河流水动力条件对大型底栖动物分布影响研究进展

大型底栖无脊椎动物(简称"底栖动物")是河流生态系统重要的生物类群,其组成与分布受河流水动力条件影响显著.对世界范围内不同气候带的7条大型河流的研究发现,底栖动物在河流纵向上展现出了明显的分布特征:①山区树线以上,粗颗粒有机物有限,直接收集者占绝对优势,其中流速大的河段以适应流水的摇蚊幼虫为主,流速低的河段以寡毛类为主.②树线以下的上游河段,充足的凋落物进入河流,流速大的河段以抗冲刷能力强的水生昆虫(如蜉蝣目)为主,流速低的河段以寡毛类和摇蚊幼虫为主.③中下游河段以及河口地区,河流比降小、水深大、流速小、底质较细,受一定程度的人类活动影响,寡毛类、摇蚊幼虫和软体动物等较为常见,其中寡毛类和软体动物主要栖息在淤泥底质中,摇蚊幼虫在沙质河中更为常见.底栖动物的物种数量及组成与底质的稳定性、河流含沙量、降水量等因素相关.水动力条件中的底质、含沙量及流速对底栖动物的影响最为显著:①底栖动物物种数随着底质粒径和稳定性的降低而减少,在卵石底质中达到最大值.②含沙量增加导致底栖动物的物种数和密度显著下降.③汛期水动力条件的改变直接导致底栖动物密度和优势种变化,汛期过后则优势种恢复,密度达到年内最大值.研究推测气候通过影响底栖动物食物网来影响其密度,而不是种类.建议今后增强气候变化对底栖动物食物网及密度综合影响的研究.     

Use of Maryland Biological Stream Survey Data to Determine Effects of Agricultural Riparian Buffers on Measures of Biological Stream Health

This study was undertaken to determine the importance of riparian buffers to stream ecology in agricultural areas. The original Maryland Biological Stream Survey (MBSS) data set was partitioned to represent agricultural sites in Maryland's Coastal Plain and Piedmont regions. ANOVA, multiple linear regression (MLR), and CART regression tree models were developed using riparian and site catchment landscape characteristics. MBSS data were both stratified by physiographic region and analyzed as a combined data set. All models indicated that land management at the site was not the controlling factor for fish IBIs (FIBI) at that site and, hence, using FIBI to evaluate site-scale factors would not be a prudent procedure. Measures of instream habitat and location in the stream network were the dominant explanatory factors for FIBI models. Both CART and MLR models indicated that forest buffers were influential on benthic IBIs (BIBI). Explanatory variables reflected instream conditions, adjacent landscape influence, and chemistry in the Coastal Plains sites, all of which are relatively site specific. However, for Piedmont sites, hydrologic factors were important, in addition to adjacent landscape influence, and chemistry. Both Coastal Plain and Piedmont CART models identified several hydrologic factors, emphasizing the dominant control of hydrology on the physical habitat index (PHI). Riparian buffers were a secondary influence on PHI in the Coastal Plain, but not in the Piedmont. Between 40% and 70% of the variation in FIBI, BIBI, and PHI was explained by the “easily obtainable” variables available from the MBSS data set. While these are empirical results specific to Maryland, the general findings are of use to other locations where the establishment of forest buffers is considered as an aquatic ecosystem restoration measure.     

丹江口水库底栖动物群落次级生产力空间分布

于2007年7月—2008年5月,分季度对丹江口水库底栖动物群落及水环境进行为期一年的调查。运用经验公式估算丹江口水库大型底栖动物群落的生产力,并分析底栖动物密度、生物量、生产力及P/B系数的空间分布,探讨环境因子与底栖动物群落生产力空间分布的关系。结果显示,丹江口水库底栖动物年平均密度、生物量及生产力分别为4 761 ind·m~(-2)、1.61 g DM·m~(-2)和35.45 g DM·m~(-2)·y~(-1),P/B系数为22.0 y~(-1)。不同区域生产力差异很大,湖泊区达61.80 g DM·m~(-2)·y~(-1),而支流区仅有5.48 g DM·m~(-2)·y~(-1)。P/B系数同样在湖泊区达到最大,为34.0 y~(-1);在丹江过渡区最低,为13.1 y~(-1)。颤蚓是生产力的主要贡献者,周年生产力为31.85 g DM·m~(-2)·y~(-1),占总生产力的90%。湖泊区由于其稳定的水动力条件,为颤蚓提供了非常适宜的生境,因此具有很高的生产力水平。与之相反,支流区由于水体扰动较大,底栖动物生物量及生产力水平均较低。从生产力的角度研究丹江口水库底栖动物群落的空间分布规律及影响因子,对丹江口水库的生态管理具有参考价值。     

北京河流大型底栖动物空间格局及其环境响应研究

大型底栖动物群落结构及多样性对于区域河流环境状况具有重要的指示意义。基于2014年5月—2015年8月间北京市河流大型底栖动物群落结构调查数据,分析底栖动物的生物多样性特征和空间格局。调查共发现大型底栖动物151种(或分类单元),隶属于5门9纲67科127属,水生昆虫占绝对优势。聚类分析表明76个采样点可被分为4组,组1主要包含北部山区的潮白河水系,具有较为典型的山溪型河流底栖动物特征,组2主要包含永定河山峡段和北运河水系的清河,组3主要包含大清河水系和北运河水系的温榆河、北沙河、南沙河等,二者具有城市河流兼有山溪型河流底栖动物的特征,组4主要包含北运河水系,具有典型的城市河流底栖动物特征。优势种分析表明:组1的优势种为热水四节蜉(Baetis thermicus)、秀丽白虾(Exopalaemon modestus)和网栖石蛾(Cheumatopsyche sp.),组2为直突摇蚊(Orthocladius sp.)、钩虾(Gammarus sp.)和长足摇蚊(Tanypus sp.),组3为摇蚊科幼虫(larvae of Chironomidae)和寡毛类(Oligochaeta),组4是以中华摇蚊(Chironomus sinicus)为代表的摇蚊幼虫。功能摄食类群研究表明:组1以收集者和滤食者占绝对优势,相对丰度分别为60%和29.6%;组2、组3、组4均以收集者占绝对优势,相对丰度分别为97.7%、90%、97.5%。物种数、Shannon-Wiener多样性指数、Pielou均匀度指数和Margalef丰富度指数的组间差异性显著(P0.05)。研究表明,北京河流大型底栖动物受河流自然环境变化的影响显著,形成了典型的山区-城市底栖动物空间格局,山区河流中保持了较高的生物多样性,城市河流及其过渡区的大型底栖动物退化明显,大型底栖动物能够明显指示环境状况的变化并可指导河流环境的保护与恢复。     

太子河流域大型底栖动物栖境适宜性

应用加权平均法和无度量多维标定(NMS)法,检测到影响太子河流域大型底栖动物空间分布最重要的栖境因子依次为底质、流速和水深. 对太子河流域大型底栖动物主要优势类群的栖境适宜度进行研究,结果表明:不同物种对生境表现出明显的趋异性,多数物种喜栖息在粗糙卵石底质的生境; 大型底栖动物的流速偏好性与其摄食方式、生活型和形体结构相关,对水深的偏好性差异较小. 对该流域主要优势种热水四节蜉(Baetis thermicus)的栖境适宜性研究表明,热水四节蜉偏好小卵石底质,最适流速为0.4 m/s,最适水深为0.2 m. 栖境适宜度指数的预测模型显示,热水四节蜉个体数在多数采样点的实测值小于预测值,表明除栖境指标外,其他的环境要素亦对该种的分布有重要影响.      

Analysis of macroinvertebrate assemblages in relation to environmental gradients among lotic habitats of California's Central Valley

We assessed relationships between environmental characteristicsand macroinvertebrate assemblages in lotic habitats of California's Central Valley with community metric and multivariate statistical approaches. Using canonical ordinationanalyses, we contrasted results when assemblage structure was assessed with macroinvertebrate metrics, as suggested for use inindices of biotic integrity, or with genera abundances. Our objectives were to identify metrics or taxa diagnostic of loticenvironmental stressors and compare the capacity of theseapproaches to detect stressors in order to suggest how they mightbe used to diagnose stressors. For macroinvertebrate metrics,redundancy analysis (RDA) extracted three axes correlated withchannel morphology and substrates. For genera abundances, canonical correspondence analysis (CCA) extracted two axescorrelated with soluble salts and with channel morphology andsubstrates but did not separate these gradients onto differentaxes. Cluster analyses identified five RDA and five CCA sitegroups, which exhibited differences for environmental variables,metrics, or genera abundances, and agreement between the analysesin partitioning of sites was greater than if sites were partitioned randomly. These approaches differ in their abilityto detect environmental stressors, because they measure differentaspects of assemblages and would be complementary in design ofnew metrics diagnostic of stressors.     

Use of man-made impoundment in mitigating acid mine drainage in the North Branch Potomac River

The US Department of the Army, Baltimore District Corps of Engineers, oversees a long-term monitoring study to assess and evaluate effects of the Jennings-Randolph reservoir on biota in the North Branch Potomac River. The reservoir was intended, in part, to mitigate effects of acid mine drainage originating in upstream and headwater areas. The present study assessed recovery of benthos and fish in this system, six years after completion of the reservoir. Higher pH and lower iron and sulfate concentrations were observed upstream of the reservoir compared to preimpoundment conditions, suggesting better overall water quality in the upper North Branch. Water quality improved slightly directly downstream of the reservoir. However, the reservoir itself was poorly colonized by macrophytes and benthic organisms, and plankton composition suggested either metal toxicity and/or nutrient limitation. One large tributary to the North Branch and the reservoir (Stony River) was shown to have high (and possibly toxic) levels of manganese, iron, zinc, and aluminum due to subsurface coal mine drainage. Macroinvertebrate diversity and number of taxa were higher in sites downstream of the reservoir in the present study. Compared with previous years, the present study suggested relatively rapid recovery in the lower North Branch due to colonization from two major unimpacted tributaries in this system: Savage River and South Branch Potomac. Abundance of certain mayfly species across sites provided the most clear evidence of longitudinal gradients in water quality parameters and geomorphology. Fish data were consistent with macroinvertebrate results, but site-to-site variation in species composition was greater. Data collected between 1982 and 1987 suggested that certain fish species have unsuccessfully attempted to colonize sites directly downstream of the reservoir despite the more neutral pH water there. Our results show that recovery of biota in the North Branch Potomac was attributed to decreased acid inputs from mining operations and dilution from the Savage River, which contributed better water quality. Continued improvement of North Branch Potomac biota may not be expected unless additional mitigation attempts, either within the reservoir or upstream, are undertaken.     

Macroinvertebrate assemblages of surface mine wetlands of Southwest Virginia,USA

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Are pharmaceuticals more harmful than other pollutants to aquatic invertebrate species: a hypothesis tested using multi-biomarker and multi-species responses in field collected and transplanted organisms

The aim of this study was to test if pharmaceuticals could explain observed responses of field collected and transplanted invertebrate species (Hydropsyche exocellata, Echinogammarus longisetosus, and Daphnia magna). The study was performed in the middle and lower course of Llobregat river basin, which is affected by pharmaceuticals and other pollutants coming from sewage treated effluents. Up to 10 different endpoints including enzyme activities related with detoxication mechanisms (i.e. glutathione S transferase, catalase, esterases), the oxidative stress damage marker (lipid peroxidation), and individual responses (mortality, post-exposure feeding rates) were assessed. Biological responses were complemented with a detailed chemical analysis of metals, detergents, pesticides, pharmaceuticals and other general water quality variables to allow identifying causal abiotic factors. Estimated hazard indexes of measured pollutants indicated that pesticides and metals accounted for most of the predicted toxicity (>95%) in the most contaminated site and that the predicted toxicity of pharmaceuticals was marginal (<5%). The three species showed a clear impact across the studied gradient indicated by higher levels of feeding inhibition and of mortality towards lower reaches. Specific responses such as inhibition of cholinesterase activities were closely related to high and presumable toxic levels of diazinon, whereas unspecific responses such as enhanced levels of antioxidant defensive mechanism and of lipid peroxidation levels were associated with most pollutant classes as well as with high and presumable toxic levels of salt and ammonia. These results indicate that pesticides, salinity, ammonia probably had greater effects on the studied species than pharmaceuticals.     

An Evaluation of Qualitative Indexes of Physical Habitat Applied to Agricultural Streams in Ten U.S. States1

Hughes, Robert M., Alan T. Herlihy, and Philip R. Kaufmann, 2010. An Evaluation of Qualitative Indexes of Physical Habitat Applied to Agricultural Streams in Ten U.S. States. Journal of the American Water Resources Association (JAWRA) 46(4): 792-806. DOI: 10.1111/j.1752-1688.2010.00455.x Abstract: Assessment of stream physical habitat condition is important for evaluating stream quality globally. However, the diversity of metrics and methods for assessing physical habitat condition confounds comparisons among practitioners. We surveyed 51 previously sampled stream sites (0.0-6.3 m wide) located in regions of row-crop agriculture in Oregon, California, North Dakota, South Dakota, Nebraska, Iowa, Minnesota, Pennsylvania, Maryland, and West Virginia to evaluate the comparability of four indexes of physical habitat condition relative to each other. We also compared the indexes to previously calculated indexes of fish and macroinvertebrate condition. The physical habitat indexes included the Stream Visual Assessment Protocol Version 2 of the Natural Resources Conservation Service, the qualitative habitat evaluation index of the Ohio Environmental Protection Agency, the rapid bioassessment protocol of the United States Environmental Protection Agency (USEPA), and a qualitative physical habitat index based on USEPA quantitative physical habitat measurements. All four indexes were highly correlated with each other, but low-to-moderately correlated with biotic index scores for fish and macroinvertebrate assemblages. Moderately high correlations occurred between some macroinvertebrate biotic index scores and quantitative metrics. We conclude that additional research is needed to increase the predictive and diagnostic capabilities of qualitative physical habitat indexes.