Establishing archipelagic landscape ecological network with full connectivity at dual spatial scales

An archipelagic landscape ecological network (ALEN) is important for optimizing the bird migration route and providing reference for island biodiversity maintenance. The ALEN with full connectivity at dual spatial scales was established in this study. Ecological nodes and routes at archipelago scale, as well as ecological sources and corridors at island scale, were identified to constitute the ALEN based on the habitat suitability and integrating the approaches of Euclidean distance and Least cost distance. Then, the landscape structures of the ALEN were analyzed and the optimization measures were proposed to improve the habitat quality and network connectivity. Miaodao Archipelago, an important and typical archipelago in North China, was selected as the study area. Results indicated that the ALEN was composed of 32 nodes and 81 routes at archipelago scale, and 42 sources and 76 corridors at island scale. At archipelago scale, the ecological efficiency of the ALEN was determined by the landscape resistance and position of different islands, and the landscape structure optimization should focus on the islands that involved the indispensable routes. At island scale, the number and spatial distribution of the sources, as well as the landscape structure of the corridors, contributed the most to the ecological efficiency. More ecological sources with uniform distribution should be added, and the corridor width of 50 m was practical to implement the ALEN. The ALEN realized the full connectivity, that is, the bird species could flow (flight or walk) all over the nodes and sources along the routes and corridors across the dual spatial scales, and the balance of efficiency and cost was achieved. The ALEN could be widely applied in different archipelagos with distinct ecological functions and external disturbances.