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Author Wagner, F.; Herault, B.; Stahl, C.; Bonal, D.; Rossi, V.
Title Modeling water availability for trees in tropical forests Type Journal Article
Year 2011 Publication Agricultural and Forest Meteorology Abbreviated Journal Agric. For. Meteorol.
Volume 151 Issue 9 Pages 1202-1213
Keywords Water balance model; Amazonian rainforest; Time domain reflectometer; Bayesian inference; Tree drought stress
Abstract Modeling soil water availability for tropical trees is a prerequisite to predicting the future impact of climate change on tropical forests. In this paper we develop a discrete-time deterministic water balance model adapted to tropical rainforest climates, and we validate it on a large dataset that includes micrometeorological and soil parameters along a topographic gradient in a lowland forest of French Guiana. The model computes daily water fluxes (rainfall interception, drainage, tree transpiration and soil plus understorey evapotranspiration) and soil water content using three input variables: daily precipitation, potential evapotranspiration and solar radiation. A novel statistical approach is employed that uses Time Domain Reflectometer (TDR) soil moisture data to estimate water content at permanent wilting point and at field capacity, and root distribution. Inaccuracy of the TDR probes and other sources of uncertainty are taken into account by model calibration through a Bayesian framework. Model daily output includes relative extractable water, REW, i.e. the daily available water standardized by potential available water. The model succeeds in capturing temporal variations in REW regardless of topographic context. The low Root Mean Square Error of Predictions suggests that the model captures the most important drivers of soil water dynamics, i.e. water refilling and root water extraction. Our model thus provides a useful tool to explore the response of tropical forests to climate scenarios of changing rainfall regime and intensity. (C) 2011 Elsevier B.V. All rights reserved.
Address [Wagner, F; Herault, B] Univ Antilles Guyane, UMR Ecol Forets Guyane, F-97387 Kourou, France, Email: fabien.wagner@ecofog.gf
Corporate Author Thesis
Publisher (up) Elsevier Science Bv Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-1923 ISBN Medium
Area Expedition Conference
Notes WOS:000294032000005 Approved no
Call Number EcoFoG @ webmaster @ Serial 337
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Author Molto, Q.; Herault, B.; Boreux, J.-J.; Daullet, M.; Rousteau, A.; Rossi, V.
Title Predicting tree heights for biomass estimates in tropical forests -A test from French Guiana Type Journal Article
Year 2014 Publication Biogeosciences Abbreviated Journal Biogeosciences
Volume 11 Issue 12 Pages 3121-3130
Keywords
Abstract The recent development of REDD+ mechanisms requires reliable estimation of carbon stocks, especially in tropical forests that are particularly threatened by global changes. Even though tree height is a crucial variable for computing aboveground forest biomass (AGB), it is rarely measured in large-scale forest censuses because it requires extra effort. Therefore, tree height has to be predicted with height models. The height and diameter of all trees over 10 cm in diameter were measured in 33 half-hectare plots and 9 one-hectare plots throughout northern French Guiana, an area with substantial climate and environmental gradients. We compared four different model shapes and found that the Michaelis-Menten shape was most appropriate for the tree biomass prediction. Model parameter values were significantly different from one forest plot to another, and this leads to large errors in biomass estimates. Variables from the forest stand structure explained a sufficient part of plot-to-plot variations of the height model parameters to improve the quality of the AGB predictions. In the forest stands dominated by small trees, the trees were found to have rapid height growth for small diameters. In forest stands dominated by larger trees, the trees were found to have the greatest heights for large diameters. The aboveground biomass estimation uncertainty of the forest plots was reduced by the use of the forest structure-based height model. It demonstrated the feasibility and the importance of height modeling in tropical forests for carbon mapping. When the tree heights are not measured in an inventory, they can be predicted with a height-diameter model and incorporating forest structure descriptors may improve the predictions. © Author(s) 2014. CC Attribution 3.0 License.
Address Université de Liège, Liège, Belgium
Corporate Author Thesis
Publisher (up) European Geosciences Union Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 17264189 (Issn) ISBN Medium
Area Expedition Conference
Notes Export Date: 3 July 2014; Correspondence Address: Molto, Q.; Université des Antilles et de la Guyane, UMR Ecologie des Forêts de Guyane, Kourou, France; email: quentin.molto@gmail.com Approved no
Call Number EcoFoG @ webmaster @ Serial 550
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Author Harper, Anna B. ; Williams, Karina E. ; McGuire, Patrick ; Duran Rojas, Maria Carolina ; Hemming, Debbie ; Verhoef, Anne ; Huntingford, Chris ; Rowland, Lucy ; Marthews, Toby ; Breder Eller, Cleiton ; Mathison, Camilla ; Nobrega, Rodolfo L.B. ; Gedney, Nicola ; Vidale, Pier Luigi ; Otu-Larbi, Fred ; Pandey, Divya
Title Improvement of modeling plant responses to low soil moisture in JULESvn4.9 and evaluation against flux tower measurements Type Journal Article
Year 2021 Publication Geoscientific Model Development Abbreviated Journal
Volume 14 Issue 6 Pages 3269-3294
Keywords
Abstract Drought is predicted to increase in the future due to climate change, bringing with it myriad impacts on ecosystems. Plants respond to drier soils by reducing stomatal conductance in order to conserve water and avoid hydraulic damage. Despite the importance of plant drought responses for the global carbon cycle and local and regional climate feedbacks, land surface models are unable to capture observed plant responses to soil moisture stress. We assessed the impact of soil moisture stress on simulated gross primary productivity (GPP) and latent energy flux (LE) in the Joint UK Land Environment Simulator (JULES) vn4.9 on seasonal and annual timescales and evaluated 10 different representations of soil moisture stress in the model. For the default configuration, GPP was more realistic in temperate biome sites than in the tropics or high-latitude (cold-region) sites, while LE was best simulated in temperate and high-latitude (cold) sites. Errors that were not due to soil moisture stress, possibly linked to phenology, contributed to model biases for GPP in tropical savanna and deciduous forest sites. We found that three alternative approaches to calculating soil moisture stress produced more realistic results than the default parameterization for most biomes and climates. All of these involved increasing the number of soil layers from 4 to 14 and the soil depth from 3.0 to 10.8 m. In addition, we found improvements when soil matric potential replaced volumetric water content in the stress equation (the “soil14psi” experiments), when the critical threshold value for inducing soil moisture stress was reduced (“soil14p0”), and when plants were able to access soil moisture in deeper soil layers (“soil14_dr*2”). For LE, the biases were highest in the default configuration in temperate mixed forests, with overestimation occurring during most of the year. At these sites, reducing soil moisture stress (with the new parameterizations mentioned above) increased LE and increased model biases but improved the simulated seasonal cycle and brought the monthly variance closer to the measured variance of LE. Further evaluation of the reason for the high bias in LE at many of the sites would enable improvements in both carbon and energy fluxes with new parameterizations for soil moisture stress. Increasing the soil depth and plant access to deep soil moisture improved many aspects of the simulations, and we recommend these settings in future work using JULES or as a general way to improve land surface carbon and water fluxes in other models. In addition, using soil matric potential presents the opportunity to include plant functional type-specific parameters to further improve modeled fluxes.
Address
Corporate Author Thesis
Publisher (up) European Geosciences Union 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 Approved no
Call Number EcoFoG @ webmaster @ Serial 1057
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Author Dejean, A.; Grangier, J.; Leroy, C.; Orivel, J.
Title Host plant protection by arboreal ants: looking for a pattern in locally induced responses Type Journal Article
Year 2008 Publication Evolutionary Ecology Research Abbreviated Journal Evol. Ecol. Res.
Volume 10 Issue 8 Pages 1217-1223
Keywords aggressiveness; ant-plant relationships; Azteca; biotic defence; induced responses
Abstract Background: Among arboreal ants, both territorially dominant species and plant-ants (e.g. species associated with myrmecophytes or plants housing them in hollow structures) protect their host trees against defoliators. Yet, locally induced responses, or the recruitment of nest-mates when a worker discovers it wound on its host-tree, were only noted in plant-ants. We wondered whether this might be due to the examination of the phenomenon being restricted to only six plant-ant species belonging to four genera. Based on the ant genus Azteca, a Neotropical group of arboreal species, we compared five species. The territorially dominant, carton-nester A. chartifex, three plant-ant species [A. alfari and A. ovaticeps associated with myrmecophitic Cecropia (Cecropiaceae), and A. bequaerti associated with Tococa guianensis (Melastomataceae)], and A. schimperi thought to be a temporary social parasite of true Cecropia ants. Methods: We artificially inflicted wounds to the foliage of the host tree of the different ant species. We then compared the number of workers on wounded versus control leaves. Results: We noted a locally induced response in the three plant-ant species as well as in the territorially dominant species, but very slightly so in A. schimperi.
Address [Grangier, Julien; Orivel, Jerome] Univ Toulouse 2, Lab Evolut & Diversite Biol, CNRS, UMR 5174, Toulouse, France, Email: alain.dejean@wanadoo.fr
Corporate Author Thesis
Publisher (up) EVOLUTIONARY ECOLOGY LTD Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1522-0613 ISBN Medium
Area Expedition Conference
Notes ISI:000264041000008 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 119
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Author Millet, J.; Pascal, J.P.; Kiet, L.C.
Title Effects of Disturbance Over 60 Years on a Lowland Forest in Southern Vietnam Type Journal Article
Year 2010 Publication Journal of Tropical Forest Science Abbreviated Journal J. Trop. For. Sci.
Volume 22 Issue 3 Pages 237-246
Keywords Lowland tropical forest; disturbance impact; floristic composition; forest structure; Tan Phu forest
Abstract MILLET J, PASCAL JP & MET LC. 2010. Effects of disturbance over 60 years on a lowland forest in southern Vietnam. Tropical lowland forests are some of the most threatened in the world and this is particularly the case in Vietnam. This study aimed to identify changes in species composition and forest structure in the Tan Phu lowland forest resulting from disturbance over a 60 year period. Analysis of forest composition and structure rely on data from 25 plots of 0.5-ha size established in a lowland secondary forest. The five forest stands described differed greatly from the three forest stand types described in 1943. Some long-lived shade-tolerant species had been replaced by pioneer species, such as Cratoxylon formosum and Shorea roxburghii. In addition to altering composition, forest disturbances had resulted in large changes in forest structure. While in the past, forest stands had a large number of exploitable trees, current forest stands have few trees in the diameter class > 50 cm and sometimes no trees in the diameter class > 80 cm. This paper provides notable results on forest tree ecology, forest dynamics and on the state of secondary forests in Vietnam. This is particularly important as future goods and services will increasingly have to come from such forests.
Address [Millet, J.] Univ Lyon 1, F-69622 Villeurbanne, France, Email: jerome.millet@ird.if
Corporate Author Thesis
Publisher (up) FOREST RESEARCH INST MALAYSIA Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0128-1283 ISBN Medium
Area Expedition Conference
Notes ISI:000280653200003 Approved no
Call Number EcoFoG @ webmaster @ Serial 283
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Author Sellan, G. ; Brearley, FQ. ; Nilus, R. ; Ttin, J. ; Majalap-Lee, N.
Title Differences in soil properties among contrasting soil types in Northern Borneo Type Journal Article
Year 2021 Publication Journal of Tropical Forest Science Abbreviated Journal
Volume 33 Issue 2 Pages 191-202
Keywords
Abstract Soil in the tropics is high in diversity, and despite the diversity of Borneo’s forest–soil associations, there is a paucity of data on its soil properties. We investigated the differences between three soil types in the Kabili–Sepilok Forest Reserve, Sabah, Malaysia, encompassing the contrasting alluvial, sandstone and heath forest typologies. We examined the distribution of nutrients between soil types and through soil depths, and assessed the extent of spatial autocorrelation in the three soil types. We confirmed the fertility gradient from alluvial to heath forest soil found by others. Soil elemental concentrations declined in deeper horizons with the exception of exchangeable sodium and aluminium that remained constant through alluvial and sandstone soil profiles. Spatial autocorrelation was present in all three soil types and strongest in the sandstone soil. Overall, we show how bedrock, erosion, leaching and topography influence soil properties across this mosaic of soil types and note their importance in influencing tree communities and their ecological functioning.
Address
Corporate Author Thesis
Publisher (up) FOREST RESEARCH INST MALAYSIA Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0128-1283 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 1017
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Author Picard, Nicolas ; Mortier, Frédéric ; Ploton, Pierre ; Liang, Jingjing ; Derroire, Géraldine ; Bastin, Jean-François ; Ayyappan, Narayanan ; Bénédet, Fabrice ; Bosela, Faustin Boyemba ; Clark, Connie J. ; Crowther, Thomas W. ; Obiang, Nestor Laurier Engone ; Forni, Eric ; Harris, David ; Ngomanda, Alfred ; Poulsen, John R. ; Sonké, Bonaventure ; Couteron, Pierre ; Gourley-Fleury, Sylvie
Title Using Model Analysis to Unveil Hidden Patterns in Tropical Forest structures Type Journal Article
Year 2021 Publication Frontiers in Ecology and Evolution Abbreviated Journal
Volume 9 Issue Pages 599200
Keywords
Abstract When ordinating plots of tropical rain forests using stand-level structural attributes such as biomass, basal area and the number of trees in different size classes, two patterns often emerge: a gradient from poorly to highly stocked plots and high positive correlations between biomass, basal area and the number of large trees. These patterns are inherited from the demographics (growth, mortality and recruitment) and size allometry of trees and tend to obscure other patterns, such as site differences among plots, that would be more informative for inferring ecological processes. Using data from 133 rain forest plots at nine sites for which site differences are known, we aimed to filter out these patterns in forest structural attributes to unveil a hidden pattern. Using a null model framework, we generated the anticipated pattern inherited from individual allometric patterns. We then evaluated deviations between the data (observations) and predictions of the null model. Ordination of the deviations revealed site differences that were not evident in the ordination of observations. These sites differences could be related to different histories of large-scale forest disturbance. By filtering out patterns inherited from individuals, our model analysis provides more information on ecological processes
Address
Corporate Author Thesis
Publisher (up) Frontiers Media Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
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Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 1029
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Author Heu, Katy ; Romoli, Ottavia ; Schonbeck, Johan Claes ; Ajenoe, Rachel ; Epelboin, Yanouk ; Kircher, Verena ; Houel, Emeline ; Estevez, Yannick ; Gendrin, Mathilde
Title The Effect of Secondary Metabolites Produced by Serratia marcescens on Aedes aegypti and Its Microbiota Type Journal Article
Year 2021 Publication Frontiers in Microbiology Abbreviated Journal
Volume 12 Issue Pages 645701
Keywords
Abstract Serratia marcescens is a bacterial species widely found in the environment, which very efficiently colonizes mosquitoes. In this study, we isolated a red-pigmented S. marcescens strain from our mosquito colony (called S. marcescens VA). This red pigmentation is caused by the production of prodigiosin, a molecule with antibacterial properties. To investigate the role of prodigiosin on mosquito- S. marcescens interactions, we produced two white mutants of S. marcescens VA by random mutagenesis. Whole genome sequencing and chemical analyses suggest that one mutant has a nonsense mutation in the gene encoding prodigiosin synthase, while the other one is deficient in the production of several types of secondary metabolites including prodigiosin and serratamolide. We used our mutants to investigate how S. marcescens secondary metabolites affect the mosquito and its microbiota. Our in vitro tests indicated that S. marcescens VA inhibits the growth of several mosquito microbiota isolates using a combination of prodigiosin and other secondary metabolites, corroborating published data. This strain requires secondary metabolites other than prodigiosin for its proteolytic and hemolytic activities. In the mosquito, we observed that S. marcescens VA is highly virulent to larvae in a prodigiosin-dependent manner, while its virulence on adults is lower and largely depends on other metabolites
Address
Corporate Author Thesis
Publisher (up) Frontiers Media 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 Approved no
Call Number EcoFoG @ webmaster @ Serial 1024
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Author Chanson, Anaïs ; Moreau, Corrie S. ; Duplais, Christophe
Title Assessing Biosynthetic Gene Cluster Diversity of Specialized Metabolites in the Conserved Gut Symbionts of Herbivorous Turtle Ants Type Journal Article
Year 2021 Publication Frontiers in Microbiology Abbreviated Journal
Volume 12 Issue Pages 678100
Keywords insect-microbe mutualism, ants, metagemonic, biosynthetic gene cluster, gut bacteria, Cephalotes
Abstract Cephalotes are herbivorous ants (>115 species) feeding on low-nitrogen food sources, and they rely on gut symbionts to supplement their diet by recycling nitrogen food waste into amino acids. These conserved gut symbionts, which encompass five bacterial orders, have been studied previously for their primary nitrogen metabolism; however, little is known about their ability to biosynthesize specialized metabolites which can play a role in bacterial interactions between communities living in close proximity in the gut. To evaluate the biosynthetic potential of their gut symbionts, we mine 14 cultured isolate genomes and gut metagenomes across 17 Cephalotes species to explore the biodiversity of biosynthetic gene clusters (BGCs) producing specialized metabolites. The diversity of BGCs across Cephalotes phylogeny was analyzed using sequence similarity networking and BGC phylogenetic reconstruction. Our results reveal that the conserved gut symbionts involved in the nutritional symbiosis possess 80% of all the 233 BGCs retrieved in this work. Furthermore, the phylogenetic analysis of BGCs reveals different patterns of distribution, suggesting different mechanisms of conservation. A siderophore BGC shows high similarity in a single symbiont across different ant host species, whereas a BGC encoding the production of non-ribosomal peptides (NRPs) found different symbionts within a single host species. Additionally, BGCs were abundant in four of the five bacterial orders of conserved symbionts co-occurring in the hindgut. However, one major symbiont localized alone in the midgut lack BGCs. Because the spatial isolation prevents direct interaction with other symbionts, this result supports the idea that BGCs are maintained in bacteria living in close proximity but are dispensable for an alone-living symbiont. These findings together pave the way for studying the mechanisms of BGC conservation and evolution in gut bacterial genomes associated with Cephalotes. This work also provides a genetic background for further study, aiming to characterize bacterial specialized metabolites and to understand their functional role in multipartite mutualisms between conserved gut symbionts and Cephalotes turtle ants.
Address
Corporate Author Thesis
Publisher (up) Frontiers Media 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 Approved no
Call Number EcoFoG @ webmaster @ Serial 1049
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Author Bréchet, L.; Courtois, E.A.; Saint-Germain, T.; Janssens, I.A.; Asensio, D.; Ramirez-Rojas, I.; Soong, J.L.; Van Langenhove, L.; Verbruggen, E.; Stahl, C.
Title Disentangling Drought and Nutrient Effects on Soil Carbon Dioxide and Methane Fluxes in a Tropical Forest Type Journal Article
Year 2019 Publication Frontiers in Environmental Science Abbreviated Journal Front. Environ. Sci.
Volume 7 Issue 180 Pages
Keywords carbon dioxide; drought; fertilization; methane; nitrogen; phosphorus; soil GHG fluxes; tropical forest
Abstract Tropical soils are a major contributor to the balance of greenhouse gas (GHG) fluxes in the atmosphere. Models of tropical GHG fluxes predict that both the frequency of drought events and changes in atmospheric deposition of nitrogen (N) will significantly affect dynamics of soil carbon dioxide (CO2) and methane (CH4) production and consumption. In this study, we examined the combined effect of a reduction in precipitation and an increase in nutrient availability on soil CO2 and CH4 fluxes in a primary French Guiana tropical forest. Drought conditions were simulated by intercepting precipitation falling through the forest canopy with tarpaulin roofs. Nutrient availability was manipulated through application of granular N and/or phosphorus (P) fertilizer to the soil. Soil water content (SWC) below the roofs decreased rapidly and stayed at continuously low values until roof removal, which as a consequence roughly doubled the duration of the dry season. After roof removal, SWC slowly increased but remained lower than in the control soils even after 2.5 months of wet-season precipitation. We showed that drought-imposed reduction in SWC decreased the CO2 emissions (i.e., CO2 efflux), but strongly increased the CH4 emissions. N, P, and N × P (i.e., NP) additions all significantly increased CO2 emission but had no effect on CH4 fluxes. In treatments where both fertilization and drought were applied, the positive effect of N, P, and NP fertilization on CO2 efflux was reduced. After roof removal, soil CO2 efflux was more resilient in the control plots than in the fertilized plots while there was only a modest effect of roof removal on soil CH4 fluxes. Our results suggest that a combined increase in drought and nutrient availability in soil can locally increase the emissions of both CO2 and CH4 from tropical soils, for a long term.
Address Lawrence Berkeley National Laboratory, Climate and Ecosystem Science Division, Berkeley, CA, United States
Corporate Author Thesis
Publisher (up) Frontiers Media S.A. Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2296665x (Issn) ISBN Medium
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Notes Export Date: 16 December 2019; Correspondence Address: Bréchet, L.; Centre of Excellence PLECO (Plant and Ecosystems), Department of Biology, University of AntwerpBelgium; email: laeti.brechet@gmail.com Approved no
Call Number EcoFoG @ webmaster @ Serial 899
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