Multi-scenario simulation for spatial optimization of rural settlements in alpine valley areas: a case study of Wenchuan County, China

Optimizing rural settlement layout in alpine valleys with fragile ecosystems and frequent disasters is vital for ecological protection and livelihood improvement. However, conventional planning approaches often fail to systematically integrate detailed assessments, nuanced classifications, and dynamic multi-agent simulations, reducing effectiveness in complex terrains. This study takes Wenchuan County as a case study, integrating multi-criteria decision-making, multi-agent systems, and land use suitability assessment to classify rural settlements and simulate development under different scenarios. Results show: (1) Rural settlement categories ranked by prevalence are agglomeration and upgrading (AU) >characteristic protection (CP) > generally surviving (GS) > relocation and evacuation (RE) > suburban integration (SI). Spatially, AU > CP > GS > SI > RE, with sparse distribution in uninhabitable areas. (2) The three scenarios—economic priority (Scenario I), ecological priority (Scenario II), and balanced development (Scenario III)—increase settlement area by 738.02 ha, 10.04 ha, and 586.72 ha, respectively. Scenario I is likely to threaten ecological stability, whereas Scenario II has limited capacity to guarantee land for rural development. In contrast, Scenario III occupies only 48.71% of the ecological land used in Scenario I, thereby reducing ecological disturbance. (3) Under these scenarios, land use suitability increases by 15.12%, 2.71%, and 12.63%, respectively. Settlement fragmentation increases while spatial aggregation and dominance decrease, indicating that an “extensive dispersion with localized concentrations” pattern is optimal. The proposed framework enhances land use efficiency and provides a complementary decision-making tool and spatial perspective for rural planning.