Evolution characteristics and interaction mechanism of human-earth relationships in the Qinling-Daba Mountain Areas: A case study of three cities in Southern Shaanxi

As a strategically significant location, ecological highland, and economically underdeveloped area in China, the Qinling-Daba Mountain is characterized by pronounced contradictions in human-earth relationships, manifested in severe soil erosion, frequent geological disasters, excessive land exploitation. Based on remote sensing and geospatial data, this study employed the coupling coordination degree and the geographically weighted regression (GWR) model to explore the spatio-temporal evolution and interaction mechanism of human-earth relationships in the Qinling-Daba Mountain areas of Southern Shaanxi. Results indicated that the population tended to concentrate in central urban areas, and vegetation coverage increased by 98% of the region. During this period, cropland decreased by 4103.06 km², primarily converted into forest land, construction land, and grassland. Over 60% of the study area presented low human activity intensity, while region with higher and high natural environment index accounted for more than 75%. The coupling degree and coordination degree of the human-earth relationships exhibited a spatial distribution characterized by higher values in river valley basins and central urban areas, and lower values in the undulating mountainous regions to the north and south. There was an observable expansion in areas with low coupling and severe incoordination, while areas with higher coupling and mild incoordination showed a shrinking trend. The human-earth interaction exhibited significant temporal dynamics and spatial heterogeneity. The correlation between natural indicators and the proportion of cropland gradually declined over time, while the correlation with the proportion of construction land steadily strengthened. Only water yield and temperature were positively influenced by human activity intensity in regions exceeding 70%, whereas the remaining interaction relationships within the human-earth system were negatively impacted in areas above 50%. The findings of this study could offer valuable decision-making support for ecological conservation and high-quality economic development in Southern Shaanxi.