Abstract:Ecological land patches with greater ecological service value are an important guarantee for maintaining regional ecological security in the semiarid areas of Northwest China. Eco-service plaques with small ecological service values rely on large plaques. In the natural state, plaques of different sizes have a distinct hierarchical nature. A hierarchical network extraction model framework was constructed with Baotou City as the research area, combining with the hierarchical nature of different ecological value habitat patches. The hierarchical ecological network was evaluated by selecting appropriate graph theory network measurement indicators. The results showed that the hierarchical ecological network was constructed based on the hierarchical network extraction model, so the number of the first, second and third layers of ecological sources was 8, 31 and 123, and the number of potential corridors on the first, second and third floors was 8, 35 and 151, and the corresponding number of the first, second, and third layers of ecological nodes was 7, 28 and 47;the α, β, γ indexes were calculated to evaluate the hierarchical network structure, with the increase of the low-level source and the number of corridors, the more loops available for material flow in a low-level network was, the lowerlevel ecological networks were better than the higher-level average connectivity. The hierarchical ecological network constructed for semi-arid areas can provide theoretical guidance for the ecological construction of Baotou City and had important reference value for semiarid urban ecological planning.
