Integrating two aspects analysis of hydrological connectivity based on structure and process to support muddy coastal restoration

With social and economic development and population growth, a series of human activities have intensified the destruction and degradation of muddy coastal wetlands, thus it is necessary to strengthen their protection and restoration. Hydrological connectivity is a basic condition for the existence and restoration of wetland ecosystems. This study selected the northern buffer zone of Yancheng National Nature Reserve (YNNR) as the research area. Combining field survey data with GF-2 remote sensing data, hydrological structure and process connectivity were integrated to evaluate the hydrological connectivity through internal and land-sea aspects. On this basis, the restoration priority area and the easy restoration area were determined by hot spot analysis and minimum unit of restoration. Our results showed that: 1) the hydrological connectivity within the region was great, with most of the total area. Land use types had a greater impact on the hydrological connectivity, and the hydrological connectivity of the farming pond area were generally higher than for farmland; 2) the sea-land hydrological connectivity decreased from the sea to the land, which was vertical with the coastal seawall, but the rate of change varied.; 3) the hydrological connectivity hotspot analysis showed that the site of the level 1 priority restoration was almost the same as the salt water dominant restoration area; the priority level 2 was in the freshwater dominant restoration area, accounting for 8.87% of the area; 4) the easy-to-restore areas were mainly distributed in the priority restoration areas of level 1–3, with an area of 11.7 km2, accounting for 6% of the study area. These research results can provide a better scientific basis for regional muddy wetland restoration planning activities.