Trade-Offs and Optimization of Ecosystem Services in the Plain Terminal Lake Basin: A Case Study of Xinjiang

Influenced by climate change and human activities, plain terminal lake basins (PTLB) in arid regions experience significant shrinkage, resulting in a decline in ecosystem services (ESs) such as windbreak and sand fixation (SF) and habitat quality (HQ). However, systematic assessments of these services in such basins are limited. A key research challenge is to define and enhance the contribution of plain terminal lakes within the ESs framework of their respective basins. Therefore, this study focused on the Ebinur Lake Basin (ELB), Manas River Basin (MRB), and Tarim River Basin (TRB) in Xinjiang. We adopted both the InVEST and RWEQ models to assess ESs in these regions, by employing the production possibility frontier (PPF) to optimize various ESs, including carbon storage (CS), water yield (WY), HQ, and SF. The results indicated a general upward trend in ESs across these key basins, with a particularly significant increase in the CS. Spatial analysis revealed that regions with improved ESs were mainly concentrated in the mountainous and oasis areas of the basins, with the most pronounced improvement observed in the TRB. Within these basins, the interactions between the different ESs mainly exhibited synergistic relationships. However, notable concave trade-off relationships existed between WY and CS, WY and HQ, and HQ and SF, particularly in the TRB. This was largely attributed to increased trade-offs between WY and other ESs, resulting from the widespread agricultural expansion in the TRB. We plotted the optimal Pareto efficiency curves for ESs across the three basins to obtain the corresponding optimization results, and made recommendations for the enhancement of ESs. In summary, this study lays a solid scientific foundation for establishing ecological protection boundaries and promoting high-quality sustainable development in the PTLB of arid areas.