漓江大型底栖动物群落时空分布及水质生物评价

于2012年1月(枯水期)和8月(丰水期)在漓江上游甘棠江段、中游大圩江段和下游福利江段采集到大型底栖动物样品共374个,采用均匀度指数、Margalef丰富度指数、Simpson指数和Shannon-Wiener指数分析了漓江大型底栖动物的多样性.结果表明,漓江水系大型底栖动物群落结构的时空分布差异显著,枯水期采集到42个分类单元、8632个底栖动物,物种数和个体数均少于丰水期采集到的46个分类单元、10842个底栖动物,但枯水期主要河段的物种多样性比丰水期要好.漓江中、下游大型底栖动物的功能摄食类群均以刮食者为主,表明中、下游生态系统的初级生产力属性要高于上游.采用BI指数(Biotic Index)对漓江各江段进行水质生物评价,结果显示,漓江水系枯水期的水生态质量要优于丰水期;上游和下游水生态质量相对较好,中游水生态质量较差.因此,建议在丰水期加强漓江中游大圩段的环境保护力度,提高漓江整体水生态质量.     

德兴铜矿废水对乐安江底栖动物群落的影响

对乐安江水系的底栖动物及其生活环境进行的研究表明，位于乐安江上游的德兴铜矿排出的大量酸性废水对主活在该水系中的底栖动物的分布及其群落结构会产生直接影响．废水中的各种污染物质，尤以重金属（特别是铜和铅、锌、镉）对底栖动物群落的抑制作用最大．在下游，随着同污染源距离的增加，河流的污染状况逐渐减轻，底栖动物种类多样性逐渐增加，清洁种类逐渐恢复．另外，河流水量的季节性变化对河流自身的净化作用会产生很大影响．     

辽河流域典型支流土地利用方式对大型底栖动物群落时空分布特征的影响

通过辽河流域典型支流(清河和凡河)不同土地利用类型区3个水期大型底栖动物及环境因子调查,研究土地利用方式对大型底栖动物分布特征的影响.结果表明,河流大型底栖动物群落四节蜉科(Baetidae)、扁蜉科(Heptageniidae)、纹石蛾科(Hydropsychidae)及石蝇科(Perlidae)等生物类群主要分布在辽河流域内林地为主的河流中;以耕地和居民点为主的土地利用方式下,河流大型底栖动物主要以摇蚊科(Chironomidae)类群为主;颤蚓科(Tubificidae)等寡毛类大型底栖动物在以城市发展为主的土地利用区域内河流中优势明显.河流中大型底栖动物生物多样性、丰富度及EPT%由高到低依次为林地耕地居民点城市,FBI值由低到高依次为林地耕地居民点城市.不同土地利用方式导致河流生境因子空间差异性显著,大型底栖动物群落相似性较低,且生物密度在空间上呈显著差异,但时间上差异不显著.底质、DO与大型底栖动物多样性等指数呈正相关关系,TN、TP、NH3-N、BOD5、CODCr与大型底栖动物生物指数呈不同程度负相关关系.生物与环境联合分析(BIO-ENV)表明,底质、DO、TN、BOD5是影响区域内大型底栖动物群落特征的最显著的主导环境因子.综合上述研究结果可得,土地利用方式通过对河流生境及水质产生影响,进而使大型底栖动物群落组成及多样性特征发生明显变化.     

海河流域河流生态系统健康评价

随着经济发展,人类活动对河流生态系统的胁迫日益强烈,生态系统健康状况受到严重威胁.本研究以海河流域2010年73个采样点的水质、营养盐和底栖动物指标为例,采用指标体系法,从化学完整性和生物完整性两方面评价了流域内河流生态系统健康.结果表明,海河流域河流生态系统健康状况整体较差,有72.6%的样点处于"极差"健康状态,同时表现出明显的地区集聚效应;河流水质与人类活动强度密切相关;海河流域水体富营养化趋势明显;流域内底栖动物多样性低,清洁物种较少.氨氮、总氮、总磷等营养盐指标是影响河流生态系统健康的关键因子,应从控制上述指标入手,遏制海河流域河流生态系统健康恶化.对于河流生态系统健康评价,多因子的综合评价法优于单因子评价法.     

人为活动对冈曲河大型底栖动物空间分布的影响

为监测人为活动对高海拔山区河流的影响,以香格里拉冈曲河为例,应用多维统计分析与排序分析,探讨大型底栖动物群落对人为活动的响应. 研究表明,冈曲河受到低浓度重金属污染,农业活动和水体富营养化程度相对较轻,总体水质状况符合国家地表水环境质量标准(GB3838—2002)Ⅰ,Ⅱ类水质标准. 聚类分析显示,大型底栖动物群落可分为4组:组Ⅰ(北支翁水河)与组Ⅱ(南支格咱河)采样点受人为活动的影响最轻;组Ⅲ采样点主要受开矿和农业活动影响;组Ⅳ采样点受重金属污染相对较重. 4组采样点在无度量多维标定法(NMS)排序轴上的分布差异明显,组Ⅰ与组Ⅱ采样点体现出空间分布差异,而人为活动主要影响组Ⅲ与组Ⅳ采样点. 随河级增加,底栖动物的群落结构除受到水深、河宽、水温、浊度和海拔高度等环境因子的影响外,组Ⅲ与组Ⅳ采样点影响底栖动物群落退化的主要因素为Cu,Pb和NO-₃-N. 石蛭科和毛缘蛾蚋为组Ⅰ采样点的指示种;叉襀和倍叉襀等敏感类群为组Ⅱ采样点的主要指示种;组Ⅲ的指示种为中耐污种短石蛾和蜉蝣,以及强耐污种寡毛类;涡虫为组Ⅳ采样点的指示种,表明涡虫具有较高的重金属污染耐受性.      

A BASKET SAMPLING TECHNIQUE FOR QUANTIFYING RIVERINE MACROBENTHOS1

ABSTRACT: A colonization basket sampling technique for quantifying macroinvertebrates in rubble bottom rivers is described. Basket samplers were compared to collections made using the Surber square foot sampler. Procedure for processing samples is described. Macrobenthos were more accurately quantified by basket samplers because both surface and subsurface habitats were sampled, no organisms were lost when samplers were removed from the river, substrata and associated fauna were retained for analysis, and the samplers were used efficiently in both pool and riffle areas. At the end of the colonization period the basket samplers contained one-half cubic foot of river bottom and macroinvertebrates spatially arranged within.     

Development and evaluation of a Macroinvertebrate Biotic Integrity Index (MBII) for regionally assessing Mid-Atlantic Highlands Streams

The Macroinvertebrate Biotic Integrity Index (MBII) was developed from data collected at 574 wadeable stream reaches in the Mid-Atlantic Highlands region (MAHR) by the U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment Program (EMAP). Over 100 candidate metrics were evaluated for range, precision, responsiveness to various disturbances, relationship to catchment area, and redundancy. Seven metrics were selected, representing taxa richness (Ephemeroptera richness, Plecoptera richness, Trichoptera richness), assemblage composition (percent non-insect individuals, percent 5 dominant taxa), pollution tolerance [Macroinvertebrate Tolerance Index (MTI)], and one functional feeding group (collector-filterer richness). We scored metrics and summed them, then ranked the resulting index through use of independently evaluated reference stream reaches. Although sites were classified into lowland and upland ecoregional groups, we did not need to develop separate scoring criteria for each ecoregional group. We were able to use the same metrics for pool and riffle composite samples, but we had to score them differently. Using the EMAP probability design, we inferred the results, with known confidence bounds, to the 167,797 kilometers of wadeable streams in the Mid-Atlantic Highlands. We classified 17% of the target stream length in the MAHR as good, 57% as fair, and 26% as poor. Pool-dominated reaches were relatively rare in the MAHR, and the usefulness of the MBII was more difficult to assess in these reaches. The process used for developing the MBII is widely applicable and resulted in an index effective in evaluating region-wide conditions and distinguishing good and impaired reaches among both upland and lowland streams dominated by riffle habitat.     

IMPACTS OF URBAN LANDUSE ON MACROINVERTEBRATE COMMUNITIES IN SOUTHEASTERN WISCONSIN STREAMS1

ABSTRACT: Macroinvertebrates were used to assess the impact of urbanization on stream quality across a gradient of watershed imperviousness in 43 southeastern Wisconsin streams. The percentage of watershed connected imperviousness was chosen as the urbanization indicator to examine impact of urban land uses on macroinvertebrate communities. Most urban land uses were negatively correlated with the Shannon diversity index, percent of pollution intolerant Ephemeroptera, Plecoptera, and Trichoptera individuals, and generic richness. Nonurban land uses were positively correlated with these same metrics. The Hilsenhoff biotic index indicated that stream quality declined with increased urbanization. Functional feeding group metrics varied across a gradient of urbanization, suggesting changes in stream quality. Proportions of collectors and gatherers increased, while proportions of filterers, scrapers, and shredders decreased with increased watershed imperviousness. This study demonstrated that urbanization severely degraded stream macroinvertebrate communities, hence stream quality. Good stream quality existed where imperviousness was less than 8 percent, but less favorable assessments were inevitable where imperviousness exceeded 12 to 20 percent. Levels of imperviousness between 8 and 12 percent represented a threshold where minor increases in urbanization were associated with sharp declines in stream quality.     

A biological assessment of best management practice effectiveness during intensive silviculture and forest chemical application

A multi-year study was conducted to evaluate the effectiveness of Florida's Best Management Practices (BMPs) for protecting aquatic ecosystems during intensive forestry operations and forest chemical applications. Five silviculture sites adjacent to stream systems were selected for study from major eco-regions of the state. Replicate stream bioassessments, using a multimetric approach (the Stream Condition Index), were conducted as part of a `before-after, control-impact' (BACI) study design. Bioassessment stations were established above and below the treatment area to determine pre-treatment reference and test conditions. Silviculture treatments of clearcut harvesting, intensive mechanical site preparation and machine planting were then completed, during which all applicable BMPs were adhered to. In addition, two sites received an herbicide application and one site was fertilized. Following the treatments, the sites were re-sampled at the same points both one year, and two years after the first bioassessment. No significant differences in the SCI were observed between the reference and test portions of the streams that could be attributed to the silviculture operations using BMPs. Hence, the study showed that BMPs provided protection to adjacent stream ecosystems, even during intensive silviculture and forest chemical applications.     

The influence of soil macroinvertebrates on primary biodegradation of starch-containing polyethylene films

The primary biodegradability of polyethylene (PE) films containing different percentages of cornstarch (0–50%) and other additives (prooxidant, oxidized polyethylene) was tested using four species of earthworms (Eisenia fetida, Lumbricus terrestris, Aporectodea trapezoides, Aporectodea tuberculata), three species of cockroaches (Periplaneta americana, Blaberus sp.,Blattella germanica), termites (Reticulotermes flavipes), sowbugs (Porcellio laevis), and crickets (Acheta domesticus). These studies were conducted to elucidate the potential role of soil macroinvertebrates in degrading starch/PE biodegradable plastics. The results of the macroinvertebrate bioassays indicate that crickets, cockroaches, and sowbugs consumed starch-containing PE films most readily. In addition, the degree to which the films were attacked and consumed was directly related to the starch content of the film. Films with oxidized polyethylene and those containing prooxidant (vegetable oil and a transition metal catalyst) were also consumed. None of the four species of earthworms tested or the termites showed any activity toward the starch/polyethylene films. These results have important implications for determining the fate of novel plastic formulations which claim to be biodegradable in natural environments. Studies such as these, coupled with studies on microbial degradation, will help provide the type of information needed to assess the environmental fate of biodegradable starch/PE plastics and fill the voids in the scientific database regarding this rapidly developing field.