基于LEI和MSPA的南昌市城市扩张类型与生态景观类型变化关联分析

中国正处于城市化快速发展阶段,城市扩张导致大量生态景观日益破碎,分析城市扩张类型与生态景观类型的变化及其关联机制能为改善生态环境提供指导。以南昌市为研究区,采用景观扩张指数（LEI）和形态学空间格局分析法（MSPA）识别南昌市的城市扩张类型和生态用地景观类型,并通过建立缓冲区带分析城市扩张类型与生态景观类型变化的关联特征。结果表明：（1）南昌市城市扩张主要以边缘型扩张为主,生态用地以“核心”形态为主;（2）不同圈层的城市扩张类型和生态景观类型的关系在不同发展阶段差异显著;（3）在城市扩张过程中,总体上生态景观越加破碎,边缘型扩张会加速大型绿色斑块的减小,飞地型扩张促进绿色景观单元的破碎化,填充型扩张则有弱化这一过程的作用。研究结果可为控制城市无序扩张提供可靠的理论参考,并为研究区的城市有序扩张和生态环境保护提供决策依据。

The relationship analysis of urban expansion types and changes in ecological landscape types based on LEI and MSPA in the city of Nanchang

The economic growth and urbanization development of Nanchang have been accelerated significantly and considerably by China's rapid urbanization and industrialization since the reform and opening-up in the late 1980s. However, due to the rapid urban expansion, the ecological and environmental problems caused by the fragmentation of green landscapes have become more serious. Thus, this paper chose Nanchang city as an example to analyze the changes and relationship of urban expansion types and ecological landscape types, which will provide guidance for improving the ecological environments. Firstly, this paper used the Landscape Expansion Index (LEI) to identify the expansion models of the three periods, and analyzed the variations of construction land expansion from both time and space, based on the land use data of 2000, 2005, 2010 and 2015. Then, the Morphological Spatial Pattern Analysis (MSPA) method was used to obtain the ecological landscapes of the four periods, and expressed the ecological landscape fragmentation process from nine representative points. Finally, multiple buffer layers were created to explore the correlation between the variations in different expansion types and landscape types. The results are shown as follows. (1) Edge-expansion is the main expansion pattern, while ecological landscape is dominated by "core", and the variation of expansion types and landscape types varies with time. (2) The relationship between urban expansion types and ecological landscape types in different circles is significantly different at different development periods. (3) During the urban expansion process, infilling expansion is the main method to improve the compactness at the central urban area. In general, the ecological landscape is more fragmented, the edge-expansion will accelerate the reduction of large green patches, and the outlying expansion promotes the green landscape units more fragmentary, while infilling expansion has the effect of weakening the process. According to the research results, calculating the landscape expansion index of the newly approved construction land and studying the current situation of ecological landscape types will enable decision makers to identify the urban expansion trend and make scientific and developmental predictions for the next stage of development. Then, decision makers can control the disorderly urban sprawl from a macroscopic level.