关键词: 荒漠-绿洲过渡带, NDVI, SPEI, 土地利用变化, 塔里木盆地

Abstract: The desert-oasis ecotone is the connection zone between desert and oasis ecosystems. It is mainly composed of natural vegetation and is a natural barrier to maintain ecological security of the oasis in the arid area. With Landsat remote sensing images, land use and meteorological data, we analyzed the spatiotemporal characteristics of the interdecadal dynamic change of desert-oasis ecotone in the Tarim River Basin from 1990 to 2015. Over the 25 years, the area of the desertoasis ecotone continuously decreased, with an annual change rate of 1.24%. The Normalized Difference Vegetation Index (NDVI) values decreased over time, from 0.142 in 1990 to 0.127 in 2015. The area corresponding to arable land in the Tarim Basin increased from 2.45×10⁴ km² to 4.01×10⁴ km² in 2015. The continuously expanding area of arable land strongly occupied the ecological space in the desertoasis ecotone. With continuous expansion of arable land area, groundwater levels had fallen sharply due to over exploitation. With the increasing drought stress, some species with shallow root died, resulting in reduced vegetation coverage and reduced ecological barrier functions. The desert-oasis ecotone has a natural barrier function to maintain the stability of oasis-based agricultural production and protect ecological security of the oasis. In depth study of the spatiotemporal changes and related driving forces in this special zone would help propose ecological protection solutions and measures, provide scientific and technological support for the implementation of major strategies and the construction of ecological civilization in the Western China.

Key words: desert-oasis ecotone, NDVI, SPEI, land use change, Tarim Basin.