Managed hydrological connectivity as an ecological attribute in the Yellow River Delta in China

Hydrological connectivity plays a critical role in ecosystem functioning, yet it is rarely treated as an explicit ecological variable in management. Here, we combine satellite-derived connectivity estimates with multi-season environmental DNA metabarcoding to develop an ecohydrological framework that reveals how connectivity, filtered through water quality conditions, shapes invertebrate diversity and stability. In the Yellow River Delta, connectivity can either enhance or weaken biodiversity and network stability, depending on the water-quality context. Areas with favourable water quality and smaller seasonal variation in connectivity support higher local diversity and more stable co-occurrence networks, whereas areas with larger seasonal variation show weaker or inconsistent stability gains. These patterns are jointly shaped by tidal-channel structure, habitat fragmentation, monsoon forcing, and managed high-discharge events. Our framework identifies spatially and seasonally differentiated connectivity targets linked to water-quality conditions, providing operational indicators for connectivity-informed flow management in engineered deltas. Hydrological connectivity drives gains or losses in biodiversity and network stability depending on water quality windows, which could guide connectivity informed flow management in engineered deltas, according to a study using satellite data and eDNA in the Yellow River Delta.