鄱阳湖大型底栖动物群落结构的空间分布及影响因子研究

由于受人类活动干扰的加强以及受与长江干流之间"江湖关系"变化的影响,近年来鄱阳湖水生生态系统的状况及变化受到较多关注。对底栖动物群落结构的研究将有助于了解鄱阳湖生态系统结构现状及影响因子,对鄱阳湖保护对策的制定形成有效支撑。2016年7月,对鄱阳湖湖区(分别于鄱阳湖保护区和南矶山保护区)的底栖动物群落结构及相关环境因子进行了调查。调查共发现大型底栖动物27种,隶属于5门8纲,平均密度为48.40 ind.·m-2,其中主要以软体动物门为主;平均生物量为28.12 g·m-2,亦主要由软体动物门贡献。湖区主要优势种为河蚬(Corbicula fluminea)(优势度y=0.0655)、铜锈环棱螺(Bellamya aeruginosa)(y=0.0336)、霍甫水丝蚓(Limnodrilus hoffmeisteri)(y=0.0268)。底栖动物密度、生物量及多样性指数均呈现出鄱阳湖保护区高于南矶山保护区的格局,且二者在群落组成上有明显差异,鄱阳湖自然保护区主要以腹足纲和寡毛纲为主,南矶山自然保护区主要以瓣鳃纲和腹足纲为主。典范对应分析的结果显示,鄱阳湖保护区主要受到高水深、低浊度及高溶氧的影响;南矶山保护区各样点之间群落相似性较差,分别受不同因子的影响,这表明在各区域内部,局域微生境在局域群落结构的塑造上起主要作用,因此该区域内生态系统的保护应适当考虑空间尺度。

Patterns of the Macroinvertebrate Community in Poyang Lake and Related Environmental Factors

Aquatic ecosystem of Poyang Lake has been affected heavily by external disturbances in recent years, such as anthropogenic activities and the dramatic water level fluctuations caused by the mainstream of Yangtze River. The study about the macroinvertebrate community could provide an insight to the ecosystem status and help to make the effective protection strategies. Therefore, in July 2016, macroinvertebrates and the related environmental variables were surveyed in Poyang Lake area (Poyang Lake Nature Reserve (PR) and Nanjishan Nature Reserve (NR)). Finally, a total of 27 macroinvertebrate taxa were found, belonging to 5 Phylums and 8 Classes, with the mean density 48.40 ind. m^-2 which was mainly contributed by Mollusca. The mean biomass was 28.12 g m^-2, and also mainly contributed by Mollusca. Dominant species were Corbicula fluminea (dominance index y=0.0655), Bellamya aeruginosa (y=0.0336) and Limnodrilus hoffmeisteri (y=0.0268), respectively. The macroinvertebrate density, biomass and diversity index all showed a pattern that the values in PR was higher than that in NR, and the community composition was significant different between the two regions. Gastropoda and Oligochaeta dominated the PR area, while Lamellibranchia and Gastropoda dominated the NR area. Canonical Correspondence Analysis indicated that, NR area was mainly influenced by the relatively higher water depth, lower turbidity and higher dissolved oxygen, while the communities in NR area showed higher dissimilarity and were impacted by different factors. This implied that the local microhabitat played important roles in structuring the local community structures within each region. Therefore, the spatial scale should be considered properly for the protection of the Poyang Lake ecosystem.