Vegetation zonation related to the edaphic factors in the East headland of Chongming Island

We studied the relationships between the vegetation zonation and the edaphic factors including soil moisture, salinity (NaCl) and soil temperature (T) in the east headland of Chongming Island. The results are as follows: (1) Soil moisture plays an important role in the distribution and assembly of tidal flat, Scirpus mariqueter and Spartina alterniflora, among which soil moisture content was significantly different (P < 0. 05). Under the frequent flooding condition in the soil, the seaward colonization of Spartina alterniflora tended to be influenced. (2) The content of NaCl in the soil had significant (P <0.001) difference among different vegetation zones, such as tidal flat, Scirpus mariqueter and Spartina alterniflora zone. With the increase of the content of NaCl in the soil, the distribution of Scirpus mariqueter was restricted, and its relative growth rates were slower. Consequently, under brackish condition, the vegetation zone of Spartina has the highest content of NaCl, while the tidal flat has the lowest. (3) Different vegetation zones were significantly different in soil temperature (P<0.05). Among the three vegetation zones, Spartina alterniflora has the highest soil temperature, while the tidal flat has the lowest. The reason could be that the tides and floods caused the low soil temperature in the tidal flat zone, while the thick vegetation coverage in the Spartina zone protected the soil and resulted in relatively high temperature.