Spatial distribution and ecological adaptability of wetland vegetation in Yellow River Delta along a water table depth gradient.

The study with fuzzy set ordination(FSO) showed that in the National Nature Reserve in Yellow River Delta,there was a greater difference in plant habitat and vegetation type along a water table depth gradient.At the place with 40 cm to -30 cm water table depth,a transitional belt from water body to land,xerophiles and hydrophytes coexisted,plant species were most abundant,and vegetation coverage was the largest.At the place of-30 cm to-50 cm water table depth,soil salinization and alkalization had the highest degree because of the lower ground water level,while at the place with -50 cm water table depth,soil surface was relatively dry,salinization and alkalization had a lower degree,and droughttolerant vegetation took dominant place.Water table depth gradient had significant effects on soil moisture and air condition and soil physical,chemical and biological processes,and accordingly,affected the spatial distribution and ecological characters of the vegetations in the test region.