澜沧江下游水生生态环境空间分异特征分析

Spatial Characteristics for Aquatic Ecological Environment of the Lancangjiang River Downstream

摘要: 本文以澜沧江下游为研究区域，调查分析浮游植物/动物的物种数、密度以及生物多样性等生态指标的空间变化。结果表明：澜沧江下游区域浮游植物共有80种，以蓝藻门、绿藻门和硅藻门最常见；总体上浮游植物种类数以及细胞数量由上游至下游逐渐下降的趋势；多样性指数、均匀度指数和多样性阀值均较大，说明该流域浮游植物群落组成的稳定性大、水域生态环境良好。同时，发现浮游动物37种，轮虫类占据绝对优势；浮游动物种类数量以及浮游动物密度由上游至下游区域呈现出波动下降的趋势；浮游动物的生物多样性指数、均匀度指数和多样性阀值均较大，说明研究区段浮游动物群落稳定性较高，水域生态环境较好。此研究表明澜沧江下游区域的水生态环境总体较好，但存在中小程度的污染或者干扰。

Abstract: This paper investigated the spatial characteristics of aquatic ecological environment of Lang-cangjiang River along the downstream zones. There were several ecological indicators selected to be analyzed, including species composition, density, dominant species and diversity of both the phytoplankton and zooplankton communities. The result showed that there were 80 species and the dominant species included Bacillariophyta, Chlorophyta, Cyanophyta. In general, the number of species and cell density of phytoplankton decreased along the upstream-to-downstream gradient. Moreover, there were high levels of species diversity, evenness and threshold value of species diversity. This supports that the aquatic ecological environment is under a safe condition, and the species composition of phytoplankton is stable in this area. There were 37 species of zooplankton including Rotifera, Cladocera and Copepods. Rotifera was the dominant species. The number of species and cell density of zooplankton decreased with some fluctuation along the upstream-to-downstream gradient in this area. There were also high levels of species diversity, evenness and threshold value of species diversity of zooplankton. It was more supported that aquatic ecological was under safe condition and species composition of zooplankton. All the analysis showed that Landcangjiang River was under relatively healthy condition, although it was disturbed by some human activities and pollution.