Impacts of Degradation on Water, Energy, and Carbon Cycling of the Amazon Tropical Forests

Author(s):Show less -

Longo, Marcos ^[1] ; Saatchi, Sassan ^{[1, 2]} ; Keller, Michael ^{[1, 3, 4]} ; Bowman, Kevin ^[1] ; Ferraz, Antonio ^{[1, 2]} ; Moorcroft, Paul R. ^[5] ; Morton, Douglas C. ^[6] ; Bonal, Damien ^[7] ; Brando, Paulo ^{[8, 9, 10]} ; Burban, Benoit ^[11] ; Derroire, Geraldine ^[12] ; dos-Santos, Maiza N. ^[3] ; Meyer, Victoria ^[1] ; Saleska, Scott ^[13] ; Trumbore, Susan ^[14] ; Vincent, Gregoire ^[15]

Affiliation:Show less -

^[1] CALTECH, Jet Prop Lab, Pasadena, CA 91125 - USA

^[2] Univ Calif Los Angeles, Inst Environm & Sustainabil, Los Angeles, CA - USA

^[3] Embrapa Informat Agr, Campinas, SP - Brazil

^[4] US Forest Serv, Inst Trop Forestry, USDA, Rio Piedras, PR 00928 - USA

^[5] Harvard Univ, Dept Organism & Evolutionary Biol, Cambridge, MA 02138 - USA

^[6] NASA, Goddard Space Flight Ctr, Greenbelt, MD - USA

^[7] Univ Lorraine, UMR Silva, AgroParisTech, INRAE, Nancy - France

^[8] Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA - USA

^[9] Inst Pesquisa Ambiental Amazonia, Brasilia, DF - Brazil

^[10] Woods Hole Res Ctr, POB 296, Woods Hole, MA 02543 - USA

^[11] Inst Natl Rech Agr Alimentat & Environm INRAE, UMR 0745, EcoFoG, Campus Agron, Kourou - French Guiana

^[12] Univ Antilles, Univ Guyane, Ctr Cooperat Int Rech Agron Dev CIRAD, UMR EcoFoG, Agroparistech, CNRS, INRAE, Campus Agron, Kourou - French Guiana

^[13] Univ Arizona, Ecol & Evolutionary Biol, Tucson, AZ - USA

^[14] Max Planck Inst Biochem, Jena - Germany

^[15] Univ Montpellier, AMAP, IRD, CIRAD, CNRS, Montpellier - France

• Document type: Journal article
• Source: JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES; v. 125, n. 8 AUG 2020.
• Web of Science Citations: 2

Abstract

Selective logging, fragmentation, and understory fires directly degrade forest structure and composition. However, studies addressing the effects of forest degradation on carbon, water, and energy cycles are scarce. Here, we integrate field observations and high-resolution remote sensing from airborne lidar to provide realistic initial conditions to the Ecosystem Demography Model (ED-2.2) and investigate how disturbances from forest degradation affect gross primary production (GPP), evapotranspiration (ET), and sensible heat flux (H). We used forest structural information retrieved from airborne lidar samples (13,500 ha) and calibrated with 817 inventory plots (0.25 ha) across precipitation and degradation gradients in the eastern Amazon as initial conditions to ED-2.2 model. Our results show that the magnitude and seasonality of fluxes were modulated by changes in forest structure caused by degradation. During the dry season and under typical conditions, severely degraded forests (biomass loss >= 66%) experienced water stress with declines in ET (up to 34%) and GPP (up to 35%) and increases of H (up to 43%) and daily mean ground temperatures (up to 6.5 degrees C) relative to intact forests. In contrast, the relative impact of forest degradation on energy, water, and carbon cycles markedly diminishes under extreme, multiyear droughts, as a consequence of severe stress experienced by intact forests. Our results highlight that the water and energy cycles in the Amazon are driven by not only climate and deforestation but also the past disturbance and changes of forest structure from degradation, suggesting a much broader influence of human land use activities on the tropical ecosystems. (AU)

• FAPESP's process: 15/07227-6 - Long term effects of forest degradation on carbon cycling in Amazonia
• Grantee: Marcos Longo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral