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The Net Landscape Carbon Balance—Integrating terrestrial and aquatic carbon fluxes in a managed boreal forest landscape in Sweden
Author(s) -
Chi Jinshu,
Nilsson Mats B.,
Laudon Hjalmar,
Lindroth Anders,
Wallerman Jörgen,
Fransson Johan E. S.,
Kljun Natascha,
Lundmark Tomas,
Ottosson Löfvenius Mikaell,
Peichl Matthias
Publication year - 2020
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.14983
Subject(s) - environmental science , peat , eddy covariance , carbon sink , taiga , boreal , greenhouse gas , mire , carbon cycle , biome , global warming , hydrology (agriculture) , ecosystem , climate change , atmospheric sciences , ecology , geotechnical engineering , engineering , biology , geology
The boreal biome exchanges large amounts of carbon (C) and greenhouse gases (GHGs) with the atmosphere and thus significantly affects the global climate. A managed boreal landscape consists of various sinks and sources of carbon dioxide (CO 2 ), methane (CH 4 ), and dissolved organic and inorganic carbon (DOC and DIC) across forests, mires, lakes, and streams. Due to the spatial heterogeneity, large uncertainties exist regarding the net landscape carbon balance (NLCB). In this study, we compiled terrestrial and aquatic fluxes of CO 2 , CH 4 , DOC, DIC, and harvested C obtained from tall‐tower eddy covariance measurements, stream monitoring, and remote sensing of biomass stocks for an entire boreal catchment (~68 km 2 ) in Sweden to estimate the NLCB across the land–water–atmosphere continuum. Our results showed that this managed boreal forest landscape was a net C sink (NLCB = 39 g C m −2 year −1 ) with the landscape–atmosphere CO 2 exchange being the dominant component, followed by the C export via harvest and streams. Accounting for the global warming potential of CH 4 , the landscape was a GHG sink of 237 g CO 2 ‐eq m −2 year −1 , thus providing a climate‐cooling effect. The CH 4 flux contribution to the annual GHG budget increased from 0.6% during spring to 3.2% during winter. The aquatic C loss was most significant during spring contributing 8% to the annual NLCB. We further found that abiotic controls (e.g., air temperature and incoming radiation) regulated the temporal variability of the NLCB whereas land cover types (e.g., mire vs. forest) and management practices (e.g., clear‐cutting) determined their spatial variability. Our study advocates the need for integrating terrestrial and aquatic fluxes at the landscape scale based on tall‐tower eddy covariance measurements combined with biomass stock and stream monitoring to develop a holistic understanding of the NLCB of managed boreal forest landscapes and to better evaluate their potential for mitigating climate change.