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Chinese Journal of Applied Ecology ›› 2021, Vol. 32 ›› Issue (1): 113-122.doi: 10.13287/j.1001-9332.202101.017

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Spatial-temporal trend of grassland net primary production and their driving factors in the Loess Plateau, China

LIU Zheng1, YANG Jin-gui1, MA Li-hui2,3*, KE Zeng-ming2, HU Yu-mei3,4, YAN Xiao-ying1   

  1. 1College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, Shaanxi, China;
    2Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China;
    3Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China;
    4University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-07-26 Accepted:2020-10-28 Online:2021-01-15 Published:2021-07-15
  • Contact: * E-mail: gjzmlh@126.com
  • Supported by:
    National Natural Science Foundation of China (41671510) and the Key Program of Research and Development in Shaanxi Province (2020NY-155).

Abstract: Net primary productivity (NPP) of grassland is a key link and important part of the ecosystem’s carbon cycle. We estimated the changes of NPP in grasslands of the Loess Plateau with unchanged land use types during 2000-2015 and analyzed its responses to the variation of main climate factors (annual precipitation, annual heavy rainfall, annual effective rainfall days, annual average temperature, annual maximum temperature, annual minimum temperature) using piecewise linear regression and Pearson correlation analysis. The driving factors of grassland NPP were further analyzed by pixel-by-pixel with boosted regression tree analysis. The results showed that annual mean grassland NPP in the Loess Plateau showed an increasing trend during the study period, with 51.3% of the total grassland area showing a significant increasing trend. The average increase rate of annual mean NPP declined from 15.23 g C·m-2·a-1 in 2000-2004 to 3.58 g C·m-2·a-1 in 2004-2015. There was a significant positive correlation between grassland NPP and precipitation, but negative correlation with temperature factors. Annual precipitation was the dominant climatic factor affecting NPP of the whole study area with the highest relative importance. Annual maximum temperature was the dominant driving force of grassland NPP of central Loess Plateau, while annual minimum temperature mainly affected the growth of grassland in high-altitude area of the western Loess Plateau.

Key words: net primary productivity (NPP), grassland, extreme climate, Loess Plateau