Development and application of an ecological network model for a coastal megalopolis based on land-sea integration

Coastal areas,in land-sea interaction zones,are experiencing rapid urbanization,resulting in fragmentation of coastal ecosystems.Using the megalopolis of Xiamen-Zhangzhou-Quanzhou,known as Minsanjiao region,as an example,we established an ecological land-sea network using the least-cost path(LCP) algorithm based on the geospatial data(land use and land cover,marine functional zones,sensitive habitats,and protected areas).We evaluated the integrity of the ecological network using three indicators:network circuitry(α),line to node ratio(β),and network connectivity(γ).Our results show that(1) key corridors and nodes that connected the important ecological patches in the integrated land-sea network were mainly distributed in forests,grasslands(inland),and marine protected areas,while built-up areas with intensive human activities had strong barrier effects on ecological corridors;(2) coastal ecological corridors endured great pressures from rapid urbanization due to their key roles as the ecological patches connecting the land and sea and centers for urban development;(3) the high ecological network integrity scores(α = 0.86,β = 2.56,γ = 0.91) indicated a normal ecological network status in our study area.However,the rapid coastal urban development and other intensive humanactivities show early warning signals of potential ecological degradation.This research provides a new method for the landsea integration and ecological management of coastal cities though configuring the land-sea ecological network and modeling the overall land-sea ecological security of the Minsanjiao megalopolis.