The characterization and prediction of the indirect cumulative effects on ecological indicators in arid watersheds

The stability of ecosystems fundamentally depends on dynamic and mutualistic relationships among various ecological processes. However, comprehensive insights into the spatiotemporal dynamics of these processes, particularly their cumulative effects in space, remain insufficiently developed. This study systematically analyzed key ecological indicators in the arid Tarim River Basin (TRB) of northwestern China from 2000 to 2020. Key ecological indicators analyzed included Leaf Area Index (LAI), Gross Primary Productivity (GPP), Evapotranspiration (ET), and Water Use Efficiency (WUE), collected through remote sensing, field observations, and model prediction. The results revealed the dynamic interactions between surface ecological factors and soil indicators, emphasizing the influence of ecological-hydrological relationships on water resource management and overall ecosystem health. The influences of tributaries on the mainstream occurred within a 20 to 150-day time lag, presenting both positive and negative feedback effects. Furthermore, when the average tributary WUE surpassed 1.06, it was sustained for 1 to 2 months, accompanied by a marked increase in the mainstream’s WUE. Significant positive indirect cumulative effects were observed for LAI (0.27), total vegetation GPP (0.1875), ET (0.345), and soil moisture content (0.419). The results emphasize the effectiveness of multiple linear regression models in simulating ecological parameters within the mainstream of the TRB. This study advances the knowledge of ecosystem dynamics in arid environments and offers critical guidance for sustainable water resource management in the TRB and similar regions globally.