Critical slowing down of the Amazon forest after increased drought occurrence

Critical slowing down of the Amazon forest after increased drought occurrence

Van Passel, Johanna (Katholieke Universiteit Leuven)
Bernardino, Paulo N. (Katholieke Universiteit Leuven; University of Campinas)
Lhermitte, S.L.M. (TU Delft Mathematical Geodesy and Positioning; Katholieke Universiteit Leuven)
Rius, Bianca F. (University of Campinas; Federal University of Santa Catarina)
Hirota, Marina (University of Campinas; Federal University of Santa Catarina)
Conradi, Timo (University of Bayreuth)
de Keersmaecker, Wanda (Flemish Institute for Technological Research)
Van Meerbeek, Koenraad (Katholieke Universiteit Leuven)
Somers, Ben (Katholieke Universiteit Leuven)

2024

Dynamic ecosystems, such as the Amazon forest, are expected to show critical slowing down behavior, or slower recovery from recurrent small perturbations, as they approach an ecological threshold to a different ecosystem state. Drought occurrences are becoming more prevalent across the Amazon, with known negative effects on forest health and functioning, but their actual role in the critical slowing down patterns still remains elusive. In this study, we evaluate the effect of trends in extreme drought occurrences on temporal autocorrelation (TAC) patterns of satellite-derived indices of vegetation activity, an indicator of slowing down, between 2001 and 2019. Differentiating between extreme drought frequency, intensity, and duration, we investigate their respective effects on the slowing down response. Our results indicate that the intensity of extreme droughts is a more important driver of slowing down than their duration, although their impacts vary across the different Amazon regions. In addition, areas with more variable precipitation are already less ecologically stable and need fewer droughts to induce slowing down. We present findings indicating that most of the Amazon region does not show an increasing trend in TAC. However, the predicted increase in extreme drought intensity and frequency could potentially transition significant portions of this ecosystem into a state with altered functionality.

drought response
resilience
tropical forest

http://resolver.tudelft.nl/uuid:ca678379-4ee4-4d63-b3b1-e2475941b9be

https://doi.org/10.1073/pnas.2316924121

1091-6490

Proceedings of the National Academy of Sciences of the United States of America, 121 (22), e2316924121

Institutional Repository

journal article

© 2024 Johanna Van Passel, Paulo N. Bernardino, S.L.M. Lhermitte, Bianca F. Rius, Marina Hirota, Timo Conradi, Wanda de Keersmaecker, Koenraad Van Meerbeek, Ben Somers