长江口冲积岛植物群落演替现状

长江口冲积岛（崇明、横沙、长兴、九段沙）发育至今，生物、非生物环境因子起着重要作用。其中，成岛年龄、高程、土壤种类、土壤养分、土壤含盐量、土壤pH值等影响着冲积岛植物群落的形成、定居与演替。在多年野外调查基础上，本文以时间跨度，运用等差序列排序，阐述了冲积岛植物群落的植物多样性，记录并预测了历年冲积岛植物数量，采用典范对应分析（CCA）二维排序方法，对冲积岛多种生境下植物群落的演替现状和所适应的环境因子进行了分析，运用植物样方调查数据，对个别群落间的竞争作了生产量、生境等分析，为研究长江口冲积岛生态系统提供了基础资料。

Present Situation of the Plant Community Succession on Alluvial Islands at the Mouth of Yangtze River

Through the development of alluvial islands at the mouth of Yangtze River(Chongming, Hengsha, Changxing and Jiuduansha) up till now, living and nonliving environmental factors are playing important roles. Among them the age and the height of the islands, soil types, nutrient, salinity, pH, etc. make influence on the formation, colonization and succession of the plant communities. On the basis of field working for several years, applying arithmetic series ordering according to time, the essay expounded the diversity of plant communities, recorded and predicted the plant amount of the past years on alluvial islands. It analyzed the succession status quo of plant communities under various habitats and the environmental factors accustomized by using Canonical correspondence Analysis (CCA), it also made biomass and habitat analysis on the competitions among isolated communities according to the investigation data of plant quadrats. All of these investigation results give basic information to understand the ecosystem on alluvial islands at the mouth of Yangtze River.