Emerging hot spot analysis and the spatial-temporal trends of NDVI in the Jing River Basin of China

As an important indicator of vegetation coverage, the normalized difference vegetation index (NDVI) reflects the changing pattern and evolving trend of the environment. In the Loess Plateau, vegetation plays a critical role in soil and water conservation, which strongly affects the achievement of sustainable development goals. The study of the spatial distribution and temporal trends of NDVI is of great practical importance for the planning of soil and water conservation measures and the evaluation of the environmental situation. In this study, the NDVI, precipitation, land use and land cover data of the Jing River Basin were collected, the emerging hot spot patterns of the NDVI analyzed, the characteristics of spatial distribution and temporal variation of the NDVI in the basin obtained, and the impacts on NDVI from the climate changes and the land cover changes discussed. The results show that the NDVI in Jing River Basin represents a spatial trend of decreasing from northwest to southeast. The emerging hot spot analysis results show that diminishing cold spot, oscillating hot spot and intensifying hot spot are predominant patterns in the basin. The whole basin shows a statistically significant upward trend of high value aggregation of NDVI. The temporal trend of NDVI in the basin varies from - 0.0171 to 0.0185 per year. The increasing trend of vegetation coverage in the basin is statistically significant. The positive correlation between the NDVI and the precipitation mainly observed upstream of the basin reveals that the growth of vegetation in the Loess Plateau is more dependent on the water supply from the precipitation. Land cover transition patterns and the land use patterns also impact the spatial-temporal trends of the vegetation coverage in the basin. The study results may be helpful for the vegetation restoration, soil and water conservation and sustainable development of the Jing River Basin.