Water-salt thresholds of Suaeda salsa,Tamarix chinensis,and Phragmites australis on the interpretation of formation mechanism of quasi-circular vegetation patches
Quasi-circular vegetation patches(QVPs)occur in the area with a distance of 25 km from the Bohai Sea to the land in the Yellow River Delta,which are featured by a fast succession rate and high biodiversity.QVPs are ideal targets for studying water-salt interaction and vegetation succession in the Yellow River Delta.Revealing for-mation processes and mechanisms of the QVPs is of important practical significance for restoring vegetation in the saline tidal flat in the Delta.Based on the water-salt thresholds and living habits of Suaeda salsa,Tamarix chinen-sis,and Phragmites australis,which are the dominant plant species in QVPs,and the distribution patterns of halo-phyte vegetation communities in the gentle lowland of the Delta,we analyzed the formation processes and mecha-nisms of QVPs.The results showed that the local redistribution of water-salt caused by waterlogged microtopography in the gentle lowland was the basis for the formation of QVPs.Suaeda salsa was located in the outermost edge of QVPs with high soil salinity(1.0％-2.1％)and humid zone.To the center of QVPs,short and small Phragmites australis occurred,where was a medium-high soil salinity(0.12％-0.79％)and low water depth.Further to the center of QVPs,Tamarix chinensis scattered near the water mark line,which is a local area with a medium soil salinity(0.16％-0.70％)and low water depth.Phragmites australis and Imperata cylindrica are located in the cen-ter of the QVPs where was a low soil salinity(0.1％-0.32％)and high water depth.In spring and winter,the gray white salt belt with high salinity appeared outside of Suaeda salsa where was a local high salinity(1.6％-3.4％)and dry zone,which was caused by the movement and accumulation of salt caused by evaporation.Therefore,a quasi-circular vegetation patch with ring structure and relatively stable area was formed.We can thus build an eco-logical restoration model of microtopography construction in combination with water and salt control to promote the progressive succession of vegetation,which provides a nature-based solution for vegetation restoration of saline tidal flat in the Yellow River Delta.
Suaeda salsaTamarix chinensisPhragmites australiswater-salt thresholdquasi-circular vegetation patchformation process
万方数据
维普
