Riverine landscape of the Middle Platte River: Hydrological connectivity and physicochemical heterogeneity

Fluvial processes create diverse riverine habitats and sustain hydrological connectivity across broad floodplains of the Middle Platte River. The riverine habitats have hierarchical characteristics and distinctive temporal variability. River regulation reduces the hydrologic fluctuation and the degree of surface hydrological connectivity between the river flow and the riverine habitats in the floodplain. Two fundamental questions are: (a) how does hydrology of riverine habitats respond to river discharge? (b) what are the riverine landscape patterns as results of the hydrological change? It was hypothesized that discharge and hydrological connectivity are the main factors controlling diversity of the riverine habitats and patterns of the riverine landscape. The hydrological connectivity is determined by quantifying hydrological connections and interactions between the riverine habitats and the main channel in landscape scale. Multiple correlation and regression methods were used to quantify the hydrological interactions. The results suggest a rank of the hydrological connectivity between the riverine habitats and the main channel (from high to low) as: side-channel, disconnected backwater, connected backwater, wet meadow pond, riparian pond, tributary, permanent slough, and intermittent slough. Physicochemical and spatial analysis results reveal the riverine habitat heterogeneity and landscape patterns in response to the river discharge. The hydrological connectivity serves as a driving force for biodiversity of the river ecosystem. Thus, an effective biodiversity conservation strategy should focus on sustaining hydrological connectivity, so that the river itself may maintain its braided flowpaths and maintain hydrologic and ecologic interactions among riverine landscape components. This research contributes to our understanding of the complexity of the riverine landscape in the Middle Platte River. It is also relevant to a fundamental question: how does the hydrological connectivity affect the river ecosystems? The study results (The landscape digital maps, hydrological and physicochemical data) show clearly the riverine landscape patterns and the effects of hydrological and climatic factors on the landscape processes. These results may serve for river ecosystem assessment, planning, habitat conservation and restoration, and water resources management