长江口九段沙植物群落研究

长江口九段沙属于发育早期的河口沙洲，植被完全保持着自然演替的早期状况。对九段沙湿地高等植物群落的结构特点及演替特征进行研究。研究结果表明：九段沙湿地植被分布几乎覆盖整个沙岛，生物量丰富。高等植物中多克隆植物，植物群落结构简单，生物多样性低，植被具原生性，群落演替的早期原生特征明显，演替过程在没有引种互花米草之前人为干扰少，互花米草的引种加速了九段沙湿地植被的陆地化演替进程。最后提出保护和开发利用九段沙植被的适应原则。

Studies on plant community on the Jiuduansha Shoals at the Yangtze Estuary

The study was carried out on the Jiuduansha Shoals at the Yangtze Estuary. Jiuduansha Shoals are newly formed shoals, and comprise three parts: Shangsha, Zhongsha and Xiasha. In order to assess the plant community on the Jiuduansha shoals and put forward suggestions for environmental protection and exploiture in this area, we took the field investigations on the shoals in 2000 and 2001. The article focused on the advance vegetation community composition,structure , features, and the growth characteristics.;The research results showed:(1)The vegetation on the Jiuduansha Shoals obviously lies in the early stage of natural community succession. (2)the vegetation on the Jiuduansha Shoals is mostly clone-vegetation and the composition and structure of plant communities were relatively simple.(3)The species diversity on the Jiuduansha Shoals was low and the vegetation keeps its initial feature.(4)The vegetation on Shangsha is relatively well-developed, has distinct vegetation belts, and is consisted of 13 plant species. The dominant species are Phragmites australis and Scirpus mariqueter in the south-west and north-east respectively.(5)The dominant species on both Zhongsha and Xiasha is Scirpus mariqueter, and there are man-planted Spartina alterniflora(introduced species)and Phragmites australis (local species)communities on Zhongsha, which were about 1 km2, and were planted as an ecological engineering in 1997.(6)Introduced Spartina alterniflora and Phragmites australis communities have accelerated the process of vegetation communities succession, and the man-made interference on the Jiuduansha Shoals is comparatively deficient. ;The authors suggest that the vegetation on the Jiuduansha Shoals should be well managed, and give the available principles on protecting and developing the vegetation on the Jiuduansha Shoals.