Spatio-temporal distribution and response relationship of NDVI based on GeoDetector in the arid regions in Northwest China

Abstract

Vegetation is an essential component of the earth's ecosystem. Exploring the dynamic changes of vegetation and its influencing factors in the arid regions in Northwest China (NWAC) is of great significance to the restoration and management of the regional ecological environment. In this paper, based on the long time series Normalized Difference Vegetation Index (NDVI) data (2000–2020), we analyzed the ecological changes in the NWAC at different spatial and temporal scales by using Theil-Sen Median and Mann-Kendall (Sen-MK), hurst index and others, and discussed the driving factors affecting NDVI changes using GeoDetector. The results indicate that the NDVI in the NWAC shows a significant upward trend (growth rate of 1.5×103 per year). Approximately 10% of the NWAC was ecologically improved, while 3% was degraded. In addition, the future changes of NDVI in the NWAC are characterized by anti-persistence. Precipitation (q = 0.502) is the main factor affecting NDVI in the NWAC, and the interaction with other factors has the strongest effect on the spatial differentiation of NDVI in the whole region. The results of this study can help to better understand the intricate mechanism of vegetation change, and provide a scientific foundation for future vegetation restoration and rational implementation of ecological projects in the NWAC.