典型海岛景观生态网络构建以崇明岛为例

人类活动的日益频繁使得海岛生物多样性保护压力不断增大,构建景观生态网络是缓解海岛生物多样性压力的重要途径。基于RS和GIS,运用最小阻力距离法和重力模型构建了崇明岛景观生态网络,结果显示:崇明岛景观生态网络由重要生态功能斑块和生态廊道构成;重要生态斑块共17个,面积170.6 km2,占崇明岛总面积的12%,其中东滩湿地为核心生态源地,东平国家森林公园附近区域为核心生态节点;生态廊道共25条,包括核心生态廊道17条,总长度分别为164.2 km和74.1 km,其中东滩湿地和北湖湿地之间廊道以及东风西沙周边廊道是崇明岛生态连接的关键;随着生态廊道宽度的增大,景观生态网络中最适宜景观比例相应减少,中等适宜景观和不适宜景观比例则有所增大,网络构建的难度也随之上升。

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.