Repository logo
 

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

Published version
Peer-reviewed

Type

Article

Change log

Authors

Rowland, Lucy 
Oliveira, Rafael S 
Bittencourt, Paulo RL 
Barros, Fernanda V 

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 NiƱo 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 NiƱo 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.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El NiƱo on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

Description

Keywords

drought, optimality theory, plant hydraulics, stomatal models, tropical forest, Biochemical Phenomena, Droughts, El Nino-Southern Oscillation, Forests, Models, Biological, Plant Stomata, Trees, Tropical Climate, Xylem

Journal Title

Philos Trans R Soc Lond B Biol Sci

Conference Name

Journal ISSN

0962-8436
1471-2970

Volume Title

373

Publisher

The Royal Society