Impacts of Different Flood Pulses' Intensities on Lateral Hydrological Connectivity and Habitats in Riparian Wetlands

ABSTRACT When influenced by flood pulses, the ecosystems in rivers and floodplain wetlands become highly dynamic, with biological communities such as waterbirds and fish developing dependencies on surrounding water depth and flow velocity. However, current studies primarily focus on macroscale qualitative analyses and do not address the complex relationship between flood pulses and habitats. This paper examines lateral hydrologic connectivity and habitat changes in floodplain wetland systems resulting from flood pulses, utilizing a geostatistical connectivity function joined with a two‐dimensional hydrodynamic model. This method enhances the quantitative accuracy and spatiotemporal dynamic characterization capabilities of hydrological connectivity, filling a research gap in the study of dynamic mechanisms and complex system modelling related to hydrological connectivity. The results reveal (1) overall connectivity (TC), general connectivity (GC) and the effective connectivity (EC) increase with the decrease of flood frequency. Among them, the dynamic change of EC is most significant. (2) Complex hydrodynamic changes induced by different types of flood pulses can result in nonlinear alterations in the lateral hydrologic connectivity of floodplain wetlands. That is, there are phase differences in the growth rate of lateral hydrologic connectivity. (3) Overall, waterbirds are fit to survive under low flood pulse conditions (50% ≤ P ≤ 100%). Fish and phytoplankton can survive under high flood pulse conditions (1% ≤ P < 2%). Benthos are adapted to survive in moderate flood pulse conditions (10% ≤ P < 20%). Moreover, sediment suspension is more likely to occur in high flood pulse conditions. These findings contribute to the restoration of wetland ecosystems and the improvement of riverine hydrological connectivity.