Ecological risk assessment of landscape in arid area watersheds under ecological water conveyance: A case study of Taitema Lake

The Taitema Lake Basin serves as an ecological barrier in the south of the Tarim Basin, connecting with the Qiemo, Ruoqiang, and Milan oases, collectively preventing the expansion and merging of the desert, specifically inhibiting the convergence of the Taklamakan Desert and Lop Nur. In recent years, with changes in the natural environment and an increase in water usage, the downstream flow of the Tarim River has decreased, leading to the gradual drying up of Taitema Lake and exacerbating desertification, resulting in frequent sandstorms. Subsequently, under the influence of ecological water transfer projects, Taitema Lake has gradually recovered, and the ecological environment has improved. This study focuses on Taitema Lake and its nearby regions, constructing the Regional Landscape Ecological Risk Index (ERI) to assess landscape ecological risks before and after ecological engineering and determine ecological benefits. The results indicate that the EWC (Ecological Water Conveyance) project effectively supplements water in the intermediate and lower courses of the Tarim River and the terminal lakes, significantly bolstering ecological conditions in the lake basin and reducing risks. However, the current EWC project is relatively extensive, and the water reaching the Tarim River and Taitema Lake depends entirely on the surplus water from upstream production and daily life. Additionally, the distribution of downstream water depends entirely on natural topography, leading to uneven spatiotemporal distribution of water resources and significant evaporation losses. Rational hydraulic engineering measures should be taken to re-plan the distribution of rivers and lakes, achieving the maximum ecological benefits of the EWC project.