基于生态安全格局的南京都市区生态控制边界划定

以南京都市区为例,通过生态敏感性分析获取了研究区既有的高生态敏感空间,采用最小费用路径方法辨识了对研究区具有重要生态意义的潜在生态廊道和生态关键区,采用图谱理论中的景观连接度指数辅助确定生态廊道宽度,构建了研究区潜在的生态网络。在此基础上,整合既有和潜在生态空间,科学划定生态控制边界,实现了研究区现存和潜在的重要自然生态空间保护。研究结果表明:1)生态敏感性分析能够识别出研究区既有的高生态敏感性区域,并指出其呈现出"大而孤立,小且分散,连接性不佳"的空间特征。2)遴选出的71处生态源地、119条重要廊道和61个关键生态斑块共同组成了研究区的生态网络,显著提升了原有生态空间的景观连接性和研究区域的总体生态安全水平。3)生态网络分析可以弥补敏感性分析只考虑既有自然生态空间的局限,二者的组合使用可为不同尺度上生态控制边界的划定提供简明的分析框架。研究结果可为南京都市区生态控制线划定和生态环境保护提供重要的参考,对其他城市生态控制边界的划定也具有一定的借鉴意义。

Development of ecological control boundaries in Nanjing metropolis district based on ecological security patterns

Developing ecological control boundaries is an effective way to protect ecological space, maintain regional ecological security patterns, and control urban sprawl. However, previous studies on the methods to develop ecological control boundaries usually only considered the existing high ecological sensitive areas and neglected potential ecological spaces. Potential ecological spaces usually offer significant contribution in maintaining the balance of urban and regional ecosystems via ecological connectivity. By not considering potential ecological spaces, the designated ecological units become isolated habitat islands and the ecological vulnerability of the city or region increases. Taking the Nanjing metropolis district as a case study, and from the perspective of ecological security, the present study attempted to present a new method to develop ecological control boundaries by integrating ecological sensitivity analysis with ecological networks analysis. These ecological control boundaries aimed to protect the existing and potential important ecological spaces simultaneously in the study area. An eco-sensitivity index system was first established by selecting nine indexes based on local conditions, with the highly sensitive ecological spaces of the study area obtained with spatial analysis in Geographical Information System (GIS). The potential ecological networks were developed with the least-cost path method and supported by GIS. The results revealed that:1) ecological sensitivity analysis was effective in identifying the existing high ecological sensitivity spaces, with the spatial pattern of high ecological sensitivity areas demonstrating that no matter how large or small, ecological sensitivity patches are usually isolated and scattered; and 2) by considering the ecological sensitivity areas simultaneously, 71 sources, 119 important corridors, and 61 key ecological patches were selected to develop the ecological networks. The developed ecological networks can significantly enhance the original landscape connectivity, and can effectively improve overall ecological security both at the urban and regional scales. After the analysis, further suggestions were provided for planning and improvement of the ecological control boundaries in the Nanjing metropolis district. The study indicated that ecological sensitivity analysis could capture the established natural status effectively but neglect the importance of potential ecological connectivity; however, ecological network analysis could make up for this shortcoming perfectly. Therefore, combining ecological sensitivity analysis with ecological networks analysis as performed in the present study is very useful and is a good method to develop ecological control boundaries on different scales.