Analysis of vegetation coverage changes and driving forces in the source region of the yellow river.

As a significant ecological barrier, the source region of the Yellow River serves as a crucial water source in China, and its vegetation dynamics play a pivotal role in water conservation. Monitoring vegetation dynamics is essential for ecological protection and the achievement of sustainable development goals, as it facilitates systematic assessment of vegetation restoration, supports the advancement of ecological civilization, and promotes coordinated economic and environmental development. Based on the newly released AVHRR GIMMS NDVI3g data from 1982 to 2020 provided by the NASA Goddard Space Flight Center, this study aims to identify the driving mechanisms influencing vegetation dynamics in the source region of the Yellow River over the past 40 years (1982-2020) by utilizing ordered cluster analysis, Pearson correlation analysis, and the Geodetector method. The influence of each driving factor on NDVI was systematically examined, and the spatial and temporal characteristics of vegetation as well as the effects of key drivers were clarified to inform ecological protection and sustainable development strategies. The results indicate that: (1) the overall NDVI in the source region of the Yellow River exhibited a significant upward trend from 1982 to 2020, with a noticeable shift occurring in 2009. Prior to 2009, NDVI demonstrated a slight declining trend, whereas a significant increase was observed afterward; (2) NDVI distribution displayed a spatial gradient, increasing from northwest to southeast, with higher values in the southeast and lower values in the northwest; (3) the interaction between any two driving factors had a more substantial influence on NDVI than individual factors, demonstrating a two-factor enhancement effect. Notably, the interaction between precipitation and temperature with other variables exhibited the strongest explanatory power, with q-values exceeding 0.5. Overall, natural factors such as temperature and precipitation played a crucial role in NDVI variation, and the abrupt change in 2009 may be attributed to regional warming and the implementation of ecological protection measures.