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Wenxin Zhang

Researcher

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Revisiting the role of transpiration in the variation of ecosystem water use efficiency in China

Author

  • Huaiwei Sun
  • Mengge Lu
  • Yong Yang
  • Jianing Chen
  • Jingfeng Wang
  • Dong Yan
  • Jie Xue
  • Wenxin Zhang

Summary, in English

Efforts to develop effective climate strategies necessitate a better understanding of the relationship between terrestrial water and carbon cycles. Water use efficiency (WUE) has been often used to characterize this relationship, while the role of transpiration (T) in the variation of ecosystem WUE has been less investigated. Here, we partitioned WUEET (the ratio of gross primary productivity (GPP) to evapotranspiration (ET)) into a two-component process, i.e., the ratio of gross primary productivity to plant transpiration, GPP/T, that is WUET, and the ratio of plant transpiration to evapotranspiration, T/ET. Based on two GPP datasets (i.e., GPP based on the light use efficiency model or the vegetation index- NIRv) and the GLEAM ET dataset, this study investigated the role of T in the variation of WUE in the ecosystem level and how the role is affected by drought. We found that drought can lead to the change of ET partitioning, thus affecting the variability of WUE. The variability of WUEET was dominated by WUET. In general, the proportion of T increased gradually from humid to arid areas. To adapt to drought conditions, vegetation in arid areas tend to have a high stress resistance by increasing their WUE. We further found that WUET has stronger seasonal stability than WUEET. GPP dominated WUEET variability in humid/sub humid areas, while ET and GPP jointly dominated WUEET variability in semi-arid/arid areas. GPP dataset based on light use efficiency (LUE) could better reflect the impact of drought on vegetation. This study contributes to a better understanding of the change mechanism of ecosystem WUE and emphasizes the critical role of physiological process components in water-carbon cycling.

Department/s

  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • Dept of Physical Geography and Ecosystem Science
  • MERGE: ModElling the Regional and Global Earth system

Publishing year

2023-04-01

Language

English

Publication/Series

Agricultural and Forest Meteorology

Volume

332

Document type

Journal article

Publisher

Elsevier

Topic

  • Physical Geography
  • Ecology

Keywords

  • Evapotranspiration partition
  • Gross primarily productivity
  • Water and carbon coupling
  • Water availability
  • Water use efficiency

Status

Published

ISBN/ISSN/Other

  • ISSN: 0168-1923