Construction and optimization of ecological network in karst regions under rocky desertification disturbance: A case study of Qujing City, China

Constructing ecological networks is a promising strategy to reconcile urban development with habitat fragmentation. However, there is limited knowledge regarding methods to construct and optimize ecological networks in karst regions. This study focuses on Qujing City in Yunnan Province, China, a typical karst region. Ecological sources are identified by integrating morphological spatial pattern analysis, landscape connectivity, habitat quality, and rocky desertification sensitivity. A resistance surface modified by rocky desertification is used in the minimum cumulative resistance model to extract potential corridors. The network structure is assessed using complex network indicators to identify key components. To enhance resilience, an improved low-degree-first edge-adding method incorporating rocky desertification sensitivity was developed and evaluated through robustness simulations. The findings indicate that: (1) Qujing City contains 79 ecological sources, including 6 at level 1, 14 at level 2, and 59 at level 3, predominantly located in the north-central region, covering woodland and grassland areas and the total area was 5423.04 km2. (2) A total of 91 ecological corridors were identified, comprising 10 primary corridors, 24 secondary corridors, and 57 tertiary corridors, with lengths of 156.84 km, 490.72 km, and 988.89 km, respectively. (3) The addition of 27 supplementary edges significantly enhanced the ecological network’s robustness to rocky desertification, increasing its resistance to both random and targeted disturbances. Optimization improved the ecological network’s connectivity, robustness, and stability, enhancing ecological flow and reducing vulnerability to rocky desertification. This study offers a novel approach to ecological network design and conservation in karst regions.