Does the disturbance hypothesis explain the biomass increase in basin-wide Amazon forest plot data?

• Main Authors: Gloor , M.(auteur de correspondance) (University of Leeds(Royaume Uni).), Phillips , Oliver L. (University of Leeds(Royaume Uni).), Lloyd , J.J. (University of Leeds(Royaume Uni).), Lewis , Simon L. (University of Leeds(Royaume Uni).), Malhi , Yadvinder (University of Oxford(Royaume Uni).), Baker , T.R. (University of Leeds(Royaume Uni).), Lopez-Gonzales , G. (University of Leeds(Royaume Uni).), Peacock , J. (University of Leeds(Royaume Uni).), Almeida , S. (Museu Paraense Emilio Goeldi (Brésil).), Alves de Oliveira , Alessandro-C. (Instituto Nacional de Pesquisas do Amazonia(Brésil).), Alvarez , E. (University of Colombia(Colombie).), Amaral , I. (Instituto Nacional de Pesquisas do Amazonia(Brésil).), Arroyo , L. (Missouri Botanical GardenMuseo de Historia Natural Noel Kempff Mercado, St-Louis, MOSanta Cruz(Bolivie).), Aymard , G. (Universidad Nacional Experimental de Los Llanos Occidentales(Vénézuela).), Banki , O. (Utrecht University(Pays-Bas).), Blanc , Lilian (INRA , Kourou (France). UMR 0745 Ecologie des Forêts de Guyane), Bonal , Damien (INRA , Champenoux (France). UMR 1137 Ecologie et Ecophysiologie Forestières), Brando , P. (Instituto de Pesquisa Ambiental da Amazônia(Brésil).), Chao , Kuo-Jung (Institute of Ecology and Evolutionary Biology(Taïwan (province de Chine)).), Chave , Jérôme (Université de Toulouse, Université Paul Sabatier, Toulouse(France). UMR5174 Evolution et diversité biologique (EDB) ), Davila , N. (Universidad Nacional de la Amazonia Peruana(Pérou).), Erwin , T. (Smithsonian Institution National Museum of Natural History, Washington(Etats-Unis).), Silva , J. (Universidad de San Abad del Cusco(Pérou).), Di Fiore , A. (New York State University(Etats-Unis).), Feldpausch , T.R. (University of Leeds(Royaume Uni).), Freitas , A. (Emilio Goeldi Museum(Brésil).), Herrera , R. (Instituto Venezolano de Investigaciones Cientificas, Caracas(Vénézuela).), Higuchi , N. (Instituto National de Pesquisas de Amazonia(Brésil).), Honorio , E. (Instituto de Investigaciones de la Amazonía Peruana(Pérou).), Jimenez , E. (Universidad Nacional de Colombia(Colombie).), Killeen , T. (Conservation International, Washington(Etats-Unis).), Laurance , W. (Smithsonian Tropical Research Institute, Ancón(Panama).), Mendoza , C. (Manejo Forestal de los Bosques Tropicales de Bolivia(Bolivie).), Monteagudo , A. (Jardın Botanico de Missouri, Oxapampa(Pérou).), Andrade , A. (Instituto Nacional de Pesquisas do Amazônia, Manaus(Brésil).), Neill , D. (Fundacion Jatun SachaFundacion Jatun Sacha and Missouri Botanical Garden(Equateur).), Nepstad , D. (Woods Hole Research Center(Etats-Unis).), Nunez Vargas , P. (Universidad San Antonio Abad del Cusco(Pérou).), Penuela , M.C. (Universidad Nacional de Colombia, Leticia(Colombie).), Pena Cruz , A. (Universidad Nacional de Colombia, Bogota(Colombie).), Prieto , A. (Universidad Nacional de Colombia, Bogota(Colombie).), Pitman , N. (Duke University(Etats-Unis).), Quesada , C. (University of Leeds(Royaume Uni).), Salomao , R. (Museu Paraense Emilio Goeldi(Brésil).), Silveira , Marcos (Universidade Federal do Acre(Brésil).), Schwarz , Michael (Friedrich Schiller University in Jena(Allemagne).), Stropp , J. (Utrecht University(Pays-Bas).), Ramirez , F. (Universidad Nacional de la Amazonía Peruana(Pérou).), Ramirez , H. (University of the Andes(Vénézuela).), Rudas , A. (Universidad Nacional de Colombia, Bogota(Colombie).), Ter Steege , H. (National Herbarium of the Netherlands, Utrecht(Pays-Bas).), Silva , N. (Center for International Forestry ResearchEmpresa Brasileira de Pesquisa Agropecuária, TapajosBelém(Brésil).), Torres , A. (Universidad de Los Andes(Vénézuela).), Terborgh , J. (Duke University(Etats-Unis).), Vasquez , R. (Jardin Botanico de Missouri(Pérou).), Van Der Heijden , G. (University of Leeds(Royaume Uni).)
• Format: Publication
• Language: English
• Published: 2009
• Subjects: AMAZON RAINFOREST; artefact; augmentation; biomasse; biomasse forestière; CARBON SINK; changement climatique; DISTURBANCE; forêt amazonienne; MORTALITY; POWER LAW; échantillonnage

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.