0003778 This U.S.-Brazil award provides support from the Division of International Programs for a cooperative research between Dr. George Vourlitis, California State University, San Marcos, and Dr. Nicolau Priante Filho at Universidade Federal de Mato Grosso, in Cuiaba, Brazil. They will study the land use implications on the net ecosystem production and energy balance of tropical forest ecosystem. This project will build upon an existing collaboration between the two institutions to measure the net ecosystem production (NEP) of Amazonian tropical transitional forest. NEP is the forest assimilation of atmospheric CO2 through gross primary production minus ecosystem CO2 loss to the atmosphere by plant and soil respiration. They have been measuring the NEP of Brazilian cerradao (the tropical seasonal forest) and will now add the measurement of cattle pasture, which is the dominant form of land cover change in southern Amazonia. There is an urgent need to understand the role of tropical terrestrial ecosystems in the global CO2 balance. This research will fill in a gap in our understanding of tropical ecosystem carbon cycling. The PIs will measure the NEP of mature, intact cerradao and cattle pasture of northern Mato Grosso. They will then link measurements of NEP and microclimate to a process-based model to assess the implications of land cover change on the seasonal and interannual rates and patterns of NEP. Besides the benefit to this area of research, this project will include the training of young researchers on both sides, exposing them to new research methods and technology.
