Abstract:

Based on MODIS NDVI data from 2000 to 2020, along with key climatic variables, including annual mean temperature, precipitation, drought index and soil moisture, obtained from the National Tibetan Plateau Data Center and the UK National Centre for Atmospheric Science, this study integrated trend analysis and First−difference multiple regression analysis to systematically examine the spatiotemporal variation in NDVI across major vegetation types (grassland, forest and cropland) in Inner Mongolia. The research further elucidated their differential responses to climate change. The results indicated that: (1) from 2000 to 2020, the  NDVI in Inner Mongolia showed a significant increasing trend across more than 90% of the region. (2) All major vegetation types exhibited significant NDVI increases, with cropland having the highest growth rate (5.7×10⁻³·y⁻¹) and the Gobi desert the lowest (8.2×10⁻⁴·y⁻¹). (3) The sensitivity of NDVI to climatic factors differed considerably among vegetation types. Increased precipitation and soil moisture promoted coverage in most vegetation types, whereas a rise in mean annual temperature exerted a suppressive effect. Notably, grassland NDVI was the most sensitive to changes in both soil moisture and drought. Integrated analysis confirmed that water availability was the key limiting factor controlling vegetation cover dynamics in Inner Mongolia. Despite the overall regional greening trend, the high sensitivity of grassland ecosystems to warming and drought underscores their underlying vulnerability. Hence, future efforts should prioritize adaptive management and conservation strategies for grasslands to enhance regional climate resilience and support the sustainable development of Inner Mongolia's ecological environment.

Key words: Vegetation sensitivity, Climate change, First?difference multiple regression method, Inner Mongolia