底栖动物功能摄食类群对酸性矿山废水的响应

为研究底栖动物功能摄食类群对酸性矿山废水的响应机理及高岚河硫铁矿对香溪河生态环境的影响状况,2006年9月、11月及2007年1月、3月、5月、7月对高岚河3个河段12个样点(受损河段G1—G3、恢复河段G4—G8、对照河段D1—D4)底栖动物进行了调研,同时测定了各样点水体金属含量(Cd、Cr、Cu、Mn、Pb、Zn、Fe、Al、Ca和Mg)、pH值、电导、水温、总溶解性固体、盐度、溶氧、流速、水深、水面宽度等理化指标。对3个河段底栖动物群落功能摄食类群群落结构及理化指标进行了对比分析,结果表明,受酸性矿山废水的影响,受损河段金属含量及电导、总固体悬浮物明显高于对照河段和恢复河段,受损河段pH值显著低于其他河段;而对照河段和恢复河段各项理化指标不存在明显差异。共采集底栖动物213种,隶属7纲,59科,四节蜉(Baetis sp.)、侧枝纹石蛾(Ceratopsyche sp.)、锯形蜉(Serratella sp.)和扁蜉(Heptagenia sp.)为研究区域优势类群;功能摄食类群相对丰度收集者最大,刮食者和滤食者次之,捕食者和撕食者最小,分别为48.8%、20.6%、17.0%、9.0%、4.7%。受损河段底栖动物各功能摄食类群密度和生物多样性指数明显低于对照河段和恢复河段,且组成相对单一;刮食者对酸性矿山废水反应最为敏感。非度量多维标度排序和多响应置换过程分析表明,受损河段底栖动物各功能摄食类群群落结构同对照河段和恢复河段存在较大差异,而对照河段和恢复河段群落结构相似性较高。典型对应分析发现,矿山酸性废水的排放是影响底栖动物功能摄食类群分布的主要因素。

Response of macroinvertebrate functional feeding groups to acid mine drainage in the Gaolan River

To study the mechanism underlying the responses of macroinvertebrate functional feeding groups to acid mine drainage and the influence of the Gaolan River pyrite on the ecological environment of the Xiangxi River system, macroinvertebrates were quantitatively investigated at 12 sites along 3 sections (Impacted portion:G1-G3, Recovering portion:G4-G8, Control portion:D1-D4) of the Gaolan River in September and November 2006 and January, March, May, and July 2007; a total of 192 macroinvertebrate samples were collected. Simultaneously, water samples were collected at each site and transported to the laboratory, where their concentrations of 10 metallic elements (Cd, Cr, Cu, Mn, Pb, Zn, Fe, Al, Ca, and Mg) were determined using ICP-AES. Other physical and chemical parameters were measured in the field:pH, conductivity, water temperature, total dissolved solid, salinity, and dissolved oxygen were measured using HORIBA W-23; flow velocity was measured using a hydrometric propeller; water depth and width were measured using a band tape. Comparative analyses were performed to study the macroinvertebrates'' functional feeding groups, community structure, and physicochemical parameters among the 3 sections of the Gaolan River. The results showed that metal content, conductance, and total dissolved solids were significantly higher in the impacted section than those in the control and recovering parts, especially at site G1; and there were no significant differences between the control and recovery sections. A total of 213 taxa belonging to 7 classes and 59 families were collected; Baetis sp., Ceratopsyche sp., Serratella sp. and Heptagenia sp. were the dominant taxa, with relative abundances of 18.7%, 11.3%, 9.6%, and 7.2%, respectively. Gather-collector was the main functional feeding group in the Xiangxi River system, followed by scraper, predator, and filter-collector. The shredder feeding group only accounted for a small part, with relative abundances of 48.8%, 20.6%, 17.0%, 9.0%, and 4.7%, respectively. A one-way ANOVA was used to compare densities among the 3 river sections, and the main result showed that the functional feeding group density of impacted sites was significantly lower than those of other river sections. The same analysis was also used to analyze the biodiversity of the functional feeding groups among the 3 river sections. The results showed that the Shannon-Wiener diversity and richness of gathering-collectors, scrapers, and predators were lower in the impacted section than in the other 2 sections, but there were no differences between the control and recovering sections; the two indices of filter-collectors were highest in the control section, followed by the recovering section, and lowest in the impacted section. The diversity indices of Shredders in the control portion were significantly higher than those in the other 2 sections. Non-metric multidimensional scaling and multi-response permutation procedure analysis showed that the community structure of the macroinvertebrate functional feeding group in the impacted river section were significantly different from those of the control and recovering sections. Finally, canonical correspondence analysis was used to study the relationship between functional feeding group communities and physicochemical parameters, the results of which showed that acid mine drainage was the main factor impacting the community structures of macroinvertebrates functional feeding groups in the study area.