关键词: 昆仑山北坡, 绿洲荒漠关键带, 生境质量, 荒漠化遥感生态指数, 于田绿洲

Abstract:

Habitat is a comprehensive index to evaluate the quality of ecology, reflecting the coupling state of water, soil, air, biology, and other factors. The desertification remote sensing ecological index (DRSEI) can be used as a multi-index evaluation model to quantify the impact of human activities (such as resources and protection) on habitats in arid areas. Specifically, Xinjiang is located in inland northwest China, where the arid ecosystem is fragile. As the oasis-desert critical zone is extremely sensitive to environmental (climatic) changes, there is an urgent need to perform ecological environmental quality assessment. In this research, we explored the spatial and temporal characteristics of the quality of the ecological surroundings quality of the oasis-desert critical zone on the northern slope of the Kunlun Mountains from 2004 to 2021, using the DRSEI model. Then, considering the Yutian Oasis as the study area, analysis was performed using remote sensing, GIS, and mathematical analysis. The Yutian Oasis is located on the northern slope of the Kunlun Mountains and in the southern margin of the Tarim Basin, in Hotan Prefecture, Xinjiang Uygur Autonomous Region. The Yutian Oasis serves as an important economic and transportation hub on the southern route of the Silk Road. Simultaneously, this study introduces a remote sensing ecological index for desertification, which couples surface vegetation, soil moisture, land surface temperature, surface dryness, and desertification degree. Specifically, they respectively represent land surface greenness, moisture, thermal condition, dryness, and desertification status. The results show that fluctuations in Yutian Oasis habitats increased over time: The value of DRSEI increased from 0.3545 in 2004 to 0.3953 in 2021, a change of 0.0408 (+11.5%); the proportion of excellent DRSEI ∈ (0.6-1.0) increased from 22.45% to 27.27%; and the proportion of poor DRSEI ∈ (0.0-0.2) and moderately poor DRSEI ∈ (0.2-0.4) decreased from 63.31% to 52.82%. Essentially, the soil-regulated vegetation index and humidity index in DRSEI are positive effects, increasing from 2004 to 2021, whereas the degree of soil drying, surface heat, and desertification are negative effects, and decreased over time. The analysis of mathematical statistics (such as Sen, variation coefficient) revealed that the habitat of the Yutian Oasis is generally improving; the proportion of rising areas increases, the center of the oasis is stable, and the local edge areas are fluctuating. A time series prediction was developed and verified in the final step; approximately 62.18% of the Yutian Oasis may decrease in the future, specifically in 24.21% of the area located on the north, northeast, and south edges. In future research, we are planning to focus on the effects of a wide range of soil salinization, in addition to other environmental factors, on ecological surroundings quality in this region. The research findings provide a theoretical basis for protecting the ecological quality of oases in arid regions and offer theoretical support for safeguarding ecological security, border security, and national defense security on the northern slope of the Kunlun Mountains.

Key words: the northern slope of Kunlun Mountains, oasis-desert critical zone, ecological habitat environment quality, desertification remote sensing ecological index, Yutian Oasis