Abstract: The Threeriversource National Park is of great significance for the protection of regional ecological environment and habitats for many species. Based on the GLASS vegetation coverage products from 2000 to 2018, we used linear regression and Hurst index to analyze the spatiotemporal changes of vegetation coverage, and used Pearson coefficient and residual trend analysis to explore the impacts of climate changes and human activities on vegetation dynamics. The vegetation coverage of the Threeriversource National Park was low, with a mean value of 0.24, which slightly increased during the period 2000-2018. The vegetation coverage in mostareas of the park was increasing, and most of which showed positive sustainable trends. Based on the overlay analysis of trend change and Hurst index, the sustainable growth of vegetation was predominant (61.34%), followed by continuous degradation and uncertain types in future change. Precipitation was the primary factor driving the changes of vegetation coverage, followed by temperature. Human activities had the least impact on the changes of vegetation coverage. The increases of temperature and precipitation in recent years improved water and heat conditions, and consequently promoted vegetation growth.

Key words: linear regression, Hurst index, Pearson coefficient, residual trend analysis, vegetation coverage.