TY - JOUR
T1 - Reframing tropical savannization
T2 - linking changes in canopy structure to energy balance alterations that impact climate
AU - Stark, Scott C.
AU - Breshears, David D.
AU - Aragón, Susan
AU - Villegas, Juan Camilo
AU - Law, Darin J.
AU - Smith, Marielle N.
AU - Minor, David M.
AU - de Assis, Rafael Leandro
AU - de Almeida, Danilo Roberti Alves
AU - de Oliveira, Gabriel
AU - Saleska, Scott R.
AU - Swann, Abigail L.S.
AU - Moura, José Mauro S.
AU - Camargo, José Luis
AU - da Silva, Rodrigo
AU - Aragão, Luiz E.O.C.
AU - Oliveira, R. Cosme
N1 - Funding Information:
This work was primarily supported by NSF Macrosystems Biology EF‐1340604 to Michigan State University, EF‐1340624 to University of Arizona, and EF‐1340649 to University of Washington. Additional support was provided for SC Stark by NASA award #NNX17AF65G and NSF‐DEB‐1754357, EF‐1550686, and DEB‐1950080, 1702379 awards and by USDA NIFA. DD Breshears and DJ Law were supported by the Arizona Ag Experiment Station (AZRT‐1390130‐M12‐222) and NSF‐DEB 1550756 and 1824796 (DDB). DRA Almeida was supported by the São Paulo Research Foundation (#2018/21338‐3 and #2019/14697‐0). S Aragon was supported by a CNPq PDJ grant (150827/2013‐0) and a CAPES‐PNPD post‐doctoral scholarship. POPA‐PELD (Long Term Ecological Monitoring of Western Pará) establishment was supported by the Programa Piloto para a Proteção das Florestas Tropicais do Brasil– INPA/FINEP/European Union 64.00.0021.00, INPA‐PPI‐1‐3010, the Programa de Pesquisa em Biodiversidade (PPBio) and by the Centro de Estudos Integrados da Biodiversidade Amazônica (CENBAM), INPA and CNPq grant (441443/2016‐8). JCV received support from the Proyecto “Trayectorias de sistemas socio‐ecológicos y sus determinantes en cuencas estratégicas en un contexto de cambio ambiental. Código 110180863961” Convocatoria 808‐2018 Proyectos de ciencia, tecnología e innovación y su contribución a los retos de país‐ Colciencias. LEOC Aragão was supported by CNPq 305054/2016‐3, FAPESP 2018/15001‐6. We also wish to thank the Researchers and staff of the Biological Dynamics of Forest Fragments Project (BDFFP), the Large Scale Biosphere‐Atmosphere Experiment in the Amazon (LBA, in Santarém and Manaus), and PPBio of the National Institute for Amazonian Research (INPA, Brazil), and the Federal University of Western Pará (UFOPA) for exceptional support. This is study 759 of the BDFFP Technical Series. Author contributions: SC. Stark led the study and manuscript development, DD. Breshears, S Aragón, JC Villegas, DJ Law, DM Minor, RL de Assis, SR Saleska, ALS Swann, JMS Moura, R da Silva, LEOC Aragão, JL Camargo, and RC Oliveira helped develop and implement the study and participated in manuscript development. MN Smith, DRAlves de Almeida, G de Oliveira conducted analysis, and contributed substantial conceptual development to the manuscript.
Funding Information:
This work was primarily supported by NSF Macrosystems Biology EF-1340604 to Michigan State University, EF-1340624 to University of Arizona, and EF-1340649 to University of Washington. Additional support was provided for SC Stark by NASA award #NNX17AF65G and NSF-DEB-1754357, EF-1550686, and DEB-1950080, 1702379 awards and by USDA NIFA. DD Breshears and DJ Law were supported by the Arizona Ag Experiment Station (AZRT-1390130-M12-222) and NSF-DEB 1550756 and 1824796 (DDB). DRA Almeida was supported by the São Paulo Research Foundation (#2018/21338-3 and #2019/14697-0). S Aragon was supported by a CNPq PDJ grant (150827/2013-0) and a CAPES-PNPD post-doctoral scholarship. POPA-PELD (Long Term Ecological Monitoring of Western Pará) establishment was supported by the Programa Piloto para a Proteção das Florestas Tropicais do Brasil– INPA/FINEP/European Union 64.00.0021.00, INPA-PPI-1-3010, the Programa de Pesquisa em Biodiversidade (PPBio) and by the Centro de Estudos Integrados da Biodiversidade Amazônica (CENBAM), INPA and CNPq grant (441443/2016-8). JCV received support from the Proyecto “Trayectorias de sistemas socio-ecológicos y sus determinantes en cuencas estratégicas en un contexto de cambio ambiental. Código 110180863961” Convocatoria 808-2018 Proyectos de ciencia, tecnología e innovación y su contribución a los retos de país- Colciencias. LEOC Aragão was supported by CNPq 305054/2016-3, FAPESP 2018/15001-6. We also wish to thank the Researchers and staff of the Biological Dynamics of Forest Fragments Project (BDFFP), the Large Scale Biosphere-Atmosphere Experiment in the Amazon (LBA, in Santarém and Manaus), and PPBio of the National Institute for Amazonian Research (INPA, Brazil), and the Federal University of Western Pará (UFOPA) for exceptional support. This is study 759 of the BDFFP Technical Series. Author contributions: SC. Stark led the study and manuscript development, DD. Breshears, S Aragón, JC Villegas, DJ Law, DM Minor, RL de Assis, SR Saleska, ALS Swann, JMS Moura, R da Silva, LEOC Aragão, JL Camargo, and RC Oliveira helped develop and implement the study and participated in manuscript development. MN Smith, DRAlves de Almeida, G de Oliveira conducted analysis, and contributed substantial conceptual development to the manuscript.
Publisher Copyright:
© 2020 The Authors.
PY - 2020/9/1
Y1 - 2020/9/1
N2 - Tropical ecosystems are undergoing unprecedented rates of degradation from deforestation, fire, and drought disturbances. The collective effects of these disturbances threaten to shift large portions of tropical ecosystems such as Amazon forests into savanna-like structure via tree loss, functional changes, and the emergence of fire (savannization). Changes from forest states to a more open savanna-like structure can affect local microclimates, surface energy fluxes, and biosphere–atmosphere interactions. A predominant type of ecosystem state change is the loss of tree cover and structural complexity in disturbed forest. Although important advances have been made contrasting energy fluxes between historically distinct old-growth forest and savanna systems, the emergence of secondary forests and savanna-like ecosystems necessitates a reframing to consider gradients of tree structure that span forest to savanna-like states at multiple scales. In this Innovative Viewpoint, we draw from the literature on forest–grassland continua to develop a framework to assess the consequences of tropical forest degradation on surface energy fluxes and canopy structure. We illustrate this framework for forest sites with contrasting canopy structure that ranges from simple, open, and savanna-like to complex and closed, representative of tropical wet forest, within two climatically distinct regions in the Amazon. Using a recently developed rapid field assessment approach, we quantify differences in cover, leaf area vertical profiles, surface roughness, albedo, and energy balance partitioning between adjacent sites and compare canopy structure with adjacent old-growth forest; more structurally simple forests displayed lower net radiation. To address forest–atmosphere feedback, we also consider the effects of canopy structure change on susceptibility to additional future disturbance. We illustrate a converse transition—recovery in structure following disturbance—measuring forest canopy structure 10 yr after the imposition of a 5-yr drought in the ground-breaking Seca Floresta experiment. Our approach strategically enables rapid characterization of surface properties relevant to vegetation models following degradation, and advances links between surface properties and canopy structure variables, increasingly available from remote sensing. Concluding, we hypothesize that understanding surface energy balance and microclimate change across degraded tropical forest states not only reveals critical atmospheric forcing, but also critical local-scale feedbacks from forest sensitivity to additional climate-linked disturbance.
AB - Tropical ecosystems are undergoing unprecedented rates of degradation from deforestation, fire, and drought disturbances. The collective effects of these disturbances threaten to shift large portions of tropical ecosystems such as Amazon forests into savanna-like structure via tree loss, functional changes, and the emergence of fire (savannization). Changes from forest states to a more open savanna-like structure can affect local microclimates, surface energy fluxes, and biosphere–atmosphere interactions. A predominant type of ecosystem state change is the loss of tree cover and structural complexity in disturbed forest. Although important advances have been made contrasting energy fluxes between historically distinct old-growth forest and savanna systems, the emergence of secondary forests and savanna-like ecosystems necessitates a reframing to consider gradients of tree structure that span forest to savanna-like states at multiple scales. In this Innovative Viewpoint, we draw from the literature on forest–grassland continua to develop a framework to assess the consequences of tropical forest degradation on surface energy fluxes and canopy structure. We illustrate this framework for forest sites with contrasting canopy structure that ranges from simple, open, and savanna-like to complex and closed, representative of tropical wet forest, within two climatically distinct regions in the Amazon. Using a recently developed rapid field assessment approach, we quantify differences in cover, leaf area vertical profiles, surface roughness, albedo, and energy balance partitioning between adjacent sites and compare canopy structure with adjacent old-growth forest; more structurally simple forests displayed lower net radiation. To address forest–atmosphere feedback, we also consider the effects of canopy structure change on susceptibility to additional future disturbance. We illustrate a converse transition—recovery in structure following disturbance—measuring forest canopy structure 10 yr after the imposition of a 5-yr drought in the ground-breaking Seca Floresta experiment. Our approach strategically enables rapid characterization of surface properties relevant to vegetation models following degradation, and advances links between surface properties and canopy structure variables, increasingly available from remote sensing. Concluding, we hypothesize that understanding surface energy balance and microclimate change across degraded tropical forest states not only reveals critical atmospheric forcing, but also critical local-scale feedbacks from forest sensitivity to additional climate-linked disturbance.
KW - Amazon
KW - Earth System Models
KW - climate change
KW - energy balance
KW - forest transitions
KW - lidar
KW - rapid field assessment
KW - savannization
KW - vegetation structure
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U2 - 10.1002/ecs2.3231
DO - 10.1002/ecs2.3231
M3 - Article
AN - SCOPUS:85091855377
VL - 11
JO - Ecosphere
JF - Ecosphere
SN - 2150-8925
IS - 9
M1 - e03231
ER -