Journal of Resources and Ecology ›› 2022, Vol. 13 ›› Issue (1): 129-141.DOI: 10.5814/j.issn.1674-764x.2022.01.015

• Industry Ecology and Regional Development • Previous Articles     Next Articles

Alpine Grassland Aboveground Biomass and Theoretical Livestock Carrying Capacity on the Tibetan Plateau

ZHANG Xianzhou1,2(), LI Meng3, WU Jianshuang4, HE Yongtao1,2, NIU Ben1,*()   

  1. 1. Lhasa Plateau Ecosystem Research Station, 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. School of Geographic Sciences, Nantong University, Nantong, Jiangsu 226007, China
    4. Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
  • Received:2021-09-13 Accepted:2021-10-13 Online:2022-01-30 Published:2022-01-08
  • Contact: NIU Ben
  • About author:ZHANG Xianzhou, E-mail: zhangxz@igsnrr.ac.cn
  • Supported by:
    The Second Tibetan Plateau Scientific Expedition and Research Program (STEP)(2019QZKK1002);The National Natural Sciences Foundation of China(41807331);The West Light Foundation of the Chinese Academy of Sciences(2018)

Abstract:

The accurate simulation and prediction of grassland aboveground biomass (AGB) and theoretical livestock carrying capacity are key steps for maintaining ecosystem balance and sustainable grassland management. The AGB in fenced grassland is not affected by grazing and its variability is only driven by climate change, which can be regarded as the grassland potential AGB (AGBp). In this study, we compiled the data for 345 AGB field observations in fenced grasslands and their corresponding climate data, soil data, and topographical data on the Qinghai-Tibetan Plateau (TP). We further simulated and predicted grassland AGBp and theoretical livestock carrying capacity under the climate conditions of the past (2000-2018) and future two decades (2021-2040) based on a random forest (RF) algorithm. The results showed that simulated AGBp matched well with observed values in the field (R2 = 0.76, P < 0.001) in the past two decades. The average grassland AGBp on the Tibetan Plateau was 102.4 g m-2, and the inter-annual changes in AGBp during this period showed a non-significant increasing trend. AGBp fluctuation was positively correlated with growing season precipitation (R2 = 0.57, P < 0.001), and negatively correlated with the growing season diurnal temperature range (R2 = 0.51, P < 0.001). The average theoretical livestock carrying capacity was 0.94 standardized sheep units (SSU) ha-1 on the TP, in which about 54.1% of the areas showed an increasing trend during the past two decades. Compared with the past two decades, the theoretical livestock carrying capacity showed a decreasing trend in the future, which was mainly distributed in the central and northern TP. This study suggested that targeted planning and management should be carried out to alleviate the forage-livestock contradiction in grazing systems on the Tibetan Plateau.

Key words: alpine grassland, aboveground biomass, carrying capacity, climate change, random forest, Tibetan Plateau