Assessing landscape connectivity and constructing ecological networks in the urban megaregion: a case study of Changsha-Zhuzhou-Xiangtan urban agglomeration in China

Abstract

Rapidly urbanising regions face ecological problems including reduced ecological connectivity and declining ecosystem service functions, and the construction of ecological networks is a significant way to ensure the improvement of ecological connectivity and promote urban ecological security. This research takes the Changsha-Zhuzhou-Xiangtan urban agglomeration in China as an example, analysing the spatiotemporal change of the landscape pattern and the degree of fragmentation during the period of 2000-2020 based on the matrix of land use and land cover change and landscape pattern index. Besides, this research construct ecological networks based on the data in 2020, and makes some technological innovation based on the characteristics of the study area. The research shows that: 1) From 2000 to 2020, the urban expansion of Changsha-Zhuzhou-Xiangtan urban agglomeration mainly consumed arable land and forest land, and the degree of ecological spatial fragmentation of Changsha-Zhuzhou-Xiangtan urban agglomeration increased in the past 20 years. 2) The ecological source area of Changsha-Zhuzhou-Xiangtan urban agglomeration is about 11,813km2, accounting for about 42% of the total area, which mainly consists of forest and waterbody in the southern part of Zhuzhou City and the western part of Changsha City. There are 262 potential corridors, mainly in the central part of the city, connecting important ecological sources in the east-west and north-south directions. In addition, the Green Centre plays an important ecological connectivity and shield role. 3) Identifying ecological sources combined with local policies and planning and setting resistance surfaces based on POI data provide new methods for the construction of ecological networks in the Changsha-Zhuzhou-Xiangtan urban agglomeration, thus guiding urban planning and layout more effectively.