鄱阳湖湿地灰化苔草草甸群落特征及多样性

Investigation on community characteristics and α-diversity of Carex cinerascens meadow steppe in Poyang Lake wetland

灰化苔草(Carex cinerascens)是鄱阳湖湿地草甸的主要建群种,对鄱阳湖生态系统功能的发挥起着重要作用。本研究于2010年采用样方法对吴城地区鄱阳湖湿地灰化苔草草甸3个样地的植被组成、盖度、高度、地上生物量及物种多样性等特征进行了调查分析。结果表明,研究区内群落组成简单,植物种类比较贫乏,主要植物种仅8种,优势种为灰化苔草。3个样地中的物种丰富度、多样性指数和优势度指数最高分别为0.88、1.35和0.65,最低分别为0.46、0.46和0.23。相关分析表明,苔草草甸群落物种多样性更多地受丰富度的影响。苔草群落盖度为63.27%～100%,高度为4.25～14.12cm,地上生物量为1 377～3 080kg.hm-2,均低于以往调查数据。水位的变化和放牧干扰可能是影响鄱阳湖苔草草甸群落特征的主要因素。

Carea cinerascens, which is one of main constructive species at meadow steppe in wetland of Poy- ang Lake, plays an important role in functioning Poyang Lake ecosystem. A research of simple investiga- tion was conducted to determine the species composition, community coverage, height, aboveground bio- mass and species s-diversity of C. cinerascens meadow steppe in three plots located in Wutown, Jiangxi province in 2010. The results showed that species composition of C. cinerascens community was simple and only 8 main species were observed in these plots, among which C. cinerascens was dominant. The highest and lowest values of Margalef richness index, Shannon-Wiener diversity index and Simpson sominance index of C. cinerascens community in three plots were 0.88, 1.35, 0.65 and 0.46, 0.46, 0.23, respective- ly. It was suggested by correlation analysis that Margalef richness index was more closely associated with the species diversity of C. cinerascens community. The community coverage（63.27 % -- 100 % ）, community height（4.25--14. 12 cm） and aboveground biomass（1 377--3 080 kg. ha 1） were lower than those in average years. Variation of water level and grazing disturbance may be responsible for the changes of C. cinerascens community in Poyang Lake wetland.