Hydrological connectivity dynamics and conservation priorities for surface-water patches in the Yellow River Delta National Nature Reserve, China

Abstract

Hydrological connectivity is important for the long-term persistence of water-dependent organism inhabiting floodplain and coastal wetlands, as surface-water patches not only create temporary habitats for them, but also provide dispersal opportunities. Improving understanding of how hydrological connectivity varies with respect to surface-water dynamics is an important step to maintain biodiversity in dynamic coastal environments. Using a series of available remote sensing images, we extracted surface-water patches across a 12-year (2006–2017) and assessed the corresponding hydrological connectivity using the landscape connectivity metrics. Furthermore, we identified important surface-water patches serve as connectivity providers in surface-water networks. Particularly, the threshold distance, needed for analysis of hydrological connectivity, was determined by “Distance- Landscape Connectivity Metrics” curves. We focused on China's Yellow River Delta (YRD), a globally significant floodplain and coastal wetland. Results showed that hydrological connectivity, fluctuating in a range of 0.0726 to 0.0908 during 2006-2017, varied with the number and spatial distribution of water patches. Our study highlight that water patches in Dawenliu Restoration (DR) could serve as ideal high-priority targets for specific management aimed at maintaining or improving hydrological connectivity. We also found that the suitable threshold distance for analyzing hydrological connectivity of the Yellow River Delta National Natural Reserve (YRDNR) is 500 m.