Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (3): 306-318.DOI: 10.17521/cjpe.2021.0444

Special Issue: 生态遥感及应用 光合作用

• Research Articles • Previous Articles     Next Articles

Spatiotemporal variation and its driving mechanism of photosynthetic vegetation in the Loess Plateau from 2001 to 2020

HE Jie1, HE Liang1, LÜ Du2, CHENG Zhuo3, XUE Fan1, LIU Bao-Yuan1,3, ZHANG Xiao-Ping1,2,*()   

  1. 1State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China
    2Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, Yangling, Shaanxi 712100, China
    3State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
  • Received:2021-12-01 Accepted:2022-03-22 Online:2023-03-20 Published:2022-10-11
  • Contact: ZHANG Xiao-Ping
  • Supported by:
    National Natural Science Foundation of China(41877083);National Natural Science Foundation of China(41440012);National Natural Science Foundation of China(41230852)

Abstract:

Aims The objectives of this study were to reveal the changing trends and regional differences of vegetation fractional coverage on the Loess Plateau 20 years after the implementation of the “Grain for Green (GFG)” policy, and to quantify the contribution of climate and human activities to the change of vegetation fractional coverage and its spatial distribution in the region.

Methods The spatial and temporal variation of photosynthetic vegetation (PV) fractional coverage on the Loess Plateau from 2001 to 2020 and its drivers and contributions were analyzed based on MODIS-PV and meteorological data, and using the methods of the Mann-Kendall method, the Sen estimator, and multivariate residual trend analysis.

Important findings Regional vegetation fractional coverage increased from 40% in 2001 to 60% in 2020. Vegetation fractional coverage of the Loess Plateau showed a significant increasing trend over 20 years, with an increasing rate of 0.8%·a-1. The proportion of the area with an increasing trend of vegetation fractional coverage for the entire region was 90%, and the proportion of the area with a significant increase was 71%. The contribution to the increase of vegetation fractional coverage in the region was mainly in the loess hilly region (2/5), followed by the sandy hilly region (1/4) and the rocky mountain region (1/5). Within the different geomorphology divisions, vegetation fractional coverage in the loess hilly region increased rapidly in Yulin and Yanʼan in Shaanxi. Vegetation fractional coverage in Ordos, Nei Mongol, changed the fastest in the sandy hilly region. Human activities and climate change contributed 76% and 24%, respectively, to the increase of vegetation fractional coverage on the Loess Plateau during the study period. The areas where human activities contributed positively to vegetation fractional coverage were mainly located in the loess hilly and sandy hilly regions in the northern part of Yanʼan in Shaanxi, the southern part of Taiyuan in Shanxi, the southern part of Tongxin in Ningxia, and the hills and plateaus of Pingliang and Qingyang in Gansu where the ecological projects funded by the Chinese government have been well implemented.

Key words: Loess Plateau, vegetation fractional coverage, spatial and temporal variation, human activities, residual analysis