TY - JOUR
T1 - Direct and indirect effects of climatic variations on the interannual variability in net ecosystem exchange across terrestrial ecosystems
AU - Shao, Junjiong
AU - Zhou, Xuhui
AU - Luo, Yiqi
AU - Li, Bo
AU - Aurela, Mika
AU - Billesbach, David
AU - Blanken, Peter D.
AU - Bracho, Rosvel
AU - Chen, Jiquan
AU - Fischer, Marc
AU - Fu, Yuling
AU - Gu, Lianhong
AU - Han, Shijie
AU - He, Yongtao
AU - Kolb, Thomas
AU - Li, Yingnian
AU - Nagy, Zoltan
AU - Niu, Shuli
AU - Oechel, Walter C.
AU - Pinter, Krisztina
AU - Shi, Peili
AU - Suyker, Andrew
AU - Torn, Margaret
AU - Varlagin, Andrej
AU - Wang, Huimin
AU - Yan, Junhua
AU - Yu, Guirui
AU - Zhang, Junhui
N1 - Publisher Copyright:
© 2016 J. Shao et al.
PY - 2016
Y1 - 2016
N2 - Climatic variables not only directly affect the interannual variability (IAV) in net ecosystem exchange of CO2 (NEE) but also indirectly drive it by changing the physiological parameters. Identifying these direct and indirect paths can reveal the underlying mechanisms of carbon (C) dynamics. In this study, we applied a path analysis using flux data from 65 sites to quantify the direct and indirect climatic effects on IAV in NEE and to evaluate the potential relationships among the climatic variables and physiological parameters that represent physiology and phenology of ecosystems. We found that the maximum photosynthetic rate was the most important factor for the IAV in gross primary productivity (GPP), which was mainly induced by the variation in vapour pressure deficit. For ecosystem respiration (RE), the most important drivers were GPP and the reference respiratory rate. The biome type regulated the direct and indirect paths, with distinctive differences between forests and non-forests, evergreen needleleaf forests and deciduous broadleaf forests, and between grasslands and croplands. Different paths were also found among wet, moist and dry ecosystems. However, the climatic variables can only partly explain the IAV in physiological parameters, suggesting that the latter may also result from other biotic and disturbance factors. In addition, the climatic variables related to NEE were not necessarily the same as those related to GPP and RE, indicating the emerging difficulty encountered when studying the IAV in NEE. Overall, our results highlight the contribution of certain physiological parameters to the IAV in C fluxes and the importance of biome type and multi-year water conditions, which should receive more attention in future experimental and modelling research.
AB - Climatic variables not only directly affect the interannual variability (IAV) in net ecosystem exchange of CO2 (NEE) but also indirectly drive it by changing the physiological parameters. Identifying these direct and indirect paths can reveal the underlying mechanisms of carbon (C) dynamics. In this study, we applied a path analysis using flux data from 65 sites to quantify the direct and indirect climatic effects on IAV in NEE and to evaluate the potential relationships among the climatic variables and physiological parameters that represent physiology and phenology of ecosystems. We found that the maximum photosynthetic rate was the most important factor for the IAV in gross primary productivity (GPP), which was mainly induced by the variation in vapour pressure deficit. For ecosystem respiration (RE), the most important drivers were GPP and the reference respiratory rate. The biome type regulated the direct and indirect paths, with distinctive differences between forests and non-forests, evergreen needleleaf forests and deciduous broadleaf forests, and between grasslands and croplands. Different paths were also found among wet, moist and dry ecosystems. However, the climatic variables can only partly explain the IAV in physiological parameters, suggesting that the latter may also result from other biotic and disturbance factors. In addition, the climatic variables related to NEE were not necessarily the same as those related to GPP and RE, indicating the emerging difficulty encountered when studying the IAV in NEE. Overall, our results highlight the contribution of certain physiological parameters to the IAV in C fluxes and the importance of biome type and multi-year water conditions, which should receive more attention in future experimental and modelling research.
KW - Climatic variations
KW - Direct and indirect effects
KW - Interannual variability
KW - Net ecosystem exchange
KW - Physiological parameters
KW - Relative importance
UR - http://www.scopus.com/inward/record.url?scp=85010982911&partnerID=8YFLogxK
U2 - 10.3402/tellusb.v68.30575
DO - 10.3402/tellusb.v68.30575
M3 - Article
AN - SCOPUS:85010982911
SN - 0280-6509
VL - 68
JO - Tellus, Series B: Chemical and Physical Meteorology
JF - Tellus, Series B: Chemical and Physical Meteorology
IS - 1
M1 - 30575
ER -