Ecological vulnerability assessment and driving force analysis of small watersheds in Hilly Regions using sensitivity-resilience-pressure modeling

Pingquan City, the origin of five rivers, serves as the core water conservation zone for the Beijing-Tianjin-Hebei region and exemplifies the characteristics of small watersheds in hilly areas. In recent years, excessive mining and intensified human activities have severely disrupted the local ecosystem, creating an urgent need for ecological vulnerability assessment to enhance water conservation functions. This study employed the sensitivity-resilience-pressure model, integrating various data sources, including regional background, hydro-meteorological data, field investigations, remote sensing analysis, and socio-economic data. The weights of the model indices were determined using an entropy weighting model that combines principal component analysis and the analytic hierarchy process. Using the ArcGIS platform, the spatial distribution and driving forces of ecological vulnerability in 2020 were analyzed, providing valuable insights for regional ecological restoration. The results indicated that the overall Ecological Vulnerability Index (EVI) was 0.389, signifying moderate ecological vulnerability, with significant variation between watersheds. The Daling River Basin had a high EVI, with ecological vulnerability primarily in levels IV and V, indicating high ecological pressure, whereas the Laoniu River Basin had a low EVI, reflecting minimal ecological pressure. Soil type was identified as the primary driving factor, followed by elevation, temperature, and soil erosion as secondary factors. It is recommended to focus on key regions and critical factors while conducting comprehensive monitoring and assessment to ensure the long-term success of ecological management efforts.