Assessing evidence for a pervasive alteration in tropical tree communities

In Amazonian tropical forests, recent studies have reported increases in aboveground biomass and in primary productivity, as well as shifts in plant species composition favouring fast-growing species over slow-growing ones. This pervasive alteration of mature tropical forests was attributed to global environmental change, such as an increase in atmospheric CO2 concentration, nutrient deposition, temperature, drought frequency, and/or irradiance. We used standardized, repeated measurements of over 2 million trees in ten large (16–52 ha each) forest plots on three continents to evaluate the generality of these findings across tropical forests. Aboveground biomass increased at seven of our ten plots, significantly so at four plots, and showed a large decrease at a single plot. Carbon accumulation pooled across sites was significant (+0.24 MgC ha−1 y−1, 95% confidence intervals [0.07, 0.39] MgC ha−1 y−1), but lower than reported previously for Amazonia. At three sites for which we had data for multiple census intervals, we found no concerted increase in biomass gain, in conflict with the increased productivity hypothesis. Over all ten plots, the fastest-growing quartile of species gained biomass (+0.33 [0.09, 0.55] % y−1) compared with the tree community as a whole (+0.15 % y−1); however, this significant trend was due to a single plot. Biomass of slow-growing species increased significantly when calculated over all plots (+0.21 [0.02, 0.37] % y−1), and in half of our plots when calculated individually. Our results do not support the hypothesis that fast-growing species are consistently increasing in dominance in tropical tree communities. Instead, they suggest that our plots may be simultaneously recovering from past disturbances and affected by changes in resource availability. More long-term studies are necessary to clarify the contribution of global change to the functioning of tropical forests.

Bibliographic Details

Main Authors:	56791 Chave, Jérôme Laboratoire Evolution et Diversité Biologique CNRS/Université Paul Sabatier, 58564 Condit, Richard Center for Tropical Forest Science, Smithsonian Tropical Research Institute (autor/a), 97319 Muller Landau, Helene C. Center for Tropical Forest Science, Smithsonian Tropical Research Institute (autor/a), 124251 Thomas, Sean C. Faculty of Forestry, University of Toronto (autor/a), 44775 Ashton, Peter S. Center for Tropical Forest Science, Arnold Arboretum Asia Program, Harvard University Herbaria, (autor/a), 51898 Bunyavejchewin, Sarayudh Thai National Park Wildlife and Plant Conservation Department, Chatuchak Bangkok, Thailand (autor/a), 58106 Co, Leonardo L. Institute of Biology, University of the Philippines (autor/a), 61300 Dattaraja, Handanakere Center for Ecological Sciences, Indian Institute of Science, Bangalore, India (autor/a), 61383 Davies, Stuart J. Center for Tropical Forest Science, Smithsonian Tropical Research Institute (autor/a), 65979 Esufali, Shameema Department of Botany, Faculty of Science, University of Peradeniya (autor/a), 66127 Ewango, Corneille E.N. Department of Botany, University of Missouri (autor/a)
Format:	Texto biblioteca
Language:	eng
Published:	Reino Unido Plos Biology 2008
Subjects:	BOSQUE TROPICAL, ARBOLES, BIOMASA, CARBONO, ALOMETRIA, CRECIMIENTO, BIOMASA AEREA, ECUACIONES ALOMETRICAS, BOSQUES AMAZÓNICOS, ALTERACIONES, AMAZONIA, CICLO DEL CARBONO, INVENTARIOS FORESTALES, BIOMASS, FOREST INVENTORIES, TROPICAL FORESTS, AMAZONIAN FORESTS, TROPICAL RAIN FORESTS, TREES, CARBON, GROWTH,
Online Access:	http://orton.catie.ac.cr/repdoc/A11143i/A11143i.pdf https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.0060045&type=printable
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