硅藻群落结构的差异:比较样本采集过程与空间梯度

硅藻种群的分布与其所处的生境条件密切相关,但在实际过程中的一些人为因素,例如取样方法、样本的制备以及藻种鉴定都可能会干扰到种群结构的分析结果.因此很有必要探究这些人为因素是否会对真实的硅藻群落生态学研究产生误导性的判断,以免干扰硅藻生物水质评价的客观性.选取采样方法及样本制备为代表的人为因素对硅藻群落生态分析结果引入的误差大小进行评估.结果显示,子样本之间(同一样品重复制作的玻片样本)和样品之间(同一样点重复取样)群落结构差异大小分别是1.26%和1.97%,同一条河流的样点之间则为3.38%,而所选定的跨河流研究区域的样点间群落结构差异最大(42.03%).生态学的排序结果和数理统计分析表明,在硅藻群落结构分析中,现场取样方法和样本制备过程相对于不同生境条件所引起的变化,并不会带来较大的差异.因此在河流附生硅藻的群落生态学研究中,可基本不考虑取样方法等因子的干扰,而是侧重于环境因子对硅藻生态分布的影响.

Variation in diatom community structures:Comparison between sampling procedures and spatial gradients

The distribution of diatom is closely related to the habitat characteristics.But some anthropogenic factors, such as sampling method, sample preparation and species identification may affect the result of analyzing community structure.It is necessary to ensure no misleading judgments that would be generated by these factors in the diatom community ecology study because such misleading judgments may affect the evaluation of water quality.This paper was to quantify the amount of variability in community structure of benthic diatom, which related to sampling method and sample preparation.The results showed that the variability in community structure was minimal among sub-samples (repeated microscope slides of the same sample) and samples (repeated sampling at the same site), 1.26% and 1.97%, respectively.Differences in community structure were 3.38% at two sites located in the same river.Amount of dissimilarity in community structure across the streams was up to 42.03%.Multivariate analysis suggested that field sampling and sample preparation did not contribute to a large amount of variation in our analysis of diatom community structure that related to habitat conditions across sites.Therefore, in the study of diatoms community in river areas, emphasis should be put on the effects of environments rather than the factors about sampling methods.