松花江下游底栖动物群落结构与水质生物学评价

1999—2005年对松花江下游江南屯断面及支流梧桐河断面进行了11次底栖动物生态调查.调查期间共发现底栖动物39种,其中水生昆虫21种,软体动物12种,环节动物4种,甲壳动物2种.江南屯与梧桐河底栖动物的种类组成呈现显著差异,在发现的39种底栖动物中,仅有14种于两断面都有分布.分布于江南屯断面的主要底栖动物及其出现率为:纹石蚕100%,箭蜓80%,黑龙江短沟蜷80%,钩虾80%,二尾蜉60%,细蜉60%,灯蛾蜉60%,东北田螺60%.分布于梧桐河断面的主要底栖动物及其出现率为:黑龙江短沟蜷100%,东北田螺100%,扁蛭100%,珍珠蚌60%.从栖息密度来看,梧桐河断面中软体动物密度最大, 优势种为东北田螺,江南屯断面则以水生昆虫占优势.此外,两断面的底栖动物数量在不同年份也存在显著变化.水质生物学评价结果表明,梧桐河断面多年处于中污染状态,江南屯断面的污染状况在总体上较梧桐河断面轻,这主要是由于梧桐河断面高负荷的耗氧有机物引起水体中溶解氧含量匮乏,从而导致底栖动物的生存条件严重恶化.      

长江流域鄂西四河流大型底栖动物群落结构特征及水质生物学评价

鄂西水系是国家级水源保护区，也是湖北省重要的生态旅游区。为了解鄂西水生态健康状况，于2014年10月~2017年1月不同时段在宜昌国家可持续发展实验示范区卷桥河（J）、清江利川段（Q）、宜昌市水源地黄柏河（H）和丹江口入库河流天河郧西段（T）开展了底栖动物群落特征研究。研究表明：4个河段共采集到大型底栖动物5门8纲18目61科。基于底栖动物指示种耐污性及其丰度占比分析，表明J、Q和T三河流污染程度沿水流方向呈加重趋势，而H水体健康状况整体较好。运用FBI和SIGNAL底栖生物评价指数，显示四条河流健康程度沿水流方向均呈下降趋势，但H变化趋势平缓，结果表明H水体上下游均处于较健康状态，其他3条河流上游或源头水体健康状况良好，下游受到较重污染。对主要环境因子（TP、NH₃-N、COD_Mn和TN）做主成分分析表明，轴1的解释率达到65.1%，表明轴1可以有效表征主要环境压力梯度。FBI和SIGNAL指数与轴1线性拟合度均较高，表明二者在鄂西河流水生态健康评估中可作为快速生物评价指数。     

澜沧江梯级水坝库区大型底栖动物群落结构及水质生物学评价

梯级水电开发虽然可以最大程度地利用河流的水能资源,但同时也是对河流生态系统的大规模扰动.大型底栖动物被认为是开展梯级水坝水生态系统变化和演替研究的指示生物类群.本文选取澜沧江中下游水电基地为研究区,于2016年开展漫湾和大朝山梯级水坝库区大型底栖动物群落采样调查,分析梯级库区大型底栖动物的群落结构和分布格局,基于生物指数(BI)开展水质生物学评价.结果表明:大型底栖动物物种组成以寡毛纲、软体动物门及昆虫纲的摇蚊类为主,优势种则以软体动物门的河蚬占绝对优势;群落密度和生物量分布格局表现为静水区显著高于过渡区;静水区功能摄食群密度组成以收集者(GC)和滤食者(FC)占优势,生物量组成则以滤食者(FC)占优势;ABC曲线和生物指数分析表明,上游漫湾库区群落稳定性及水质优于下游大朝山库区,反映了梯级水坝沿着河流纵向梯度水环境逐渐变差的趋势,澜沧江梯级水坝库区大型底栖动物群落结构、分布格局和库区水质状况受梯级水坝运行影响表现为明显的累积效应和富营养化效应.     

大型底栖动物快速评价指数BMWP在太子河流域的应用

大型底栖动物快速生物评价方法可快速判断河流在人为活动影响下的生态状况,对河流健康评价研究和河流保护与管理具有重要的意义。基于太子河46个样点的大型底栖动物监测数据,探讨大型底栖动物生物监测工作组(Biological Monitoring Working Party,BMWP)指数的适用性。采用方差分析研究了BMWP指数对重要水环境参数的响应程度,研究结果表明BMWP指数随地表水水质级别的降低呈显著地下降趋势。利用回归分析研究了BMWP指数与其他生物指数、生境状况的回归关系,结果显示BMWP指数与底栖动物香农多样性指数(R2=0.74)、底栖动物完整性指数(R2=0.85)以及生境质量评估指数(R2=0.60)均呈显著线性回归关系(p0.01),表明BMWP指数可以有效指示与反映不同河段的生物状况及其栖息地质量。利用BMWP指数对采样点进行的河流健康评价结果显示太子河46个采样点中,极好和良好的采样点占45.7%,一般的样点占21.7%,差和极差的样点为32.6%。BMWP指数对河流生态状况指示灵敏,能够准确反映河流健康状况。同时,野外监测、物种鉴定和指数计算简便,是河流健康评价中表征能力较强的快速生物评价指数。     

The Application of A Tiered Testing Approach to the Management of Dredged Sediments for Disposal at Sea in Canada

Canada, and other signatories to the London Convention 1972 on the prevention of marine pollution by dumping, are preparing to ratify a 1996 Protocol to this convention. Among the improvements to this international agreement, is a new process for the Assessment of Waste and Other Matter, which is to be adopted by signatory parties. the process includes a step in which material considered potentially acceptable for sea disposal must be characterized by chemical, physical and biological properties. Canada's interpretation and intended implementation of this characterization step is presented for the assessment of dredged sediments. This tiered testing approach involves using chemical screening limits for contaminants, and biological testing when screening levels are exceeded. Dredged material containing specified substances (e.g., cadmium, mercury, PAHs, PCBs, etc.) below or at screening levels would generally be considered of little environmental concern for disposal at sea. Wastes above the screening levels would require more detailed assessment before their suitability for disposal at sea could be determined.     

Status of Aquatic Bioassessment in U.S. EPA Region IX

U.S. EPA Region IX is supporting bioassessment programs in Arizona, California, Hawaii and Nevada using biocriteria program and Regional Environmental Monitoring and Assessment Program (R-EMAP) resources. These programs are designed to improve the state, tribal and regional ability to determine the status of water quality. Biocriteria program funds were used to coordinate with Arizona, California and Hawaii which resulted in these states establishing reference conditions and in developing biological indices. U.S. EPA Region IX has initiated R-EMAP projects in California and Nevada. These U.S. EPA Region IX sponsored programs have provided an opportunity to interact with the States and provide them with technical and management support. In Arizona, several projects are being conducted to develop the State's bioassessment program. These include the development of a rotational random monitoring program; a regional reference approach for macroinvertebrate bioassessments; ecoregion approach to testing and adoption of an alternate regional classification system; and development of warm-water and cold-water indices of biological integrity. The indices are projected to be used in the Arizona Department of Environmental Quality (ADEQ) 2000 water quality assessment report. In California, an Index of Biological Integrity (IBI) has been developed for the Russian River Watershed using resources from U.S. EPA's Non-point Source (NPS) Program grants. A regional IBI is under development for certain water bodies in the San Diego Regional Water Quality Control Board. Resources from the U.S. EPA Biocriteria program are being used to support the California Aquatic Bioassessment Workgroup (CABW) in conjunction with the California Department of Fish & Game (CDFG), and to support the Hawaii Department of Health (DoH) Bioassessment Program to refine biological metrics. In Nevada, R-EMAP resources are being used to create a baseline of aquatic information for the Humboldt River watershed. U.S. EPA Region IX is presently working with the Nevada Division of Environmental Protection (NDEP) to establish a Nevada Aquatic Bioassessment Workgroup. Future R-EMAP studies will occur in the Calleguas Creek watershed in Southern California, and in the Muddy and Virgin River watersheds in southern Nevada, and the Walker River watershed in eastern California and west-central Nevada.     

Methods development and use of macroinvertebrates as indicators of ecological conditions for streams in the Mid-Atlantic Highlands Region

The Mid-Atlantic Highlands Assessment (MAHA) included the sampling of macroinvertebrates from 424 wadeable stream sites to determine status and trends, biological conditions, and water quality in first through third order streams in the Mid-Atlantic Highlands Region (MAHR) of the United States in 1993–1995. We identified reference and impaired sites using water chemistry and habitat criteria and evaluated a set of candidate macroinvertebrate metrics using a stepwise process. This process examined several metric characteristics, including ability of metrics to discriminate reference and impaired sites, relative scope of impairment, correlations with chemical and habitat indicators of stream disturbance, redundancy with other metrics, and within-year variability. Metrics that performed well were compared with metrics currently being used by three states in the region: Pennsylvania, Virginia, and West Virginia. Some of the metrics used by these states did not perform well when evaluated using regional data, while other metrics used by all three states in some form, specifically number of taxa, number of EPT taxa, and Hilsenhoff Biotic Index, performed well overall. Reasons for discrepancies between state and regional evaluations of metrics are explored. We also provide a set of metrics that, when used in combination, may provide a useful assessment of stream conditions in the MAHR.     

Comparison of macroinvertebrate sampling methods for nonwadeable streams

Bioassessment of nonwadeable streams in the United States is increasing, but methods for these systems are not as well-developed as for wadeable streams. In this study, we compared six macroinvertebrate field sampling methods for nonwadeable streams adapted from those used by three major programs: the U.S. Environmental Protection Agencys Environmental Monitoring and Assessment Program-Surface Waters, the U.S. Geological Surveys National Water Quality Assessment Program, and the Ohio Environmental Protection Agency, Division of Surface Water Biocriteria Program. We performed all six methods at 60 sites across four rivers and measured water chemistry and physical habitat at each site to assess abiotic conditon. Sites were divided into two groups: those influenced by navigational lock and dam structures (restricted flow, or RF) and those free-flowing or with lowhead dams (run-of-the-river, or ROR). Metrics based on passive Hester-Dendy artificial substrate samplers differed greatly from active sampling methods (i.e., using nets) but represented abiotic conditions well in both ROR and RF sites. Although metric values were similar across certain sampling methods, the metrics significantly correlated with abiotic variables varied among methods and between ROR and RF sites. These results emphasize that methods are not interchangeable, and the ability to detect certain stressors depends on sampling method.The U.S. Governments right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

Impervious Surface Area as a Predictor of the Effects of Urbanization on Stream Insect Communities in Maine, U.S.A.

The influence of urbanization on stream insect communities was determined by comparing physical, chemical, and biological characteristics of streams draining 20 catchments with varyinglevels of urban land-cover in Maine (U.S.A). Percent total impervious surface area (PTIA), which was used to quantify urbanland-use, ranged from 1–31% among the study catchments.Taxonomic richness of stream insect communities showed an abruptdecline as PTIA increased above 6%. Streams draining catchmentswith PTIA < 6% had the highest levels of both total insect and EPT (Ephemeroptera + Plecoptera + Trichoptera) taxonomic richness. These streams contained insect communities with a totalrichness averaging 33 taxa in fall and 31 taxa in spring; EPT richness ranged from an average of 15 taxa in fall and 13 taxa inspring. In contrast, none of the streams draining catchments with6–27% PTIA had a total richness > 18 taxa or an EPT richness> 6 taxa. Insect communities in streams with PTIA > 6% were characterized by the absence of pollution-intolerant taxa. The distribution of more pollution-tolerant taxa (e.g.Acerpenna (Ephemeroptera); Paracapnia, Allocapnia (Plecoptera); Optioservus, Stenelmis (Coleoptera); Hydropsyche, Cheumatopsyche (Trichoptera)), however, showed little relation to PTIA. In contrast to the apparent threshold relationship between PTIA and insect taxonomic richness, both habitat qualityand water quality tended to decline as linear functions of PTIA.Our results indicate that, in Maine, an abrupt change in stream insect community structure occurs at a PTIA above a threshold ofapproximately 6% of total catchment area. The measurement of PTIA may provide a valuable tool for predicting thresholds for adverse effects of urbanization on the health of headwater streams in Maine.     

Assessing Ecological Integrity of Ozark Rivers to Determine Suitability for Protective Status

Preservation of extraordinary natural resources, protection of water quality, and restoration of impaired waters require a strategy to identify and protect least-disturbed streams and rivers. We applied two objective, quantitative methods to determine stream ecological integrity of headwater reaches of 10 Ozark rivers, 5 with Wild and Scenic River federal protective status. Thirty-four variables representing macroinvertebrate and fish assemblage characteristics, in-stream habitat, riparian vegetation, water quality, and watershed attributes were quantified for each river and analyzed using two multivariate approaches. The first approach, cluster and discriminant analyses, identified two groups of river with only one variable (% forested watershed) reliably distinguishing groups. Our second approach employed ordinal scaling to compare variables for each river to conceptually ideal conditions that were developed as a composite of optimal attributes among the 10 rivers. The composite distance of each river from ideal was then calculated using a unidimensional ranking technique. Two rivers without Wild and Scenic River designation ranked highest relative to ideal (highest ecological integrity), and two others, also without designation, ranked most distant from ideal (lowest ecological integrity). Fish density, number of intolerant fish species, and invertebrate density were influential biotic variables for scaling. Contributing physical variables included riparian forest cover, water nitrate concentration, water turbidity, percentage of forested watershed, percentage of private land ownership, and road density. These methods provide a framework for refinement and application in other regions to facilitate the process of establishing least-disturbed reference conditions and identifying rivers for protection and restoration.