Sanchez-Martinez Pablo, Martius Lion R, Bittencourt Paulo, Silva Mateus, Binks Oliver, Coughlin Ingrid, Negrão-Rodrigues Vanessa, Athaydes Silva João, Da Costa Antonio Carlos Lola, Selman Rachel, Rifai Sami, Rowland Lucy, Mencuccini Maurizio, Meir Patrick
School of GeoSciences, University of Edinburgh, Edinburgh, UK.
Department of Geography, Faculty of Environment Society and Economy, University of Exeter, Exeter, UK.
Nat Ecol Evol. 2025 May 15. doi: 10.1038/s41559-025-02702-x.
Drought-induced mortality is expected to cause substantial biomass loss in the Amazon basin. However, rainforest responses to prolonged drought are largely unknown. Here, we demonstrate that an Amazonian rainforest plot subjected to more than two decades of large-scale experimental drought reached eco-hydrological stability. After elevated tree mortality during the first 15 years, ecosystem-level structural changes resulted in the remaining trees no longer experiencing drought stress. The loss of the largest trees led to increasing water availability for the remaining trees, stabilizing biomass in the last 7 years of the experiment. Hydraulic variables linked to physiological stress, such as leaf water potential, sap flow and tissue water content, converged to the values observed in a corresponding non-droughted control forest, indicating hydraulic homeostasis. While it prevented drought-induced collapse, eco-hydrological stabilization resulted in a forest with reduced biomass and carbon accumulation in wood. These findings show how tropical rainforests may be resilient to persistent soil drought.
干旱导致的死亡预计将在亚马逊流域造成大量生物量损失。然而，雨林对长期干旱的反应在很大程度上尚不清楚。在此，我们证明，一个经历了二十多年大规模实验干旱的亚马逊雨林地块达到了生态水文稳定状态。在最初15年树木死亡率升高之后，生态系统层面的结构变化使得剩余树木不再遭受干旱胁迫。最大树木的损失导致剩余树木可利用的水分增加，在实验的最后7年生物量趋于稳定。与生理胁迫相关的水力变量，如叶片水势、液流和组织含水量，收敛至在相应非干旱对照林中观察到的值，表明水力稳态。虽然它防止了干旱导致的崩溃，但生态水文稳定导致森林生物量减少，木材中的碳积累降低。这些发现表明了热带雨林如何可能对持续的土壤干旱具有恢复力。
