Enhanced dominance of soil moisture stress on vegetation growth in Eurasian drylands

Yu Zhang; Yangjian Zhang; Xu Lian; Zhoutao Zheng; Guang Zhao; Tao Zhang; Minjie Xu; Ke Huang; Ning Chen; Ji Li; Shilong Piao

doi:10.1093/nsr/nwad108

Enhanced dominance of soil moisture stress on vegetation growth in Eurasian drylands

Natl Sci Rev. 2023 Apr 24;10(8):nwad108. doi: 10.1093/nsr/nwad108. eCollection 2023 Aug.

Authors

Yu Zhang^{1

2}, Yangjian Zhang^{1

2}, Xu Lian^{3

4}, Zhoutao Zheng¹, Guang Zhao¹, Tao Zhang⁵, Minjie Xu⁵, Ke Huang^{1

6}, Ning Chen⁷, Ji Li^{1

8}, Shilong Piao^{3

9}

Affiliations

¹ Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
² College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100190, China.
³ Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
⁴ Department of Earth and Environmental Engineering, Columbia University, New York, NY 10027, USA.
⁵ College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China.
⁶ Department of Geosciences and Natural Resource Management, University of Copenhagen, Copenhagen 1350, Denmark.
⁷ Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
⁸ Department of Geography, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430078, China.
⁹ State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China.

Abstract

Despite the mounting attention being paid to vegetation growth and their driving forces for water-limited ecosystems, the relative contributions of atmospheric and soil moisture dryness stress on vegetation growth are an ongoing debate. Here we comprehensively compare the impacts of high vapor pressure deficit (VPD) and low soil water content (SWC) on vegetation growth in Eurasian drylands during 1982-2014. The analysis indicates a gradual decoupling between atmospheric dryness and soil dryness over this period, as the former has expanded faster than the latter. Moreover, the VPD-SWC relation and VPD-greenness relation are both non-linear, while the SWC-greenness relation is near-linear. The loosened coupling between VPD and SWC, the non-linear correlations among VPD-SWC-greenness and the expanded area extent in which SWC acts as the dominant stress factor all provide compelling evidence that SWC is a more influential stressor than VPD on vegetation growth in Eurasian drylands. In addition, a set of 11 Earth system models projected a continuously growing constraint of SWC stress on vegetation growth towards 2100. Our results are vital to dryland ecosystems management and drought mitigation in Eurasia.

Keywords: decoupling; non-linear relation; soil water content; vapor pressure deficit; vegetation growth.