How does ecological water conveyance promote the improvement of habitat quality in the lower reaches of inland rivers in arid regions? A ′past-future' perspective

Amidst the growing impact of increasing human activities and climate change, the downstream sections of inland river basins in arid regions have often encountered flow disruptions and substantial habitat deterioration. Ecological water conveyance (EWC) has become a pivotal approach to addressing these challenges. This research aims to unveil the key mechanisms influencing Habitat Quality (HQ) in these areas and seeks to refine EWC strategies to improve HQ. To achieve this, we present a comprehensive framework that integrates the SD-PLUSInVEST-OPGD models to assess both the historical and future HQ of the Tarim River (TR) and its lower reaches. The findings indicate that between 1990 and 2020, the HQ along the TR experienced a gradual decline, while the lower reaches saw an initial decrease, followed by a period of fluctuating recovery. Throughout the EWC period (2000-2020), the downward trend in the lower reaches was significantly mitigated. However, under three projected climate change scenarios (2020-2050), if EWC is not sustained, the HQ of the TR is expected to deteriorate. In the lower reaches, a slight improvement in HQ is observed only during the 2020-2030 timeframe under the SSP245 and SSP126 scenarios, with a declining trend occurring in all other periods. The HQ in the lower reaches is crucial in determining the overall trends in HQ. Groundwater depth emerges as the dominant factor influencing HQ in the lower reaches. Although the current EWC model suffices to maintain HQ under current climatic conditions and human activities, it will fall short under future scenarios of high carbon emissions. Therefore, it is imperative to optimize water conveyance strategies and enhance water resource utilization efficiency.