|   | 
Details
   web
Records
Author Fayad, I.; Baghdadi, N.; Bailly, J.-S.; Barbier, N.; Gond, V.; Herault, B.; El Hajj, M.; Fabre, F.; Perrin, J.
Title (up) Regional scale rain-forest height mapping using regression-kriging of spaceborne and airborne LiDAR data: Application on French Guiana Type Journal Article
Year 2016 Publication Remote Sensing Abbreviated Journal Remote Sensing
Volume 8 Issue 3 Pages 240
Keywords Airborne LiDAR; Canopy height mapping; Forests; French Guiana; ICESat GLAS
Abstract LiDAR data has been successfully used to estimate forest parameters such as canopy heights and biomass. Major limitation of LiDAR systems (airborne and spaceborne) arises from their limited spatial coverage. In this study, we present a technique for canopy height mapping using airborne and spaceborne LiDAR data (from the Geoscience Laser Altimeter System (GLAS)). First, canopy heights extracted from both airborne and spaceborne LiDAR were extrapolated from available environmental data. The estimated canopy height maps using Random Forest (RF) regression from airborne or GLAS calibration datasets showed similar precisions (~6 m). To improve the precision of canopy height estimates, regression-kriging was used. Results indicated an improvement in terms of root mean square error (RMSE, from 6.5 to 4.2 m) using the GLAS dataset, and from 5.8 to 1.8 m using the airborne LiDAR dataset. Finally, in order to investigate the impact of the spatial sampling of future LiDAR missions on canopy height estimates precision, six subsets were derived from the initial airborne LiDAR dataset. Results indicated that using the regression-kriging approach a precision of 1.8 m on the canopy height map was achievable with a flight line spacing of 5 km. This precision decreased to 4.8 m for flight line spacing of 50 km. © 2016 by the authors.
Address BRGM, 3 Avenue Claude Guillemin, Orléans, France
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 ISBN Medium
Area Expedition Conference
Notes Export Date: 22 April 2016 Approved no
Call Number EcoFoG @ webmaster @ Serial 675
Permanent link to this record
 

 
Author Van Langenhove, L.; Depaepe, T.; Vicca, S.; van den Berge, J.; Stahl, C.; Courtois, E.; Weedon, J.; Urbina, I.; Grau, O.; Asensio, D.; Peñuelas, J.; Boeckx, P.; Richter, A.; Van Der Straeten, D.; Janssens, I.A.
Title (up) Regulation of nitrogen fixation from free-living organisms in soil and leaf litter of two tropical forests of the Guiana shield Type Journal Article
Year 2019 Publication Plant and Soil Abbreviated Journal Plant Soil
Volume Issue Pages
Keywords Free-living nitrogen fixation; French Guiana; Molybdenum; Nutrients; Phosphorus; Tropical forest
Abstract Background and aims: Biological fixation of atmospheric nitrogen (N 2 ) is the main pathway for introducing N into unmanaged ecosystems. While recent estimates suggest that free-living N fixation (FLNF) accounts for the majority of N fixed in mature tropical forests, the controls governing this process are not completely understood. The aim of this study was to quantify FLNF rates and determine its drivers in two tropical pristine forests of French Guiana. Methods: We used the acetylene reduction assay to measure FLNF rates at two sites, in two seasons and along three topographical positions, and used regression analyses to identify which edaphic explanatory variables, including carbon (C), nitrogen (N), phosphorus (P) and molybdenum (Mo) content, pH, water and available N and P, explained most of the variation in FLNF rates. Results: Overall, FLNF rates were lower than measured in tropical systems elsewhere. In soils seasonal variability was small and FLNF rates differed among topographies at only one site. Water, P and pH explained 24% of the variation. In leaf litter, FLNF rates differed seasonally, without site or topographical differences. Water, C, N and P explained 46% of the observed variation. We found no regulatory role of Mo at our sites. Conclusions: Rates of FLNF were low in primary rainforest on poor soils on the Guiana shield. Water was the most important rate-regulating factor and FLNF increased with increasing P, but decreased with increasing N. Our results support the general assumption that N fixation in tropical lowland forests is limited by P availability. © 2019, The Author(s).
Address Department of Microbiology and Ecosystem Science, University of Vienna, Althanstr. 14, Vienna, 1090, Austria
Corporate Author Thesis
Publisher Springer International Publishing Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0032079x (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 868
Permanent link to this record
 

 
Author Van Langenhove, L.; Depaepe, T.; Vicca, S.; van den Berge, J.; Stahl, C.; Courtois, E.; Weedon, J.; Urbina, I.; Grau, O.; Asensio, D.; Peñuelas, J.; Boeckx, P.; Richter, A.; Van Der Straeten, D.; Janssens, I.A.
Title (up) Regulation of nitrogen fixation from free-living organisms in soil and leaf litter of two tropical forests of the Guiana shield Type Journal Article
Year 2020 Publication Plant and Soil Abbreviated Journal Plant Soil
Volume 450 Issue 1-2 Pages 93-110
Keywords Free-living nitrogen fixation; French Guiana; Molybdenum; Nutrients; Phosphorus; Tropical forest; acetylene; leaf litter; molybdenum; nitrogen fixation; nutrient cycling; phosphorus; rainforest; reduction; soil biota; soil carbon; soil nitrogen; soil water; topographic effect; tropical forest; French Guiana
Abstract Background and aims: Biological fixation of atmospheric nitrogen (N2) is the main pathway for introducing N into unmanaged ecosystems. While recent estimates suggest that free-living N fixation (FLNF) accounts for the majority of N fixed in mature tropical forests, the controls governing this process are not completely understood. The aim of this study was to quantify FLNF rates and determine its drivers in two tropical pristine forests of French Guiana. Methods: We used the acetylene reduction assay to measure FLNF rates at two sites, in two seasons and along three topographical positions, and used regression analyses to identify which edaphic explanatory variables, including carbon (C), nitrogen (N), phosphorus (P) and molybdenum (Mo) content, pH, water and available N and P, explained most of the variation in FLNF rates. Results: Overall, FLNF rates were lower than measured in tropical systems elsewhere. In soils seasonal variability was small and FLNF rates differed among topographies at only one site. Water, P and pH explained 24% of the variation. In leaf litter, FLNF rates differed seasonally, without site or topographical differences. Water, C, N and P explained 46% of the observed variation. We found no regulatory role of Mo at our sites. Conclusions: Rates of FLNF were low in primary rainforest on poor soils on the Guiana shield. Water was the most important rate-regulating factor and FLNF increased with increasing P, but decreased with increasing N. Our results support the general assumption that N fixation in tropical lowland forests is limited by P availability. © 2019, The Author(s).
Address Department of Microbiology and Ecosystem Science, University of Vienna, Althanstr. 14, Vienna, 1090, Austria
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 0032079x (Issn) ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 971
Permanent link to this record
 

 
Author Clair, B.; Ruelle, J.; Thibaut, B.
Title (up) Relationship between growth stress, mechanical-physical properties and proportion of fibre with gelatinous layer in chestnut (Castanea sativa Mill.) Type Journal Article
Year 2003 Publication Holzforschung Abbreviated Journal Holzforschung
Volume 57 Issue 2 Pages 189-195
Keywords growth stress; longitudinal Young's modulus; shrinkage; normal wood; tension wood; gelatinous layer; Castanea Sativa
Abstract A range of mechanical and physical properties were determined for 96 specimens of chestnut wood and for wood types ranging from compression to tension wood; tests included (1) growth stress, (2) longitudinal Young's modulus in green and air-dried states (3) shrinkage in longitudinal and tangential directions. Anatomical observations permitted determination of the proportion of fibres with a gelatinous layer. The influence of these atypical fibres on macroscopic wood properties is examined and discussed. A basic model is proposed to determine their properties in theoretically isolated conditions.
Address Univ Montpellier 2, Lab Mecan & Genie Civil, F-34095 Montpellier 5, France, Email: clair@lmgc.univ-montp2.fr
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:000181797800011 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 274
Permanent link to this record
 

 
Author Niamke, F.B.; Amusant, N.; Charpentier, J.P.; Chaix, G.; Baissac, Y.; Boutahar, N.; Adima, A.A.; Kati-Coulibaly, S.; Jay-Allemand, C.
Title (up) Relationships between biochemical attributes (non-structural carbohydrates and phenolics) and natural durability against fungi in dry teak wood (Tectona grandis L. f.) Type Journal Article
Year 2011 Publication Annals of Forest Science Abbreviated Journal Ann. For. Sci.
Volume 68 Issue 1 Pages 201-211
Keywords Tectona grandis; Teak heartwood; Phenolic compound; Non-structural carbohydrate; Natural durability
Abstract Introduction Non-structural carbohydrates and phenolic compounds are implicated in the natural durability of wood. In order to find the chemical traits of natural durability in teak wood, the radial distribution of phenolics compounds and non-structural carbohydrates were studied in trees ranked by contrasting natural durability class against Antrodia sp. Methods Non-structural carbohydrates were analyzed by spectrophotometry after enzymatic assays and phenolics compounds using HPLC. Results High concentrations of starch, sucrose, glucose, and fructose were found in the sapwood, whereas only trace amounts were found in the heartwood. In the sapwood, low concentrations of H1 (a hydroxycinnamic acid derivative) were specifically detected. Tectoquinone was also detected in the sapwood but its content increased dramatically in the heartwood. 2-(Hydroxymethyl) anthraquinone and P1, an unidentified compound, were only detected in the heartwood and at high concentrations (>3 mg equivalent 5-methoxyflavone g(-1) dry weight. Lower concentrations of 1,4-naphthoquinone, anthraquinone-2-carboxylic acid, and lapachol were also only detected in the heartwood. H1 and tectoquinone present in the sapwood could be considered as phenolic precursors of the synthesis of heartwood toxic phenolics in the heartwood. Conclusion Correlations between natural durability and chemical composition of heartwood (quinone derivatives, P1, and non-structural carbohydrates) suggest that P1, 2-(hydroxymethyl) anthraquinone and tectoquinone could be natural durability traits. Heartwood extractives,
Address [Niamke, FB; Baissac, Y; Jay-Allemand, C] Univ Montpellier 2, F-34095 Montpellier 05, France, Email: Christian.jay-allemand@univ-montp2.fr
Corporate Author Thesis
Publisher Springer France Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1286-4560 ISBN Medium
Area Expedition Conference
Notes WOS:000290447600021 Approved no
Call Number EcoFoG @ webmaster @ Serial 340
Permanent link to this record
 

 
Author Wernsdorfer, H.; Caron, H.; Gerber, S.; Cornu, G.; Rossi, V.; Mortier, F.; Gourlet-Fleury, S.
Title (up) Relationships between demography and gene flow and their importance for the conservation of tree populations in tropical forests under selective felling regimes Type Journal Article
Year 2011 Publication Conservation Genetics Abbreviated Journal Conserv. Genet.
Volume 12 Issue 1 Pages 15-29
Keywords Genetic diversity; Gene flow; Population dynamics; Simulation model; Conservation; Forest management
Abstract Determining how tropical tree populations subject to selective felling (logging) pressure may be conserved is a crucial issue for forest management and studying this issue requires a comprehensive understanding of the relationships between population demography and gene flow. We used a simulation model, SELVA, to study (1) the relative impact of demographic factors (juvenile mortality, felling regime) and genetic factors (selfing, number and location of fathers, mating success) on long-term genetic diversity; and (2) the impact of different felling regimes on population size versus genetic diversity. Impact was measured by means of model sensitivity analyses. Juvenile mortality had the highest impact on the number of alleles and genotypes, and on the genetic distance between the original and final populations. Selfing had the greatest impact on observed heterozygote frequency and fixation index. Other factors and interactions had only minor effects. Overall, felling had a greater impact on population size than on genetic diversity. Interestingly, populations under relatively low felling pressure even had a somewhat lower fixation index than undisturbed populations (no felling). We conclude that demographic processes such as juvenile mortality should be modelled thoroughly to obtain reliable long-term predictions of genetic diversity. Mortality in selfed and outcrossed progenies should be modelled explicitly by taking inbreeding depression into account. The modelling of selfing based on population rate appeared to be oversimplifying and should account for inter-tree variation. Forest management should pay particular attention to the regeneration capacities of felled species.
Address [Wernsdoerfer, Holger] Ctr INRA Nancy, INRA, Lab Etude Ressources Foret Bois LERFoB, UMR1092, F-54280 Champenoux, France, Email: holger.wernsdoerfer@cirad.fr
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 1566-0621 ISBN Medium
Area Expedition Conference
Notes ISI:000285971900002 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 289
Permanent link to this record
 

 
Author Privet, K.; Vedel, V.; Fortunel, C.; Orivel, J.; Martinez, Q.; Cerdan, A.; Baraloto, C.; Pétillon, J.
Title (up) Relative effciency of pitfall trapping vs. nocturnal hand collecting in assessing soil-dwelling spider diversity along a structural gradient of neotropical habitats Type Journal Article
Year 2020 Publication Diversity Abbreviated Journal Diversity
Volume 12 Issue 2 Pages 81
Keywords Araneae; Diversity indices; Functional diversity; Guiana shield; Sampling methods; Species richness; Turnover; Araneae
Abstract Assessing spider diversity remains a great challenge, especially in tropical habitats where dozens of species can locally co-occur. Pitfall trapping is one of the most widely used techniques to collect spiders, but it suffers from several biases, and its accuracy likely varies with habitat complexity. In this study, we compared the efficiency of passive pitfall trapping versus active nocturnal hand collecting (\"HC) to capture low understory-dwelling spider taxonomical (morpho-species) and functional (hunting guilds) diversity along a structural gradient of habitats in French Guiana. We focused on four habitats describing a structural gradient: garden to the orchard to the forest edge to the undisturbed forest. Overall, estimated morpho-species richness and composition did not vary consistently between habitats, but abundances of ground-hunting spiders decreased significantly with increasing habitat complexity. We found habitat-dependence differences in taxonomic diversity between sampling strategies: NHC revealed higher diversity in the orchard, whereas pitfalls resulted in higher diversity in the forest. Species turnover resulted in high dissimilarity in species composition between habitats using either method. This study shows how pitfall trapping is influenced by habitat structure, rendering this sampling method incomplete for complex, tropical environments. However, pitfall traps remain a valuable component of inventories because they sample distinct assemblage of spiders. © 2020 by the authors.
Address International Center for Tropical Botany, Department of Biological Sciences, Florida International University, 11200 S.W. 8th Street, Miami, FL 33199, United States
Corporate Author Thesis
Publisher Mdpi Ag Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 14242818 (Issn) ISBN Medium
Area Expedition Conference
Notes Export Date: 16 March 2020; Correspondence Address: Privet, K.; CNRS, Ecobio (Ecosystèmes, biodiversité, évolution), Université de RennesFrance; email: kprivet@hotmail.fr Approved no
Call Number EcoFoG @ webmaster @ Serial 923
Permanent link to this record
 

 
Author Gond, V.; Guitet, S.
Title (up) Remote Sensing in Post-Logging Diagnoses for Forest Management in French Guiana Type Journal Article
Year 2009 Publication Bois et Forets des Tropiques Abbreviated Journal Bois For. Trop.
Volume 63 Issue 299 Pages 5-13
Keywords selective logging; logging impact inspections; French Guiana; remote sensing; forest management
Abstract This study is part of the activities carried out to monitor tow-impact logging operations in humid tropical forests. The sustainability of these activities is highly dependent on the scale of logging damage, and managers therefore need to carry out effective checks on the quality of forestry work. In this study, remote sensing was used to track the extension of logging operations and to assess damage, through images acquired during and after logging in each parcel. Analysis of the high-resolution images (10 m) clearly identifies logged-over clearings and some skidding tracks, allowing assessments of gaps opening up in the canopy. Several parcels were monitored in this French Guiana study. A simple diagnostic procedure was established for each parcel to assess logging intensity and identify new logging tracks and timber losses. The remote sensing toot thus helps to make more accurate assessments of logging quality and to draw relevant conclusions for the logging company. The study has demonstrated the usefulness of remote sensing to identify damage after logging. The quality of restitution of the damage was validated by means of a database on the logging terrain and through field missions. This post-logging inspection tool can now be automated for fully operational use by forest managers.
Address [Gond, Valery] Univ Laval, Fac Foresterie, Umr Ecofog Guyane francaise, Cirad,UR 36, Quebec City, PQ G1V OA6, Canada
Corporate Author Thesis
Publisher CIRAD-CENTRE COOPERATION INT RECHERCHE AGRONOMIQUE POUR Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-579X ISBN Medium
Area Expedition Conference
Notes ISI:000266156700001 Approved no
Call Number EcoFoG @ webmaster @ Serial 280
Permanent link to this record
 

 
Author Quilichini, A.; Macquart, D.; Barabe, D.; Albre, J.; Gibernau, M.
Title (up) Reproduction of the West Mediterranean endemic Arum pictum (Araceae) on Corsica Type Journal Article
Year 2010 Publication Plant Systematics and Evolution Abbreviated Journal Plant Syst. Evol.
Volume 287 Issue 3-4 Pages 179-187
Keywords Floral volatiles; Ocimene; Insect pollination; Reproductive success; Sphaeroceridae; Thermogenesis
Abstract Pollination in the genus Arum appears to be in general a complex deceptive pollination process. The genus Arum is composed of 28 species, all belonging to the subgenus Arum, except A. pictum, the only species of the subgenus Gymnomesium, which is basal and sister to all other Arum species. The aim of this paper is to document the pollination ecology of the insular Arum pictum, the only Arum species to flower in autumn, on the island of Corsica (France). The anthesis cycle of A. pictum occurs during the day, attracting sphaerocerid flies and staphylinid beetles early in the morning and late in the afternoon of the first day. The pollen is released from the anthers early in the morning of the second day before the departure of the insects. Its thermogenic cycle matches the anthesis cycle with an original and unique, bimodal temperature pattern of the appendix (morning and afternoon), contrary to the unimodal pattern found in all other studied Arum species. Data from reproductive success and seed sets suggest that sexual reproduction in this species is limited by pollen (e.g. attracting lured insects) rather than by resources. The biology of this Western Mediterranean species appears to be different from other Western European Arum and close to some Eastern Mediterranean species. Further studies are needed to establish whether Arum pictum represents some ancestral stage or whether its peculiar biological traits are adapted to its insular distribution.
Address [Quilichini, Angelique; Gibernau, Marc] CNRS, UMR 8172, Ecole Forets Guyane, F-97387 Kourou, France, Email: marc.gibernau@ecofog.gf
Corporate Author Thesis
Publisher SPRINGER WIEN Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0378-2697 ISBN Medium
Area Expedition Conference
Notes ISI:000279479800008 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 51
Permanent link to this record
 

 
Author Foucaud, J.; Orivel, J.; Fournier, D.; Delabie, J.H.C.; Loiseau, A.; Le Breton, J.; Cerdan, P.; Estoup, A.
Title (up) Reproductive system, social organization, human disturbance and ecological dominance in native populations of the little fire ant, Wasmannia auropunctata Type Journal Article
Year 2009 Publication Molecular Ecology Abbreviated Journal Mol. Ecol.
Volume 18 Issue 24 Pages 5059-5073
Keywords biological invasion; clonality; human disturbance; parthenogenesis; social organization; Wasmannia auropunctata
Abstract The invasive ant species Wasmannia auropunctata displays both ecologically dominant and non-dominant populations within its native range. Three factors could theoretically explain the ecological dominance of some native populations of W. auropunctata: (i) its clonal reproductive system, through demographic and/or adaptive advantages; (ii) its unicolonial social organization, through lower intraspecific and efficient interspecific competition; (iii) the human disturbance of its native range, through the modification of biotic and abiotic environmental conditions. We used microsatellite markers and behavioural tests to uncover the reproductive modes and social organization of dominant and non-dominant native populations in natural and human-modified habitats. Microsatellite and mtDNA data indicated that dominant and non-dominant native populations (supercolonies as determined by aggression tests) of W. auropunctata did not belong to different evolutionary units. We found that the reproductive system and the social organization are neither necessary nor sufficient to explain W. auropunctata ecological dominance. Dominance rather seems to be set off by unknown ecological factors altered by human activities, as all dominant populations were recorded in human-modified habitats. The clonal reproductive system found in some populations of W. auropunctata may however indirectly contribute to its ecological dominance by allowing the species to expand its environmental niche, through the fixation over time of specific combinations of divergent male and female genotypes. Unicoloniality may rather promote the range expansion of already dominant populations than actually trigger ecological dominance. The W. auropunctata model illustrates the strong impact of human disturbance on species' ecological features and the adaptive potential of clonal reproductive systems.
Address [Foucaud, Julien; Fournier, Denis; Loiseau, Anne; Estoup, Arnaud] Montpellier SupAgro, Cirad, IRD, INRA,UMR CBGP, F-34988 Montferrier Sur Lez, France, Email: julien.foucaud@legs.cnrs-gif.fr
Corporate Author Thesis
Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0962-1083 ISBN Medium
Area Expedition Conference
Notes ISI:000272452700009 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 191
Permanent link to this record