Partitioning controls on Amazon forest photosynthesis between environmental and biotic factors at hourly to interannual timescales

Wu, J; Guan, K; Hayek, M; Restrepo-Coupe, N; Wiedemann, KT; Xu, X; Wehr, R; Christoffersen, BO; Miao, G; da Silva, R; de Araujo, AC; Oliviera, RC; Camargo, PB; Monson, RK; Huete, AR; Saleska, SR

Partitioning controls on Amazon forest photosynthesis between environmental and biotic factors at hourly to interannual timescales

Wu, J Guan, K Hayek, M Restrepo-Coupe, N

Wiedemann, KT Xu, X Wehr, R Christoffersen, BO Miao, G da Silva, R de Araujo, AC Oliviera, RC Camargo, PB Monson, RK Huete, AR

Saleska, SR

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Publication Type:: Journal Article
Citation:: Global Change Biology, 2017, 23 (3), pp. 1240 - 1257
Issue Date:: 2017-03-01

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Field	Value	Language
dc.contributor.author	Wu, J	en_US
dc.contributor.author	Guan, K	en_US
dc.contributor.author	Hayek, M	en_US
dc.contributor.author	Restrepo-Coupe, N https://orcid.org/0000-0003-3921-1772	en_US
dc.contributor.author	Wiedemann, KT	en_US
dc.contributor.author	Xu, X	en_US
dc.contributor.author	Wehr, R	en_US
dc.contributor.author	Christoffersen, BO	en_US
dc.contributor.author	Miao, G	en_US
dc.contributor.author	da Silva, R	en_US
dc.contributor.author	de Araujo, AC	en_US
dc.contributor.author	Oliviera, RC	en_US
dc.contributor.author	Camargo, PB	en_US
dc.contributor.author	Monson, RK	en_US
dc.contributor.author	Huete, AR https://orcid.org/0000-0003-2809-2376	en_US
dc.contributor.author	Saleska, SR	en_US
dc.date.available	2016-09-08	en_US
dc.date.issued	2017-03-01	en_US
dc.identifier.citation	Global Change Biology, 2017, 23 (3), pp. 1240 - 1257	en_US
dc.identifier.issn	1354-1013	en_US
dc.identifier.uri	http://hdl.handle.net/10453/77440
dc.description.abstract	© 2016 John Wiley & Sons Ltd Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance-derived GEP in a central Amazon evergreen forest into two main causes: variation in environmental drivers (solar radiation, diffuse light fraction, and vapor pressure deficit) that interact with model parameters that govern photosynthesis and biotic variation in canopy photosynthetic light-use efficiency associated with changes in the parameters themselves. Our fitted model was able to explain most of the variability in GEP at hourly (R2= 0.77) to interannual (R2= 0.80) timescales. At hourly timescales, we found that 75% of observed GEP variability could be attributed to environmental variability. When aggregating GEP to the longer timescales (daily, monthly, and yearly), however, environmental variation explained progressively less GEP variability: At monthly timescales, it explained only 3%, much less than biotic variation in canopy photosynthetic light-use efficiency, which accounted for 63%. These results challenge modeling approaches that assume GEP is primarily controlled by the environment at both short and long timescales. Our approach distinguishing biotic from environmental variability can help to resolve debates about environmental limitations to tropical forest photosynthesis. For example, we found that biotically regulated canopy photosynthetic light-use efficiency (associated with leaf phenology) increased with sunlight during dry seasons (consistent with light but not water limitation of canopy development) but that realized GEP was nonetheless lower relative to its potential efficiency during dry than wet seasons (consistent with water limitation of photosynthesis in given assemblages of leaves). This work highlights the importance of accounting for differential regulation of GEP at different timescales and of identifying the underlying feedbacks and adaptive mechanisms.	en_US
dc.relation	http://purl.org/au-research/grants/arc/DP140102698
dc.relation.ispartof	Global Change Biology	en_US
dc.relation.isbasedon	10.1111/gcb.13509	en_US
dc.subject.classification	Ecology	en_US
dc.subject.mesh	Plant Leaves	en_US
dc.subject.mesh	Trees	en_US
dc.subject.mesh	Ecosystem	en_US
dc.subject.mesh	Seasons	en_US
dc.subject.mesh	Photosynthesis	en_US
dc.subject.mesh	Forests	en_US
dc.title	Partitioning controls on Amazon forest photosynthesis between environmental and biotic factors at hourly to interannual timescales	en_US
dc.type	Journal Article
utslib.citation.volume	3	en_US
utslib.citation.volume	23	en_US
utslib.for	050206 Environmental Monitoring	en_US
utslib.for	090905 Photogrammetry and Remote Sensing	en_US
utslib.for	05 Environmental Sciences	en_US
utslib.for	06 Biological Sciences	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
pubs.organisational-group	/University of Technology Sydney/Strength - CAMGIS - Centre for Advanced Modelling and Geospatial lnformation Systems
utslib.copyright.status	closed_access
pubs.issue	3	en_US
pubs.publication-status	Published	en_US
pubs.volume	23	en_US

Abstract:

© 2016 John Wiley & Sons Ltd Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance-derived GEP in a central Amazon evergreen forest into two main causes: variation in environmental drivers (solar radiation, diffuse light fraction, and vapor pressure deficit) that interact with model parameters that govern photosynthesis and biotic variation in canopy photosynthetic light-use efficiency associated with changes in the parameters themselves. Our fitted model was able to explain most of the variability in GEP at hourly (R2= 0.77) to interannual (R2= 0.80) timescales. At hourly timescales, we found that 75% of observed GEP variability could be attributed to environmental variability. When aggregating GEP to the longer timescales (daily, monthly, and yearly), however, environmental variation explained progressively less GEP variability: At monthly timescales, it explained only 3%, much less than biotic variation in canopy photosynthetic light-use efficiency, which accounted for 63%. These results challenge modeling approaches that assume GEP is primarily controlled by the environment at both short and long timescales. Our approach distinguishing biotic from environmental variability can help to resolve debates about environmental limitations to tropical forest photosynthesis. For example, we found that biotically regulated canopy photosynthetic light-use efficiency (associated with leaf phenology) increased with sunlight during dry seasons (consistent with light but not water limitation of canopy development) but that realized GEP was nonetheless lower relative to its potential efficiency during dry than wet seasons (consistent with water limitation of photosynthesis in given assemblages of leaves). This work highlights the importance of accounting for differential regulation of GEP at different timescales and of identifying the underlying feedbacks and adaptive mechanisms.

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http://hdl.handle.net/10453/77440