The Amazon basin in transition

• Published in: Nature (London) 2012-01, Vol.481 (7381), p.321-328
• Main Authors: Davidson, Eric A., de Araújo, Alessandro C., Artaxo, Paulo, Balch, Jennifer K., Brown, I. Foster, C. Bustamante, Mercedes M., Coe, Michael T., DeFries, Ruth S., Keller, Michael, Longo, Marcos, Munger, J. William, Schroeder, Wilfrid, Soares-Filho, Britaldo S., Souza, Carlos M., Wofsy, Steven C.
• Format: Article
• Language: English
• Subjects: 704/106/242; 704/106/694; 704/158/2454; 704/158/47; Adaptation; Agricultural expansion; Agriculture; Animal and plant ecology; Animal, plant and microbial ecology; Biogeochemical cycles; Biological and medical sciences; Biomass; Brazil; Carbon; Carbon Cycle; Carbon sequestration; Climate Change; Climate variability; Deforestation; Drought; Droughts; Dry season; Ecosystem; Ecosystems; El Nino; Environmental aspects; Fires; Forestry; Forests; Fundamental and applied biological sciences. Psychology; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; Humanities and Social Sciences; Hydrologic cycle; Land use; Methods; multidisciplinary; Precipitation; Precipitation (Meteorology); Rain; review-article; River discharge; River flow; Rivers; Science; Science (multidisciplinary); Seasons; Synecology; Terrestrial ecosystems; Trees - metabolism
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature10717

A synthesis of recent research shows that the effects of human actions have already altered the regional hydrology and energy balance of parts of the Amazon basin, and that interactions between deforestation, fire and climate change are likely to further alter carbon storage, precipitation patterns and river discharge. Can the Amazon take the strain? The vast forest–river system of the Amazon basin is changing rapidly owing to human impacts. Humans have been there for many thousands of years, but the region is now home to some 25 million people. Here Eric Davidson and colleagues synthesize recent research — much of it from the Large Scale Biosphere-Atmosphere Experiment in Amazonia — on the effects of climate change and disturbances such as deforestation and fire on the functioning of the Amazon basin. Although the forest is resilient to individual disturbances, and Brazil may well be able to maintain economic development without destroying its forests, the interacting effects of multiple disturbances have already altered the regional hydrology and energy balance. And there are indications that the Amazon may even be transitioning from a net carbon sink to a net carbon source. Agricultural expansion and climate variability have become important agents of disturbance in the Amazon basin. Recent studies have demonstrated considerable resilience of Amazonian forests to moderate annual drought, but they also show that interactions between deforestation, fire and drought potentially lead to losses of carbon storage and changes in regional precipitation patterns and river discharge. Although the basin-wide impacts of land use and drought may not yet surpass the magnitude of natural variability of hydrologic and biogeochemical cycles, there are some signs of a transition to a disturbance-dominated regime. These signs include changing energy and water cycles in the southern and eastern portions of the Amazon basin.