Identify Optimization Type of Rural Settlements Based on “Production–Living–Ecological” Functions and Vitality: A Case Study of a Town in Northern China

Rural settlements are developing in the direction of functional diversification, driven by rapid urbanization, but also leading to a decline in their vitality as a result of the rapid concentration of rural population in cities. Therefore, this study proposed a theoretical framework to refine the optimization approach for rural settlements from the perspective of “production–living–ecological” functions (PLEF) and vitality. Taking a town in the farming–pastoral ecotone in northern China as a case, we evaluated the level of the PLEF of rural settlements. After exploring the functional requirements of villagers, we revealed the vitality of rural settlements based on social network analysis. The Tapio decoupling model was used to identify the optimization type of rural settlements considering the PLEF and vitality. The results showed that the PLEF of rural settlements was higher in areas with flat terrain, convenient transportation, and rich economies. Rural settlements closer to the central town were stronger in vitality. The PLEF of rural settlements was generally correlated with vitality, which means that rural settlements with a higher level of PLEF also had a stronger vitality. Rural settlements were classified into five types: suburban integration, characteristics protection, agglomeration and upgrading, general survival, relocation, and merger, according to the characteristics of a combination of PLEF and vitality. This study contributes to a deeper comprehension of the functional and structural characteristics of rural settlements and will be beneficial in guiding rural spatial reconstruction.