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Chinese Journal of Applied Ecology ›› 2019, Vol. 30 ›› Issue (7): 2309-2319.doi: 10.13287/j.1001-9332.201907.002

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Spatial-temporal dynamics of grassland NPP and its driving factors in the Loess Plateau, China

LIU Yang-yang1, WANG Qian1, YANG Yue2, GANG Cheng-cheng3, ZHANG Zhao-ying4, TONG Lin-jing1, LI Jian-long1*   

  1. 1Department of Ecology, School of Life Science, Nanjing Univer-sity, Nanjing 210023, China;
    2Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection of the People’s Republic of China, Nanjing 210042, China;
    3Institute of Soil and Water Conservation, Northwest Agriculture and Forestry University, Yangling 712100, Shaanxi, China;
    4International Institute for Earth System Science, Nanjing University, Nanjing 210023, China.
  • Received:2018-10-11 Online:2019-07-15 Published:2019-07-15
  • Contact: * E-mail: lijianlongnju@163.com

Abstract: We estimated grassland NPP using CASA model in the Loess Plateau during 2000-2015 and further analyzed the spatiotemporal dynamics, stability and persistence of grassland NPP. The driving factors of grassland NPP were analyzed from four aspects, i.e., vegetation types, topographic factors, climate change, and human activities. The results showed that the average NPP was 202.93 g C·m-2·a-1. The grassland NPP showed an increasing trend with an average increase rate of 2.43 g C·m-2·a-1. The distribution of NPP in grassland had obvious spatial heterogeneity, which was generally high in the south and low in the north. 91.2% of the total grassland area showed an increasing trend, mainly distributed in most areas of Shaanxi Province, Longdong and Longzhong areas of Gansu Province, and most parts of Qinghai Province. The regions with a stable growth condition of grassland NPP mainly located in the south of Ordos, northern Shaanxi, and Gansu. The future change trend of grassland NPP would be consistent with that of the past in most areas. The grassland NPP would continue to increase in most areas of Shaanxi Province, Longzhong and Longdong areas in Gansu Province. The average NPP of slope grassland was 703.37 g C·m-2·a-1, while that of alpine and subalpine grassland was 57.28 g C·m-2·a-1. The grassland NPP was higher in high altitude area and relative low in plain and hilly area. The increased precipitation promoted the increase of grassland NPP during the study period. Human activities such as improvement of overgrazing and returning cropland to grassland also played an important role in the increase of grassland NPP in the Loess Plateau.