Spatio-temporal evolution characteristics and driving mechanisms of river systems in typical plain river network region

The plain river network region is faced with ecological and environmental challenges such as insufficient hydrological connectivity and degradation of ecosystem services under the influence of urbanization and human activities, and therefore attention needs to be paid to river system changes in this region and the synergistic benefits of natural-social-economic multidimensional factors. This study took the Lixiahe region, a typical plain river network area, as the research object, using Mann-Kendall, spatial autocorrelation analysis and Random Forest to analyze the spatiotemporal evolution of its river system from 2013 to 2025 and quantify driving mechanisms from natural, social and economic factors. The results showed that: (1) From 2013 to 2025, the Lixiahe Plain river network system tended to be trunk and artificial, with the number and connectivity of river networks showing an upward trend while the curvature of river network decreased significantly. (2) The global Moran’s I index of the Lixiahe Plain river network decreased from 0.612 to 0.534, indicating a continued weakening of spatial agglomeration in the water area and exhibiting characteristics of edge fragmentation. (3) The spatial characteristics of the Lixiahe Plain river network system were mainly affected by human activities, especially the influence of socio-economic factors (urbanization rate, etc.) far exceeded that of natural factors, and the driving mechanism was dominated by socio-economic factors. Studies have shown that river system management and ecological restoration in plain river network regions need to fully coordinate socio-economic development policies, ensure watershed water ecological security by harmonizing the development of multiple driving factors, and promote coordinated development between socio-economic progress and river network patterns.