Multi-temporal evaluation and optimization of ecological network in multi-mountainous city

In karst multi-mountainous areas, there are a large number of urban remnant mountains (URMs) in urban built-up areas, which are an important part of urban green space system and have important and unique ecosystem service functions. However, the densifying development inside the city has been leading to the reduction of the number and area of the URMs and the decrease of the connectivity of the urban green space system, resulting in the fragile urban ecological environment. The construction and optimization of ecological network (EN) is an effective way to protect important urban ecological patches and improve the stability of urban green space ecosystem. Taking the central area of Anshun, a typical multi-mountainous city, as the study area, based on the land use data of 2007, 2012 and 2017, the ecological sources were identified by morphological spatial pattern analysis (MSPA) and the potential ecological corridors were extracted by the minimum cumulative resistance model (MCR), and the ENs of the three periods were identified. 18 ecological sources were selected for each of the three periods, with a total area of 833.67 hm2, 713.25 hm2 and 806.85 hm2, respectively and the intersection area of ecological sources reached 650.58 hm2. The ecological corridors and ecological sources dwindled with time. The Gravity model was used to extract the important EN corridor, the InVEST model was used to quantify the comprehensive habitat quality. The EN was optimized by adding extra ecological sources, mending ecological breakpoints and extracting habitat quality map patches. It is suggested to add 6 ecological sources and 34 ecological corridors, protect ecological nodes and build stepping stone patches. The results of this study could not only provide a scientific and reasonable basis for the ecological protection and the development of ecological protection strategies in the urban central area of Anshun, but also enrich the theoretical research of urban biodiversity conservation planning and ecological restoration practice in multi-mountainous cities