基于边介数的省域生态廊道构建方法优化

我国城市建设和生态保护工作均对土地资源有大量需求，二者之间的矛盾在经济优先发展区表现尤为明显.为了有效地改善生态环境，管控土地利用并引导其变化发展，需要建设具备不可替代特征的省域生态廊道.最小累积阻力模型（minimum cumulative resistance，MCR）是识别生态廊道最常用、有效的模型，但在应用于省域尺度时，MCR模型识别的潜在廊道路由存在冗余的问题.因此，通过引入网络科学中的边介数指数（edge-betweenness）对MCR模型进行优化，计算潜在廊道路由的边介数指数值，选取出其中最为重要和简明的结构来连通生态源地，即提取潜在路由中的骨干路由（backbone route）和关键战略点（key strategic point）作为不可替代的结构来指导省域生态廊道建设.将优化后的MCR模型应用于广东省，构建了全长5 493 km的省域生态廊道，其中包含生态源地20处，关键战略点11个，骨干生态廊道29条.骨干路由与关键战略点构成的不可替代省域生态廊道（irreplaceable provincial corridor）能够实现"廊道数量和占地面积最少、连通性基本不变"的目标.研究显示，边介数能够对潜在路由进行优化筛选，识别出维护省域生态安全的关键结构；不可替代生态廊道能够指导省域生态规划和土地空间的发展利用，并为更高水平的生态安全环境提供了演进的基础；同时也为土地资源紧张的地区提供了建设生态廊道的参考与依据. 

Optimization of Construction Method of Provincial Ecological Corridor Based on Edge-Betweenness

Whatever urban construction or ecological protection both need land resources, and their contradiction is more apparent in economic priority areas. In order to improve the ecological environment effectively, it is necessary to build a provincial ecological corridor with irreplaceable characteristics to control land use and guide land change and development. An optimized model improved by edge-betweenness is proposed based on an index of network science, which indicates the use frequency and importance. It screens that the potential ecological corridors by its value of edge-betweenness and the use of the most important and concise structure could connect the ecological source areas. In other words, the backbone route and key strategic point are used as the irreplaceable structure to guide the construction of the provincial ecological corridor. Domestic urban construction and environmental protection have a significant demand for land resources. The contradiction between the two is especially evident in the economic priority zone. The recognition of the potential route by the model of minimum cumulative resistance (MCR) will be redundant when applied to a macro area such as a province. The optimized model is applied to Guangdong Province to construct a provincial ecological corridor with 5493 km length. This system includes 20 ecological sources, 11 key strategic points, and 29 backbone corridors. The results show that irreplaceable provincial ecological corridor composed of backbone route and key strategic points can realize the goal of maintaining the unchangeable connectivity by the least corridor''s number and land area. The edge-betweenness can optimize and screen the potential routes, and identify the key structure to maintain the ecological security of the province. The irreplaceable ecological corridor can guide provincial ecological planning and the development and utilization of land space, provide an evolutionary basis for a higher level of ecological security environment. The research results can also be used as a reference and basis for the construction of ecological corridors in areas with limited land resources.