Differential evaluation of multi-scale ecological security pattern construction based on MSPA model—a case study of the Lijiang River Basin in China

The establishment of ecological security patterns (ESPs) is crucial for maintaining ecosystem integrity; however, how spatial scale effects influence ESP optimization remains insufficiently understood. Taking the Lijiang River Basin—a typical karst landscape in Southwest China—as a study area, this research systematically compared ESPs constructed at three spatial resolutions (10 m, 30 m, and 100 m). We integrated morphological spatial pattern analysis (MSPA), landscape connectivity metrics, and circuit theory, validating the outputs through a dual approach using protected area overlap and Normalized Difference Vegetation Index (NDVI) data. Our findings revealed distinct scale-dependent characteristics: (1) Core habitats (ranging from 3,197 to 3,471 km²) were predominantly distributed in the northern and eastern regions, with the 30 m resolution yielding the largest contiguous core area (3,471 km²). (2) The identification of ecological sources exhibited scale dependency, capturing 11 sources (2,385 km²) at 10 m, 9 sources (3,057 km²) at 30 m, and 12 sources (2,484 km²) at 100 m, characterized by non-linear responses in probability of connectivity (dPC) values. (3) Landscape network connectivity indices (α, β, and γ) peaked at the 10 m resolution (0.37, 1.56, and 0.60, respectively), whereas the 30 m resolution achieved the highest spatial overlap with existing protected areas (73.9%). (4) NDVI-based validation confirmed the superior ecological quality of identified sources across all scales (p < 0.001, Cohen’s d > 0.8), with the 10 m resolution demonstrating the strongest effect size (d = 0.846). (5) Sensitivity analysis across distance thresholds (1–30 km) demonstrated the robustness of the connectivity model, with variation in key metrics remaining below 20%. The multi-scale comparison highlighted critical trade-offs: the 10 m resolution offers high ecological fidelity by capturing micro-habitats (20–50 m) essential for precise corridor design, whereas the 30 m resolution aligns better with macro-policy formulation. Based on these findings, we propose a hierarchical ESP framework featuring zone-specific conservation strategies: ecological preservation in the northern reserves (1,391 km²), corridor restoration in the eastern transit zones (45 km), and stepping-stone enhancement in the southern fragmented landscapes (12.4 km²). This study provides actionable guidance for spatial planning in karst regions and highlights that spatial resolution is a fundamental determinant of ESP efficacy.