Using SPOT VEGETATION for analyzing dynamic changes and influencing factors on vegetation restoration in the Three-River Headwaters Region in the last 20 years (2000–2019), China

Abstract

Knowledge of the relationship between the dynamic changes of vegetation with the natural environment and anthropogenic activities will be critical for developing ecosystem adaptation strategies. This study is focused on using SPOT VEGETATION to reveal the spatial heterogeneity and driving forces on vegetation NDVI dynamics in the Three-River Headwaters Region (TRHR) of China from 2000 to 2019, through a combination of factors regression and geo-detector methods to analyze vegetation NDVI dynamics at multiple time scales and explore the relationship between natural and anthropogenic factors with vegetation NDVI. The results of this study show that:(1)The vegetation NDVI of the TRHR from 2000 to 2019 showed a fluctuating upward trend with a linear tendency being 0.00326·yr−1, which was mainly due to the increase of the land with high vegetation cover (mainly mountain forest and alpine scrub meadow);(2)Precipitation was not only the dominant influencing factor of the spatial distribution of NDVI in the TRHR from 2000 to 2019, whose average contribution of the precipitation to NDVI was 0.5573, but also determined the fitting accuracy of the regression function. The higher the precipitation coefficient value in the regression function, the better the fitting accuracy of the regression function. The annual precipitation and other factors when taken together strong enhanced one another;(3)In the last 20 years, the q values of most driving factors were relatively stable, and the q value distribution showed obvious stratification characteristics;(4)The precipitation gradient affected the interpretation degree of NDVI spatial heterogeneity in the TRHR. With precipitation increasing the explanatory power of the factors stabilizes, and the NDVI tended to be more influenced by elevation and temperature in the eastern part of the TRHR where precipitation was higher. As the climate has transitioned from warm and dry to warm and humid, and the implementation of ecological projects such as ecological restoration and protection, it is reasonable assurance that sustainable vegetation restoration in the TRHR will continue in the future.