Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (2): 162-175.DOI: 10.17521/cjpe.2020.0387

• Research Articles • Previous Articles     Next Articles

Effects of land cover and phenology changes on the gross primary productivity in an Artemisia ordosica shrubland

YUAN Yuan1,2, MU Yan-Mei1,2, DENG Yu-Jie1, LI Xin-Hao1,2, JIANG Xiao-Yan1,2, GAO Sheng-Jie1,2, ZHA Tian- Shan1,2,3, JIA Xin1,2,3,*()   

  1. 1School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
    2Yanchi Ecology Research Station of Mau Us Desert, Beijing 100083, China
    3Key Laboratory of State Forestry and Grassland Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
  • Received:2020-11-23 Accepted:2021-05-25 Online:2022-02-20 Published:2021-07-22
  • Contact: JIA Xin
  • Supported by:
    National Natural Science Foundation of China(32071843);National Natural Science Foundation of China(31670708);National Natural Science Foundation of China(32071842);National Natural Science Foundation of China(31670710);Fundamental Research Funds for the Central Universities(2015ZCQ-SB-02)


Aims We aimed to examine how changes in vegetation cover and phenology affect the trend of gross primary productivity (GPP) in an Artemisia ordosica shrubland in the Mau Us Desert during the first two decades of the 21th century.

Methods We used the vegetation photosynthesis model (VPM) in combination with remote sensing data (MODIS) to simulate GPP dynamics during 2005-2018. Eddy covariance (EC) measurements of GPP (GPPFlux) were used to parameterize and validate the VPM model. The “derivation and threshold” approach was used to determine the start (SOS) and the end of the growing season (EOS), as well as the length of the growing season (LOS) for each year. Ordinary least squares (OLS) regression was used to examine the variations in temperature, normalized differences vegetation index (NDVI), and GPP over time. OLS, multiple, and partial correlation analyses were used to test the relationships among temperature, NDVI, phenology, and GPP.

Important findings (1) Modeled GPP well captured the dynamics of GPPFlux, whereas the MODIS product (MOD17A2H) significantly underestimated GPPFlux. (2) NDVI, annual maximum NDVI(NDVImax), and annual GPP all showed an increasing trend during 2005-2018, indicating the role of vegetation recovery in promoting GPP. (3) SOS showed an advancing trend (2.1 d·a-1) and EOS showed a delaying trend (1.5 d·a-1), and therefore both SOS and EOS contributed to the increasing trend of LOS (3.6 d·a-1). (4) Annual GPP was higher with greater LOS (6.44 g C·m-2·a-1 for 1 day increase in LOS). (5) Increases in vegetation cover and growing season length explained 79% and 57% of the variations in GPP, respectively. (6) Increases in vegetation cover played a more important role than growing season extension in promoting GPP.

Key words: gross primary productivity, vegetation index, phenological phase, climate change, vegetation photosynthesis model, Mau Us Desert