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Impacts of Degradation on Water, Energy, and Carbon Cycling of the Amazon Tropical Forests
  • +16
  • Marcos Longo,
  • Sassan S. Saatchi,
  • Michael Keller,
  • Kevin W. Bowman,
  • Antonio Ferraz,
  • Paul R Moorcroft,
  • Douglas Morton,
  • Damien Bonal,
  • Paulo Brando,
  • Benoît Burban,
  • Géraldine Derroire,
  • Maiza Nara dos-Santos,
  • Victoria Meyer,
  • Scott Saleska,
  • Susan Trumbore,
  • Grégoire Vincent,
  • Sassan Saatchi,
  • Damien Bonal,
  • Paulo Brando
Marcos Longo
Jet Propulsion Laboratory, California Institute of Technology, Jet Propulsion Laboratory, California Institute of Technology

Corresponding Author:[email protected]

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Sassan S. Saatchi
Jet Propulsion Laboratory, California Institute of Technology
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Michael Keller
USDA Forest Service, USDA Forest Service
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Kevin W. Bowman
Jet Propulsion Lab (NASA), Jet Propulsion Lab (NASA)
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Antonio Ferraz
Unknown, NASA Jet Propulsion Laboratory,University of California Los Angeles Institute of the Environment and Sustainability
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Paul R Moorcroft
Harvard University, Harvard University
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Douglas Morton
Goddard Space Flight Center (NASA), NASA Goddard Space Flight Center
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Damien Bonal
INRA
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Paulo Brando
Woods Hole Research Center
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Benoît Burban
INRAE UMR 0745 EcoFoG, INRAE UMR 0745 EcoFoG
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Géraldine Derroire
CIRAD, CIRAD
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Maiza Nara dos-Santos
Brazilian Agricultural Research Corporation, Brazilian Agricultural Research Corporation
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Victoria Meyer
Jet Propulsion Laboratory, NASA Jet Propulsion Laboratory
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Scott Saleska
University of Arizona, University of Arizona
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Susan Trumbore
Max Planck Institute for Biogeochemistry, Max Planck Institute for Biogeochemistry
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Grégoire Vincent
Institut de Recherche pour le Developpement, Univ Montpellier, IRD, CIRAD, CNRS, INRAE
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Sassan Saatchi
NASA Jet Propulsion Laboratory
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Damien Bonal
INRAE Centre Grand-Est Nancy
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Paulo Brando
University of California Irvine,Instituto de Pesquisa Ambiental da Amazônia
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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°C) relative to intact forests. In contrast, the relative impact of forest degradation on energy, water, and carbon cycles markedly diminishes under extreme, multi-year droughts, as a consequence of severe stress experienced by intact forests. Our results highlight that the water and energy cycles in the Amazon are not only driven by 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.
Aug 2020Published in Journal of Geophysical Research: Biogeosciences volume 125 issue 8. 10.1029/2020JG005677