Township-Scale Identification of Social–Ecological System Resilience in a Small Basin: A Case Study of the Erhai Lake Basin

Small plateau lake basins are sensitive social–ecological systems in which ecological protection, rural development, and institutional governance are closely intertwined. Therefore, fine-scale resilience assessment is needed to support adaptive basin governance. However, integrated township-scale assessments of social–ecological system resilience in such basins remain limited. Taking 13 township-level units in the Dali City portion of the Erhai Lake Basin as a case study, this paper integrates social–ecological system theory with the pressure–state–response framework to construct a 30-indicator resilience evaluation system. It measures social resilience, ecological resilience, and comprehensive social–ecological resilience at four time points from 2010 to 2025, and examines their temporal trends, spatial differentiation, and governance implications. The results show that average social resilience rose from 0.509 to 0.682, ecological resilience from 0.503 to 0.658, and comprehensive resilience from 0.506 to 0.668. Linear mixed-effects modelling confirmed a significant upward trend in comprehensive resilience, with an average increase of 0.053 per five-year interval, while Global Moran’s I indicated weak but consistently positive spatial clustering. However, township-level heterogeneity persisted in improvement magnitude and resilience sources. Neither ecological advantages nor social development alone can sustainably enhance comprehensive resilience; stronger coordination between the two is required. Based on an “ecological protection × social development” matrix, the townships are classified into four types: dual vulnerability, economic priority, ecological priority, and coordinated development. This typology provides a basis for differentiated adaptive governance in ecologically fragile basins.