Using the salinity preferences of benthic macroinvertebrates to classify running waters in brackish marshes in Germany

Marshland streams along European coastlines are typically located in the transition zone from limnic to brackish conditions. They constitute a distinct and important stream type within the German stream typology, which is predominantly characterised by tidal influence and salinity. According to the Water Framework Directive (WFD) the basis for the abiotic classification of European transitional and coastal waters is the ‘Venice System’ (Weber, M., 2005. Ergebnisse der Bestandsaufnahme 2004 zur Umsetzung der europäischen Wasserrahmenrichtlinie (WRRL) in den Küstengewässern Mecklenburg-Vorpommerns. Rostocker Meeresbiol. Beitr. 14, 7–15). However, the extreme spatial and temporal variability in salinity and tidal influence determines and controls the macroinvertebrate communities of marshland river and stream ecosystems and hampers the application of the ‘Venice System’. Earlier, purely biotic classifications of brackish waters typically classify different brackish water zones, each with a specific macroinvertebrate community, and often yield unsatisfactory results due to the extensively dynamic abiotic factors found in marshland streams. In practice, the permanent impact of tidal charge means that stable salinity zones do not exist. This effect can than be intensified by freshwater discharges after heavy rainfall or high tides in combination with strong winds that hinder discharge into the open sea. To overcome the restricted applicability of abiotic and biotic classification systems, we present a scoring system for marshland streams that combines the abiotic salinity classes of the ‘Venice System’ with the salinity preferences of the macroinvertebrate community. This proposal is based on literature data for macroinvertebrate salinity tolerances and preferences. According to the 137 references that were evaluated, 151 macroinvertebrate taxa were classified into six salinity groups. In a second step, we applied this scoring scheme to empirical data from two official quality assessment surveys. These surveys had been carried out in ten estuary tributaries of German marshland areas in Lower Saxony and Schleswig-Holstein in order to implement the WFD. Applying the scoring system to these data revealed a clear (and expected) gradient that was not expressed in the abiotic data. Thus we conclude that the biotic salinity preferences of benthic macroinvertebrates are a useful baseline metric for the ecological assessment of marshland streams and other transitional waters. Regional revision and adaptation of taxonomic salinity preferences would broaden the applicability of this assessment to transitional waters worldwide.     

A list of macroinvertebrates in Dutch water types: A first step towards an ecological classification of surface waters based on key factors

An ecological classification of surface waters in the Netherlands is presented. This classification is based on literature data and the authors opinions concerning the habitat range of macroinvertebrate taxa. Water types were defined by key factors. Taxa were assigned to these water types and provided with a characterizing weight. The list may be a useful tool in the ecological management of waters.     

The efficacy of DNA barcoding in the classification,genetic differentiation,and biodiversity assessment of benthic macroinvertebrates

Macroinvertebrates have been recognized as key ecological indicators of aquatic environment and are the most commonly used approaches for water quality assessment. However, species identification of macroinvertebrates (especially of aquatic insects) proves to be very difficult due to the lack of taxonomic expertise in some regions and can become time‐consuming. In this study, we evaluated the feasibility of DNA barcoding for the classification of benthic macroinvertebrates and investigated the genetic differentiation in seven orders (Insecta: Ephemeroptera, Plecoptera, Trichoptera, Diptera, Hemiptera, Coleoptera, and Odonata) from four large transboundary rivers of northwest China and further explored its potential application to biodiversity assessment. A total of 1,144 COI sequences, belonging to 176 species, 112 genera, and 53 families were obtained and analyzed. The barcoding gap analysis showed that COI gene fragment yielded significant intra‐ and interspecific divergences and obvious barcoding gaps. NJ phylogenetic trees showed that all species group into monophyletic species clusters whether from the same population or not, except two species (Polypedilum. laetum and Polypedilum. bullum). The distance‐based (ABGD) and tree‐based (PTP and MPTP) methods were utilized for grouping specimens into Operational Taxonomic Units (OTUs) and delimiting species. The ABGD, PTP, and MPTP analysis were divided into 177 (p = .0599), 197, and 195 OTUs, respectively. The BIN analysis generated 186 different BINs. Overall, our study showed that DNA barcoding offers an effective framework for macroinvertebrate species identification and sheds new light on the biodiversity assessment of local macroinvertebrates. Also, the construction of DNA barcode reference library of benthic macroinvertebrates in Eurasian transboundary rivers provides a solid backup for bioassessment studies of freshwater habitats using modern high‐throughput technologies in the near future.     

Young-of-the-year fish assemblages as an alternative to adult fish monitoring for ecological quality evaluation of running waters

Studies on the Upper Mississippi River, particularly over the last 15 years, have contributed to our understanding of trophic processes in large rivers. The framework established by earlier population-specific studies, however, cannot be overlooked. Examination of the feeding habits of fish ranging from planktivores to piscivores gave the first indication that trophic processes were influenced by the spatial complexity and annual hydrological patterns of river-floodplain ecosystems. Experimental studies, which have often been considered impossible or impractical in large rivers, demonstrated the potential for biotic controls of system dynamics through predator–prey and competitive interactions. Such studies have been particularly helpful in understanding the potential impact of non-native species, including zebra mussels and Asian carp, to biodiversity and secondary production. Our understanding of riverine ecosystem function expanded greatly as food web studies began the application of a new tool—natural stable isotopes. Studies employing stable isotopes illustrated how food webs in a number of large rivers throughout the world are supported by the autochthonous production of microalgae. This study, coupled with other studies testing the prevailing models of riverine ecosystem function, has brought us to a point of better understanding the nature of river ecosystem functions. It is through looking back at the earlier studies of fish diet that we should realize that the temporal and spatial complexities of river ecosystem function must still be addressed more fully. This and a better grasp of the significance of the arrangement of patches within the riverine landscape will prove beneficial, as we assess the appropriate scale of river rehabilitation with an eye on how rehabilitation promotes productivity within complex ecosystems, including the Upper Mississippi River.     

DIATMOD: diatom predictive model for quality assessment of Portuguese running waters

A predictive model for diatoms based on an adaptation of the River Invertebrate Prediction and Classification System/Australian River Assessment System approaches was evaluated as an effective tool for measuring stream ecological quality. This type of model was originally developed in UK and later in Australia and is extensively used to obtain ecological quality assessments with macroinvertebrates. The first step for the model construction was the definition of six consistent reference biological groups (ANOSIM: Global R = 0.77; P < 0.001) after classification (UPGMA) and ordination (nMDS) of 120 reference sites containing 254 different diatom taxa (species and infra-specific rank). A set of five environmental variables (slope, hydrological regime, mean annual temperature, mean annual precipitation and alkalinity) correctly discriminated 67% of reference sites (stepwise forward discriminant analysis, Jackknifed classification). The model was statistically accurate (slope = 1.07, intercept = −0.68, R ² = 0.65) and was validated by an independent set of reference data (13 reference sites; 70% correct answers). In addition, the model was tested by running data from 113 potentially disturbed sites. The model (DIATMOD) was well correlated with a general abiotic degradation gradient (Spearman correlations, R ² = 0.53, P < 0.001; and PCA analysis) and also with several specific pressure variables such as nitrates, phosphates, urban area, connectivity and land use (P < 0.001). Most diatom indices assess chemical contamination and we showed here that through predictive modelling the potential of diatoms as bioindicators increases as they also responded to hydromorphological changes. Further investigation on model potential consists in: testing different probability levels for taxa inclusion (here it was >0.5 as the most common models); comparing with alternative classification systems; assessing the influence of substrate type and seasonal variation in assessments.     

松花江流域大型底栖动物群落结构与水质评价

【目的】松花江流域是中国最早的工业基地之一,其水生态环境遭到严重破坏,环境保护工作面临巨大挑战。开展松花江流域水质评价及典型生物类群多样性状况调查,可为松花江流域生态系统的保护和修复提供依据。【方法】于2016年7月调查整个松花江流域近岸的大型底栖动物群落组成和测定水质理化指标,开展其水质理化特征评价和生物指数评价,并探讨底栖动物群落分布与水环境因子间的关系。【结果】理化指标评价结果显示,南源松花江水质状况最差,处于中度污染;北源松花江处于轻度污染;梧桐河水质最好,处于良好状态。松花江流域3个河段的底栖动物群落结构存在空间差异性。另外,梧桐河的物种多样性最高,北源松花江次之,南源松花江最低。溶解氧和营养元素K的浓度是驱动底栖动物群落组成发生显著性差异的主要环境因子。生物指数评价结果显示,3个河段水质均处于轻度污染状态。【结论】松花江流域水质处于轻度到中度污染状态。有机污染是松花江流域面临的主要水质环境问题,对松花江流域底栖动物群落结构产生了显著影响。因此,控制有机质的输入是维持松花江流域水生态系统平衡的重要举措之一。     

Morphological alterations of lake shores in Europe: A multimetric ecological assessment approach using benthic macroinvertebrates

Besides pollution, lakes are affected by human alterations of lake-shore morphology. However, ecological effects of such alterations have rarely been studied systematically. Hence, we developed tools to assess the ecological effects of anthropogenic morphological alterations on European lake-shores based on pressure-specific response patterns of littoral macroinvertebrate community composition. Littoral invertebrates were sampled from 51 lakes in seven European countries. Sampling covered a range of natural to heavily morphologically degraded sites including natural shorelines, recreational beaches, ripraps and retaining walls. Biological data were supplemented by standardized morphological data that were collected via a Lake Habitat Survey (LHS) protocol and subsequently used to develop a morphological stressor index. Two biotic multimetric indices were developed based on habitat-specific samples (Littoral Invertebrate Multimetric based on HAbitat samples, LIMHA) and composite samples (Littoral Invertebrate Multimetric based on COmposite samples, LIMCO) through correlations with the morphological stressor index. Similarity analyses showed strong spatial differences in macroinvertebrate community composition between four main geographical regions, i.e. Western, Northern, Central and Southern Europe. The morphological stressor index as well as LIMCO and LIMHA have been developed for each geographical region specifically, thereby optimizing correlations of LIMCO and LIMHA with the respective morphological stressor index. The metric composition of LIMCO and LIMHA and their correlation coefficients with the morphological stressor index are comparable to existing national and regional methods that assess morphological lakeshore degradation via macroinvertebrate communities. Hence, LIMCO and LIMHA indices constitute a new stressor-specific assessment tool that enables comparable lake morphology assessment across Europe, as it has been developed involving a uniform methodology followed by regionalized optimization. These tools fulfil the standards of the EU Water Framework Directive and thus may complement existing assessment approaches used in lake monitoring focusing solely on lake eutrophication so far.     

Hydromorphological restoration of running waters: effects on benthic invertebrate assemblages

1. River restoration has received considerable attention, with much recent focus on restoring river hydromorphology to improve impoverished aquatic communities. However, we still lack a clear understanding of the response of aquatic biota to river restoration. 2. We studied the effects of hydromorphological restoration on benthic invertebrate assemblages in 25 river sites in Germany using standardised methods. Restoration efforts were primarily aimed to restore habitat heterogeneity; correspondingly, habitat diversity increased at most sites. 3. Similarity of benthic invertebrate assemblages between restored and unrestored river sections was low (mean similarity was 0.32 for Jaccard and 0.46 for Sørensen). Community‐based metrics, such as the percentage of Ephemeroptera, Plecoptera and Trichoptera taxa, also differed between restored and unrestored sections. 4. Only three of the 25 restored sections were classified as having ‘good ecological quality’ class according to the European Water Framework Directive criteria; hence, poor water quality is probably one factor impeding recolonisation. 5. Our results show that isolated restoration measures do not necessarily result in positive effects on aquatic biota and that better understanding of the interconnectedness within a catchment is required before we can adequately predict biotic responses to structural river restoration.     

Effect of ecological group classification schemes on performance of the AMBI benthic index in US coastal waters

The AZTI Marine Biotic Index (AMBI) requires less geographically-specific calibration than other benthic indices, but has not performed as well in US coastal waters as it has in the European waters for which it was originally developed. Here we examine the extent of improvement in index performance when the Ecological Group (EG) classifications on which AMBI is based are derived using local expertise. Twenty-three US benthic experts developed EG scores for each of three regions in the United States, as well as for the US as a whole. Index performance was then compared using: (1) EG scores specific to a region, (2) national EG scores, (3) national EG scores supplemented with standard international EG scores for taxa that the US experts were not able to make assignments, and (4) standard international EG scores. Performance of each scheme was evaluated by diagnosis of condition at pre-defined good/bad sites, concordance with existing local benthic indices, and independence from natural environmental gradients. The AMBI performed best when using the national EG assignments augmented with standard international EG values. The AMBI using this hybrid EG scheme performed well in differentiating apriori good and bad sites (>80% correct classification rate) and AMBI scores were both concordant and correlated (r_s = 0.4–0.7) with those of existing local indices. Nearly all of the results suggest that assigning the EG values in the framework of local biogeographic conditions produced a better-performing version of AMBI. The improved index performance, however, was tempered with apparent biases in score distribution. The AMBI, regardless of EG scheme, tended to compress ratings away from the extremes and toward the moderate condition and there was a bias with salinity, where high quality sites received increasingly poorer condition scores with decreasing salinity.     

Development of a multimetric index based on benthic macroinvertebrates for the assessment of natural wetlands in Southwest Ethiopia

Biotic indices are widely applied for conservation and management of aquatic resources since they allow water resources monitoring agencies to get insight in complex biological data and yield policy relevant information. Despite the worldwide popularity of biotic indices, little information on their use and applicability in Eastern Africa is available. Here, we develop a multimetric index based on macroinvertebrates to assess the ecological condition of natural wetlands in Southwest Ethiopia. Index development was based on a dataset of 222 samples collected during two consecutive years from 63 sites located at eight different wetlands. We used physico-chemical and hydro-morphological variables (land use pattern, habitat alteration, hydrological modification and chemical water quality) to classify sites as reference or degraded. We tested a total of 58 potential metrics representing various aspects of macroinvertebrate assemblages including family richness, composition, tolerance measures and presence and abundance of functional feeding groups. Metrics were selected for the development of a final index based on their sensitivity in discriminating reference from impaired sites, strength of correlation with the anthropogenic disturbance gradient, chemical measurements, and the degree of redundancy. Metrics retained for the final index were:overall family richness, family richness of Ephemeroptera, Odonata and Trichoptera (EOT), and percentage of filterer–collectors. The final index, derived from the sum of three metric scores, was divided into five water quality classes (very bad, bad, moderate, good and very good). Our final multimetric macroinvertebrate index (MMI) distinguished well between reference and impaired wetland sites and showed a significant negative response to a gradient of disturbances (R² = 0.86, p < 0.05). Moreover, it classified a validation dataset accurately with a correctly classified instances of 80% and a Cohen's Kappa value of 0.6. This MMI can be considered as a robust and sensitive tool that can be applied to evaluate the ecological condition of natural wetlands in Ethiopia, where wetland resources are under high pressure as a result of agricultural activities such as grazing and urbanization.     

Monitoring and assessment of water quality in the Haraz River of Iran,using benthic macroinvertebrates indices

The objective of this study was to assess the relationship between river water quality and the distribution of benthic macroinvertebrate communities in the Haraz River in Iran. Using a surber net sampler, benthic macroinvertebrate communities along the stream was sampled in wet and dry seasons of 2015 at nine stations with three replications. The physicochemical water quality parameters were measured in the field by water checker. Hilsenhoff biotic Indices, Shannon Wiener Diversity Indices, Average Score per Taxon (ASPT) Index and Pielou Evenness Index were applied to carry out a biological assessment of water quality. A total of 3781 (spring 769, summer 1092, autumn 1095 and winter 825) benthic macroinvertebrate specimens belonging to 4 orders, 11 classes and 16 families were identified. The lowest number of taxa was recorded in spring while the highest was recorded in autumn. Station 9 had the lowest number of taxa while the highest number of taxa was recorded at station 3. The average values (±SD) of the water quality parameters were temperature 14.75?±?4.38 °C, pH 7.93?±?0.62, water flow 14.11?±?9.04 m³ s^?1, electric conductivity 532.75?±?161.35 μmohs cm^?1, total dissolved solids 296.61?±?76.21 mg L^?1, salinity 0.28?±?0.07 mg L^?1, turbidity 580.77?±?149.92 NTU and dissolved oxygen 8.08?±?0.75 mg L^?1. The assessment of stations 1 to 6 indicated that water quality conditions were suitable. In addition, substantial level of organic pollution was observed in stations 7 and 8. In station 9 water quality was fairly poor, requiring a more favourable management based on the capacity of the self-purification of the Haraz River.     

The studies of ecological environmental quality assessment in Anhui Province based on ecological footprint

Under the dual pressures of the socio-economic development and the increase in population density, the ecological environmental quality issues in Anhui Province have become increasingly prominent, which seriously handicap the sustainable development of regional economy, and it is more important to evaluate ecological environmental quality. By using the data of ecological environment, society, economy and population in Anhui Province, this paper measures ecological footprint, ecological environmental carrying capacity and ecological deficit and surplus in Anhui Province based on ecological footprint. The results show that ecological environmental quality in Anhui Province is not in the best state of the coordinated development, and the relationship between the supply and the demand of per ecological footprint almost is not in balance.     

Evaluating the performance of artificial neural networks for the classification of freshwater benthic macroinvertebrates

Macroinvertebrates form an important functional component of aquatic ecosystems. Their ability to indicate various types of anthropogenic stressors is widely recognized which has made them an integral component of freshwater biomonitoring. The use of macroinvertebrates in biomonitoring is dependent on manual taxa identification which is currently a time-consuming and cost-intensive process conducted by highly trained taxonomical experts. Automated taxa identification of macroinvertebrates is a relatively recent research development. Previous studies have displayed great potential for solutions to this demanding data mining application. In this research we have a collection of 1350 images from eight different macroinvertebrate taxa and the aim is to examine the suitability of artificial neural networks (ANNs) for automated taxa identification of macroinvertebrates. More specifically, the focus is drawn on different training algorithms of Multi-Layer Perceptron (MLP), probabilistic neural network (PNN) and Radial Basis Function network (RBFN). We performed thorough experimental tests and we tested altogether 13 training algorithms for MLPs. The best classification accuracy of MLPs, 95.3%, was obtained by two conjugate gradient backpropagation variations and scaled conjugate gradient backpropagation. For PNN 92.8% and for RBFN 95.7% accuracies were achieved. The results show how important a proper choice of ANN is in order to obtain high accuracy in the automated taxa identification of macroinvertebrates and the obtained model can outperform the level of identification which is made by a taxonomist.     

An ecological quality status assessment procedure for soft-sediment benthic habitats: Weighing alternative approaches

An assessment procedure for determining the ecological quality status of soft-sediment benthic habitats requires the following aspects: (1) habitat assignation of the samples (habitat approach), (2) reference or target conditions for the benthic parameters (reference approach), and (3) the selection of indicator tools to assess the relative quality status (indicator approach). For all these aspects, different approaches exist, and the indicator selection and reference approaches are largely documented. The aspect of the habitat approach is sometimes neglected, but is essential in determining the reference conditions per habitat type. Benthic habitats differ in structure and function, and as such will show wide variations in statistics or measures between habitats. A major problem, mainly in coastal soft-bottom systems, is to track the deviation lines within data of the different benthic habitat types. This study shows that both a classical community analysis and the use of habitat suitability maps seem to be appropriate tools, but further fine-tuning is necessary. For the second assessment step, an objective assessment of reference conditions is a challenge in areas lacking pristine or minimally disturbed sites, and areas of which historic data are not available. This can be remedied by using a dataset of the area with a good spatial and temporal coverage of the benthic data, thereby avoiding data originating from highly impacted areas. For the third aspect in the assessment procedure, we recommend the use of different indicators with different properties (parameters, algorithms) since it indicates their weaknesses and strengths in the local region.In general, this study showed us that it is valuable to test different existing approaches for EcoQ assessment in a local area, revealing strengths, weaknesses and shortcomings within the assessment regarding data, habitat identification, monitoring strategy, reference settings and indicator use. All these aspects need to be taken into account within an ecological quality status assessment of an area in order to improve its confidence.     

The role of micro-organisms in the ecological connectivity of running waters

1. Riparian zones hold a central place in the hydrological cycle, owing to the prevalence of surface and groundwater interactions. In riparian transition zones, the quality of exfiltrating water is heavily influenced by microbial activities within the bed sediments. This paper reviews the role of micro-organisms in biogeochemical cycling in the riparian-hyporheic ecotone. 2. The production of organic substances, such as cellulose and lignin, by riparian vegetation is an important factor influencing the pathways of microbial processing in the riparian zone. For example, anaerobic sediment patches, created by entrainment of allochthonous organic matter, are focal sites of microbial denitrification. 3. The biophysical structure of the riparian zone largely influences in-stream microbial transformations through the retention of organic matter. Particulate and dissolved organic matter (POM and DOM) is retained effectively in the hyporheic zone, which drives biofilm development and associated microbial activity. 4. The structure of the riparian zone, the mechanisms of POM retention, the hydrological linkages to the stream and the intensity of key biogeochemical processes vary greatly along the river continuum and in relation to the geomorphic setting. However, the present state of knowledge of organic matter metabolism in the hyporheic zone suggests that lateral ecological connectivity is a basic attribute of lotic ecosystems. 5. Due to their efficiency in transforming POM into heterotrophic microbial biomass, attached biofilms form an abundant food resource for an array of predators and grazers in the interstitial environments of rivers and streams. The interstitial microbial loop, and the intensity of microbial production within the bed sediments, may be a primary driver of the celebrated high productivity and biodiversity of the riparian zone. 6. New molecular methods based on the analysis of the low molecular weight RNA (LMW RNA) allow unprecedented insights into the community structure of natural bacterial assemblages and also allow identification and study of specific strains hitherto largely unknown. 7. Research is needed on the development and evaluation of sampling methods for interstitial micro-organisms, on the characterization of biofilm structure, on the analysis of the biodegradable matter in the riparian-hyporheic ecotone, on the regulation mechanisms exerted on microbiota by interstitial predators and grazers, and on measures of microbial respiration and other key activities that influence biogeochemical cycles in running waters. 8. Past experiences from large-scale alterations of riparian zones by humans, such as the River Rhine in central Europe, undeniably demonstrate the detrimental consequences of disconnecting rivers from their riparian zones. A river management approach that uses the natural services of micro-organisms within intact riparian zones could substantially reduce the costs of clean, sustainable water supplies for humans.     

Design and implementation of rapid assessment approaches for water resource monitoring using benthic macroinvertebrates

Abstract Benthic macroinvertebrates are the group of organisms most widely used for assessment of water resources. Rapid assessment approaches are intended to be efficient and cost effective; savings are found in reduced sampling and more efficient data analysis. Rapid bioassessment programmes have been quickly accepted and now cover most of the United States (US) and equivalent programmes cover all of the United Kingdom (UK). Rapid bioassessment programmes are designed to screen large regions, pinpointing trouble spots worthy of more detailed attention. Fundamental to all rapid bioassessment methods is the classification of streams so that comparisons can be made between reference areas and areas of concern, or test sites with similar characteristics. Both the UK and US approaches assess habitat characteristics. These characteristics are used to predict the fauna expected at a test site in the UK approach; in the US they are used as an aid to classification and interpretation of aquatic faunal data. Habitat assessments in the US are also used to determine whether poor water quality or degraded habitat are stressing the invertebrate communities. This is a major development in approaches to water resource assessment. In the UK, a model developed using multivariate statistics uses a few environmental variables thought to be unaffected by human activities to predict the fauna expected at a test site. The US approaches analyse data using several indices (or metrics) presumed to represent ecological features of interest. These indices have a range of sensitivities to different kinds of stress and must be calibrated for the area of interest. The two approaches have been developed in isolation but may have much to offer each other. Developing programmes are advised to consider both. Future needs include: development of procedures that can be applied to large rivers and to lakes; further refinement of ecological principles underlying metric choice; the inclusion of chemical criteria and toxicity tests to establish thresholds that indicate impairment; and development of criteria indicating the necessity for implementation of quantitative assessment studies.     

Towards a multimetric index for the assessment of Dutch streams using benthic macroinvertebrates

This study describes the development of a macroinvertebrate based multimetric index for two stream types, fast and slow running streams, in the Netherlands within the AQEM project. Existing macroinvertebrate data (949 samples) were collected from these stream types from all over the Netherlands. All sites received a ecological quality (post-)classification ranging from 1 (bad status) to 4 (good status) based on biotic and abiotic variables, using a combination of multivariate analysis and expert-judgement. A number of bioassessment metrics was tested for both stream types (fast and slow running streams) to examine their power to discriminate between streams of different ecological quality within each stream type. A metric was selected for inclusion in the final multimetric index when there was no overlap of the 25th and 75th percentile between one (or more) ecological quality class(es). Out of all metrics tested, none could distinguish between all four ecological quality classes without overlap of the 25th and 75th percentile between one or more of the classes. Instead, metrics were selected that could distinguish between one (or more) ecological quality class(es) and all others. Finally, 10 metrics were selected for the assessment of slow running streams and 11 metrics for the assessment of fast running streams. Class boundaries were established, to make the assignment of scores to the individual metrics possible. The class boundaries were set at the 25th and/or 75th percentile of the individual metric values. The individual metrics were combined into a multimetric index. Calibration showed that 67% of the samples from slow running streams and 65% of the samples from fast running streams were classified in accordance to their post-classification. In total, only 8% of the samples differed more than one quality class from the post-classification. The multimetric index was validated with data collected in the Netherlands from 82 sites for the purpose of the AQEM project. Validation showed that 54% of the streams were classified correctly.     

Addressing a gap in the Water Framework Directive implementation: Rocky shores assessment based on benthic macroinvertebrates

A gap in the European Water Framework Directive (WFD) is addressed, aiming for the development of an ecological quality status assessment tool based solely on the Biological Quality Element benthic macroinvertebrates from intertidal rocky shores. The proposed Rocky shore Macroinvertebrates Assessment Tool (RMAT) was tested and validated along disturbance gradients (organic enrichment). During the whole process, the response of widely used metrics (e.g. Hurlbert index, Shannon-Wiener index, AZTI’s Marine Biotic Index; Bentix biotic index) and models (i.e., metrics combined) was compared to results provided by the Marine Macroalgae Assessment Tool to the same sampling sites.The RMAT is a multimetric index compliant with the WFD based on the benthic macroinvertebrates community, combining ‘abundance’ (Hurlbert index) and ‘taxonomic composition’ (Bentix index using density and biomass data) metrics. It performed well along anthropogenic disturbance gradients, showing ecological quality increasing from close to far away from the disturbance.The RMAT is a promising tool for rocky shore ecological assessment in the scope of the WFD or other monitoring activities worldwide.