Arid Zone Research ›› 2023, Vol. 40 ›› Issue (8): 1322-1332.doi: 10.13866/j.azr.2023.08.13

• Ecology and Environment • Previous Articles     Next Articles

Analysis of the spatiotemporal variation characteristics and driving factors of grassland vegetation cover in Ningxia based on geographical detectors

WEN Miaoxia(),HE Xuegao,LIU Huan,ZHANG Jing,LUO Chen,JIA Fengming,WANG Yigui,HU Yunyun()   

  1. Northwest Surveying and Planning Institute of National Forestry and Grassland Administration, Key Laboratory of National Forestry and Grassland Administration on Ecological Hydrology and Disaster Prevention in Arid Regions, Xi’an 710048, Shaanxi, China
  • Received:2023-01-27 Revised:2023-03-17 Online:2023-08-15 Published:2023-08-24

Abstract:

This study aims to examine the spatiotemporal variation characteristics of grassland vegetation cover at the regional scale and analyze its driving factors. The findings will provide a scientific reference and decision-making basis for the scientific formulation of protection and restoration models, treatment measures, and the sustainable management of the grassland ecosystem in Ningxia, which are crucial for maintaining the balance of the regional grassland ecosystem and promoting ecological protection and high-quality development in the Yellow River Basin. In this study, the NDVI time series dataset of SPOT/VEGETATION (2000-2019) was used as the data source. The annual mean method, Theil-Sen Median trend analysis, and Mann-Kendall test were employed to study the spatiotemporal distribution and variation characteristics of grassland vegetation cover in Ningxia. Furthermore, the Hurst index method was used to analyze the sustainability characteristics and future development trends of grassland vegetation cover. Simultaneously, the influence of 13 factors, such as average precipitation, altitude, and gross domestic product, on the spatiotemporal distribution was quantified based on the geographical detectors approach. The results show that from 2000 to 2019, the average annual NDVI of vegetation in Ningxia grassland showed a fluctuating growth trend, with a growth rate of 0.005 per year. The regional fluctuation was quite different, with extremely high and high vegetation cover areas concentrated in the Liupan Mountains and the irrigation area along the Yellow River. Overall, the NDVI change showed a low to medium fluctuation trend, and the regional fluctuation was quite different. The vegetation cover condition improved significantly over the 20-year period, with a small degradation area and a favorable overall change trend. However, 59.341% of the grasslands are projected to face potential risks of continuous degradation or transformation from improvement to degradation in the future. The most sensitive environmental factor influencing grassland vegetation distribution response was precipitation, and climate and soil had the strongest interaction explanatory power overall. The relationship between the factors affecting the distribution and variation characteristics of grassland vegetation primarily manifested as mutual reinforcement or nonlinear enhancement, with no independent relationship between the factors. This study provides a scientific reference and decision-making basis for the sustainable management of the grassland ecosystem in Ningxia.

Key words: NDVI, trend analysis, spatiotemporal variation, driving factor, grassland, Ningxia