How do ecosystem service flows mediate the impact of urban greenspace on elderly health? The case of Shanghai

• Ecosystem service flows mediate how urban greenspace affects elderly health. • Their mediating effect is significant and stronger than greenspace’s direct effect. • Healthier elderly benefit most from service flows; effects are minimal for the disabled. • Outdoor recreation flow correlates most strongly with elderly health. While extensive research has demonstrated the positive association between urban greenspace and elderly health, the mediating role of ecosystem service flows (i.e., the actual supply of ecosystem services accessible to residents) remains poorly understood. Drawing upon data from 215,199 elderly participants in Shanghai’s Seventh National Population Census, this study employed structural equation modeling and bivariate Moran’s I analysis to investigate how three critical ecosystem service flows—air purification, temperature regulation, and outdoor recreation—mediate the relationship between greenspace exposure and elderly health. Our findings indicated that: (1) ecosystem service flows exhibited a significant mediating effect ( β = 0.041, p < 0.05), surpassing the direct impact of greenspace alone ( β = 0.038, p < 0.05); (2) this mediation varies by baseline health status, with the strongest effect observed among healthier individuals and the weakest among those with severe disabilities; and (3) outdoor recreation exhibited the strongest spatial association with elderly health (Moran’s I = -0.04 to 0.17), outperforming temperature regulation (Moran’s I = -0.05 to 0.14) and air purification (Moran’s I = -0.03 to 0.11). These results highlight that enhancing elderly health through urban greening requires not only expanding green infrastructure but also strategically strengthening the delivery of ecosystem service flows most critical to health outcomes.