京津冀城市群生态网络构建与优化

生态安全是人类生活的基本保障,快速城镇化致使大型生态源地破碎化、岛屿化,生态环境问题日益严重。构建生态网络不仅能加强生态源地间的连通性,完善生态功能,还能提高生态系统的综合能力,改善恶化的生态环境问题。以京津冀为研究区,基于地理空间分析技术确定京津冀生态源地,对研究区内的林地、湿地、草地,结合生态红线等进行区域叠加从而完成源地提取;基于最小成本路径方法,考虑土地利用及高程影响因子,提取京津冀城市群生态廊道,分析统计廊道分布情况;结合重力模型与重要生态源地连通性筛选出京津冀重要生态廊道,叠加现有国道、河流构建生态网络,对重要生态节点进行分析。研究结果表明,生态源地面积占研究区总面积比例为21.76%,林地、湿地、草地面积占总生态源地面积分别为82.78%,11.05%,6.17%;不同地貌区域生态源地类型不同,林地主要分布在山区,湿地主要分布在平原区域,草地主要分布在研究区西北部;景观成本值平原区域高于草原和山区,北京、天津、石家庄城区及周边景观成本值最高;采用最小成本路径模型提取廊道579条,其中张家口、承德区域生态网络较好,平原区域生态源地及生态节点缺失较为严重。最后,对北京、天津、白洋淀、衡水湖等重点生态区域提出修复和保护意见,为京津冀城市群发展提供参考。此外,本研究对其他地区生态网络的构建提供理论依据与技术支持。

Development and optimization of the ecological network in the Beijing-Tianjin-Hebei metropolitan region

Ecological security is the basic safeguard of human life. Rapid urbanization can cause fragmentation of large habitats and islands, and the deteriorating ecological environment is an increasingly serious problem. The establishment of an ecological network can not only enhance the connectivity between habitat patches and improve ecological function, but can also increase the comprehensive ability of the ecosystem and ameliorate the deterioration of the ecological environment. In this paper, the Beijing-Tianjin-Hebei metropolitan region was studied as the research zone. The ecological sources of the Beijing-Tianjin-Hebei metropolitan region were determined based on the Geographical Information System (GIS), and extracted via an overlap area of the forest, wetland, and grassland areas of the research zone, and the ecological red line; based on the least-cost-path method, we considered land use and elevation factors to extract the ecological corridors of the Beijing-Tianjin-Hebei metropolitan region to analyze and calculate the distribution of the ecological corridors. Integrating a gravity model and connectivity among important ecological sources, the critical ecological corridors of the Beijing-Tianjin-Hebei metropolitan region were selected, and then were overlaid with the current national roads and rivers to develop an ecological network and analyze the significant ecological nodes. The results indicated the ecological source area accounted for 21.76% of the total study area; the forest, wetland, and grassland was 82.78%, 11.05%, and 6.17% of the total study area, respectively. Different geomorphology regions have different ecological source types; the forest was mainly distributed in mountainous regions, and wetland was mainly distributed in the plains regions, and grassland was mainly distributed in the northwest research area. As for the landscape impedance, the plains regions were higher than grasslands and forests, and the highest landscape impedance was found in the urban areas of Beijing, Tianjin, and Shijiazhuang. Among the 579 corridors selected according to the least-cost-path method, Zhangjiakou and Chengde areas showed better ecological networks, and the plains regions exhibited a serious loss in ecological sources and nodes. Finally, restoration and protection suggestions for the key ecological zones, such as Beijing, Tianjin, Baiyang Lake, and Hengshui Lake, have been provided in the study to offer reference for the development of the Beijing-Tianjin-Hebei metropolitan region. In addition, this study contributes to the theoretical and technical support needed to design ecological networks in other regions.