Tempo-spatial variation of wetlands at the Yellow River Mouth and its control factors

Based on the long-term series data retrieved from the Landsat remote sensing images (1976—2020), this paper is devoted to the study of tempo-spatial variations of wetlands in the present Yellow River deltaic lobe since the last channel shifting in 1976. Significant differences in the distribution pattern of wetlands are observed for the present (Q8) and the abandoned (Qingshuigou) river mouths. The wetlands in the current deltaic lobe have experienced four stages of temporal and spatial variations with time, i.e the stages of rapid accretion, stable growing, rapid erosion and relatively stable. The wetland growth at the present active Q8 river mouth is primarily dominated by the water and sediment discharges from the upper reach of the river associated with sedimentation off the river mouth, particularly after the water-sediment regulation since 2002. In contrast, the spatial-temporal variation of the abandoned Qingshuigou wetlands is dominated by tidal and wave erosion induced by estuary dynamics. The wetland retreats rapidly together with the increasing coastal erosion and channel refilling, by which vegetation habitat on both sides of the abandoned channel are destroyed. In combination with the Yellow River’s water and sediment discharge, the dynamic mechanism dominating the wetland evolution is discussed in this paper, that is important to the countermeasures for future conservation and restoration of wetlands.