Study on habitat suitability change and habitat network of rare wintering cranes in important international wetlands

Abstract

Chongming Dongtan wetland is a typical estuarine wetland, located in Chongming District, Shanghai, China, with high ecological significance. The protection of wintering crane's habitat has attracted the wide attention of the international community. Because of the importance of the region in the protection of international biodiversity and the protection of crane habitats, it is of great reference value to study the habitat suitability changes of rare wintering cranes with spatial and temporal distribution characteristics and the distribution of habitat corridors with spatial characteristics, to improve the habitat quality of crane habitats in globally important wetlands. Based on the remote sensing image data of Chongming Dongtan and the field survey data of rare wintering cranes, this study obtained the land use change of Chongming Dongtan from 1986 to 2021 by ENVI and ArcGIS10.8 software, evaluated the habitat suitability of wintering cranes in 36 years by GIS technology, and constructed the habitat corridor of wintering cranes by using the minimum cumulative resistance model(MCR). The results showed that from 1986 to 2021, the number of four typical wintering cranes in Chongming Dongtan showed a general downward trend. In the past 36 years, the habitat suitability of wintering cranes in the internationally important wetland of Chongming Dongtan has gradually changed from a suitable area to an unsuitable area. The suitable areas are mainly distributed in the eastern and northern parts of the study area, and the unsuitable areas are mainly distributed in the western construction land area. The habitat quality of cranes is deteriorating. The overall resistance distribution of Chongming Dongtan in 2021 shows a trend of low resistance value in the east and high resistance value in the west, and the degree of obstruction is strong in the south and weak in the north. There are 208 potential habitat corridors for wintering cranes in Chongming Dongtan, with a total length of 377.12 km. Get 127 Habitat nodes. The density of habitat corridors in the eastern part of the study area is significantly higher than that in the western region, and the ecological space in the eastern region is well connected. Finally, this study proposes the identification of important habitat corridors based on gravity model and the analysis of habitat network structure based on graph theory, which provides a reference for improving the stability of habitat network by means of habitat node optimization, stepping stone increase and ecological restoration. This study is different from previous studies on large-scale ecological conditions such as cities or urban coastal zones. From the perspective of the construction of regional wetland rare species habitat network and the protection of international important wetland biodiversity with important ecological value, it is helpful to optimize the suitable habitat pattern of rare overwintering cranes and provide a method basis for the protection of rare species habitat and the construction of habitat network in regional wetlands. At the same time, Chongming Dongtan is the only internationally important wetland in Shanghai. Wintering cranes are the most important biological resources of wetlands. The study of habitat suitability changes and habitat networks can effectively promote the development of internationally important wetland cities in Shanghai.