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Partnerships for enhanced engagement in research (PEER)
Cycle 4 (2015 Deadline)

Functional diversity of interrelated photosynthesis and water use of Central Amazonian trees

PI: Tomas Domingues (, University of São Paulo
U.S. Partner: Pierre Gentine, Columbia University
Project Dates: November 2015 - October 2020

Project Overview

4-445 Tree Canopy Measurements
Team member Maquelle Garcia takes measurements at the top of the tree canopy (photo courtesy of Dr. Domingues).

This project will generate novel understanding on the diversity of plant traits related to water use and photosynthesis. The functional diversity present in a given community is a key dimension of biodiversity that effectively modulates how forests respond to disturbances, such as logging, precipitation, and temperature extremes or the increase in carbon dioxide concentration. It also determines the extent of the feedback between forest and climate, therefore informing us on possible consequences of forest mortality or land use change. To better predict the resilience of the forest and its capacity to provide ecosystem services, it is essential to evaluate the current spectrum of functional diversity, still a major unknown component in biodiversity research. Dr. Domingues and his colleagues will use a new approach looking at the carbon and water cycles as fundamentally coupled at both the leaf and tree level. In order to achieve a qualitative and quantitative assessment of water and carbon strategies by Amazonian trees, they will continuously monitor both the transport of water in tree trunks and the continuous expansion and contraction of the tree’s bole diameter, which relates to water storage, mobilization of photosynthetic products, and growth. This will be complemented by leaf-level measurements of photosynthetic apparatus and hydraulics to comprehend the individual link of photosynthesis with water usage. This novel dataset will demonstrate the coupling between transport of water and carbon within trees and how it relates to forest productivity. The new data will be applied to broader scales by using land-surface and ecosystem models to simulate the interaction between forest and atmosphere at different scenarios of functional diversity. This step will be achieved by collaboration with U.S. Government-supported partner Pierre Gentine, who is implementing a soil-plant-atmosphere-continuum model able to reproduce the carbon and water relationship in the Community Land Model. Brazilian students will also receive much-needed training in computational modeling.

The proposed research will shed light on the role of biodiversity not only in maintaining and improving quality of life for inhabitants of the Amazon region but also for improving water security in other areas. By characterizing current variability in water and carbon use strategies expressed by Amazonian trees, it is possible to assess how much biodiversity loss within this group is tolerable, without seriously compromising ecosystem functioning. The information to be generated by this project will help in evaluating ecosystem integrity in areas where disturbance has already occurred. For example, it will be possible to assess disparities between pristine forest and secondary vegetation, in terms of ecosystem response to water stress whether from bottom up (soil to leaves induced by dry soil conditions) or top down (from leaves to soil induced by dry or hot weather conditions), according to species composition of the community. As a result, plant communities can be evaluated in terms of resilience to further climatic extremes. The products of this research will also aid in guiding species selection for vegetation restoration efforts. For example, such information will be of great value to local community initiatives focusing on production of tree saplings for reforestation programs or ecosystem improvement actions.

Summary of Recent Activities

During the second quarter of 2019, the PI Dr. Domingues reports that his project team continues to focus on data collection at their research site (a forest plot near Manaus). Project researchers based in Manaus visit the field site on a biweekly basis. They are also engaged in summarizing the results so far with regard to two main themes. The first is ecosystem functioning, or the use of carbon and water by the forest, with the researchers’ findings to be presented at the Association for Tropical Biology and Conservation (ATBC) meeting in Madagascar in August 2019. The second theme involves development of methods for demonstrating to the non-scientist community how different tree species use resources, particularly highlighting how biodiversity matters for ecosystem resilience. Project researchers Maquelle Garcia and Sabrina Garcia are spending time in with Dr. Domingues at his university in Ribeirão Preto to focus on the data analysis and drafting of papers.

During the last half of 2019, plans call for field activities to continue. As noted above, team members will attend the ATBC meeting in Madagascar, and during that event they will host a special session on large-scale experimentation in the tropics. Overall, team members will present eight posters and talks. In addition, preparations are being made for the exchange visit of Maquelle Garcia to the University of Arizona from October 2019 through March 2020. She will be working with Prof. Jia Hu and will advance her analyses of leaf and wood anatomy, generating important data for her PhD thesis that will allow the PEER team to link water use to anatomical characteristics of different species. She will also have the support of Prof. Scott Saleska, who has been working with the Amazon for about 20 years now. Furthermore, Sabrina and Maquelle are making progress on their manuscripts, which Dr. Domingues expects should be submitted to international peer-refereed journals by October 2019. Meanwhile, the PI also reports that a manuscript he co-authored with PEER team members Katrin Fleischer, Sabrina Garcia, Adriana Grandis, and Carlos Quesada has been accepted for publication by Nature GeoSciences. A link will be posted here on this page as soon as the paper is available online.

Following are links to several other papers and a book reported by the PI as being based on his and his team's PEER-supported work:

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