鄱阳湖典型洲滩植物物种多样性季节动态特征

Seasonal Dynamic Characteristics of Species Diversity of Typical Hygrophilous Vegetation in Poyang Lakeshore Wetland

洲滩植物是湿地生态系统重要组成部分,在湿地生态系统物质循环与能量转换过程中起着关键作用。洲滩植物群落物种多样性体现湿地生态系统结构的稳定性与复杂性,对湿地生态系统健康与生态功能维持具有重要意义。本研究通过样方与样线调查法对鄱阳湖典型洲滩植物群落多样性进行了实地调查与分析。研究结果表明:鄱阳湖典型洲滩植物群落优势种重要值均值在0.5以上,在群落中占有主导地位;与春季相比,阿及苔草、水蓼、菰、香蒲和南荻等群落物种多样性在秋季有不同程度的下降,而虉草群落和灰化苔草群落物种多样性在秋季则有所升高;芦苇和南荻群落在互为伴生过程中可能由于生长机理不同和生态位重叠现象,二者Shannon-Wiener多样性指数呈现出此消彼长的关系,其中春季南荻群落物种多样性较高,秋季则以芦苇群落物种多样性较高。相关分析表明,鄱阳湖湿地典型洲滩植物群落物种多样性与生物量之间无明显相关性,生物量主要受到群落内优势种的类型、生长特性、繁殖方式,以及微地形的影响。

Hygrophilous vegetation plays a critical role in the processes of wetland ecosystem material circulation and energy transformation. Species diversity of hygrophilous vegetation communities can reflect the stability, as well as complexity of wetland ecosystem structure. Random subplots and sampling lines were utilized to investigate the typical hygrophilous vegetation communities in Poyang Lake wetland. Results showed that the average important values of dominant species of studied typical hygrophilous vegetation communities were above 0.5, which indicated their dominant status. Compared to those in spring, the diversity of Carex argi community, Polygonum hydropiper community, Zizania latifolia community, Typha angustifolia community and Miscanthus sacchariflor community declined in autumn. However, the biodiversity of Phragmites communis and Carex cinerascens community ascended in autumn, this is because that the dominance of the dominant species was weaken by delayed recession of water level, while frequently switching between grass beach and water brought substantial nutrients in autumn. Because of different growth mechanisms and niche overlapping, the diversity of Phragmites communis community and Miscanthus sacchariflor community had a reciprocal relationship along the seasons. At last, insignificant correlation was found between plant biomass and biodiversity indices.