黄河伊洛河中下游鱼类多样性及群落结构

为了解伊洛河中下游鱼类多样性、群落结构及其与环境因子的关系,于2016年2-12月对伊洛河中下游5个河段开展鱼类多样性及环境调查.共采集鱼类12361尾,43种,隶属于4目9科37属.伊洛河中下游鱼类群落的Shannon-Wiener多样性指数、Margalef丰富度指数、Pielou均匀度指数和Simpson指数变化范围分别为1.75~2.38、2.44~3.63、0.59~0.76和0.73~0.86.各指数均以西草甸河段最高.各河段优势种以（Hemiculter leucisculus）、似鳊（Pseudobrama simoni）、鲫（Carassius auratus）、兴凯鱊（Acheilognathus chankaensis）和鳑鲏属（Rhodeus）等小型或广适性鱼类为主.丰度/生物量比较（ABC）曲线显示,除西草甸河段外,各河段优势鱼类群落均受到不同程度的干扰.其中七里铺和黑石关鱼类群落处于严重干扰状态,以小型鱼类或大型鱼类的幼鱼为主.采用冗余分析方法分析了鱼类群落结构与环境因子的关系,发现除了河床、水流、捕捞等因子以外,氨氮、总磷浓度与pH是导致伊洛河中下游鱼类群落结构差异的主要影响因子.针对伊洛河鱼类多样性现状,建议加强流域水质监管,恢复河流连通性,推进保护区全面禁渔,开展生态修复等以恢复伊洛河河流健康.     

珠江干流梯级开发对鱼类的影响与减缓对策

2013年6—7月对珠江龙滩库尾至长洲坝下江段干支流鱼类进行了调查,共采集到鱼类6418尾,隶属于10目23科82属122种.分析了渔获物的种类组成与分布、生态类型、珍稀濒危特有鱼类采样情况、各江段群落相似度和鱼类多样性等,并与该区域鱼类历史记录进行了对比分析.总体来看,珠江干流梯级开发后,由于大坝阻隔、水文情势改变等,鱼类资源发生了较大变化,河海洄游性鱼类和河口鱼类受大坝阻隔影响分布范围变窄;珍稀濒危特有鱼类由于生境破坏,种群规模变小,濒危程度加剧;库中江段流水性鱼类种类数和资源量显著下降,静缓流鱼类成为优势种;外来鱼类种类多、分布广.对导致珠江干流鱼类资源衰退的其他原因进行了分析,主要包括过度捕捞、生境破坏、水污染和外来鱼类入侵等.针对珠江干流梯级开发及鱼类资源现状,提出了栖息地保护、河流连通性恢复、鱼类增殖放流站建设、生态调度、渔政管理和生态补偿等措施建议.     

Evaluation of aquatic ecological systems through dynamics of ichthyofaunal diversity in a Himalayan torrential river,Murti

The biodiversity hotspot region of the Eastern Himalayas consists of a vast freshwater network enriched with species diversity. Many small-scale torrential rivers and water reaches contribute to the species pool of all the major rivers by converging downstream. These reaches are most likely to be degraded at a faster rate as compared to the large-scale rivers following an increased rate of urbanization, habitat alterations, and changing climatic conditions. Therefore, this study aims to explore River Murti, which is a representative small scale river system characterized by a large altitudinal gradient and a diverse watershed area. Ichthyofaunal diversity (i.e., diversity, evenness & richness) and 21 environmental variables are measured through a tri-seasonal sampling effort conducted along 14 selected locations. A total of 41 fish species (including species belonging to 4 Near Threatened, 8 Vulnerable, and 1 Endangered) are found inhabiting this river. Ichthyofaunal assemblage is found to be primarily modulated by habitat diversity and landscape variables. Three Aquatic Ecological Systems (AES) have been identified along this river in a top-down approach based on recorded environmental variables. We have calculated an observed/expected ratio for each diversity indices along 14 locations based on predicted temporal variability using boosted regression (BRT) models. The evaluation of diversity status has been kept at 0.5 to account for a 50% loss or deviation from observed (O/E50). This evaluation has been successfully used to delineate AES1 with majorly “Impaired” status and thus ensures its importance in terms of species conservation. Our study indicates the contribution of 11 major environmental drivers modulating the species assemblage patterns in these AES. Amongst them, altitude, substrate coarseness, river morphology, and shelter availability are strongly associated with species diversity as per the BRT models. These underlying factors are also correlated with “basin pressure,” suggesting that anthropogenic disturbances, as well as the changing climate, might play an important role in the gradual change in environmental conditions, which in turn could cause a shift in species assemblage structure.     

基于多维度指数的雅鲁藏布江鱼类多样性评价及群落构建过程分析

雅鲁藏布江是我国西藏地区最大的河流,孕育着独特的水生生物资源。近年来随着人类活动的干扰与河流开发的推进,亟待对该流域水生生物多样性进行全面调查评估。本研究基于雅鲁藏布江全流域的鱼类资源调查数据,整合物种多样性、功能多样性和系统发育多样性3个维度12项指数,对该流域鱼类多样性进行评价分析。结果显示,24个调查样点中共采集到37种鱼类,隶属于3目7科24属;其中土著鱼类27种,外来鱼类10种;鲤形目鲤科鱼类为优势类群。基于Bray-Curtis相异度的层次聚类可将雅鲁藏布江鱼类群落划分为4组,表现为帕隆藏布汇口以上/以下江段及两个江段内干支流间存在较大差异,这与区域生物地理学过程及河流环境梯度密切相关。利用12项多样性指数对各组群的鱼类多样性进行评估,结果表明,除Simpson多样性指数、Pielou均匀度指数、平均配对种间系统发育距离指数和平均最近种间系统发育距离(MNTD)指数外,其他指数检测到组间的显著性差异。不同多样性指数之间的相关关系表现各异:与丰富度相关的多项指数间存在显著或极显著的正相关,功能离散度指数和MNTD指数与其他指数间多存在显著或极显著的负相关,表明不同类别的多样性指数各自具有独特的指示价值。基于群落功能性状结构和系统发育结构的检验结果显示,大多数样点驱动鱼类群落聚合的过程为种间竞争排斥,推测与雅鲁藏布江水体营养贫瘠、食物来源稀缺导致的种间营养竞争关系紧张有关。本文整合多维度多样性指数对雅鲁藏布江流域鱼类多样性及群落构建过程进行探究,以期为该流域鱼类资源保护和管理提供科学依据,也为应用多维度指数评价淡水鱼类多样性提供参考借鉴。     

Estimation of ecological high flow

Floods can destroy fish habitat. During a flood a fish has to seek shelters (refuges) to survive. It is necessary to know the maximum discharge that the fish can sustain against the strong current. Ecological and hydraulic engineers can simulate the flow condition of high flow for designing the refuge when restoring and enhancing the rivers are needed. Based on the average ratio of the mean and maximum velocities invariant with time, discharge and water level, this paper tries to introduce the concept of ecological high flow. The mean‐maximum velocity ratio can be used to estimate the mean velocity of the river. If the maximum velocity of the cross section is replaced by the maximum sustained swimming speeds of fish, the mean velocity of ecological high flow can be calculated with the constant ratio. The cross‐sectional area can be estimated by the gage height. Then the ecological high flow can be estimated as the product of mean velocity of ecological high flow multiplied by the cross‐sectional area. The available data of the upstream of the Dacha River where is the habitat of the Formosan landlocked salmon were used to illustrate the estimation of the ecological high flow. Any restoration project at Sonmou that try to improve the stream habitat can use the ecological high flow to design the hydraulic structure at suitable location to offer refuges for the Formosan landlocked salmon that is an endangered species in Taiwan Copyright © 2005 John Wiley & Sons, Ltd.     

Effects of fluvial processes and human activities on stream macro-invertebrates

Benthic macro-invertebrates are vital components of river ecosystems.The effects of fluvial processes and human activities on the distribution of macro-invertebrates were studied through field investigations and experiment.Sixty-one sampling sites on 31 rivers in China were selected to investigate the structures of macro-invertebrate assemblages.The rivers,according to their fluvial conditions,are classified as streams with a stable channel bed,degrading channel bed,aggrading channel bed,and intensive bed load motion.The structures of macro-invertebrate fauna for the four types of rivers are very different.Stable rivers have a large number of individuals,abundant fauna, and high biodiversity;while the density and taxa richness for degrading rivers are small,and those for aggrading rivers are much less;whereas the ecology of rivers with intensive bed load motion are the worst.This paper proposes that streambed stability is the primary influential factor shaping the structure of benthic macro-invertebrate communities.Organic pollution can obviously result in the decrease of biodiversity,in the simplification of macro-invertebrate structures,and in the distortion of functional feeding group composition.In a river with high total nitrogen content,the relative abundance of collector-gatherers is high,and that of collector-filterers,scrapers,shredders,and predators are low.Scrapers,shredders,and predators disappear in severely polluted rivers.The isolation of aquatic habitat results in a distinct decrease of individual numbers and taxa richness.This result demonstrates that the connectivity of aquatic habitat significantly affects macro-invertebrate assemblages.A practical method to calculate a Habitat Suitability Index(HSI) is proposed,integrating the effects of the primary physical(including biotic and abiotic) and chemical factors.The biodiversity and taxa richness increase non-linearly with HSI.     

Impact of reservoirs and channelization on lowland river macroinvertebrates: A case study from Central Europe

In order to assess and compare the ecological impacts of channelization and shallow lowland reservoirs, macroinvertebrate communities of a lowland metapotamal river below reservoirs with epilimnial release were studied. The study was carried out in the Dyje River (Czech Republic) at five sites located from 1.5 to 22.5 km downstream of the reservoir outfall. The five sites differed in the degree of channel modification from natural muddy banks to riprap regulation. Seven samples were collected during the years 1998 and 1999 at each site using a semiquantitative method. The data were processed using multivariate analyses and methods for assessing the ecological and functional structure of communities. Altogether, 261 species of benthic macroinvertebrates were recorded including several rare and threatened taxa. Based on the results of principal component analysis (PCA), most of the variability within the species data (the first PCA axis) was explained by the degree of channel modification, from natural muddy banks with aquatic vegetation to a man-made riprap. The second axis was strongly correlated with current velocity. The sites differed in species richness, total abundances, proportion of individual functional feeding groups, pattern of the distribution of the current preference groups, and values of several biotic indexes, all of which also corresponded to the degree of channel modification. Thus, the morphological man-made modifications of the river channel were found to be the main factor affecting lowland river macroinvertebrates and their biodiversity. Our results suggest that the biggest threat to benthic macroinvertebrate diversity of lowland rivers comes from channelization. The impact of reservoirs can be completely overwhelmed by the impact of channelization, especially when muddy banks with aquatic vegetation present a substantial part of habitat diversity and significantly contribute to the total species pool.     

基于鱼类生物完整性指数的广东鉴江流域环境质量评估

根据鉴江流域21个观测点鱼类调查所收集的数据,结合历史资料的记录,初步构建基于鱼类生物完整性评价的26个初选指标,并根据指标属性分类进行初筛,对10个通过的候选指标进行分布范围、判别能力和Pearson相关性分析,确定了由总的种类数占期望值的百分比、鲤科鱼类占总种类数的百分比、鳑鲏亚科鱼类占总种类数的百分比、耐受性强鱼类占总种类数的百分比和产漂流性卵鱼类占总种类数的百分比共5个主评指标组成的生物完整性指数体系,并用于鉴江流域部分河段的生态健康评价.结果表明,凌江鱼类完整性相对较好,罗江一般,平定水、袂花江和鉴江干流较差,小东江最差;鉴江流域大多数河段的综合健康状态处于较差状态,需要对鉴江流域进行生态修复以达到相对健康状态.评价结果与河流受人为干扰的实际情况相吻合,研究构建的评价体系可供周边地区使用和借鉴.     

Cost/benefit analysis of a benthic monitoring programme of organic benthic enrichment using different sampling and analysis methods

To investigate the combined effects of decreasing taxonomic resolution (i.e. species, family, phylum), the use of different mesh-size (1.0 mm and 0.5 mm) and the type of samplers used (van Veen vs. corers taken by divers) on the quality of data obtained, a comparative study was undertaken with the overall aim of identifying cost efficient methods for routinely monitoring the ecological change caused by Mediterranean fish farming. The results clearly showed that information loss was relatively low as data were aggregated at higher taxonomic levels, particularly up to the level of family or even order. It was also found that the extra information gained by sieving samples through a 0.5 mm sieve did not improve the ability to distinguish the potentially impacted sites from the control stations. Finally, it was found that a relatively large proportion of the available information concerning the community structure such as abundance, biomass or diversity is lost when sampling is carried out with corers. A cost/benefit ratio analysis for the two sampling and the two sieving methods showed minimal values for the van Veen samples (for both sieve fractions) at the family level, indicating that analysis at this level gives the best balance between precision of the results and decrease in taxonomic effort. However, if the time needed to sort the samples is included in the analysis, then samples taken with corers using a 0.5 mm sieve and identified to families seems like a good compromise between precision and cost.     

Ecological classification of macrophytes and phytobenthos for rivers in Germany according to the water framework directive

A new assessment system for macrophytes and phytobenthos in German rivers meeting the requirements of the Water Framework Directive (WFD) of the European Community is described. Biocoenotic types based on biological, chemical and hydromorphological data from over 200 river sites covering the main ecoregions, hydromorphological stream types and degradation forms have been defined. For developing a classification system the quality element macrophytes and phytobenthos was divided into three components: macrophytes, benthic diatoms and remaining phytobenthos. For macrophytes seven types including one subtype, for benthic diatoms 14 types including three subtypes and for the remaining phytobenthos five river types were identified. The benthic vegetation at reference condition was described for most of the river types. Degradation is characterised as deviation in benthic vegetation species composition and abundance from the reference biocoenosis. For classification in five ecological status classes, several metrics were developed and used in combination with existing indices. For some of the described river types additional investigations are necessary before a classification system can be developed.     

Development of a River Macrophyte Index (RMI) for assessing river ecological status

We present the process of developing a macrophyte based index (River Macrophyte Index – RMI) for assessing river ecological status, that would be applicable for rivers with moderate to high water alkalinity, flowing over low slope terrain. A reference value and boundary values were determined for five ecological classes. The relation between the developed index and two existing indices, the Reference Index (RI) and the Trophic Index of Macrophytes (TIM), and selected environmental variables was established. The RMI is based on species composition and abundance from 208 sampling sites being in reference or good hydromorphological conditions and differing in the catchment land use. The percentage of natural areas in the sub-catchment was used for classifying macrophyte taxa into 5 ecological groups. 65 plant taxa, of which 47 were identified as indicator taxa, were included in the analysis. To assess the ecological status of a river site, the presence of at least 3 indicator taxa is necessary, otherwise the assessment is considered inconclusive. RMI is expected to indicate multiple pressures on the river, including trophic level. The developed index and RI and TIM indices differed in relation to slope, distance to source and catchment size.     

Short-term impact of reservoir cleaning on the microhabitat use of three non-salmonid fishes in a piedmont river in south west France

As with many rivers of the Pyrenees Mountains, reservoirs on the River Ariège (SW Francc) are used for hydroelectricity generation, irrigation and to maintain summer flows in the River Garonne. Two river reservoirs on the River Ariège were simultaneously emptied in April 1991 to remove accumulated sediment. Fish and ten environmental variables were sampled using Point Abundance Sampling by electrofishing before (February 1991) and one year later (February 1992) at three study sites downstream of the dams. We examined the short-term impact of reservoir cleaning on the relative abundance, habitat availability and habitat use of three species of small fish: minnow Phoxinus phoxinus (L.), gudgeon Gobio gobio (L.) and stone loach Barbatula barbatula (L.).¶After the reservoir cleaning, areas covered by gravel, sand and mud increased significantly as the result of the sediment release. The three species did not react in the same manner to these environmental changes. Stone loach appeared to be the most sensitive species, with its relative abundance decreasing at all sites. Conversely, minnow seemed to be the most resistant species and as such is a leading pioneer species for colonizing new or impacted stretches of rivers channels. Finally, the number of gudgeon decreased particularly at the most downstream site where large deposits of mud were recorded.     

Gender of large river deltas and parasitizing rivers

Deltas are the most dynamic part of large rivers and the characteristics of deltas reflect the basic nature of morphodynamics,ecology and anthropogenic influence.The authors investigated many deltas of...     

Biliary fluorescent aromatic compounds (FACs) measured by fixed wavelength fluorescence (FF) in several marine fish species from the NW Mediterranean

The fixed wavelength fluoresce (FF) method was used to estimate the levels of fluorescent aromatic compounds (FACs) in the bile of fourteen fish species of commercial and/or ecological interest. Sampling was carried out in the NW Mediterranean at depths ranging from 50 to 1000 m during four seasonal cruises. During the summer sampling period, some species were also collected from another site (Vilanova fishing grounds) for comparison. Baseline levels of the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, pyrene and benzo[a]pyrene were measured. Some seasonality was observed, with reduced FF levels in summer and no differences among sites, consistent with sediment PAH levels. We discuss our results in relation to fish phylogeny, season, depth, diet, trophic level and swimming capacity. Overall FF levels indicated differences among species; the suprabenthic feeders from shallow and deep communities, and Mullus barbatus in particular, displayed elevated FF values and are potential candidates for additional monitoring studies.     

‘Natural’ rivers, ‘hydromorphological quality’ and river restoration: a challenging new agenda for applied fluvial geomorphology

Fluvial geomorphology is rapidly becoming centrally involved in practical applications to support the agenda of sustainable river basin management. In the UK its principal contributions to date have primarily been in flood risk management and river restoration. There is a new impetus: the European Union's Water Framework and Habitats Directives require all rivers to be considered in terms of their ecological quality, defined partly in terms of ‘hydromorphology’. This paper focuses on the problematic definition of ‘natural’ hydromorphological quality for rivers, the assessment of departures from it, and the ecologically driven strategies for restoration that must be delivered by regulators under the EU Water Framework Directive (WFD). The Habitats Directive contains similar concepts under different labels. Currently available definitions of ‘natural’ or ‘reference’ conditions derive largely from a concept of ‘damage’, principally to channel morphology. Such definitions may, however, be too static to form sustainable strategies for management and regulation, but attract public support. Interdisciplinary knowledge remains scant; yet such knowledge is needed at a range of scales from catchment to microhabitat. The most important contribution of the interdisciplinary R&D effort needed to supply management tools to regulators of the WFD and Habitats regulations is to interpret the physical habitat contribution to biodiversity conservation, in terms of ‘good ecological quality’ in rivers, and the ‘hydromorphological’ component of this quality. Contributions from ‘indigenous knowledge’, through public participation, are important but often understated in this effort to drive the ‘fluvial hydrosystem’ back to spontaneous, affordable, sustainable self‐regulation. Copyright © 2006 John Wiley & Sons, Ltd.     

Modelling basin-scale distribution of fish occurrence probability for assessment of flow and habitat conditions in rivers

Abstract

Flow regimes play an important role in sustaining biodiversity in river ecosystems. However, the effects of flow regimes on riverine fish have not been clearly described. Therefore, we propose a new methodology to quantitatively link habitat conditions (such as flow indices and physical habitat conditions) to the occurrence probability (OP) of fish species. We developed a basin-scale fish distribution model by integrating the concept of habitat suitability assessment with a distributed hydrological model in order to estimate the OP of fish, with particular attention to flow regime. A generalized linear model was used to evaluate the relationship between the probabilities of fish occurrence and major environmental factors in river sections. A geomorphology-based hydrological model was adopted to simulate river discharge, which was used to calculate 10 flow indices. The occurrence probabilities of 50 fish species in the Sagami River in Japan were modelled. For the prediction accuracy, field survey results that included at least five observations of both the presence and the absence of each species were required to obtain relatively reliable prediction (accuracy > 60%). Using the developed model, important habitat conditions for each species were identified, which showed the importance of low-flow events for more than 10 species, including Hypomesus nipponensis and Rhinogobius fluviatilis. The model also confirmed the positive effects of natural flow and the negative effect of river-crossing structures, such as dams and weirs, on the OP of most species. The suggested approach enables us to evaluate and project the ecological consequences of water resource management policy. The results demonstrate the applicability of the fish distribution model to provide quantitative information on the flow required to maintain fish communities.

Editor Z.W. Kundzewicz; Guest editor M. Acreman

Citation Sui, P., Iwasaki, A., Saavedra, V.O.C., and Yoshimura, C., 2013. Modelling basin-scale distribution of fish occurrence probability for assessment of flow and habitat conditions in rivers. Hydrological Sciences Journal, 59 (3–4), 618–628.     

Ecological condition,biodiversity and major environmental challenges in a tropical river network in the Bago District in South-central Myanmar: First insights to the unknown

Freshwater ecosystems in the Indo-Burma biodiversity hotspot face immediate threats through habitat loss and species extinction. Systems to monitor ecological status and trends in biodiversity are therefore crucially needed. Myanmar is part of Indo-Burma but with no past experience of biomonitoring in freshwaters. In this study, we aimed to assess the ecological and biodiversity status of a lowland river network in south-central Myanmar by identifying and quantifying pressures using macroinvertebrates as bioindicators. Novel data on water quality (nutrients, sediments and metals), hydromorphology (Morphological Quality Index; MQI), habitat quality (Litter-Siltation Index; LSI), land use, and macroinvertebrates were collected from 25 river sites. The dominant pressures on rivers were urban land use, inputs of untreated sewage, in-stream and riparian garbage littering, run-off from agricultural fields and plantations, as well as physical habitat degradation. Water chemistry data indicated inputs of sediments and nutrients to degraded streams, but no obvious metal pollution. The LSI and MQI indices indicated high perturbation in agricultural and urban areas, respectively. Ecological status was assessed using a first version of a modified Average Score per Taxon index (ASPT), while biodiversity was assessed by family richness within the orders Ephemeroptera, Plecoptera, Trichoptera, Coleoptera and Odonata (EPTCO), which was tested against the pressure gradient by principal component regressions. ASPT had high diagnostic capabilities (R² = 0.68, p < 0.001) and showed that the index can be used to evaluate ecological water quality in this region. Biodiversity, expressed as family richness, also declined along the gradient (R² = 0.59, p = 0.041), giving support to the fact that current land-use practices in this area are unsustainable.     

Zoogeomorphological behaviours in fish and the potential impact of benthic feeding on bed material mobility in fluvial landscapes

Foraging by benthivorous fish can affect bed material mobility and sediment flux. This paper collates evidence of benthic feeding effects at local scales and evaluates the possibility that large numbers of foraging fish, each of which accomplishes a small amount of geomorphic work when feeding, may have a cumulative effect across river systems. A first synthesis of research from several disciplines provides a deeper understanding of how fish disturb and condition bed materials with implications for sediment mobility. To evaluate the spatial extent of benthic feeding and therefore the potential for it to have a large-scale effect, the distribution of benthivorous fish is established across a large river network. After quality control, the dataset yields a comprehensive set of fish community information based on over 61 000 individuals and 30 species at 176 sites. The factors that are likely to mediate foraging and its geomorphological effectiveness are considered. A novel scoring system that incorporates three key controls (fish feeding behaviour, fish abundance and fish body size) is then applied across the river network to predict where geomorphologically effective benthic feeding is feasible and its possible relative magnitude. Our results demonstrate, for the first time, that the potential for zoogeomorphic impacts is widespread but variable in space as a function of community composition and the abundance of key benthivores. An initial calibration against measured field impacts suggests that benthic feeding may cause measurable geomorphological disturbance at more than 90% of sites in this large network. Together, previous work and this unique analysis suggest that benthic feeding is sufficiently effective and extensive to warrant additional research. Investigating the role of benthivorous fish in fluvial geomorphology is important because it may yield results that challenge the assumption that biota are irrelevant sources of energy in geomorphological systems. Key research questions and a roadmap to facilitate progress are identified. © 2018 John Wiley & Sons, Ltd.