Evaluating the impact of drought-vegetation loss coupling on eco-hydrological stability in the Yellow River Basin, China

Under the dual pressures of increasing extreme climate events and escalating environmental vulnerability, the degradation of hydrological systems and vegetation loss may create a positive feedback loop within the eco-hydrological system (EHS), assessing the eco-hydrological stability has become an urgent priority. However, most previous studies have focused on assessing risks from the perspective of drought alone, often overlooking the temporal effects of vegetation responses to drought when linking drought with vegetation loss. The potential of evaluating risks through eco-hydrological stability remains largely unknown. Therefore, this study constructed the Standardized Compound Drought-Vegetation Loss Index (SCDVI) using a Copula model based on vegetation response patterns to drought, and quantified EHS risk based on stability (i.e., resistance and resilience) in the Yellow River Basin (YRB), China. Results indicated that the response pattern in the YRB exhibited substantial spatial heterogeneity and seasonal variations, with productivity being more significantly and sensitively affected during the summer when short-term response patterns dominated (64.1 % of the area had a response time of less than three months). The southeastern YRB, primarily located in the warm temperate deciduous broadleaf forest region, exhibited the lowest eco-hydrological stability. The study also found that regions with high vegetation productivity were more prone to a high resistance–low resilience trade-off, while areas with low vegetation productivity exhibited the opposite trade-off. These findings provide scientific insights for implementing targeted eco-hydrological restoration strategies to facilitate a balance between water resource sustainability and vegetation stability.