Zoning for rural settlements improvement in the Wumeng Mountains considering the “Three Zones and Three Lines” and land suitability

The objective of this study was to identify the zoning types for the rural settlement improvement in the Wumeng Mountains. The recognition criteria were established to implement the differentiated strategies. Territorial spatial planning was fully integrated with the rural revitalization for high-quality rural development. The research subject was taken as the rural settlements in Hezhang County, Guizhou Province, China. Firstly, the GIS spatial overlay analysis was utilized to preliminarily explore the spatial distribution relationships between rural settlements and permanent basic farmland, urban development boundaries, and ecological protection red lines, according to the rigid constraints of the “Three Zones and Three Lines” in the territorial spatial planning. Subsequently, an evaluation index system was developed for the rural settlement land suitability over three dimensions: natural conditions, ecological security, and infrastructure conditions. Indicator weights were calculated using the Analytic Hierarchy Process (AHP) and entropy weight. An evaluation model was constructed to quantify the rural settlement land suitability index. Finally, the constraints of the “Three Zones and Three Lines” were integrated with the land suitability. A national standard was established to identify the rural settlement improvement zones in order to facilitate the zoned improvement efforts. The results revealed that: 1) Rural settlements in Hezhang County exhibited a spatial density pattern with the “high density in the central area and low density in the north and south.” Settlements that interacted with the permanent basic farmland, ecological protection red lines, and urban development boundaries were classified into three types: the agricultural security type, the ecological conservation type, and the urban development type, accounting for 0.01%, 0.59%, and 8.83% of the total rural settlement area in the study region, respectively; 2) According to the natural breakpoint, the suitability index of the rural settlement land use was categorized into four levels: extremely unsuitable, unsuitable, suitable, and extremely suitable. Spatially, there was a “highly suitable in the center, unsuitable at both ends” distribution pattern. The area of each suitability level shared an initial increase followed by a decrease; 3) According to the Hezhang County's requirements to preserve the historical culture and distinctive tourism resources, the interaction between settlements and the “Three Zones and Three Lines” framework, and land suitability ratings, rural settlements were categorized into the priority development zones (49.13%), improvement and enhancement zones (28.86%), urban integration zones (8.55%), relocation and consolidation zones (10.19%), and special protection zones (3.27%). The areas of different zones also exhibited a linear decreasing pattern. Tailored remediation strategies, including village clustering, industrial development, and living environment improvement, were formulated for each zone based on their unique settlement characteristics. This finding can also provide valuable case references and practical pathways for the precise territorial planning and dynamic optimization of village layouts in mountainous regions.