| Records |
Author  |
Flores, O.; Rossi, V.; Mortier, F. |
| Title |
Autocorrelation offsets zero-inflation in models of tropical saplings density |
Type |
Journal Article |
| Year |
2009 |
Publication |
Ecological Modelling |
Abbreviated Journal |
Ecol. Model. |
| Volume |
220 |
Issue |
15 |
Pages |
1797-1809 |
| Keywords |
Hierarchical Bayesian Modelling; Conditional Auto-Regressive model; Variable selection; Zero-Inflated Poisson; Posterior predictive; Paracou; French Guiana |
| Abstract |
Modelling the local density of tropical saplings can provide insights into the ecological processes that drive species regeneration and thereby help predict population recovery after disturbance. Yet, few studies have addressed the challenging issues in autocorrelation and zero-inflation of local density. This paper presents Hierarchical Bayesian Modelling (HBM) of sapling density that includes these two features. Special attention is devoted to variable selection, model estimation and comparison. We developed a Zero-Inflated Poisson (ZIP) model with a latent correlated spatial structure and compared it with non-spatial ZIP and Poisson models that were either autocorrelated (Spatial Generalized Linear Mixed, SGLM) or not (generalized linear models, GLM). In our spatial models, local density autocorrelation was modeled by a Conditional Auto-Regressive (CAR) process. 13 explicative variables described ecological conditions with respect to topography, disturbance, stand structure and intraspecific processes. Models were applied to six tropical tree species with differing biological attributes: Oxandra asbeckii, Eperua falcata, Eperua grandiflora, Dicorynia guianensis, Qualea rosea, and Tachigali melinonii. We built species-specific models using a simple method of variable selection based on a latent binary indicator. Our spatial models showed a close correlation between observed and estimated densities with site spatial structure being correctly reproduced. By contrast, the non-spatial models showed poor fits. Variable selection highlighted species-specific requirements and susceptibility to local conditions. Model comparison overall showed that the SGLM was the most accurate explanatory and predictive model. Surprisingly, zero-inflated models performed less well. Although the SZIP model was relevant with respect to data distribution, and more flexible with respect to response curves, its model complexity caused marked variability in parameter estimates. In the SUM, the spatial process alone accounted for zero-inflation in the data. A refinement of the hypotheses employed at the process level could compensate for distribution flaws at the data level. This study emphasized the importance of the HBM framework in improving the modelling of density-environment relationships. (C) 2008 Elsevier B.V. All rights reserved. |
| Address |
[Flores, O.] CNRS, Ctr Ecol Fonct & Evolut, UMR 5175, F-34293 Montpellier 5, France, Email: olivierflores@free.fr |
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ELSEVIER SCIENCE BV |
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0304-3800 |
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ISI:000267585400007 |
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no |
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EcoFoG @ eric.marcon @ |
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201 |
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| Author |
Flores, O.; Herault, B.; Delcamp, M.; Garnier, É.; Gourlet-Fleury, S. |
| Title |
Functional traits help predict post-disturbance demography of tropical trees |
Type |
Journal Article |
| Year |
2014 |
Publication |
PLoS ONE |
Abbreviated Journal |
PLoS ONE |
| Volume |
9 |
Issue |
9 |
Pages |
e105022 |
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| Abstract |
How tropical tree species respond to disturbance is a central issue of forest ecology, conservation and resource management. We define a hierarchical model to investigate how functional traits measured in control plots relate to the population change rate and to demographic rates for recruitment and mortality after disturbance by logging operations. Population change and demographic rates were quantified on a 12-year period after disturbance and related to seven functional traits measured in control plots. The model was calibrated using a Bayesian Network approach on 53 species surveyed in permanent forest plots (37.5 ha) at Paracou in French Guiana. The network analysis allowed us to highlight both direct and indirect relationships among predictive variables. Overall, 89% of interspecific variability in the population change rate after disturbance were explained by the two demographic rates, the recruitment rate being the most explicative variable. Three direct drivers explained 45% of the variability in recruitment rates, including leaf phosphorus concentration, with a positive effect, and seed size and wood density with negative effects. Mortality rates were explained by interspecific variability in maximum diameter only (25%). Wood density, leaf nitrogen concentration, maximum diameter and seed size were not explained by variables in the analysis and thus appear as independent drivers of post-disturbance demography. Relationships between functional traits and demographic parameters were consistent with results found in undisturbed forests. Functional traits measured in control conditions can thus help predict the fate of tropical tree species after disturbance. Indirect relationships also suggest how different processes interact to mediate species demographic response. |
| Address |
Centre d'Écologie Fonctionnelle et Évolutive, CNRS – UMR 5175Montpellier, France |
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Public Library of Science |
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19326203 (Issn) |
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Export Date: 7 October 2014; Coden: Polnc; Correspondence Address: Flores, O.; Cirad – Université de la Réunion, UMR PVBMT, 7 chemin de l'IRAT, France |
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EcoFoG @ webmaster @ |
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562 |
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Fisher, J.B.; Malhi, Y.; Bonal, D.; Da Rocha, H.R.; De Araujo, A.C.; Gamo, M.; Goulden, M.L.; Hirano, T.; Huete, A.R.; Kondo, H.; Kumagai, T.; Loescher, H.W.; Miller, S.; Nobre, A.D.; Nouvellon, Y.; Oberbauer, S.F.; Panuthai, S.; Roupsard, O.; Saleska, S.; Tanaka, K.; Tanaka, N.; Tu, K.P.; Von Randow, C. |
| Title |
The land-atmosphere water flux in the tropics |
Type |
Journal Article |
| Year |
2009 |
Publication |
Global Change Biology |
Abbreviated Journal |
Glob. Change Biol. |
| Volume |
15 |
Issue |
11 |
Pages |
2694-2714 |
| Keywords |
Amazon; eddy covariance; evaporation; evapotranspiration; ISLSCP-II; LBA; model; remote sensing; tropical |
| Abstract |
Tropical vegetation is a major source of global land surface evapotranspiration, and can thus play a major role in global hydrological cycles and global atmospheric circulation. Accurate prediction of tropical evapotranspiration is critical to our understanding of these processes under changing climate. We examined the controls on evapotranspiration in tropical vegetation at 21 pan-tropical eddy covariance sites, conducted a comprehensive and systematic evaluation of 13 evapotranspiration models at these sites, and assessed the ability to scale up model estimates of evapotranspiration for the test region of Amazonia. Net radiation was the strongest determinant of evapotranspiration (mean evaporative fraction was 0.72) and explained 87% of the variance in monthly evapotranspiration across the sites. Vapor pressure deficit was the strongest residual predictor (14%), followed by normalized difference vegetation index (9%), precipitation (6%) and wind speed (4%). The radiation-based evapotranspiration models performed best overall for three reasons: (1) the vegetation was largely decoupled from atmospheric turbulent transfer (calculated from X decoupling factor), especially at the wetter sites; (2) the resistance-based models were hindered by difficulty in consistently characterizing canopy (and stomatal) resistance in the highly diverse vegetation; (3) the temperature-based models inadequately captured the variability in tropical evapotranspiration. We evaluated the potential to predict regional evapotranspiration for one test region: Amazonia. We estimated an Amazonia-wide evapotranspiration of 1370 mm yr(-1), but this value is dependent on assumptions about energy balance closure for the tropical eddy covariance sites; a lower value (1096 mm yr(-1)) is considered in discussion on the use of flux data to validate and interpolate models. |
| Address |
[Fisher, Joshua B.; Malhi, Yadvinder] Univ Oxford, Environm Change Inst, Sch Geog & Environm, Oxford OX1 3QY, England, Email: joshbfisher@gmail.com |
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WILEY-BLACKWELL PUBLISHING, INC |
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Edition |
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1354-1013 |
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| Notes |
ISI:000270662000011 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
101 |
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Fine, P.V.A.; Metz, M.R.; Lokvam, J.; Mesones, I.; Zuniga, J.M.A.; Lamarre, G.P.A.; Pilco, M.V.; Baraloto, C. |
| Title |
Insect herbivores, chemical innovation, and the evolution of habitat specialization in Amazonian trees |
Type |
Journal Article |
| Year |
2013 |
Publication |
Ecology |
Abbreviated Journal |
Ecology |
| Volume |
94 |
Issue |
8 |
Pages |
1764-1775 |
| Keywords |
Amazonia; Ecological speciation; Ecotypes; Herbivory; Natural enemies; Plant defense; Protium subserratum; Terra firme forests; Tropical rain forests; White-sand forests |
| Abstract |
Herbivores are often implicated in the generation of the extraordinarily diverse tropical flora. One hypothesis linking enemies to plant diversification posits that the evolution of novel defenses allows plants to escape their enemies and expand their ranges. When range expansion involves entering a new habitat type, this could accelerate defense evolution if habitats contain different assemblages of herbivores and/or divergent resource availabilities that affect plant defense allocation. We evaluated this hypothesis by investigating two sister habitat specialist ecotypes of Protium subserratum (Burseraceae), a common Amazonian tree that occurs in white-sand and terra firme forests. We collected insect herbivores feeding on the plants, assessed whether growth differences between habitats were genetically based using a reciprocal transplant experiment, and sampled multiple populations of both lineages for defense chemistry. Protium subserratum plants were attacked mainly by chrysomelid beetles and cicadellid hemipterans. Assemblages of insect herbivores were dissimilar between populations of ecotypes from different habitats, as well as from the same habitat 100 km distant. Populations from terra firme habitats grew significantly faster than white-sand populations; they were taller, produced more leaf area, and had more chlorophyll. White-sand populations expressed more dry mass of secondary compounds and accumulated more flavone glycosides and oxidized terpenes, whereas terra firme populations produced a coumaroylquinic acid that was absent from white-sand populations. We interpret these results as strong evidence that herbivores and resource availability select for divergent types and amounts of defense investment in white-sand and terra firme lineages of Protium subserratum, which may contribute to habitat-mediated speciation in these trees. © 2013 by the Ecological Society of America. |
| Address |
Department of Biology, University of Florida, Gainesville, FL 32611, United States |
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00129658 (Issn) |
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Export Date: 30 August 2013; Source: Scopus; Coden: Ecola; doi: 10.1890/12-1920.1; Language of Original Document: English; Correspondence Address: Department of Integrative Biology, 1005 Valley Life Sciences Building 3140, University of California, Berkeley, CA 94720-3140, United States |
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no |
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EcoFoG @ webmaster @ |
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500 |
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| Author |
Fine, P.V.A.; Baraloto, C. |
| Title |
Habitat Endemism in White-sand Forests: Insights into the Mechanisms of Lineage Diversification and Community Assembly of the Neotropical Flora |
Type |
Journal Article |
| Year |
2016 |
Publication |
Biotropica |
Abbreviated Journal |
Biotropica |
| Volume |
48 |
Issue |
1 |
Pages |
24-33 |
| Keywords |
Amazon; Endemic; Functional traits; Habitat specialization; Niche conservatism; Speciation |
| Abstract |
White-sand forests represent natural laboratories of evolution over their long history throughout Amazonia and the Guiana Shield and pose significant physiological challenges to the plants and animals they host. The study of diversification in plant lineages comprising species endemic to white-sand forest can therefore give insights into processes of evolution and community assembly in tropical forests. In this article, we synthesize recent studies of white-sand forests to integrate patterns of plant species distribution with processes of lineage diversification and community assembly in the white-sand flora. We contrast lineages that have radiated uniquely in these habitats (e.g., Pagamea, Rubiaceae), with cosmopolitan lineages comprising specialists to white-sand forests and other habitats that may have arisen via ecological speciation across habitat gradients (e.g., Protium, Burseraceae). In both cases, similar suites of functional traits have evolved, including investment in dense, long-lived tissues that are well-defended structurally and chemically. White-sand endemics, therefore, play an important role in biodiversity conservation because they represent unique combinations of functional and phylogenetic diversity. Furthermore, white-sand endemics may respond differently than other tropical forest plant species to contemporary global changes because they comprise resilient functional types that may better withstand increased drought, temperature, and invasions of exotic pests in these regions. © 2016 The Association for Tropical Biology and Conservation. |
| Address |
Department of Biological Sciences and International Center for Tropical Botany, Florida International University, Miami, FL, United States |
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Cited By :3; Export Date: 12 February 2016 |
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no |
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EcoFoG @ webmaster @ |
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659 |
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| Author |
Fichaux, M.; Béchade, B.; Donald, J.; Weyna, A.; Delabie, J.H.C.; Murienne, J.; Baraloto, C.; Orivel, J. |
| Title |
Habitats shape taxonomic and functional composition of Neotropical ant assemblages |
Type |
Journal Article |
| Year |
2019 |
Publication |
Oecologia |
Abbreviated Journal |
Oecologia |
| Volume |
189 |
Issue |
2 |
Pages |
501-513 |
| Keywords |
Formicidae; Functional diversity; Habitat filtering; Rainforest; Traits; Formicidae |
| Abstract |
Determining assembly rules of co-occurring species persists as a fundamental goal in community ecology. At local scales, the relative importance of environmental filtering vs. competitive exclusion remains a subject of debate. In this study, we assessed the relative importance of habitat filtering and competition in structuring understory ant communities in tropical forests of French Guiana. Leaf-litter ants were collected using pitfall and Winkler traps across swamp, slope and plateau forests near Saül, French Guiana. We used a combination of univariate and multivariate analyses to evaluate trait response of ants to habitat characteristics. Null model analyses were used to investigate the effects of habitat filtering and competitive interactions on community assembly at the scale of assemblages and sampling points, respectively. Swamp forests presented a much lower taxonomic and functional richness compared to slope and plateau forests. Furthermore, marked differences in taxonomic and functional composition were observed between swamp forests and slope or plateau forests. We found weak evidence for competitive exclusion based on null models. Nevertheless, the contrasting trait composition observed between habitats revealed differences in the ecological attributes of the species in the different forest habitats. Our analyses suggest that competitive interactions may not play an important role in structuring leaf-litter ant assemblages locally. Rather, habitats are responsible for driving both taxonomic and functional composition of ant communities. |
| Address |
International Center for Tropical Botany, Department of Biological Sciences, Florida International University, Miami, FL 33199, United States |
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Springer Verlag |
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00298549 (Issn) |
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no |
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EcoFoG @ webmaster @ |
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863 |
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Ferry, B.; Morneau, F.; Bontemps, J.D.; Blanc, L.; Freycon, V. |
| Title |
Higher treefall rates on slopes and waterlogged soils result in lower stand biomass and productivity in a tropical rain forest |
Type |
Journal Article |
| Year |
2010 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
| Volume |
98 |
Issue |
1 |
Pages |
106-116 |
| Keywords |
biomass; community ecology; growth; mortality; productivity; soil waterlogging; topography; treefall; tropical moist forest; wood density |
| Abstract |
P>1. Relationships between tropical rain forest biomass and environmental factors have been determined at regional scales, e.g. the Amazon Basin, but the reasons for the high variability in forest biomass at local scales are poorly understood. Interactions between topography, soil properties, tree growth and mortality rates, and treefalls are a likely reason for this variability. 2. We used repeated measurements of permanent plots in lowland rain forest in French Guiana to evaluate these relationships. The plots sampled topographic gradients from hilltops to slopes to bottomlands, with accompanying variation in soil waterlogging along these gradients. Biomass was calculated for > 175 tree species in the plots, along with biomass productivity and recruitment rates. Mortality was determined as standing dead and treefalls. 3. Treefall rates were twice as high in bottomlands as on hilltops, and tree recruitment rates, radial growth rates and the abundance of light-demanding tree species were also higher. 4. In the bottomlands, the mean wood density was 10% lower than on hilltops, the basal area 29% lower and the height:diameter ratio of trees was lower, collectively resulting in a total woody biomass that was 43% lower in bottomlands than on hilltops. 5. Biomass productivity was 9% lower in bottomlands than on hilltops, even though soil Olsen P concentrations were higher in bottomlands. 6. Synthesis. Along a topographic gradient from hilltops to bottomlands there were higher rates of treefall, which decreased the stand basal area and favoured lower allocation to height growth and recruitment of light-demanding species with low wood density. The resultant large variation in tree biomass along the gradient shows the importance of determining site characteristics and including these characteristics when scaling up biomass estimates from stand to local or regional scales. |
| Address |
[Ferry, Bruno; Morneau, Francois; Bontemps, Jean-Daniel] AgroParisTech, ENGREF Nancy, UMR 1092, CS 14216, F-54000 Nancy, France, Email: bruno.ferry@engref.agroparistech.fr |
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WILEY-BLACKWELL PUBLISHING, INC |
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0022-0477 |
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ISI:000272657400012 |
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no |
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EcoFoG @ eric.marcon @ |
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87 |
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Ferry, B.; Bontemps, J.-D.; Blanc, L.; Baraloto, C. |
| Title |
Is climate a stronger driver of tree growth than disturbance? A comment on Toledo et al. (2011) |
Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Ecology |
Abbreviated Journal |
J. Ecol. |
| Volume |
100 |
Issue |
5 |
Pages |
1065-1068 |
| Keywords |
Basal area change; Bolivia; Climate; Disturbance; Logging; Plant-climate interactions; Tree growth; Tropical forest |
| Abstract |
1.A recent article published by Toledo (2011b) investigates the effects of spatial variations in climate and soil, and of logging disturbance, on tree and forest growth in Bolivia. It concludes that climate is the strongest driver of tree and forest growth and that climate change may therefore have large consequences for forest productivity and carbon sequestration. However, serious methodological and conceptual discrepancies have been found that challenge these conclusions. 2.Because of an errant coding of 'time after logging' in the regression analysis, and because floristic changes induced by logging could not be incorporated into the analysis, the effect of logging on the average diameter growth is likely to have been strongly underestimated. 3.Basal area growth was improperly calculated as basal area change, and it displayed surprisingly high values, even among unlogged plots. We hypothesize that either these plots may be actually located in secondary forests recovering from past logging, or measurement biases may have hampered the data set. 4.Regardless of climate-growth relationships established across these plots, any inference concerning the potential effects of climate change on forest growth would require a specific quantitative assessment. 5.Synthesis. It is critical to re-assess the relative weight of climate and logging disturbance as driving factors of tree and forest growth, and to find an explanation for the very high basal area increment reported among the unlogged plots. We provide specific recommendations for further analyses of this and similar data sets. © 2012 British Ecological Society. |
| Address |
INRA, UMR Ecologie des Forêts de Guyane, 97379 Kourou, French Guiana |
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00220477 (Issn) |
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Cited By (since 1996): 1; Export Date: 4 September 2012; Source: Scopus; Coden: Jecoa; doi: 10.1111/j.1365-2745.2011.01895.x; Language of Original Document: English; Correspondence Address: Ferry, B.; AgroParisTech, ENGREF-Nancy, UMR 1092, F-54000 Nancy, France; email: bruno.ferry@engref.agroparistech.fr |
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EcoFoG @ webmaster @ |
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426 |
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Ferrer, A.; Dixon, A.F.; Gibernau, M.; Hemptinne, J.L. |
| Title |
Ovarian dynamics and specialisation in ladybirds |
Type |
Journal Article |
| Year |
2010 |
Publication |
Ecological Entomology |
Abbreviated Journal |
Ecol. Entomol. |
| Volume |
35 |
Issue |
1 |
Pages |
100-103 |
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Ladybird beetles; oocyte resorption; ovarian dynamics; specialisation |
| Abstract |
2. This hypothesis was tested by comparing a generalist and a specialist ladybird species belonging to the same genus. 3. A resorption index was calculated for females of both species subjected to several starvation regimes. This index indicated that over a period of fasting of 3 days, the intensity of resorption was greater in the generalist than the specialist. When food was again supplied, oogenesis resumed and within 1 day was faster in the generalist than in the specialist. 4. As predicted, the resorption of oocytes and replenishment occurred faster in the generalist than in the specialist species. This is the first time, to our knowledge, that the speed and intensity of the ovarian dynamics of a predatory insect have been linked to its way of life. |
| Address |
[Ferrer, Aurelie; Hemptinne, Jean-Louis] Univ Toulouse ENFAT, CNRS, UMR 5174, F-31326 Castanet Tolosan, France, Email: jean-louis.hemptinne@educagri.fr |
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WILEY-BLACKWELL PUBLISHING, INC |
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0307-6946 |
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ISI:000273454300013 |
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no |
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EcoFoG @ eric.marcon @ |
Serial |
86 |
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Feldpausch, T.R.; Phillips, O.L.; Brienen, R.J.W.; Gloor, E.; Lloyd, J.; Lopez-Gonzalez, G.; Monteagudo-Mendoza, A.; Malhi, Y.; Alarcón, A.; Álvarez Dávila, E.; Alvarez-Loayza, P.; Andrade, A.; Aragao, L.E.O.C.; Arroyo, L.; Aymard C., G.A.; Baker, T.R.; Baraloto, C.; Barroso, J.; Bonal, D.; Castro, W.; Chama, V.; Chave, J.; Domingues, T.F.; Fauset, S.; Groot, N.; Honorio Coronado, E.; Laurance, S.; Laurance, W.F.; Lewis, S.L.; Licona, J.C.; Marimon, B.S.; Marimon-Junior, B.H.; Mendoza Bautista, C.; Neill, D.A.; Oliveira, E.A.; Oliveira dos Santos, C.; Pallqui Camacho, N.C.; Pardo-Molina, G.; Prieto, A.; Quesada, C.A.; Ramírez, F.; Ramírez-Angulo, H.; Réjou-Méchain, M.; Rudas, A.; Saiz, G.; Salomão, R.P.; Silva-Espejo, J.E.; Silveira, M.; ter Steege, H.; Stropp, J.; Terborgh, J.; Thomas-Caesar, R.; van der Heijden, G.M.F.; Vásquez Martinez, R.; Vilanova, E.; Vos, V.A. |
| Title |
Amazon forest response to repeated droughts |
Type |
Journal Article |
| Year |
2016 |
Publication |
Global Biogeochemical Cycles |
Abbreviated Journal |
Global Biogeochemical Cycles |
| Volume |
30 |
Issue |
7 |
Pages |
964-982 |
| Keywords |
carbon; forest productivity; precipitation; tree mortality; vegetation dynamics; water deficit |
| Abstract |
The Amazon Basin has experienced more variable climate over the last decade, with a severe and widespread drought in 2005 causing large basin-wide losses of biomass. A drought of similar climatological magnitude occurred again in 2010; however, there has been no basin-wide ground-based evaluation of effects on vegetation. We examine to what extent the 2010 drought affected forest dynamics using ground-based observations of mortality and growth from an extensive forest plot network. We find that during the 2010 drought interval, forests did not gain biomass (net change: −0.43 Mg ha−1, confidence interval (CI): −1.11, 0.19, n = 97), regardless of whether forests experienced precipitation deficit anomalies. This contrasted with a long-term biomass sink during the baseline pre-2010 drought period (1998 to pre-2010) of 1.33 Mg ha−1 yr−1 (CI: 0.90, 1.74, p < 0.01). The resulting net impact of the 2010 drought (i.e., reversal of the baseline net sink) was −1.95 Mg ha−1 yr−1 (CI:−2.77, −1.18; p < 0.001). This net biomass impact was driven by an increase in biomass mortality (1.45 Mg ha−1 yr−1 CI: 0.66, 2.25, p < 0.001) and a decline in biomass productivity (−0.50 Mg ha−1 yr−1, CI:−0.78, −0.31; p < 0.001). Surprisingly, the magnitude of the losses through tree mortality was unrelated to estimated local precipitation anomalies and was independent of estimated local pre-2010 drought history. Thus, there was no evidence that pre-2010 droughts compounded the effects of the 2010 drought. We detected a systematic basin-wide impact of the 2010 drought on tree growth rates across Amazonia, which was related to the strength of the moisture deficit. This impact differed from the drought event in 2005 which did not affect productivity. Based on these ground data, live biomass in trees and corresponding estimates of live biomass in lianas and roots, we estimate that intact forests in Amazonia were carbon neutral in 2010 (−0.07 Pg C yr−1 CI:−0.42, 0.23), consistent with results from an independent analysis of airborne estimates of land-atmospheric fluxes during 2010. Relative to the long-term mean, the 2010 drought resulted in a reduction in biomass carbon uptake of 1.1 Pg C, compared to 1.6 Pg C for the 2005 event. ©2016. American Geophysical Union. All Rights Reserved. |
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Centro de Investigación y Promoción del Campesinado Norte Amazónico, Riberalta, Bolivia |
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Export Date: 1 September 2016 |
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no |
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EcoFoG @ webmaster @ |
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690 |
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