2008年，我们开展了崇明东滩保护区潮间带滩涂的植物调查，重点分析了不同高程和垂直潮沟方向上植物生物量及分布的变化。

我们在植物生长高峰期调查了崇明东滩北、东、南部6条样线上的高潮区、中潮区和低潮区滩涂植被。调查发现由北至南各样线间的典型植物生物量存在显著差异，但同一样线不同高程区间植物生物量无显著区别。在北部滩涂的中潮区和低潮区，互花米草已经替代海三棱藨草成为优势群落，而且其植株密度和地上生物量均高于同科植物芦苇，其竞争优势十分明显。

在垂直潮沟方向上，调查了北部、东部和南部共3条样线，发现东部滩涂的植物地上生物量与样带距潮沟距离间存在显著相关，与潮沟距离越远，植物地上生物量下降。南部滩涂的植物地下生物量与样带距潮沟距离亦显著相关，表现为与潮沟距离越远，植物地下生物量增加。在高潮区滩涂，样带距潮沟边缘的距离显著影响植物的物种数与香农威纳多样性指数，而在中低潮区滩涂的调查则发现潮沟垂向方向上植物物种多样性的变化并不明显。

调查发现，喜盐的海三棱藨草在东滩北部和东部盐度较高地区受到互花米草的入侵威胁，在东滩南部则竞争不过藨草和糙叶苔草。目前海三棱藨草仅在东部至南部低潮区的前沿地带仍有生长，且其带宽很窄，仅20－40米。作为我国的特有植物物种以及雁鸭类喜爱的食物，保护海三棱藨草已经成为一件刻不容缓的任务。

Abstract

In 2008, the plant communities in intertidal marshes of Chongming Dongtan Nature Reserve were investigated, with emphases on the plant distribution and biomass at different elevations and at different distances from the creek edge.

In July 2008, vegetations at lower, middle and higher marshes from 6 intertidal transacts of northern, eastern and southern parts of Dongtan were investigated. Form north to south, the biomass of dominant plants were significantly different among different sampling transacts. But the difference in plant biomass were not significant among different elevations at each sampling transacts. At middle and lower marshes of the northern part of Dongtan, the invasive Spartina alterniflora was a dominant plant type by replacing the native Scirpus mariqueter. The plant density and aboveground biomass of S. alterniflora were higher than those of the plant Phragmites australis, suggesting its high competing ability.

Three transacts northern, eastern and southern parts of Dongtan were investigated to analyze the relations between plant biomass and diversity with the distance to creek edges. The relations between plant biomass and the distance to creeks were different at different transacts. At the eastern transact, the aboveground plant biomass were negatively related with the distance to creeks. At the southern transact, the belowground plant biomass were positively related with the distance to creeks. At the higher marshes, the distance to creeks significantly influenced the plant species richness and diversity, but the influences were not significant at the middle and lower marshes.

The investigations revealed that the development of Scirpus mariqueter has been greatly threatened by the invasion of Spartina alterniflora at the northern and eastern parts of Dongtan with relatively higher salinity. At the southern part of Dongtan with low salinity, Scirpus triqueter and Carex scabrifolia prevailed over S. mariqueter and became dominant plants. At present, S. mariqueter mainly occurred at the eastern parts at the south-eastern parts of the marshes by forming narrow zones of 20-40 m wide. As an endemic marsh plant and a favorite food type for ducks, the conservation of S. mariqueter is urgent.