崇明东滩盐沼植被成带性对土壤因子的响应

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

对东滩湿地不同植被带与土壤环境因子的关系进行了探讨,分析植被成带性分布与土壤含水量、土壤盐度、土壤温度之间的关系,研究表明:(1)光滩(TF)、海三棱藨草(Sm)、互花米草带(Sa)土壤含水量差异显著(P<0.05),随着土壤含水量的显著变化,海三棱藨草和互花米草种群分布呈现明显带状分布,土壤含水量对植被带的分布起到一定的平衡作用,在土壤经常性淹水下,互花米草种群的海向性拓殖受到一定抑制。(2)光滩带、海三棱藨草带、互花米草带之间的土壤盐分(NaCl)差异极显著(P<0.001),从海向陆依次为:NaCl光滩带<NaCl海三棱带<NaCl互花米草带,NaCl含量增加土壤含水量相对减小,土壤盐度和含水量的差异极大影响了海三棱藨草和互花米草植被带的分布模式,从而进一步制约了其演替进程。不同植被带间温度差异显著,总体趋势为互花米草带最高而潮滩带最低,并且互花米草带土壤温度显著高于其它各带,小尺度空间上植被对环境因子的响应明显。(3)相对于7月份而言,5月份各带内土壤含水量显著较高,但植被带间没有显著性变化。光滩最高,依次为海三棱带和互花米草带。然而,7月份土壤盐度和温度显著大于5月份,互花米草带最高,依次为海三棱和光滩带。

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 （P0.05）.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 （P0.001） 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 （P0.05）.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.