Research on Grus japonensis habitat requirements for developing restoration plans

As an endemic species in Asia, Grus japonensis reproduction and survival rely on natural wetland resources. In the Yancheng coastal wetlands, the wintering habitat of Grus japonensis had been destroyed due to rapid social and economic development. At the same time, its population also declined leading to land use changes. Therefore, it was urgent to conduct scientific restoration and management of the winter habitat. Based on the structural habitat demand for Grus japonensis, traffic light warning analysis and landscape structure index system were used to guide habitat restoration. The main conclusions were as follows: the population of Grus japonensis in Yancheng coastal wetlands reached its highest recorded number of 952 in 2000. The population showed a tendency to concentrate in the core area (CA) of the Yancheng National Nature Reserve (YNNR). The locations of restoration areas under yellow, green and peak historical state were determined by the traffic light warning analysis. Landscape indicator thresholds were set based on the landscape conditions of the habitat in 2000. After restoration, the habitat should contain at least two landscape types: Phragmites australis (P. australis), Suaeda salsa (S. salsa) and ponds, with a minimum patch area of 5.22–19.11 km2 and 5–17 patches. Habitat should be located at least 500 m from roads and farmland and 1000 m from residential areas. From the perspective of improving landscape diversity, "P. australis-pond habitat", "P. australis-S. salsa habitat", "Continuous P. australis habitat" and "Continuous S. salsa habitat" were constructed by landscape patterns. Finally, according to the land use situation around the habitat, the "Friendly" land use layout of "Salt marsh wetland--Low intensity ecological aquaculture pond--Farmland--Construction land" from sea to land was developed. This mode provides a reference for the habitat restoration of coastal wetlands.