Simulations of individual trees performance and response to elevated CO2

• Grant number: 25/12254-4
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: August 01, 2025
• End date: July 31, 2027
• Field of knowledge: Biological Sciences - Ecology - Ecosystems Ecology
• Principal Investigator: Tomas Ferreira Domingues
• Grantee: Zilza Thayane Matos Guimaraes
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 24/08543-8 - Understanding future Amazon forest dynamics and microclimate buffering through a Free Air CO2 Experiment, AP.R

Abstract

In order to acquire carbon (C) through the photosynthetic process, plants must ensure that the concomitant use of water is done so within safe margins. For that, they evolved a complex system of coordinated tissue properties (functional traits from roots, xylem, mesophyll, stomata, and cuticle). Such multi-dimensional coordination of function (trade-offs) allows for a variety of different strategies to be present in a given community, especially for the hyperdiverse Amazon Forest. Understanding those strategies is key to assessing the forest ecosystem responses to future atmospheric conditions. This work will focus on hydraulic functional traits that relate to one of the fundamental responses plants exhibit to eCO2, which is a decrease in stomatal conductance and consequent reduction of transpiration rates, increased leaf temperatures, and more favorable water status. We will evaluate how the functional and phylogenetic diversity found at the AmazonFACE experimental plots determine the range of realized coordination of functional traits describing the multi-dimensional volume occupied by the species. Also, we will use statistical analyses to form a posteriori functional groups based on functional traits, as a way to simplify the issue of high species diversity present in tropical forest communities. Such an approach is a major advancement compared to the traditional a priori subjective grouping based on successional categories. By comparing the responses of tropical species to eCO2, we will address the following research question: How will eCO2 affect the use of water by tropical and temperate trees? We will approach this overarching question with three task-specific research questions: 1) Will tropical trees and lianas responses to eCO2 result in lower dry season stress and better water status as a consequence of lower stomatal conductance? 2) Will the responses observed by both tropical trees and lianas be useful in classifying them into functional groups? and 3) Will representing the observed diversity in responses to the eCO2 and range of functional trait values in a dynamic vegetation model produce feasible tree community scenarios? (AU)