Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (12): 1486-1496.DOI: 10.17521/cjpe.2021.0187

Special Issue: 青藏高原植物生态学:遥感生态学 生态系统碳水能量通量

• Special feature: Ecosystem carbon and water fluxes in ecological vulnerable areas of China • Previous Articles     Next Articles

Variation in ecosystem water use efficiency and its attribution analysis during 1982-2018 in Qingzang Plateau

ZHENG Zhou-Tao1,*(), ZHANG Yang-Jian1,2,3   

  1. 1Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
    2CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China
    3College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China
  • Received:2021-05-17 Accepted:2021-12-15 Online:2022-12-20 Published:2023-01-13
  • Supported by:
    National Natural Science Foundation of China(41725003);National Natural Science Foundation of China(41901131);Strategic Priority Research Program of the Chinese Academy of Sciences(XDA19070303);West Light Foundation of the Chinese Academy of Sciences(2019)


Aims Water use efficiency (WUE) is a crucial parameter reflecting the coupling of carbon and water cycles in terrestrial ecosystems. Qingzang Plateau (QP) is the ecological barrier of China and its accommodated ecosystem is extremely sensitive to global change. Revealing the ecosystem WUE pattern and the driving forces is critical for improving our understanding on the process and mechanism of carbon and water cycles in the alpine ecosystem of the QP, which are the basis for vegetation conservation and restoration.

Methods Using the Global Land Surface Satellite (GLASS) data, meteorological data and vegetation type data, the spatio-temporal changes of WUE and their responses to temperature, precipitation, solar radiation, vapor pressure deficit (VPD), CO2 concentration and leaf area index (LAI) during 1982-2018 over the QP were analyzed in this study. The trend magnitude and the influencing factors on WUE were further compared among vegetation types.

Important findings (1) The WUE decreases gradually from southeast to northwest on the QP, with an overall annual mean value of 1.64 g C·kg-1. Evident differences in WUE are observed among vegetation types, with the highest value in forest and the lowest value in alpine desert. In addition, the WUE in alpine meadow is higher than that in alpine steppe. (2) The QP is prevailed by an increasing trend in WUE. Significantly increasing trends are observed in all vegetation types except for forest and cultural vegetation. Meanwhile, the variation of WUE is dominated by ecosystem gross primary productivity over 77.84% of the study area. (3) The WUE variation is mainly regulated by LAI and CO2 concentration on the QP, and these two factors both cause positive effects on WUE. Increasing VPD inhibits WUE in alpine steppe, alpine vegetation, cultural vegetation and alpine desert.

Key words: water use efficiency, Qingzang Plateau, influencing factor, leaf area index, CO2 concentration, vegetation type