TY - JOUR
T1 - Regional-Scale drivers of forest structure and function in northwestern Amazonia
AU - Higgins, Mark A.
AU - Asner, Gregory P.
AU - Anderson, Christopher B.
AU - Martin, Roberta E.
AU - Knapp, David E.
AU - Tupayachi, Raul
AU - Perez, Eneas
AU - Elespuru, Nydia
AU - Alonso, Alfonso
N1 - Funding Information:
For assistance in the field we thank Fernando Ruiz, Sulema Castro, Glenda Cardenas, and Wilber Bosmediano. For soil analyses, we thank Tapio Salo (MTT Agrifood Research Center, Finland) and Irma Puttonen. For logistic support we thank colleagues at the Instituto de Investigaciones de la Amazonia Peruana and the Universidad Nacional de la Amazonia Peruana; and the PlusPetrol corporation (Argentina), Repsol Exploracion Peru (Peru), the Smithsonian Conservation Biology Institute, and Global Geophysical Services (USA). Support for this work was provided by the Carnegie Institution for Science (USA), the National Science Foundation (USA), the American—Scandinavian Foundation (USA), Duke University (USA), and Repsol Exploracion Peru (Peru). We thank the Instituto Nacional de Recursos Naturales (Peru) for permission to collect plant specimens, and the communities of the Rio Tigre for permission to work in their forests. The Carnegie Airborne Observatory is made possible by the Gordon and Betty Moore Foundation; the Grantham Foundation for the Protection of the Environment; the John D. and Catherine T. MacArthur Foundation; the Avatar Alliance Foundation; the W. M. Keck Foundation; the Margaret A. Cargill Foundation; Mary Anne Nyburg Baker and G. Leonard Baker Jr.; and William R. Hearst III.
Publisher Copyright:
© 2015 Higgins et al.
PY - 2015/3/20
Y1 - 2015/3/20
N2 - Field studies in Amazonia have found a relationship at continental scales between soil fertility and broad trends in forest structure and function. Little is known at regional scales, however, about how discrete patterns in forest structure or functional attributes map onto underlying edaphic or geological patterns. We collected airborne LiDAR (Light Detection and Ranging) data and VSWIR (Visible to Shortwave Infrared) imaging spectroscopy measurements over 600 km2 of northwestern Amazonian lowland forests. We also established 83 inventories of plant species composition and soil properties, distributed between two widespread geological formations. Using these data, we mapped forest structure and canopy reflectance, and compared them to patterns in plant species composition, soils, and underlying geology. We found that variations in soils and species composition explained up to 70% of variation in canopy height, and corresponded to profound changes in forest vertical profiles. We further found that soils and plant species composition explained more than 90% of the variation in canopy reflectance as measured by imaging spectroscopy, indicating edaphic and compositional control of canopy chemical properties. We last found that soils explained between 30% and 70% of the variation in gap frequency in these forests, depending on the height threshold used to define gaps. Our findings indicate that a relatively small number of edaphic and compositional variables, corresponding to underlying geology, may be responsible for variations in canopy structure and chemistry over large expanses of Amazonian forest.
AB - Field studies in Amazonia have found a relationship at continental scales between soil fertility and broad trends in forest structure and function. Little is known at regional scales, however, about how discrete patterns in forest structure or functional attributes map onto underlying edaphic or geological patterns. We collected airborne LiDAR (Light Detection and Ranging) data and VSWIR (Visible to Shortwave Infrared) imaging spectroscopy measurements over 600 km2 of northwestern Amazonian lowland forests. We also established 83 inventories of plant species composition and soil properties, distributed between two widespread geological formations. Using these data, we mapped forest structure and canopy reflectance, and compared them to patterns in plant species composition, soils, and underlying geology. We found that variations in soils and species composition explained up to 70% of variation in canopy height, and corresponded to profound changes in forest vertical profiles. We further found that soils and plant species composition explained more than 90% of the variation in canopy reflectance as measured by imaging spectroscopy, indicating edaphic and compositional control of canopy chemical properties. We last found that soils explained between 30% and 70% of the variation in gap frequency in these forests, depending on the height threshold used to define gaps. Our findings indicate that a relatively small number of edaphic and compositional variables, corresponding to underlying geology, may be responsible for variations in canopy structure and chemistry over large expanses of Amazonian forest.
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U2 - 10.1371/journal.pone.0119887
DO - 10.1371/journal.pone.0119887
M3 - Article
C2 - 25793602
AN - SCOPUS:84925799663
VL - 10
JO - PLoS One
JF - PLoS One
SN - 1932-6203
IS - 3
M1 - e0119887
ER -