藻渡河流域大型底栖动物群落时空分布与水质生物评价

Temporal and spatial distribution of macrozoobenthos community and water quality bioassessment in the Zaodu River basin

为了探究藻渡河流域大型底栖动物的群落时空分布及水质现状,本研究于2016年8月(丰水期)、11月(枯水期)和2017年4月(平水期)对藻渡河流域的7个河段、24个采样点进行了生态调查。结果显示:共鉴定出32种大型底栖动物,隶属4门7纲,以水生昆虫为绝对优势类群,其优势分类单元相对丰度累计值达到69.26%。单因素方差分析显示(One-way ANOVA),藻渡河流域大型底栖动物密度和生物量组成具有显著的季节性差异,其平均值分别为69.5232 ind/m2和0.8355 g/m2。藻渡河流域7个河段大型底栖动物多样性指数(Shannon-Wiener、Margaler和Pielou指数)表现出明显的时空异质性,平水期>枯水期>丰水期;空间尺度上,自然河段[藻渡河上游(ZZS)、藻渡河中游(ZZZ)和藻渡河下游(ZZX)]>库坝区(ZDG),ZZS>ZZZ>ZZX,支流河段[马桑坎河(MSK)、鲤鱼河(LYH)和白台河(BTH)]>干流。RDA分析表明水温、溶氧和pH值等是影响藻渡河流域大型底栖动物的关键环境因子。三种水质评价方法中,BI和BPI生物指数适合藻渡河流域水质评价,调查区域内水质总体较好,并呈现出平水期和枯水期优于丰水期,支流优于干流的变化趋势。

Samples in 24 sampling sites, including seven typical sections during April(normal season),August(wet season) and November(dry season) were investigated on water environment and macrozoobenthos from 2016 to 2017 to explore the species composition and the temporal-spatial distribution of the macroinvertebrate and their relationship with environmental factors in the Zaodu River Basin and its tributaries.A total of 32 taxa(belonging to 7 classes and 4 phyla) were identified, among which the aquatic insects had the highest abundance, accounting for 69.26% of the total abundance.Significant seasonal differences were observed for macrozoobenthos′ density and biomass composition in the Zaodu River Basin, with the mean values of 69.523 2 ind/m2 and 0.835 5 g/m2,respectively.Furthermore, apparent temporal and spatial variations were obtained for the diversity indexes(Shannon-Wiener, Margaler and Pielou) in seven typical sections of the Zaodu River Basin, showing as the standard period>dry period>wet period in timescales.Spatially, the natural stream(ZZS,ZZZ and ZZX)>the dam area(ZDG),the upstream(ZZS)> the midstream(ZZZ)> the downstream(ZZX),and the tributary reach(MSK,LYH and BTH)>the mainstream.Redundancy analysis(RDA) showed that the water temperature, dissolved oxygen, pH and sediment were the critical environmental factors explaining the variation in the macroinvertebrate community in the Zaodu River Basin.Among the three water quality evaluation methods, the diversity indexes of the BI and BPI are suitable for the water quality evaluation of the Zaodu River basin.Overall, the water quality in the survey area was not polluted.The standard and dry periods were better than the wet periods, and the tributary was better than the mainstream.This study can provide essential data supporting ecological management and protection in the Zaodu River basin.