江苏东台滩涂垦区植物群落演替及多样性梯度变化研究

Study on plant community succession and diversity gradients in Jiangsu tidal flat reclamation area

基于野外调查数据,应用重要值、物种多样性指数和物种生长特征,结合时空代替法分析了江苏东台沿海滩涂2005—2013年垦区植物群落演替及植被梯度变化特征。结果表明:(1)主要优势物种互花米草和盐地碱蓬,主要分布于2013年垦区内,且二者重要值此消彼长;2009及2005年垦区内物种间重要值差异较大。(2)物种多样性受围垦年限及离海距离共同影响,总体上,物种丰富度随围垦年限及离海距离增加而增加;2013及2009年垦区内群落多样性指数和均匀度指数随离海距离增加整体增加;2005年垦区内自然植被较少,无明显规律。(3)2013年垦区内互花米草群落存在单峰现象,群落中部长势最好,盐地碱蓬于近光滩处株高及冠幅最大,远光滩处盖度及株数最大,总体随着围垦年限增加呈变差趋势,这一变化特征与水盐条件变化密切相关。

Based on field investigation data, application of important value （IV）, species diversity index, species growth characteristics and space-time substitution method, it analyzed the plant community succession and the changes of vegetation gradient in Jiangsu coastal beach of Dongtai in 2005-2013. The results are as follows. （1） The main dominant species in the study areas were Spartina alterniflora and Suaeda salsa, which mainly located in 2013 reclamation area, and the important value of Spartina alterniflora was reciprocal characteristics with Suaeda salsa. In 2009 and 2005 reclamation area, Suaeda salsa, Impertacy lindrica vat. major and Salicornia europaea were the dominant species, whose important value showed a difference with the mosaic distribution of communities. （2） Species diversity was affected by the reclamation time and the distance from the sea. Overall, species richness increased with the reclamation years and increasing distance from the sea. In 2013 and 2009 reclamation area species diversity index and evenness index increased with the distance increase from the sea on the whole; natural vegetation reclamation in 2005 was less, and had no obvious rule. （3） In 2013 the reclamation area of Spartina alterniflora community in central position was the best. Suaeda salsa had the biggest height and crown width, high coverage and number far away the beach; overall with the reclamation years increasing Suaeda salsa growth showed variation trend. The changes were closely with the water and salt condition change.