Spatiotemporal Evolution Trends and Driving Force Analysis of Vegetation Greenness in Yunnan Province

Abstract

Vegetation greenness is a key indicator for evaluating vegetation growth status and ecosystem health, playing an important role in ecological protection and management. Given the unique geographical location of Yunnan Province, studying the spatiotemporal variation in vegetation greenness and its driving factors provides a theoretical basis for environmental protection and ecological construction in the region. This study is based on MOD13A3 NDVI data, this study combined climate, socioeconomic, and air quality data, and applied Theil–Sen Median analysis, Mann–Kendall test, Hurst index trend analysis, coefficient of variation (CV), pixel-wise partial correlation analysis, and multivariate residual regression analysis to investigate the spatiotemporal variation trends and driving factors of the NDVI in Yunnan Province. The results showed the following: (1) From 2001 to 2020, the NDVI in Yunnan Province exhibited a fluctuating upward trend, with a multi-year average of 0.6342. Spatially, the NDVI showed a pattern of higher values in the south and west, and lower values in the north and east. In 40.11% of the study area, the NDVI is expected to continue increasing in the future. (2) Among the driving factors, temperature and precipitation (climate factors), GDP (socioeconomic factor), and O3 and PM2.5 (air quality factors) had the strongest positive correlations with the NDVI. The average contributions of climate, socioeconomic, and air quality factors to NDVI changes during the study period were 0.3436, 0.1153, and 0.2186, respectively. (3) Over the past two decades, the combined influence of climate, socioeconomic, and air quality factors has significantly driven NDVI increases in Yunnan Province, jointly contributing to NDVI growth in 61% of the area. Therefore, it is recommended that Yunnan Province optimizes governance strategies based on dominant driving factors through zonal management, strengthens pollution source control in key areas, promotes the adoption of clean energy alternatives, and establishes an integrated monitoring system for vegetation and air quality to precisely identify the lag effects of air pollution on vegetation.