Modelling tropical forest responses to drought and El Niño with a stomatal optimization model based on xylem hydraulics

Cleiton B. Eller, Lucy Rowland, Rafael S. Oliveira, Paulo R. L. Bittencourt, Fernanda V. Barros, Antonio C. L. Da Costa, Patrick Meir, Andrew D. Friend, Maurizio Mencuccini, Stephen Sitch, Peter Cox

Research output: Contribution to journalArticlepeer-review

Abstract

The current generation of dynamic global vegetation models (DGVMs) lacks a mechanistic representation of vegetation responses to soil drought, impairing their ability to accurately predict Earth system responses to future climate scenarios and climatic anomalies, such as El Niño events. We propose a simple numerical approach to model plant responses to drought coupling stomatal optimality theory and plant hydraulics that can be used in dynamic global vegetation models (DGVMs). The model is validated against stand-scale forest transpiration (E) observations from a long-term soil drought experiment and used to predict the response of three Amazonian forest sites to climatic anomalies during the twentieth century. We show that our stomatal optimization model produces realistic stomatal responses to environmental conditions and can accurately simulate how tropical forest E responds to seasonal, and even long-term soil drought. Our model predicts a stronger cumulative effect of climatic anomalies in Amazon forest sites exposed to soil drought during El Niño years than can be captured by alternative empirical drought representation schemes. The contrasting responses between our model and empirical drought factors highlight the utility of hydraulically-based stomatal optimization models to represent vegetation responses to drought and climatic anomalies in DGVMs.
Original languageEnglish
Pages (from-to)20170315
JournalPhilosophical Transactions of the Royal Society B: Biological Sciences
Volume373
Issue number1760
Early online date8 Oct 2018
DOIs
Publication statusPublished - 19 Nov 2018

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