Typical island landscape ecological network establishmenta case study of Chongming Island

Island ecosystem has the characteristics of vulnerability due to its limited area and isolated space, and biodiversity plays an important role in the maintenance of island ecosystem stability. However, island biodiversity conservation is under more and more pressure as the influence of human activities increases. The establishment of landscape ecological network has become an important approach to reduce the pressure of biodiversity conservation. Landscape ecological network was established in Chongming Island based on landscape classification, using minimum impedance distance method and gravity model. The results revealed that: the total area of Chongming Island reached 1416.2 km2, and areas of different landscape types showed the following descending order: farmland, construction land, tidal wetland, woodland, cultured pond and water area. The ecological network was composed of important ecological patches and ecological corridors; there were 17 important ecological patches which had a total area of 170.6 km2 accounting for 11.9% of the area of Chongming Island, of which Dongtan Wetland was the core ecological source and the region around Dongping National Forest Park was the core ecological node; there were 25 ecological corridors which contained 17 core ecological corridors, and the total length of ecological corridors and core ecological corridors relatively reached 164.2 km and 74.1 km, of which the corridor between Dongtan Wetland and Beihu Wetland, along with corridors around Dongfengxi Sandbar were the key of ecological connectivity in Chongming Island. In the components of landscape ecological network, the proportion of most suitable landscape were decreasing with the increase of ecological corridor width, while the proportion of moderately suitable landscape and non-suitable landscape showed the different trend, which made the difficulty of landscape ecological network construction increase. The establishment of landscape ecological network can make practical suggestions to optimize the landscape pattern of Chongming Island, and provide a new idea for biodiversity conservation in similar islands.