Arid Zone Research ›› 2023, Vol. 40 ›› Issue (1): 123-131.doi: 10.13866/j.azr.2023.01.13

• Ecology and Environment • Previous Articles     Next Articles

Simulation of spatial pattern and future trends of grassland net primary productivity in the Loess Plateau based on random forest model

LIU Huanhuan1(),CHEN Yin1,LIU Yue1,GANG Chengcheng2,3()   

  1. 1. College of Grassland Agriculture, Northwest A & F University, Yangling 712100, Shaanxi, China
    2. Institute of Soil and Water Conservation, Northwest A & F University, Yangling 712100, Shaanxi, China
    3. Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China
  • Received:2022-05-26 Revised:2022-08-13 Online:2023-01-15 Published:2023-02-24

Abstract:

The accurate estimation of grassland net primary productivity (NPP) is crucial to understanding the carbon cycle of grassland ecosystems and their adaption to climate change. Based on 1788 grassland biomass data and 19 environmental factors (climate, vegetation, soil, and topographic factors), we simulated the spatiotemporal dynamics of grassland NPP in the Loess Plateau from 2002 to 2020 using the random forest (RF) model. The future trends of grassland NPP under four future climate scenarios of shared socioeconomic pathways were estimated. Results showed that (1) the RF model had a good accuracy, which indicated that RF can be used to estimate grassland NPP in the Loess Plateau; (2) grassland NPP in the Loess Plateau exhibited a “high in southeastern and low in northwestern” pattern, with a mean value of 276.55 g C·m-2·a-1. The highest grassland NPP was observed in Guanzhong Plain of Shaanxi; (3) the grassland NPP in the Loess Plateau showed an overall increasing trend during 2002-2020. Regions experiencing an increase in grassland NPP accounted for 55.01% of the total land area, which is mainly located in Guanzhong Plain, western Gansu, and northern Shanxi; (4) under the wetter and warmer climate, grassland NPP in the Loess Plateau will continually increase by the end of this century. Grassland NPP will increase the most under the SSP585 scenario and the least under the SSP126 scenario. RF can be used to simulate the temporal and spatial trends of grassland NPP in the Loess Plateau. The results provide data support for the protection and sustainable development of grassland ecosystem in the Loess Plateau.

Key words: grassland ecosystems, net primary productivity (NPP), random forest, Shared Socioeconomic Pathway (SSPs), Loess Plateau