Comparative evaluation of three composite ecological restoration modes on high-cold steep slopes in the upper Lancang River

BackgroundThis study focused on three typical restoration models for high-altitude cold, steep slopes in the upper reaches of the Lancang River: “Geocell combined with vegetation-layer spraying” (Model 1), “Ecological bags with pit-planting of grasses and shrubs” (Model 2), and “Ecological bags combined with vegetation-layer spraying” (Model 3). Methods Through plot surveys and measurements of soil and vegetation indicators, a comprehensive evaluation system was established using the Analytic Hierarchy Process (AHP) to quantitatively assess the restoration effectiveness of each model. Results The results showed that all three models significantly improved slope vegetation growth and soil quality (P < 0.05), but their restoration outcomes differed markedly. Model 1 demonstrated clear advantages in community diversity and evenness (H = 1.31, Eh = 0.73) and in soil improvement, with an AHP composite score of 0.88 (Grade I, excellent). Model 3 performed best in soil nutrient accumulation (organic matter: 110.35 g/kg; available P: 125.89 mg/kg; available K: 692.07 mg/kg), achieving a composite score of 0.71 (Grade II, good). Although simple to construct, Model 2 showed prominent community simplification (H = 0.16) and a composite score of 0.49 (Grade III, moderate). Conclusions Under the experimental conditions, the “Geocell combined with vegetation-layer spraying” model provided the optimal ecological restoration effect and can serve as a technical reference for restoring similar high-altitude cold, steep slopes.