Understanding future Amazon forest dynamics and microclimate buffering through a Free Air CO2 Experiment

• Grant number: 24/08543-8
• Support Opportunities: Regular Research Grants
• Start date: January 01, 2025
• End date: December 31, 2027
• Field of knowledge: Biological Sciences - Ecology - Ecosystems Ecology
• Principal Investigator: Tomas Ferreira Domingues
• Grantee: Tomas Ferreira Domingues
• Principal researcher abroad: Kim Calders
• Institution abroad: Ghent University (UGent), Belgium
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated researchers: David Montenegro Lapola ; Gustavo Carvalho Spanner ; Izabela Fonseca Aleixo ; Tony César de Sousa Oliveira
• Associated scholarship(s): 25/15192-0 - Functional traits of naturally occurring trees before and after the exposure to elevated CO2 concentrations, BP.TT; 25/12254-4 - Simulations of individual trees performance and response to elevated CO2, BP.PD

Abstract

Forest ecosystems play a crucial role in the global carbon cycle and the global climate. Through photosynthesis and growth, forests across the globe are absorbing 30% of anthropogenic annual CO2 emissions, thus directly contributing to the mitigation of climate change. Besides their climate-regulating function, forests also provide a variety of additional ecosystem services. Tropical forests store the majority of global live biomass in forests and are considered as a biodiversity hotspot. Despite this important role tropical forests play in our climate system and society, there is increasing evidence that forests globally are under increasing pressure from climate change. How climate change impacts forests and their subsequent functions is, however, not fully understood, especially considering larger spatial and longer temporal scales.Deforestation and forest degradation account for about 12% of global anthropogenic carbon emissions, which is second only to fossil fuel combustion. This estimate is highly uncertain due to inadequate estimates of forest carbon stocks and is expected to range from 6 to 17%. Carbon emissions are partly compensated for by carbon uptake from the regrowth of secondary forests and the rebuilding of soil carbon pools following afforestation. However, the global distribution of terrestrial carbon sinks and sources remains highly uncertain. Constraining the inaccuracy of these carbon estimates is essential to support effective forest management and future climate mitigation actions. The debate concerning a possible Amazon forest die-back, i.e catastrophic losses of forest cover and biomass, illustrates the growing concern that terrestrial ecosystems (and tropical forests in particular) might not be able to maintain uptake of anthropogenic emissions at the current rate. A better understanding of forest growth dynamics will improve our understanding of the carbon cycle and mechanisms responsible for terrestrial sources and sinks of carbon, reducing their uncertainties of magnitude and distribution.The responses of forests to elevated CO2, e[CO2], have not been tested in the Amazon or anywhere else in the tropics, and there is a compelling need to reduce this uncertainty. A Free Air CO2 Enrichment (FACE) experiment is the most direct and robust scientific approach for accomplishing this. The AmazonFACE experiment will provide primary scientific information that advances our knowledge and understanding of the physiological and ecological effects of e[CO2] in tropical forests. It will provide data needed for parameterizing and improving predictive models of the long-term effects of elevated CO2 on carbon cycle and climate feedbacks. AmazonFACE is directed towards resolving a key source of uncertainty about the future of the Amazon forest: the potential for rising atmospheric CO2 concentrations to buffer tropical forests against the deleterious effects of climate change by stimulating forest growth and resilience to drought. The central pivot of AmazonFACE is a CO2 enrichment experiment of unprecedented scope and importance in a primary, old-growth forest in central Amazon, near Manaus, Brazil. The experiment will simulate the atmospheric CO2 composition of the near future (50 year) to help answer the question: "How will rising atmospheric CO2 affect the resilience of the Amazon forest, the biodiversity it harbours, and the ecosystem services it provides?". Within this project we will work at AmazonFACE to study the forest dynamics and microclimate buffering capacity using novel sensor technologies and plant functional traits. (AU)