity; Brazil; Carbon Dioxide; Climate Change; Ecosystem; Forests; Seasons; Trees; Tropical Climate; Water  
  Abstract Most of the planet's diversity is concentrated in the tropics, which includes many regions undergoing rapid climate change. Yet, while climate-induced biodiversity changes are widely documented elsewhere, few studies have addressed this issue for lowland tropical ecosystems. Here we investigate whether the floristic and functional composition of intact lowland Amazonian forests have been changing by evaluating records from 106 long-term inventory plots spanning 30 years. We analyse three traits that have been hypothesized to respond to different environmental drivers (increase in moisture stress and atmospheric CO 2 concentrations): maximum tree size, biogeographic water-deficit affiliation and wood density. Tree communities have become increasingly dominated by large-statured taxa, but to date there has been no detectable change in mean wood density or water deficit affiliation at the community level, despite most forest plots having experienced an intensification of the dry season. However, among newly recruited trees, dry-affiliated genera have become more abundant, while the mortality of wet-affiliated genera has increased in those plots where the dry season has intensified most. Thus, a slow shift to a more dry-affiliated Amazonia is underway, with changes in compositional dynamics (recruits and mortality) consistent with climate-change drivers, but yet to significantly impact whole-community composition. The Amazon observational record suggests that the increase in atmospheric CO 2 is driving a shift within tree communities to large-statured species and that climate changes to date will impact forest composition, but long generation times of tropical trees mean that biodiversity change is lagging behind climate change.  
  Address (up) Museu Paraense Emílio Goeldi, Pará, Brazil  
  Corporate Author Thesis  
  Publisher Blackwell Publishing Ltd Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 13541013 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Cited By :21; Export Date: 6 January 2020; Correspondence Address: Esquivel-Muelbert, A.; School of Geography, University of LeedsUnited Kingdom; email: adriane.esquivel@gmail.com Approved no  
  Call Number EcoFoG @ webmaster @ Serial 905  
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Author Baraloto, C.; Forget, P.M.; Goldberg, D.E. openurl 
  Title Seed mass, seedling size and neotropical tree seedling establishment Type Journal Article
  Year 2005 Publication Journal of Ecology Abbreviated Journal J. Ecol.  
  Volume 93 Issue 6 Pages 1156-1166  
  Keywords French Guiana; life-history trade-offs; microhabitat; path analysis; regeneration strategy; relative growth rate; seedling survival; shade tolerance  
  Abstract 1 We examined among- and within-species effects of seed mass for seedling establishment from seed to 5 years of age in a field experiment at Paracou, French Guiana. 2 Six seeds of each of eight species were weighed and planted into each of 120 plots (1 m(2)) throughout closed-canopy forest along 12 100-m transects in 1998. 3 We described the microhabitat of each planting site using principal components derived from measurements of light availability, soil moisture, carbon and nitrogen content, and soil phosphorus availability. Although both survival and relative growth rate (RGR) increased with increasing light availability, no other microhabitat variable significantly affected seedling performance. Nor did the magnitude of microhabitat effects on survival or RGR differ among species. 4 Larger-seeded species were more likely to survive from germination to 1 year as well as from 1 to 5 years of age. RGR for seedling height during the first year post-germination was not related to seed mass, but smaller-seeded species did grow slightly faster thereafter. Path analyses revealed that correlations between seed mass and performance were explained in part because larger seeds produced larger initial seedlings, which tended to survive better but grow more slowly. 5 We also analysed within-species effects of seed mass for the larger-seeded Eperua grandiflora and Vouacapoua americana (both Caesalpiniaceae). Larger seeds produced larger seedlings in both species, but larger seeds survived better only for Eperua. Larger seedlings grew more slowly in both species, but did not offset the early (Eperua) and later (Vouacapoua) positive direct effects of seed mass on RGR that may represent contrasting strategies for reserve deployment. 6 Our results demonstrate that seed size influences performance within and among species in part because of indirect effects of initial seedling size. However, we suggest that traits tightly correlated with seed mass at the species level, such as specific leaf area, leaf longevity and photosynthetic capacity, may also contribute to interspecific performance differences.  
  Address (up) Museum Natl Hist Nat, Dept Ecol & Gest Biodivers, UMR 5176, CNRS, Brunoy, France, Email: baraloto.c@kourou.cirad.fr  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-0477 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000233287500012 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 250  
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Author Almeras, T.; Gril, J.; Yamamoto, H. openurl 
  Title Modelling anisotropic maturation strains in wood in relation to fibre boundary conditions, microstructure and maturation kinetics Type Journal Article
  Year 2005 Publication Holzforschung Abbreviated Journal Holzforschung  
  Volume 59 Issue 3 Pages 347-353  
  Keywords anisotropy; boundary conditions; cell-wall maturation; growth strain; multilayer model; residual stress; wood fibre  
  Abstract A generalisation of existing mechanical models is proposed to account for the relation between wood macroscopic properties and fibre microstructure and chemical composition. It is applied to understanding of the origin of anisotropic maturation strains measured at the outermost surface of the xylem. Various assumptions are considered for boundary conditions of the fibre during the progressive maturation process and are applied to experimental data from the literature. Assumptions that the fibre is fully restrained in displacement, or fully unrestrained or unrestrained in the transverse direction only are all incompatible with observations. Indeed, within the tree, the fibre is restrained in the longitudinal and tangential directions, but unrestrained in the radial direction towards the bark. Mixed boundary conditions must be introduced to correctly simulate both longitudinal and tangential maturation strains. In the context of an analytical axisymmetric model, this is estimated by considering a parameter of partial release of tangential stress during maturation. Consistence with data and with finite element computation in the case of a square fibre confirmed that, because of the unrestrained radial condition, a large part of the tangential maturation stress is released in situ.  
  Address (up) Nagoya Univ, Grad Sch Bioagr Sci, Lab Biomat Phys, Chikusa Ku, Nagoya, Aichi 4648601, Japan, Email: tancrede@nuagr1.agr.nagoya-u.ac.jp  
  Corporate Author Thesis  
  Publisher WALTER DE GRUYTER & CO Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0018-3830 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000228828800016 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 256  
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Author Almeras, T.; Yoshida, M.; Okuyama, T. openurl 
  Title The generation of longitudinal maturation stress in wood is not dependent on diurnal changes in diameter of trunk Type Journal Article
  Year 2006 Publication Journal of Wood Science Abbreviated Journal J. Wood Sci.  
  Volume 52 Issue 5 Pages 452-455  
  Keywords maturation stress; growth stress; cell-wall maturation; continuous lighting; diurnal strains  
  Abstract A hypothetical mechanism for the generation of maturation stress in wood was tested experimentally. The hypothesis was that the maturation stress could partly originate in a physical mechanism related to daily changes in water pressure and associated diurnal strains. The matrix of lignin and hemicellulose, deposited in the cell wall during the night, would be put in compression by the effect of water tension during the next day. The cellulose framework, crystallizing during the day, would be put in tension by the decrease in tension at night and subsequent cell-wall swelling. This was tested on young saplings of sugi and beech. Half of the saplings were submitted to continuous lighting, which canceled diurnal strains. Saplings were tilted 40 degrees, and their uprighting movement was measured. The uprighting movement is directly due to the production of reaction wood and the concomitant development of large longitudinal maturation stress. It occurred in the continuously lighted plants at least as much as in control plants. We conclude that the generation of longitudinal maturation stress in tension or compression wood is not directly related to variations in water pressure and diurnal strains.  
  Address (up) Nagoya Univ, Grad Sch Bioagr Sci, Lab Biomat Phys, Chikusa Ku, Nagoya, Aichi 4648601, Japan, Email: t_almeras@hotmail.com  
  Corporate Author Thesis  
  Publisher SPRINGER TOKYO Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1435-0211 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000241010600012 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 222  
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Author Almeras, T.; Yoshida, M.; Okuyama, T. openurl 
  Title Strains inside xylem and inner bark of a stem submitted to a change in hydrostatic pressure Type Journal Article
  Year 2006 Publication Trees-Structure and Function Abbreviated Journal Trees-Struct. Funct.  
  Volume 20 Issue 4 Pages 460-467  
  Keywords diurnal strains; hydrostatic pressure; xylem; inner bark; mechanical properties  
  Abstract Tangential strains were measured with strain gauges at the surface of xylem and inner bark of saplings of Cryptomeria japonica D. Don. and Fagus silvatica L. during a pressurization test. The test consists in submitting the whole sapling to an artificially imposed hydrostatic pressure of increasing magnitude. The elastic response of the stems was found linear both at the surface of xylem and inner bark. A simple geometric model allows to compute radial strains in each tissue from tangential strain data. Inside inner bark, radial strains are much larger than tangential strains, because tangential strains are restrained by the core of wood. The material compliance of each tissue was computed as the ratio between the radial strain and the pressure that caused it. The material compliance of xylem is much lower than that of inner bark, but, as its thickness is much larger, its contribution to the apparent behavior of the stem is not negligible. Computation of material compliances by this pressurization test provides information about the specific behavior of each tissue in response to hydrostatic pressure. This can be used to estimate and interpret the calibration factor linking the water status of the plant to the apparent strain measured at its surface.  
  Address (up) Nagoya Univ, Grad Sch Bioagr Sci, Lab Biomat Phys, Chikusa Ku, Nagoya, Aichi 4648601, Japan, Email: t_almeras@hotmail.com  
  Corporate Author Thesis  
  Publisher SPRINGER Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0931-1890 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000237858100007 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 225  
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Author Almeras, T.; Thibaut, A.; Gril, J. openurl 
  Title Effect of circumferential heterogeneity of wood maturation strain, modulus of elasticity and radial growth on the regulation of stem orientation in trees Type Journal Article
  Year 2005 Publication Trees-Structure and Function Abbreviated Journal Trees-Struct. Funct.  
  Volume 19 Issue 4 Pages 457-467  
  Keywords biomechanics; reaction wood; maturation strain; Young's modulus; eccentricity  
  Abstract Active mechanisms of re-orientation are necessary to maintain the verticality of tree stems. They are achieved through the production of reaction wood, associated with circumferential variations of three factors related to cambial activity: maturation strain, longitudinal modulus of elasticity (MOE) and eccentric growth. These factors were measured on 17 mature trees from different botanical families and geographical locations. Various patterns of circumferential variation of these factors were identified. A biomechanical analysis based on beam theory was performed to quantify the individual impact of each factor. The main factor of re-orientation is the circumferential variation of maturation strains. However, this factor alone explains only 57% of the re-orientations. Other factors also have an effect through their interaction with maturation strains. Eccentric growth is generally associated with heterogeneity of maturation strains, and has an important complementary role, by increasing the width of wood with high maturation strain. Without this factor, the efficiency of re-orientations would be reduced by 31% for angiosperms and 26% for gymnosperms. In the case of angiosperms, MOE is often larger in tension wood than in normal wood. Without these variations, the efficiency of re-orientations would be reduced by 13%. In the case of gymnosperm trees, MOE of compression wood is lower than that of normal wood, so that re-orientation efficiency would be increased by 24% without this factor of variations.  
  Address (up) Nagoya Univ, Lab Biomat Phys, Dept Bioagr Sci, Nagoya, Aichi 4648601, Japan, Email: t_almeras@hotmail.com  
  Corporate Author Thesis  
  Publisher SPRINGER Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0931-1890 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000229890700012 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 253  
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Author Bréchet, L.; Ponton, S.; Alméras, T.; Bonal, D.; Epron, D. url  openurl
  Title Does spatial distribution of tree size account for spatial variation in soil respiration in a tropical forest? Type Journal Article
  Year 2011 Publication Plant and Soil Abbreviated Journal Plant Soil  
  Volume 347 Issue 1 Pages 293-303  
  Keywords Forest structure; Litterfall; Root mass; Soil respiration; Spatial variation; Tropical forest; aboveground production; forest inventory; litterfall; range size; size distribution; soil respiration; spatial distribution; spatial variation; stand dynamics; tropical forest  
  Abstract We explored the relationship between soil processes, estimated through soil respiration (Rsoil), and the spatial variation in forest structure, assessed through the distribution of tree size, in order to understand the determinism of spatial variations in Rsoil in a tropical forest. The influence of tree size was examined using an index (Ic) calculated for each tree as a function of (1) the trunk cross section area and (2) the distance from the measurement point. We investigated the relationships between Ic and litterfall, root mass and Rsoil, respectively. Strong significant relationships were found between Ic and both litterfall and root mass. Rsoil showed a large range of variations over the 1-ha experimental plot, from 1. 5 to 12. 6 gC m-2 d-1. The best relationship between Ic and Rsoil only explained 17% of the spatial variation in Rsoil. These results support the assumption that local spatial patterns in litter production and root mass depend on tree distribution in tropical forests. Our study also emphasizes the modest contribution of tree size distribution-which is mainly influenced by the presence of the biggest trees (among the large range size of the inventoried trees greater than 10 cm diameter at 1. 30 m above ground level or at 0. 5 m above the buttresses)-in explaining spatial variations in Rsoil. © 2011 Springer Science+Business Media B.V.  
  Address (up) Nancy Université, Université Henri Poincaré, UMR 1137, Ecologie et Ecophysiologie Forestières, Faculté des Sciences, 54500 Vandoeuvre les Nancy, France  
  Corporate Author Thesis  
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  Language Summary Language Original Title  
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  ISSN 0032079x (Issn) ISBN Medium  
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  Notes Export Date: 21 October 2011; Source: Scopus; Coden: Plsoa; doi: 10.1007/s11104-011-0848-1; Language of Original Document: English; Correspondence Address: Bréchet, L.; INRA, UMR Ecologie des Forêts de Guyane, Campus Agronomique, BP 709, 97387 Kourou cedex, French Guiana; email: laetitiabrechet@yahoo.fr Approved no  
  Call Number EcoFoG @ webmaster @ Serial 345  
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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 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 (up) National Institute for Space Research (INPE), São José dos Campos, SP, Brazil  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
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  Notes Export Date: 7 March 2016 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 669  
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Author Charles-Dominique, P.; Chave, J.; Dubois, M.A.; De Granville, J.J.; Riera, B.; Vezzoli, C. openurl 
  Title Colonization front of the understorey palm Astrocaryum sciophilum in a pristine rain forest of French Guiana Type Journal Article
  Year 2003 Publication Global Ecology and Biogeography Abbreviated Journal Glob. Ecol. Biogeogr.  
  Volume 12 Issue 3 Pages 237-248  
  Keywords Astrocaryum sciophilum; French Guiana; neotropical palaeoecology; palm ecology; population edge; refuges; scatter-hoarding; seed dispersal; spatial pattern  
  Abstract Aims Astrocaryum sciophilum (Miq.) Pulle (Arecaceae) is an understorey palm, endemic to north-eastern South America with a patchy distribution. We tested the hypothesis that the spatial distribution of this palm species is not in equilibrium but is slowly colonizing the forest understorey. Location Inventories and seed dispersal studies were conducted in the undisturbed tropical forest close to the Nouragues research station, French Guiana. Additional data were collected in the entire territory of French Guiana. Methods We studied the demography of A. sciophilum on a 20-ha plot located at the edge of its distribution. The age of the palms was estimated by postulating an exponentially decreasing abundance by age class. Direct seed dispersal experiments were also conducted, to estimate dispersal parameters. The seeds of A. sciophilum were dispersed only by rodents. This information was used to parameterize a forest growth simulator, to study the spatial spread of this species. Results Within the sampling plot, the density of A. sciophilum dropped sharply from about 500 individuals per hectare to zero. The maturation age was estimated to be 170+/-70 years, and over 55 years with 95% confidence. Seed-dispersal experiments yielded an average seed dispersal distance of 11 m and a maximum estimated dispersal distance of 125 m across a generational span of 55 years to maturity. Therefore, the maximal estimated colonization speed is 2.3 m/y. Conclusions Empirical results and numerical simulations suggest that the boundary of the A. sciophilum population is a colonization front, and that the range of this species is slowly expanding. The implications of this result in respect of palaeoenvironmental changes in this region are discussed.  
  Address (up) Natl Museum Nat Hist, Lab Ecol Gen, F-91800 Brunoy, France  
  Corporate Author Thesis  
  Publisher BLACKWELL PUBLISHING LTD Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0960-7447 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000182184100006 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 273  
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