Construction and Optimization Strategy of Ecological Security Pattern in County-Level Cities under Spatial and Temporal Variation of Ecosystem Services: Case Study of Mianzhu, China

Climate change and human activities are seriously affecting the ecological level and economic development of county-level cities. Mianzhu City is a typical county-level city located within the Chengdu-Chongqing Economic Circle and the Yangtze River Economic Belt. The study selected primary ecological sources by analyzing high-level ecosystem service functions over time, using Morphological Spatial Pattern Analysis (MSPA). Ecological resistance surfaces were constructed using natural factors to address ecological risks associated with future urbanization. The construction of the ecological security pattern (ESP) followed the source–corridor–node paradigm, incorporating changes in ecosystem service risks. From 2010 to 2020, ecosystem service functions and values in Mianzhu City declined overall, with significant spatial variations. Human activities increased in ecologically fragile areas, aggravating exposure to ecological risks from climate change and urban expansion. Ecological protection and restoration zones were identified, with nature reserves in the north and the southern center as the core. In 2020, 19 ecological sources and 46 ecological corridors were identified, with a spatial distribution pattern of “more length and short resistance in the north, less length and long resistance in the south”. Additionally, 41 ecological pinch points and 16 ecological barrier points were determined. Considering the spatial distribution of the core areas of ecosystem services and lands with human-intensive activities, setting up the general idea of the ecological restoration pattern centered on forests, river corridors, and natural and artificial landscapes. The study provides new insights into constructing and optimizing the ESP, offering crucial references for the rapid urbanization of ecological restoration and development planning in urban regions.