Biotic and climatic controls on interannual variability in carbon fluxes across terrestrial ecosystems

Junjiong Shao, Xuhui Zhou, Yiqi Luo, Bo Li, Mika Aurela, David Billesbach, Peter D. Blanken, Rosvel Bracho, Jiquan Chen, Marc Fischer, Yuling Fu, Lianhong Gu, Shijie Han, Yongtao He, Thomas Kolb, Yingnian Li, Zoltan Nagy, Shuli Niu, Walter C. Oechel, Krisztina PinterPeili Shi, Andrew Suyker, Margaret Torn, Andrej Varlagin, Huimin Wang, Junhua Yan, Guirui Yu, Junhui Zhang

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


Interannual variability (IAV, represented by standard deviation) in net ecosystem exchange of CO2 (NEE) is mainly driven by climatic drivers and biotic variations (i.e., the changes in photosynthetic and respiratory responses to climate), the effects of which are referred to as climatic (CE) and biotic effects (BE), respectively. Evaluating the relative contributions of CE and BE to the IAV in carbon (C) fluxes and understanding their controlling mechanisms are critical in projecting ecosystem changes in the future climate. In this study, we applied statistical methods with flux data from 65 sites located in the Northern Hemisphere to address this issue. Our results showed that the relative contribution of BE (CnBE) and CE (CnCE) to the IAV in NEE was 57%±14% and 43%±14%, respectively. The discrepancy in the CnBE among sites could be largely explained by water balance index (WBI). Across water-stressed ecosystems, the CnBE decreased with increasing aridity (slope=0.18%mm-1). In addition, the CnBE tended to increase and the uncertainty reduced as timespan of available data increased from 5 to 15 years. Inter-site variation of the IAV in NEE mainly resulted from the IAV in BE (72%) compared to that in CE (37%). Interestingly, positive correlations between BE and CE occurred in grasslands and dry ecosystems (r>0.45, P<0.05) but not in other ecosystems. These results highlighted the importance of BE in determining the IAV in NEE and the ability of ecosystems to regulate C fluxes under climate change might decline when the ecosystems experience more severe water stress in the future.

Original languageEnglish (US)
Pages (from-to)11-22
Number of pages12
JournalAgricultural and Forest Meteorology
StatePublished - Jun 1 2015


  • Biotic effect
  • Climatic effect
  • Climatic stress
  • Interannual variability
  • Net ecosystem exchange
  • Relative importance

ASJC Scopus subject areas

  • Forestry
  • Global and Planetary Change
  • Agronomy and Crop Science
  • Atmospheric Science


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