TY - JOUR

T1 - Amazon forest biogeography predicts resilience and vulnerability to drought

AU - Chen, Shuli

AU - Stark, Scott C.

AU - Nobre, Antonio Donato

AU - Cuartas, Luz Adriana

AU - Amore, Diogo de Jesus

AU - Restrepo-Coupe, Natalia

AU - Smith, Marielle

AU - Chitra-Tarak, Rutuja

AU - Ko, Hongseok

AU - Nelson, Bruce

AU - Saleska, Scott R.

PY - 2024/6/19

Y1 - 2024/6/19

N2 - Amazonia contains the most extensive tropical forests on Earth, but Amazon carbon sinks of atmospheric CO are declining, as deforestation and climate-change-associated droughts threaten to push these forests past a tipping point towards collapse . Forests exhibit complex drought responses, indicating both resilience (photosynthetic greening) and vulnerability (browning and tree mortality), that are difficult to explain by climate variation alone . Here we combine remotely sensed photosynthetic indices with ground-measured tree demography to identify mechanisms underlying drought resilience/vulnerability in different intact forest ecotopes (defined by water-table depth, soil fertility and texture, and vegetation characteristics). In higher-fertility southern Amazonia, drought response was structured by water-table depth, with resilient greening in shallow-water-table forests (where greater water availability heightened response to excess sunlight), contrasting with vulnerability (browning and excess tree mortality) over deeper water tables. Notably, the resilience of shallow-water-table forest weakened as drought lengthened. By contrast, lower-fertility northern Amazonia, with slower-growing but hardier trees (or, alternatively, tall forests, with deep-rooted water access), supported more-drought-resilient forests independent of water-table depth. This functional biogeography of drought response provides a framework for conservation decisions and improved predictions of heterogeneous forest responses to future climate changes, warning that Amazonia's most productive forests are also at greatest risk, and that longer/more frequent droughts are undermining multiple ecohydrological strategies and capacities for Amazon forest resilience. [Abstract copyright: © 2024. The Author(s), under exclusive licence to Springer Nature Limited.]

AB - Amazonia contains the most extensive tropical forests on Earth, but Amazon carbon sinks of atmospheric CO are declining, as deforestation and climate-change-associated droughts threaten to push these forests past a tipping point towards collapse . Forests exhibit complex drought responses, indicating both resilience (photosynthetic greening) and vulnerability (browning and tree mortality), that are difficult to explain by climate variation alone . Here we combine remotely sensed photosynthetic indices with ground-measured tree demography to identify mechanisms underlying drought resilience/vulnerability in different intact forest ecotopes (defined by water-table depth, soil fertility and texture, and vegetation characteristics). In higher-fertility southern Amazonia, drought response was structured by water-table depth, with resilient greening in shallow-water-table forests (where greater water availability heightened response to excess sunlight), contrasting with vulnerability (browning and excess tree mortality) over deeper water tables. Notably, the resilience of shallow-water-table forest weakened as drought lengthened. By contrast, lower-fertility northern Amazonia, with slower-growing but hardier trees (or, alternatively, tall forests, with deep-rooted water access), supported more-drought-resilient forests independent of water-table depth. This functional biogeography of drought response provides a framework for conservation decisions and improved predictions of heterogeneous forest responses to future climate changes, warning that Amazonia's most productive forests are also at greatest risk, and that longer/more frequent droughts are undermining multiple ecohydrological strategies and capacities for Amazon forest resilience. [Abstract copyright: © 2024. The Author(s), under exclusive licence to Springer Nature Limited.]

U2 - 10.1038/s41586-024-07568-w

DO - 10.1038/s41586-024-07568-w

M3 - Article

JO - Nature

JF - Nature

SN - 1476-4687

ER -