Éditeur(s) : HAL CCSD
Résumé : Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.
ISSN: 1476-4687

hal-01204223
https://hal.archives-ouvertes.fr/hal-01204223
DOI : 10.1038/nature14283
PRODINRA : 294797
PUBMED : 25788097

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
ISSN: 0020-7292

inserm-01065103
http://www.hal.inserm.fr/inserm-01065103
http://www.hal.inserm.fr/inserm-01065103/document
http://www.hal.inserm.fr/inserm-01065103/file/Figure.pdf
http://www.hal.inserm.fr/inserm-01065103/file/2013_Douine_-_Survival_cervical.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Chronic obstructive pulmonary disease (COPD) is the chronic respiratory disease with the most important burden on public health in terms of morbidity, mortality and health costs. For patients, COPD is a major source of disability because of dyspnea, restriction in daily activities, exacerbation, risk of chronic respiratory failure and extra-respiratory systemic organ disorders. The previous French Language Respiratory Society (SPLF) guidelines on COPD exacerbations were published in 2003. Using the GRADE methodology, the present document reviews the current knowledge on COPD exacerbation through 4 specific outlines: (1) epidemiology, (2) clinical evaluation, (3) therapeutic management and (4) prevention. Specific aspects of outpatients and inpatients care are discussed, especially regarding assessment of exacerbation severity and pharmacological approach.
Revue Des Maladies Respiratoires

hal-01560287
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01560287
DOI : 10.1016/j.rmr.2017.03.034
PUBMED : 28552256

Éditeur(s) : HAL CCSD European Respiratory Society
Résumé : IF 8.332
International audience
The respiratory manifestations of eosinophilic granulomatosis with polyangiitis (EGPA) have not been studied in detail. In this retrospective multicentre study, EGPA was defined by asthma, eosinophilia and at least one new onset extra-bronchopulmonary organ manifestation of disease. The study population included 157 patients (mean±SD age 49.4±14.1 years), with a mean±SD blood eosinophil count of 7.4±6.4×109 L-1 at diagnosis. There was a mean±SD of 11.8±18.2 years from the onset of asthma to the diagnosis of EGPA, of 1.4±8.4 years from the first onset of peripheral eosinophilia to the diagnosis of EGPA, and of 7.4±6.4 years from EGPA diagnosis to the final visit. Despite inhaled and oral corticosteroid treatment, the severity of asthma increased 3-6 months before the onset of the systemic manifestations. Asthma was severe in 57%, 48%, and 56% of patients at diagnosis, at 3 years, and at the final visit, respectively. Persistent airflow obstruction was present in 38%, 30%, and 46% at diagnosis, at 3 years, and at the final visit, respectively. In EGPA, asthma is severe, antedates systemic manifestations by a mean of 12 years, and progresses to long-term persistent airflow obstruction despite corticosteroids in a large proportion of patients, which affects long-term management and morbidity. Copyright © 2016 ERS.
ISSN: 0903-1936

hal-01406073
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01406073
DOI : 10.1183/13993003.00097-2016
PUBMED : 27587545

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : National audience
ISSN: 0761-8425

hal-01368337
https://hal.archives-ouvertes.fr/hal-01368337
PUBMED : 27209117

Éditeur(s) : HAL CCSD Society for Range Management
Résumé : Grasslands and agroecosystems occupy one-third of the terrestrial area, but their contribution to the global carbon cycle remains uncertain. We used a set of 316 site-years of CO(2) exchange measurements to quantify gross primary productivity, respiration, and light-response parameters of grasslands, shrublands/savanna, wetlands, and cropland ecosystems worldwide. We analyzed data from 72 global flux-tower sites partitioned into gross photosynthesis and ecosystem respiration with the use of the light-response method (Gilmanov, T. G., D. A. Johnson, and N. Z. Saliendra. 2003. Growing season CO(2) fluxes in a sagebrushsteppe ecosystem in Idaho: Bowen ratio/energy balance measurements and modeling. Basic and Applied Ecology 4:167-183) from the RANGEFLUX and WORLDGRASSAGRIFLUX data sets supplemented by 46 sites from the FLUXNET La Thuile data set partitioned with the use of the temperature-response method (Reichstein, M., E. Falge, D. Baldocchi, D. Papale, R. Valentini, M. Aubinet, P. Berbigier, C. Bernhofer, N. Buchmann, M. Falk, T. Gilmanov, A. Granier, T. Grunwald, K. Havrankova, D. Janous, A. Knohl, T. Laurela, A. Lohila, D. Loustau, G. Matteucci, T. Meyers, F. Miglietta, J.M. Ourcival, D. Perrin, J. Pumpanen, S. Rambal, E. Rotenberg, M. Sanz, J. Tenhunen, G. Seufert, F. Vaccari, T. Vesala, and D. Yakir. 2005. On the separation of net ecosystem exchange into assimilation and ecosystem respiration: review and improved algorithm. Global Change Biology 11: 1.424-1439). Maximum values of the quantum yield (alpha = 75 mmol.mol(-1)), photosynthetic capacity (A(max) = 3.4 mg CO(2) . m(-2).s-1), gross photosynthesis (P(g,max) = 1.16 g CO(2) . m(-2).d(-1)), and ecological light-use efficiency (epsilon(ecol) = 59 mmol . mol(-1)) of managed grasslands and high-production croplands exceeded those of most forest ecosystems, indicating the potential of nonforest ecosystems for uptake of atmospheric CO(2). Maximum values of gross primary production (8 600 g CO(2) . m(-2).yr(-1)), total ecosystem respiration (7 900 g CO(2) . m(-2).yr(-1)), and net CO(2) exchange (2 400 g CO(2) . m(-2).yr(-1)) were observed for intensively managed grasslands and high-yield crops, and are comparable to or higher than those for forest ecosystems, excluding some tropical forests. On average, 80% of the nonforest sites were apparent sinks for atmospheric CO(2), with mean net uptake of 700 g CO(2) . m(-2).yr(-1) for intensive grasslands and 933 g CO(2) . m(-2).d(-1) for croplands. However, part of these apparent sinks is accumulated in crops and forage, which are carbon pools that are harvested, transported, and decomposed off site. Therefore, although agricultural fields may be predominantly sinks for atmospheric CO(2), this does not imply that they are necessarily increasing their carbon stock.
ISSN: 1550-7424

hal-01190754
https://hal.archives-ouvertes.fr/hal-01190754
DOI : 10.2111/rem-d-09-00072.1
PRODINRA : 214043

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Tyrrhenian Sea is usually interpreted to be a Neogene back-arc basin that opened by continental rifting and oceanic spreading caused by the eastward migration of the Apennine subduction system during Miocene and Pliocene times. Rifting of the southern Tyrrhenian Sea started first along the Eastern Sardinian margin during the middle to late Miocene times, including the Messinian. The "METYSS" project aims at better constraining the relationships between crustal tectonics, salt tectonics and sedimentation from Messinian times to present-day. The "METYSS 1" cruise (2009) allowed to acquire about 1200 km of HR seismic-reflection profiles along the Eastern Sardinian margin, Western Tyrrhenian Sea. This data set clearly illustrates that this area has been highly dissected during the rifting stage by N-S trending normal faults delineating ridges and basins, as previously described. The Messinian seismic markers (UU and MU) locally display fan-shaped stratal geometries, but the mechanism responsible for such geometries, salt tectonics or rifting, has yet to be carefully deciphered. We also mapped the spatial distribution of the mobile salt. The highly variable thickness of the small confined salt basins may be related to the initial pre-Messinian basin geometry, to the fact that salt deposition was syn-rift or to salt movement. Southeastward, salt tectonics is vigorous in unconfined basins and appears to have started early during the UU deposition. More surprisingly, our data demonstrate that some of the major faults have been significantly reactivated during the post-rift period, up to late Quaternary time, as shown by bathymetric scarps and associated debris flows. Moreover, some of this post-rift deformation can be evidenced within the Plio-Quaternary sequence by a regional unconformity. The post-Miocene deformation style varies greatly between different areas of the margin, and can also be strongly influenced by the presence or absence of mobile Messinian salt.
ISSN: 0040-1951

hal-00996665
https://hal.archives-ouvertes.fr/hal-00996665
DOI : 10.1016/j.tecto.2013.12.015

Éditeur(s) : HAL CCSD
Résumé : International audience
Necroptosis is a regulated form of cell death involved in several disease models including in particular liver diseases. Receptor-interacting protein kinases, RIPK1 and RIPK3, are the main serine/threonine kinases driving this cell death pathway. We screened a noncommercial, kinase-focused chemical library which allowed us to identify Sibiriline as a new inhibitor of necroptosis induced by tumor necrosis factor (TNF) in Fas-associated protein with death domain (FADD)-deficient Jurkat cells. Moreover, Sib inhibits necroptotic cell death induced by various death ligands in human or mouse cells while not protecting from caspase-dependent apoptosis. By using competition binding assay and recombinant kinase assays, we demonstrated that Sib is a rather specific competitive RIPK1 inhibitor. Molecular docking analysis shows that Sib is trapped closed to human RIPK1 adenosine triphosphate-binding site in a relatively hydrophobic pocket locking RIPK1 in an inactive conformation. In agreement with its RIPK1 inhibitory property, Sib inhibits both TNF-induced RIPK1-dependent necroptosis and RIPK1-dependent apoptosis. Finally, Sib protects mice from concanavalin A-induced hepatitis. These results reveal the small-molecule Sib as a new RIPK1 inhibitor potentially of interest for the treatment of immune-dependent hepatitis. © 2017 Federation of European Biochemical Societies
ISSN: 1742464X

hal-01616420
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01616420
DOI : 10.1111/febs.14176
PUBMED : 28715128

Éditeur(s) : HAL CCSD Cerimes
Résumé : L'ensemble des articles est archivé sur ArchiveTémaTice. Les actes sont aussi accessibles sur le site du colloque http://www.cerimes.fr/colloquefrancomexicain
Les textes qui composent ces actes ont été présentés à l'occasion du premier colloque franco-mexicain en sciences de la communication, organisé par la Asociación mexicana en Ciencias de la comunicación (AMIC) et la Société Française des Sciences de l'Information et de la Communication (SFSIC), à Mexico, du 8 au 10 avril 2002.

Les médias classiques: radio, télévision (8 avril 2002)
Introduction . La coopération scientifique bilatérale et l'interculturel dans l'activité de recherche, Bruno Ollivier
La recherche française sur le média et les discours télévisuels: éléments pour un bilan prospectif, Guy Lochard
Parcours de la programmation télévisée au Mexique, Florence Toussaint
El regimen de la television hertziana en Mexico, Claudia I. Garcia Rubio
La question de l'éthos et du genre en communication politique, Simone Bonnafous
L'exposition de la vie privée dans les médias, André Vitalis

Identités, culture, communication (9 avril 2002)
Reconfiguraciones cimunicativas de la socialidad y reencantamientos de la communication identidad, Jesus Martin-Barbero
Identité, culture et communication, Jean François Tetu
Las organizaciones civiles en las radiodifusoras comerciales, Dr. José Cisneros E.
Les SIC et l'altérité: démarches d'une recherche sur la Chine. réflexions épitstémologiques sur les analyses de corpus à base communicationnelles de langue et de culture non-maternelles, Dominique Colomb
Transicion, reforma del estado y medios de comunicacion en Mexico, Dr. Javier Esteinou Madrid
Medios masivos y formacion psicosocial, Enrique Guinsberg

Technologies d'information et de communication ( 10 avril 2002)
Quoi de nouveau dans la recherche française en informatique et communication ? Bernard Miege
Convergencia tecnologica: perspectivas de investigacion en Mexico, Delia Crovi Druetta
Medias, technologies et public: la notion de projet au cœur d'une éventuelle médiation, Claire Noy
La formacion de profesores de educacion superior en el uso de la computadora y la internet. reflexioànes sobre el tema, Luz Maria Garay Cruz
Vers un retour à une lecture non linéaire, Schmidt C. T, Roxin I.(), Mercier D, Hufschmitt B. & Cotten J.-P
NTIC et éducation à distance. Le cas d'Edusat au Mexique face au cas français, Norma Veronica Fernandez Arriaga.
Les sciences de l'éducation et les sciences de la communication en dialogue: à propos des médias et des technologies éducatives, Geneviève Jacquinot-Delaunay
Internet et Intranet dans les organisations "un scénario récurrent", Jean-Antoine Corbalan
De l'université virtuelle au campus numérique : simple effet de traduction ou changement de paradigme, Françoise Thibault
Competencias mediacionales de los sujetos en programas educativos en entornos digitales, Maria Elena Chan Nunez
Le journal quotidien sur le Web. L'identité éditoriale au risque du formatage, Annelise Touboul
Conclusion, Carmen Gomez-Mont
Premier colloque franco-mexicain de sciences de la communication
Mexico, France

Droits : info:eu-repo/semantics/OpenAccess
ISBN : http://www.cerimes.education.fr
edutice-00000362
https://edutice.archives-ouvertes.fr/edutice-00000362
https://edutice.archives-ouvertes.fr/edutice-00000362/document
https://edutice.archives-ouvertes.fr/edutice-00000362/file/actes.pdf

Éditeur(s) : HAL CCSD Wiley/Blackwell
Résumé : 4 pages
International audience
This article documents the addition of 268 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Alburnoides bipunctatus, Chamaerops humilis, Chlidonias hybrida, Cyperus papyrus, Fusarium graminearum, Loxigilla barbadensis, Macrobrachium rosenbergii, Odontesthes bonariensis, Pelteobagrus vachelli, Posidonia oceanica, Potamotrygon motoro, Rhamdia quelen, Sarotherodon melanotheron heudelotii, Sibiraea angustata, Takifugu rubripes, Tarentola mauritanica, Trimmatostroma sp. and Wallago attu. These loci were cross-tested on the following species: Alburnoides fasciatus, Alburnoides kubanicus, Alburnoides maculatus, Alburnoides ohridanus, Alburnoides prespensis, Alburnoides rossicus, Alburnoides strymonicus, Alburnoides thessalicus, Alburnoides tzanevi, Carassius carassius, Fusarium asiaticum, Leucaspius delineatus, Loxigilla noctis dominica, Pelecus cultratus, Phoenix canariensis, Potamotrygon falkneri, Trachycarpus fortune and Vimba vimba.
ISSN: 1755-098X

hal-00823716
https://hal.archives-ouvertes.fr/hal-00823716
DOI : 10.1111/1755-0998.12095
PUBMED : 23521844

Éditeur(s) : HAL CCSD Masson
Résumé : International audience
In French Guiana, the age-standardized incidence rate of cervical cancer is four times higher than in France and the mortality rate 5.5 times higher. A survival study revealed that stage at diagnosis was the main factor influencing the prognosis, showing that early detection is crucial to increase cervical cancer survival. The present study aimed at evaluating the cervical cancer screening rate between 2006 and 2011 by age and for 3-years period in French Guiana. All pap smears realised in French Guiana were analysed in two laboratories allowing exhaustive review of screening data. The screening rate was estimated at about 54% from 2006 to 2011, with a statistical difference between coastal and rural area (56.3% versus 18.7%).Although the methodological difference did not allow comparisons with mainland France, these results could be used to evaluate the impact of organised cervical cancer screening by the French Guiana Association for Organized Screening of Cancers implemented in French Guiana since 2012.
ISSN: 0037-9085

hal-01260391
https://hal.archives-ouvertes.fr/hal-01260391
https://hal.archives-ouvertes.fr/hal-01260391/document
https://hal.archives-ouvertes.fr/hal-01260391/file/2015%2C%20Douine%20-%20Servical%20cancer.pdf

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : National audience
Sperm and embryos cryopreservation is a commonly applied technique for several years. Recently authorized in France, vitrification tends to replace gradually the conventional technique of slow freezing, so upsetting the practices in the management of patients. It allows from now on the cryopreservation of oocytes and opens new perspectives in egg donation either still in fertility preservation. This review thus attempted to examine the contribution of vitrification in the freezing of oocytes and human embryos at various stages of development. If obviously vitrification appears as the current method of choice for the cryopreservation of oocytes as well as blastocysts, the results are less cut as regards embryos to early stages. No increase in adverse obstetric and perinatal outcomes in children conceived from vitrified oocytes or embryos is noted in the literature
ISSN: 0368-2315

hal-01282445
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01282445
DOI : 10.1016/j.jgyn.2015.02.015
PUBMED : 25869444

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
The natural river water certified reference material SLRS-5 (NRC-CNRC) was routinely analysed in this study for major and trace elements by ten French laboratories. Most of the measurements were made using ICP-MS. Because no certified values are assigned by NRC-CNRC for silicon and 35 trace element concentrations (rare earth elements, Ag, B, Bi, Cs, Ga, Ge, Li, Nb, P, Rb, Rh, Re, S, Sc, Sn, Th, Ti, Tl, W, Y and Zr), or for isotopic ratios, we provide a compilation of the concentrations and related uncertainties obtained by the participating laboratories. Strontium isotopic ratios are also given. Le matériau de référence certifié d'eau de rivière naturelle SLRS-5 (NRC-CNRC) est analysé régulièrement comme contrôle qualité par dix laboratoires français étudiant les éléments majeurs et en trace dans les solutions naturelles. La plupart des mesures sont réalisées par ICP-MS. Le silicium et 35 éléments en trace (terres rares, Ag, B, Bi, Cs, Ga, Ge, Li, Nb, P, Rb, Rh, Re, S, Sc, Sn, Th, Ti, Tl, W, Y et Zr) ne sont pas certifiés par NRC-CNRC. Aucun rapport isotopique n'est disponible. Nous proposons, pour ces éléments, des valeurs moyennes et leurs incertitudes associées obtenues par les différents laboratoires participants. Le rapport isotopique de Sr est aussi mesuré.
ISSN: 1639-4488

hal-00906166
https://hal.archives-ouvertes.fr/hal-00906166
DOI : 10.1111/j.1751-908X.2013.00232.x

Éditeur(s) : HAL CCSD
Résumé : National audience
[No abstract available]
Revue Des Maladies Respiratoires

hal-01406068
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01406068
DOI : 10.1016/j.rmr.2016.04.002
PUBMED : 27209117

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
ISSN: 0025-3227

hal-01496242
https://hal.archives-ouvertes.fr/hal-01496242
DOI : 10.1016/j.margeo.2014.05.017

Éditeur(s) : HAL CCSD
Résumé : International audience
Women who drink light-to-moderately during pregnancy have been observed to have lower risk of unfavourable pregnancy outcomes than abstainers. This has been suggested to be a result of bias. In a pooled sample, including 193 747 live-born singletons from nine European cohorts, we examined the associations between light-to-moderate drinking and preterm birth, birth weight, and small-for-gestational age in term born children (term SGA). To address potential sources of bias, we compared the associations from the total sample with a sub-sample restricted to first-time pregnant women who conceived within six months of trying, and examined whether the associations varied across calendar time. In the total sample, drinking up to around six drinks per week as compared to abstaining was associated with lower risk of preterm birth, whereas no significant associations were found for birth weight or term SGA. Drinking six or more drinks per week was associated with lower birth weight and higher risk of term SGA, but no increased risk of preterm birth. The analyses restricted to women without reproductive experience revealed similar results. Before 2000 approximately half of pregnant women drank alcohol. This decreased to 39% in 2000–2004, and 14% in 2005–2011. Before 2000, every additional drink was associated with reduced mean birth weight, whereas in 2005–2011, the mean birth weight increased with increasing intake. The period-specific associations between low-to-moderate drinking and birth weight, which also were observed for term SGA, are indicative of bias. It is impossible to distinguish if the bias is attributable to unmeasured confounding, which change over time or cohort heterogeneity. © 2017, Springer Science+Business Media B.V.
ISSN: 03932990

hal-01647159
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01647159
DOI : 10.1007/s10654-017-0323-2
PUBMED : 29027084

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
The use of recombinant antigens has been shown to improve both the sensitivity and the standardization of the serological diagnosis of Farmer's lung disease (FLD). The aim of this study was to complete the panel of recombinant antigens available for FLD serodiagnosis with antigens of Lichtheimia corymbifera, known to be involved in FLD. L. corymbifera proteins were thus separated by 2D electrophoresis and subjected to western blotting with sera from 7 patients with FLD and 9 healthy exposed controls (HEC). FLD-associated immunoreactive proteins were identified by mass spectrometry based on a protein database specifically created for this study and subsequently produced as recombinant antigens. The ability of recombinant antigens to discriminate patients with FLD from controls was assessed by ELISA performed with sera from FLD patients (n = 41) and controls (n = 43) recruited from five university hospital pneumology departments of France and Switzerland. Forty-one FLD-associated immunoreactive proteins from L. corymbifera were identified. Six of them were produced as recombinant antigens. With a sensitivity and specificity of 81.4 and 77.3% respectively, dihydrolipoyl dehydrogenase was the most effective antigen for discriminating FLD patients from HEC. ELISA performed with the putative proteasome subunit alpha type as an antigen was especially specific (88.6%) and could thus be used for FLD confirmation. The production of recombinant antigens from L. corymbifera represents an additional step towards the development of a standardized ELISA kit for FLD diagnosis. © 2016 Rognon et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
ISSN: 1932-6203

hal-01367148
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01367148
DOI : 10.1371/journal.pone.0160888

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
ISSN: 0169-1368

hal-00345830
https://hal.archives-ouvertes.fr/hal-00345830

Éditeur(s) : HAL CCSD Awwa American Water Works Association
Résumé : International audience
A three-year study was conducted on the occurrence of disinfection by-products (DBPs) - trihalomethanes (THMs), haloacetic acids (HAAs), and haloacetonitriles - in drinking water of regions of Europe where epidemiology studies were being carried out. Thirteen systems in six countries (i.e., Italy, France, Greece, Lithuania, Spain, United Kingdom) were sampled. Typically chlorinated DBPs dominated. However, in most of Catalonia (Spain) and in Heraklion (Greece), brominated DBPs dominated. The degree of bromine incorporation into the DBP classes was in general similar among them. This is important, as brominated DBPs are a greater health concern. In parts of Catalonia, the reported levels of tribromoacetic acid were higher than in other parts of the world. In some regions, the levels of HAAs tended to be peaked in concentration in a different time period than when the levels of THMs peaked. In most epidemiology studies, THMs are used as a surrogate for other halogenated DBPs. This study provides exposure assessment information for epidemiology studies. © 2016 American Water Works Association.
ISSN: 0003-150X

hal-01406069
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01406069
DOI : 10.5942/jawwa.2016.108.0152

Éditeur(s) : HAL CCSD Wiley
Résumé :  
Positive aboveground biomass trends have been reported from old-growth forests across the Amazon basin and hypothesized to reflect a large-scale response to exterior forcing. The result could, however, be an artefact due to a sampling bias induced by the nature of forest growth dynamics. Here, we characterize statistically the disturbance process in Amazon old-growth forests as recorded in 135 forest plots of the RAINFOR network up to 2006, and other independent research programmes, and explore the consequences of sampling artefacts using a data-based stochastic simulator. Over the observed range of annual aboveground biomass losses, standard statistical tests show that the distribution of biomass losses through mortality follow an exponential or near-identical Weibull probability distribution and not a power law as assumed by others. The simulator was parameterized using both an exponential disturbance probability distribution as well as a mixed exponential-power law distribution to account for potential large-scale blowdown events. In both cases, sampling biases turn out to be too small to explain the gains detected by the extended RAINFOR plot network. This result lends further support to the notion that currently observed biomass gains for intact forests across the Amazon are actually occurring over large scales at the current time, presumably as a response to climate change.
ISSN: 1354-1013

hal-01032162
https://hal.archives-ouvertes.fr/hal-01032162
DOI : 10.1111/j.1365-2486.2009.01891.x