A health-service-risk framework for evaluating ecological carrying capacity in arid inland river basins: A case study of the Tarim River Basin

Ecological carrying capacity (ECC) serves as a crucial indicator for evaluating the potential of regional ecosystems and informing sustainable development strategies. However, existing research on arid inland river basins often lacks a comprehensive and integrated assessment framework. Therefore, this study proposes a novel ECC evaluation framework based on ecosystem sustainability, incorporating ecosystem health (EH), ecosystem service (ES), and ecological risk (ER). Using the Tarim River Basin (TRB) as a case study, the ecological environmental quality index (EEQI) was introduced to validate the reliability of the assessment results, while spatial correlation analysis was employed to confirm the necessity of the framework. The independent and joint effects of the drivers on ECC were analyzed using the optimal-parameter Geodetector model. The results showed that spatial clustering characteristics such as “low carrying-high health” and “low carrying-high service” exist in the TRB. Healthy ecosystems and those providing multiple services are not necessarily capable of carrying, highlighting the need for a comprehensive evaluation of ECC that combines EH, ES, and ER. The ECC evaluation, based on the “health-service-risk” framework, was significantly correlated with the EEQI (correlation coefficient = 0.694–0.770, p < 0.05), indicating that the evaluation results were reliable and accurately reflected the actual status of ECC in the TRB. The overall ECC of the TRB is minimal, with regions of low and medium carrying capacity constituting over 76.83 % of the total area. The ECC condition of the TRB gradually improved from 2000 to 2020, with areas of increased carrying capacity averaging about 16.79 % of the total area in each period. The improvements were most evident in mountainous regions. The joint effects of several factors significantly affect ECC more than the independent effects of individual components. Notably, land use intensity and landscape factors increasingly influence ECC status. This study not only provides a valuable reference for the ecological conservation, restoration, and sustainable regional development of the TRB, but also offers a robust framework for ECC assessment in other arid inland river basins.