Cycle 4 (2015 Deadline)
Functional diversity of interrelated photosynthesis and water use of Central Amazonian trees
PI: Tomas Domingues (firstname.lastname@example.org), University of São Paulo
U.S. Partner: Pierre Gentine, Columbia University
Project Dates: November 2015 - October 2018
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
By the end of the second year of this project in October 2017, the PI had a well-established team made up of a field/lab technician, one Master’s student, one PhD student, and two postdocs actively engaged. A key event in the third quarter of this year was the July 10-13 visit to Ribeirão Preto by project postdocs Adriana Grandis and Sabrina Garcia, who are normally based at INPA in Manaus. During their visit, the team analyzed project results so far and began outlining scientific manuscripts to be written. As the project moves into its third year, they are continuing to monitor trees at their field site for water and carbon use, but they are still only in the early stages of producing scientific reports. They anticipate that early in 2018 they will be in a position to translate their findings into a user-friendly summary of how forest species behave. Members of the group continue to collect and process data onecophysiological parameters on a regular basis, and they are confident that the scientific results emerging will be very useful in expanding our understanding of how biodiversity, expressed in a variety of strategies used by Amazonian trees, relates to the ecosystem services that the forest provides.
At the time of their annual report in mid-October 2017, they were planning to conduct their third Amazonia and Climate Change field course in late October and install their automated dendrometers in November. Dr. Domingues tentatively plans to visit his U.S. partner Dr. Pierre Gentine in New York in February 2018. Besides focusing on writing papers for publication in scientific journals, team members will also be working on producing didactic materials on the role of the forest in ecosystem services to be distributed to NGOs and schools.
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