Construction and Optimization of the Ecological Security Pattern in Liyang, China

Rapid urbanization with unreasonable human disturbances has caused a serious ecological crisis. By constructing an ecological-security pattern (ESP), key landscape elements can be effectively identified. ESP optimization helps to improve a city's ecosystem services and achieve the harmonious development between man and nature. Therefore, it is crucial to construct an accurate ESP and propose practical ESP optimization strategies. Taking Liyang City as an example, this paper first constructed the ESP with a combination methodology of circuit theory, graph theory, the granularity-reverse method, and the comprehensive-evaluation method. Then, strategies for ESP optimization were proposed in terms of ecological restoration and ecological source promotion. Finally, the optimized ESP was verified by quantitative assessment involving landscape connectivity and network structure. Research results show that the current ESP includes 24 ecological sources, 41 ecological corridors, and 50 ecological nodes that need ecological restoration. In the optimized ESP, 31.5 km(2) of ecological land is added, 3 ecological sources are added, 55 ecological corridors are generated, and the number of nodes in the ecological network is increased by 4. By comparing the evaluation results before and after optimization, it can be seen that the optimization scheme has a positive effect on landscape connectivity and ecological coordination of the whole region.