Monitoring and driving force analysis of net primary productivity in native grassland: A case study in Xilingol steppe, China

Abstract

Grassland is an important type of terrestrial ecosystem. Using remote sensing technology to study the change and driving force of native grassland productivity at large scale is an important way to understand the ecological status of grassland. In this study, potential and actual net primary productivity (NPP) of Xilingol steppe from 2000 to 2018 were examined based on climatic model and light-use efficiency model, respectively. NPP damage value driven by human activities was calculated from the difference between potential and actual NPP. The least square method was used to analyze the temporal and spatial variation of NPP in Xilingol and the driving role of climate and human activities on NPP. The results showed that NPP in Xilingol increased from west to east, with mean annual NPP being 271.54 g C·m-2·a-1, the area with increased NPP (grassland restoration) being 36500 km2, and the area with decreased NPP (grassland degradation) being 59900 km2. The potential NPP tended to rise under the driving force of temperature and precipitation, with an average annual increase of 6.5 g C·m-2·a-1, which indicated that regional climate played a positive role in the improvement of NPP in Xilingol steppe, and that human activities were the main driving force for grassland degradation. The value of NPP damage driven by human activities decreased from east to west and from south to north, with the highest value in Wuzhumuqin meadow and southern steppe. Human activities, such as mining and reclamation, had the most obvious negative impact on grassland NPP.