Forest-rainfall cascades buffer against drought across the Amazon

• Published in: Nature climate change 2018-06, Vol.8 (6), p.539-543
• Main Authors: Staal, Arie, Tuinenburg, Obbe A., Bosmans, Joyce H. C., Holmgren, Milena, van Nes, Egbert H., Scheffer, Marten, Zemp, Delphine Clara, Dekker, Stefan C.
• Format: Article
• Language: English
• Subjects: 631/158/2454; 704/106/35; 704/242; Aquatic Ecology and Water Quality Management; Aquatische Ecologie en Waterkwaliteitsbeheer; Buffers; Cascades; Cascading; Climate Change; Climate Change/Climate Change Impacts; Climatic extremes; Deforestation; Drought; Earth and Environmental Science; Environment; Environmental Law/Policy/Ecojustice; Forests; Leerstoelgroep Aquatische ecologie en waterkwaliteitsbeheer; Leerstoelgroep Resource Ecology; PE&RC; Rain; Rainfall; Resource Ecology; Stability; Subsidies; Transpiration; WIMEK
• ISSN: 1758-678X; 1758-6798
• DOI: 10.1038/s41558-018-0177-y

Tree transpiration in the Amazon may enhance rainfall for downwind forests. Until now it has been unclear how this cascading effect plays out across the basin. Here, we calculate local forest transpiration and the subsequent trajectories of transpired water through the atmosphere in high spatial and temporal detail. We estimate that one-third of Amazon rainfall originates within its own basin, of which two-thirds has been transpired. Forests in the southern half of the basin contribute most to the stability of other forests in this way, whereas forests in the south-western Amazon are particularly dependent on transpired-water subsidies. These forest-rainfall cascades buffer the effects of drought and reveal a mechanism by which deforestation can compromise the resilience of the Amazon forest system in the face of future climatic extremes. Tree transpiration in the Amazon enhances downwind rainfall. Research now shows that approximately one-third of Amazon rainfall originates within its own basin, with the southern half of the basin contributing most to this effect.