生态安全约束下城市群空间网络结构动态演变及关联特征分析——以环鄱阳湖城市群为例

基于景观生态安全理论和引力模型，探讨生态安全约束下的城市群空间网络结构动态演变及关联特征，不仅能为城市群空间网络结构优化提供新视角，而且可为促进城市群可持续发展提供科学依据.以环鄱阳湖城市群为研究区，将景观结构安全指数与生态系统服务价值相结合来构建生态安全指数，并引入到改进的引力模型中，对研究区空间网络结构动态演变及关联特征进行定量测度与分析.结果表明：1) 2005年-2015年环鄱阳湖城市群整体生态安全度有所降低，部分区域经历了由高生态安全度向低生态安全度的转化，生态风险提升；2) 在不考虑生态安全约束情形下，整个研究期间南昌市区始终处于核心地位，“核心-边缘”结构明显，城市空间网络结构变化呈松散趋势.在生态安全约束下，研究区多中心网络结构特征逐渐凸显，城市群空间网络结构发育程度逐步走向成熟，向协同方向优化；3) 在不考虑生态安全约束情形下，多数城市关联强度低且处于稳定的均质状态，形成以南昌市区为首位关联城市的单核心特征.在生态安全约束下，城市群空间网络关联整体呈现异速非均衡特征，并形成以南昌市区、九江市区、抚州市区和景德镇市区为首位关联城市的多中心发展模式.可见，结合生态安全指数的引力模型能有效测度生态安全约束下的城市群空间网络结构动态演变及关联特征，可为环鄱阳湖城市群可持续发展提供参考.

Spatial network structure dynamic evolution and correlation characteristics analysis of urban agglomeration under ecological security constraint： a case of urban agglomeration around the Poyang Lake

Based on the theory of landscape ecological security and gravity model，this paper discusses the spatial network structure dynamic evolution and correlation characteristics analysis of urban agglomeration under ecological security constraint， which not only provide a new perspective for the optimization of the spatial network structure of urban agglomerations， but also promotes the sustainable development of urban agglomeration.Taking the Poyang Lake urban agglomeration as the research area， combining the landscape structure security and ecosystem service value to construct the ecological security index， and introducing it into the gravity model， quantitatively measure and analyze the spatial network structure dynamic evolution and correlation characteristics in the study area.The results show as follows.1) The overall ecological security of the Poyang Lake urban agglomeration has decreased in 2005-2015， and some regions have experienced a transition from high ecological security to low ecological security， and the ecological risk increased.2) Without considering the ecological security constraints， Nanchang City has always been at the core of the whole research period，whose “core-edge” structure is significant， and the urban spatial network structure changes in a loose trend.Under the constraints of ecological security，the multi-center network structure features of the study area are gradually becoming more prominent，and the spatial network structure of urban agglomeration is gradually mature and optimized in the direction of coordination.3) Without considering the constraints of ecological security，most cities have low correlation strength andare in a stable homogeneous state，forming a single core feature of Nanchang City as the first associated city.Under the constraints of ecological security， the spatial network association of urban agglomerations presents an all-speed non-equilibrium feature， and forms a multi-center development model with Nanchang City， Jiujiang City， Fuzhou City and Jingdezhen City as the first associated cities.It's found that the gravity model combined with ecological security index is able to effectively measure the spatial network structure dynamic evolution and correlation characteristics of urban agglomeration under the constraint of ecological security，and would provide a reference for the sustainable development of the Poyang Lake urban agglomeration.