Ecological Quality Ratio Research Articles

Development and application of an ecological classification tool for fish in lakes in Ireland

A classification tool suitable for establishing the ecological status of lakes based on fish population parameters has been developed for the Republic of Ireland and Northern Ireland (EU Water Framework Directive Ecoregion 17). A lake typology relevant to fish populations in lakes from Ecoregion 17 was produced as part of the ecological classification tool development. Four lake types were determined based on fish metrics and abiotic variables from 43 “reference” lakes. The specific lake fish typology categorised lakes into low (≤67CaCO3mgL−1) or high (>67CaCO3mgL−1) alkalinity, and shallow (≤17m) or deep (>17m) maximum depth. The fish in lakes classification tool (FIL2) follows a novel multimetric predictive approach, assigning ecological status to a lake using two independent methods. FIL2 qualitatively defines a lake's ecological status based on fish metrics using discriminant classification rules and, using a generalised linear model, quantitatively derives an Ecological Quality Ratio (EQR, 0<EQR<1), along with associated confidence intervals. It is recommended that both methods are used to validate output and cross-check and highlight potential misclassification.

Spatial and temporal variability of diatom and macroinvertebrate communities: How representative are ecological classifications within a river system?

Evaluation of river condition is complicated by dynamic relationships between river assemblages and their environment. We assessed variation of ecological status classifications of stream diatom and macroinvertebrate communities within a boreal river system. We specifically examined whether results of ecological classifications are concordant across taxonomic groups and among main channel and headwater side tributaries of this river system. We further assessed whether ecological classifications are stable from year to year and whether classifications show predictable relationships to major stressor gradients. The estimated ecological condition varied considerably among and between reaches of main channel and tributaries for both examined taxonomic groups. Ecological classifications also differed between the two taxonomic groups and were generally lower and temporally more variable for diatoms. Ecological Quality Ratios (EQR) of the metrics were mainly related to pH representing a major disturbance gradient in our study, but in general, relationships to stressor gradients were weak. Our results suggest that ecological classifications could be weakly extrapolated among sites and, depending on the taxonomic group, also among different years in river systems disturbed by anthropogenic activities. Spatially and temporally extensive monitoring is therefore needed to reliably classify ecological condition of a water body. With this regard, it would be important to assess and monitor whole river networks instead of linear segments of large rivers.

Selection of metrics based on the seagrass Cymodocea nodosa and development of a biotic index (CYMOX) for assessing ecological status of coastal and transitional waters

Bioindicators, based on a large variety of organisms, have been increasingly used in the assessment of the status of aquatic systems. In marine coastal waters, seagrasses have shown a great potential as bioindicator organisms, probably due to both their environmental sensitivity and the large amount of knowledge available. However, and as far as we are aware, only little attention has been paid to euryhaline species suitable for biomonitoring both transitional and marine waters. With the aim to contribute to this expanding field, and provide new and useful tools for managers, we develop here a multi-bioindicator index based on the seagrass Cymodocea nodosa.We first compiled from the literature a suite of 54 candidate metrics, i. e. measurable attribute of the concerned organism or community that adequately reflects properties of the environment, obtained from C. nodosa and its associated ecosystem, putatively responding to environmental deterioration. We then evaluated them empirically, obtaining a complete dataset on these metrics along a gradient of anthropogenic disturbance. Using this dataset, we selected the metrics to construct the index, using, successively: (i) ANOVA, to assess their capacity to discriminate among sites of different environmental conditions; (ii) PCA, to check the existence of a common pattern among the metrics reflecting the environmental gradient; and (iii) feasibility and cost-effectiveness criteria.Finally, 10 metrics (out of the 54 tested) encompassing from the physiological (δ15N, δ34S, % N, % P content of rhizomes), through the individual (shoot size) and the population (root weight ratio), to the community (epiphytes load) organisation levels, and some metallic pollution descriptors (Cd, Cu and Zn content of rhizomes) were retained and integrated into a single index (CYMOX) using the scores of the sites on the first axis of a PCA. These scores were reduced to a 0–1 (Ecological Quality Ratio) scale by referring the values to the optimal (reference) and worst (most degraded) conditions. The ecological status of sites obtained applying CYMOX correlated significantly with the environmental gradient, validating its adequacy to reflect ecosystem health.In conclusion, the results presented here suggest that this index can be an adequate alternative for ecological status assessment in water bodies where other species are absent and, specifically, in transitional waters.

Detecting Invertebrate Species Change in Running Waters: An Approach Based on the Sufficient Sample Size Principle

The EU Water Framework Directive (WFD) is in need of a practical method and index suitable for comparing the ecological status of invertebrate fauna in rivers throughout Europe. The uncertainties that characterize lotic sampling methods can be omitted by increasing sampling effort up to a species detection probability threshold. We describe a statistical model which provides the background for applying a sampling protocol aiming to record the total number of common and abundant species. Methods, sample standards and sorting time become less significant to the result as long as the total sample is sufficiently large to detect common species. An index called the Intercalibrated Benthic Invertebrate Biodiversity Index - IBIBI - is proposed based on Observed / Expected species ratios for EPT groups. The Ecological Quality Ratio thus obtained may then be adjusted to WFD's ecological status scale within each region or river type across Europe, which then can be compared and intercalibrated. Although offering a possible solution to the problem of intercalibration, further studies are needed.

Long-term trends in benthic habitat quality as determined by Multivariate AMBI and Infaunal Quality Index in relation to natural variability: A case study in Kinsale Harbour, south coast of Ireland

Benthic Ecological Quality Ratios (EQR) are important tools for assessing the ecological status of coastal and transitional water bodies. Here, we use spatial and time-series data from Kinsale Harbour, Ireland to examine the effects of sample processing methodologies on the outputs of two EQRs: Multivariate AMBI (M-AMBI) and Infaunal Quality Index (IQI).Both EQRs were robust to changes in sieve size from 1mm to 0.5mm, and to changes in the taxa identified in spatial calibration. Both EQRs classified habitat quality in Kinsale as generally Good or High with no evidence of significant change over the time series (1981–2006). IQI classified the ecological status as higher than M-AMBI.There was a significant relationship between IQI and M-AMBI in spatial calibration, but no significant relationship between them in time series. Further research into the behaviour of EQRs in relation to natural variability over long time-scales is needed to discriminate anthropogenic impacts reliably.

Bringing European river quality into line: an exercise to intercalibrate macro-invertebrate classification methods

The Water Framework Directive (WFD) requires intercalibration to be performed to ensure that ecological status, as defined by the boundary values of national biological assessment systems, is consistent with the definitions outlined in the WFD and comparable between Member States (MS). This article describes an intercalibration of 17 national river macro-invertebrate assessment methods from the Central and Baltic regions of Europe. We explore the hypothesis that intercalibration should be successful if ratios of the observed biota to that expected in reference condition are used to compare assessments of different national assessment systems. National boundaries expressed as ecological quality ratios (EQRs) were converted to values of a common multi-metric for the purpose of comparison. Twelve MS for the High/Good boundary and nine MS for the Good/Moderate boundary (and four MS who subsequently harmonised their boundaries) were within ±0.05 EQR units of the intercalibration boundaries and were deemed to be of comparable ecological standard. The use of a reference-based approach was deemed to be successful given that all the critical pre-requisites for intercalibration were satisfied. The boundaries derived from this intercalibration represent the first common interpretation of the ecological status of rivers based on macro-invertebrate assessment methods across Europe.

Lake acidification assessed using chironomid pupal exuviae

The European Union Water Framework Directive (WFD) aims to achieve good ecological status of its waterbodies by 2015 through the determination of reference state to provide a measure of perturbation by human impacts based on taxonomic composition and abundance of aquatic species. Collections of floating pupal exuviae discarded by emerging adult midges (Diptera: Chironomidae) provide a cost-effective method for obtaining representative ecological data from lakes. Chironomid and environmental data were collected from 203 lake surveys of all WFD types found in Britain. Canonical Correspondence Analysis provided species optima and niche breadths in relation to acidity measures. An acidification score derived from species optima was produced for each lake survey and compared with the lake's reference score modelled on physical characteristics. The Ecological Quality Ratio (EQR) of observed to reference scores were classified into WFD quality bands based on the relative frequency of sensitive to tolerant chironomid species. Sampling variation of EQR was used to determine the confidence of each lake survey classification. Species-based EQR provided a sensitive measure of lake perturbation from high ecological status. Analyses were repeated with generic data obtained in much less time. Precision obtaining generic EQR was lower but still acceptable for providing a high confidence of classification at High, Good and Moderate status.

Remote sensing as a tool for monitoring water quality parameters for Mediterranean Lakes of European Union water framework directive (WFD) and as a system of surveillance of cyanobacterial harmful algae blooms (SCyanoHABs)

Remote sensing has been used from the 1980s to study inland water quality. However, it was not until the beginning of the twenty-first century that CHRIS (an experimental multi-angle sensor with good spectral and spatial resolutions) and MERIS (with good temporal and spectral resolutions) started to acquire imagery with very good resolutions, which allowed to develop a reliable imagery acquisition system so as to consider remote sensing as an inland water management tool. This paper presents the methodology developed, from the field data acquisition with which to build a freshwater spectral library and the study of different atmospheric correction systems for CHRIS mode 2 and MERIS images, to the development of algorithms to determine chlorophyll-a and phycocyanin concentrations and bloom sites. All these algorithms allow determining water eutrophic and ecological states, apart from generating surveillance maps of toxic cyanobacteria with the main objective of Assessment of the Water Quality as it was used for Monitoring Ecological Water Quality in smallest Mediterranean Reservoirs integrated in the Intercalibration Exercise of European Union Water Framework Directive (WFD). We keep on using it to monitor the Ecological Quality Ratio (EQR) in Spain inland water.

Estado ecológico del río Oja (cuenca del Ebro, La Rioja, España), mediante indicadores de macroinvertebrados

Ecological status of the Oja River (Ebro Basin, La Rioja, Spain) based on macroinvertebrate indexes This work provides results about the water quality of the Oja or Glera River (Oja-Tirbasin) during the years 2003-2007, as well as information from the historical data taken from previous basin reports (2004 report, that includes data from 1994 to 2004 and 2007 report). Seven sampling points have been selected, distributed between the three typologies dened in the Oja River: in ecotype 11, Siliceous Mediterranean mountain river, 3 points; in ecotype 26, Humid calcareous mountain river ,1 point and in ecotype 12, Mediterranean calcareous mountain rivers, 3 points. Several macro invertebrate indexes (IBMWP, IASPT, NFAM, NFPLE and EPT) and their ecological quality ratios (EQR) were calculated for each point. As a whole, 75.86 % of the IBMWP measurements show Very good or Good quality, with a 13.79 % of Moderate quality, meanwhile 10.35 % of them appear as Decient . Regarding its historic evolution, in those stretches of the river which present permanent water a progressive improvement of water quality was observed from therst available data (years 1994-95) until the most recent ones (2007), according to the most recent values of water quality classication for IBMWP (BOE, 2008).

Analyzing the (mis)behavior of Shannon index in eutrophication studies using field and simulated phytoplankton assemblages

The Shannon index of diversity H′ is a commonly used metric in ecology. The tendency of this index to show a unimodal relationship with productivity has been the subject of several studies. In the present work, the behavior of H′ and three related ecological indices (Simpson, Hill, and Evenness) was investigated using phytoplankton assemblages along a eutrophication gradient. We used both natural and simulated assemblages, whereby the comparison enabled us to assess the role of environmental ‘noise’ on index behavior. We developed simulated assemblages based on phytoplankton distributions predicted by two model types: the log series statistical model and the random fraction niche-based model. Using field data, H′ and the related Simpson index showed expected unimodal relationships with eutrophication. The same unimodal relationships were reproduced with simulated assemblages. Comparing the simulations with natural assemblages along a eutrophication gradient showed that there was much unexplained variance in the real-world data, suggesting that these diversity indices are sensitive to stochastic processes. An analysis of the simulated assemblages using relative abundance distributions suggested that increasing H′ and Simpson index values in the low range of the eutrophication gradient were due to increasing species richness, and that decreasing index values in the high range of the eutrophication gradient were due to decreasing evenness. In addition, this analysis revealed how assemblages of identical H′ values arose from contrasting community structures found in the low- and high-range of eutrophication. The high variability and non-linearity of the Shannon and Simpson indices along a eutrophication gradient suggests that these measures of diversity are inappropriate for use as water quality monitoring assessment tools. Indeed, when calculating ecological quality ratios that are employed by the European Water Framework Directive, unreliable (non-monotonic) predictions of water quality resulted.

Ecological Quality Status of the soft-bottom communities on the algerian coast: General patterns and diagnosis

Between 1995 and 2001, the soft-bottom communities along the 1180km of the Algerian coast were sampled in nine gulfs and 12 harbours, providing a total of 655 samples. Eight macrozoobenthos-based biotic indices (S, N, H′, BQI, AMBI, BENTIX, BO2A and ITI) were selected to describe the general patterns of the coastal water quality status and to establish a quality diagnosis for the different zones subjected to anthropogenic pressure (e.g., harbour construction, industrial and urban pollution). Reference values were determined for each of the eight indices selected by analyzing the indices’ parameter distribution. The Ecological Quality Ratio (EQR) was estimated for each index, resulting in an EQR Mean Score and an EQR Bad Score. From these EQR, we defined an EQS for each sample. The agreement between these EQS was analysed using the Kappa method in order to propose a survey strategy for the Algerian coastal waters that would take into account the soft-bottom biological compartment. The results clearly indicate that high and good quality assessments are prevalent in the gulfs, while quality assessments in harbours vary greatly from bad to good. The effect of pollution observed in the harbours can be classified in two main groups, according to when they were constructed and their relative degree of openness to the sea, which permits better water circulation and probably dilutes the pollution.

Large‐scale relationships between basin and riparian land cover and the ecological status of European rivers

Summary1. The main objectives of our study were (i) to establish the relative impact of pressures that degrade ecological status, especially those caused by agriculture and urbanisation, (ii) to identify regional patterns in these pressure‐impact relationships and (iii) to evaluate the relative weight of the pressures acting at the basin and riparian corridor scales, and the possible buffering effect of riparian areas.2. We developed large‐scale models linking invertebrate indices of ecological quality to river basin and riparian land cover in France, Slovakia, Estonia and U.K. Invertebrate indices, transformed to ecological quality ratios (EQR), were taken from national monitoring networks. We based the models on partial least squares (PLS) regressions at national and a hydro‐ecoregion (HER) scales. The HERs provided a framework for grouping data in terms of natural river features and human activities.3. The different national methods provided consistent results that indicated the hierarchy of pressures impacting river invertebrates at the European scale. Artificial land cover (e.g. urban and industrial sites) in the river basin represented the pressure with the most negative impact on invertebrate indices, in all countries and regions.4. The impact of agricultural land cover was more variable. Arable land had a smaller impact than urban areas and was insignificant in some models. The proportion of arable land in the river basin appeared to be a weak predictor of agricultural impacts by itself; the type of cultivation and intensity as well as the proximity to the river must be taken into account.5. At the riparian corridor scale, the negative impact of artificial areas or arable land and the positive effects of forests and pastures were demonstrated in many regions. The protective effect of riparian forests against mixed agricultural and urban pressures was demonstrated in three regions in France. Riparian corridors appear to be manageable areas, and these results strongly support the idea of including their restoration in priority actions for achieving good ecological status.

A zone-specific fish-based biotic index as a management tool for the Zeeschelde estuary (Belgium)

Fish-based indices monitor changes in surface waters and are a valuable aid in communication by summarising complex information about the environment ( Harrison and Whitfield, 2004). A zone-specific fish-based multimetric estuarine index of biotic integrity (Z-EBI) was developed based on a 13 year time series of fish surveys from the Zeeschelde estuary (Belgium). Sites were pre-classified using indicators of anthropogenic impact. Metrics showing a monotone response with pressure classes were selected for further analysis. Thresholds for the good ecological potential (GEP) were defined from references. A modified trisection was applied for the other thresholds. The Z-EBI is defined by the average of the metric scores calculated over a one year period and translated into an ecological quality ratio (EQR). The indices integrate structural and functional qualities of the estuarine fish communities. The Z-EBI performances were successfully validated for habitat degradation in the various habitat zones.

Assessment of water quality in a large lowland river (Narva, Estonia/Russia) using a new Hungarian potamoplanktic method

Phytoplankton is one of the four biological elements used for the assessment of the water quality of surface water bodies. In rivers phytoplankton-based assessment of water quality has not been conducted in Estonia up to now. The aim of the present study was to test a new Hungarian potamoplanktic method for the assessment of the water quality of the Narva River, a large river on the Estonian-Russian border. For testing the method, algal species in the phytoplankton of the Narva River were classified into functional groups. Then the Ecological Quality Ratio (EQR) was calculated and its value was compared with the corresponding values for different water quality classes given in the literature. The mean value of the EQR for the Narva River revealed seasonal variation: in most cases it indicated 'good' or 'excellent' quality classes in spring and summer and 'very bad' quality class in autumn. The median value for the vegetation period of 2001-2008 indicated 'moderate' quality class. Variation in the functional groups of phytoplankton and in the EQR values reflected the seasonal dynamics of phytoplankton and the impact of Lake Peipsi. Comparison of the results of the assessments made by using the phytoplankton EQR and benthic diatom indices revealed agreement between the two metrics in the summer period: both were sensitive to the water quality and indicated at least 'good' quality class. The new Hungarian method appears to be suitable for the assessment of water quality in this Estonian large river. However, the numerical boundaries of the EQR for different water quality classes should be specified in the future on the basis of a larger Estonian phytoplankton database.

Principles of hydromorphological surveys of Polish rivers

This paper presents the key principles of the new Polish methodology for hydromorphological river surveys which is consistent with the provisions of the Water Framework Directive. This method proposes to investigate only the main watercourse of the water body. The assessment is based on cartographic maps, satellite images and the existing databases. Field surveys are limited to selected stretches of the water body. The classification of the river's ecological status and ecological potential is based on a hierarchical system comprising four elements: hydrological regime, river continuity, channel morphology and floodplain. They are evaluated in view of features characterized by selected attributes. The method is the same for natural and heavily modified water bodies, while a simplified methodology is used to investigate artificial water bodies. It does not account for differences in abiotic type, landscape or size of the catchment area. The results are presented in abridged and field protocols. The attributes are evaluated on a five-point grading scale or through a descriptive approach which supports the calculation of ecological quality ratios for quality elements, hierarchical system elements and the water body. The usefulness of the proposed method has been tested on 11 pilot water bodies. The presented approach enables to perform hydromorphological surveys of Polish rivers by 2015, as required under the Water Framework Directive.

Ecological classification of a set of Mediterranean reservoirs applying the EU Water Framework Directive: A reasonable compromise between science and management

The Water Framework Directive EU2000/60/EC (WFD) was implemented for reservoirs at a regional scale (northeastern Spain). Twenty-one reservoirs were monitored quarterly over the course of a year. Using principal component analysis, the reservoirs were classified into types according to their geological and morphometric features. The Ecological Quality (EQ) of the reservoirs was assessed by integrating values of total chlorophyll a, cyanophyta chlorophyll a concentration, fish metrics, Secchi depth, averaged hypolimnetic oxygen concentration and total phosphorus. For each reservoir type, a reference condition of quality was selected. When possible, this reference was the reservoir displaying the best EQ; otherwise expert judgment was used. To allow comparison of quality among reservoirs belonging to different types, thus identifying intrinsic differences, an Ecological Quality Ratio (EQR) was calculated by dividing the EQ value of each reservoir by that of its reference. According to EQR, the majority of the reservoirs accomplished the quality criteria of the WFD. This study identified a number of useful indicators for EQ assessment. Moreover, because the references were chosen among similar reservoirs, low EQR values are indicative of specific problems, such as untreated or wastewater spills or droughts. The results also demonstrate that expert judgment is a reasonable compromise when the low number of water bodies available for the study prevents statistical approaches.

Implementation of the European Water Framework Directive: Natural variability associated with the CARLIT method on the rocky shores of the Ligurian Sea (Italy)

AbstractThe Water Framework Directive (WFD) 2000/60/EC, adopted by the European Community in 2000 with the goal of maintaining and improving the aquatic environments, requires that member states achieve and maintain a good ecological status of all water bodies by 2015. In the marine context, the ecological status has to be quantified applying indexes based on appropriate key biological elements, which allow the categorization of water bodies into five Ecological Status (ES) classes. The CARLIT index is a cartographic monitoring tool enabling the Ecological Quality Ratio (EQR) to be calculated using macroalgae in coastal hard bottoms as a key biological element; at present it is being applied in Spain, France and Italy. To detect actual changes of water quality and, consequently, rely on the application of indexes for the assessment of the ecological status in the marine environment, it is necessary to evaluate their sensitivity to natural variability at different temporal and spatial scales. In this study we present a first quantification of natural (spatial and temporal) variability of EQR‐CARLIT quality assessment in 2006 and 2007 along the Ligurian coast (North‐Western Mediterranean, Italy). The EQR‐CARLIT values recorded along the Ligurian coastline show that natural variability of EQR‐CARLIT is low and that it does not affect the attribution of a given stretch of coast to a particular ES class, in agreement with the major human pressures acting in the area (urbanization, river load, sea‐farming). A small‐scale variability was detected, strengthening the use of cartography of the whole rocky shore, whenever possible, or, alternatively, the assessment of the ecological status for long stretches of coast, to encompass the small‐scale variability due to local factors.

Multimetric Macroinvertebrate Index Flanders (MMIF) for biological assessment of rivers and lakes in Flanders (Belgium)

The European Water Framework Directive requires that member states assess all their surface waters based on a number of biological elements, including macroinvertebrates. Since 1989, the Flemish Environment Agency has been using the Belgian Biotic Index for assessing river water quality based on macroinvertebrates. Throughout the years, the Belgian Biotic Index has proven to be a reliable and robust method providing a good indication of general degradation of river water and habitat quality. Since the Belgian Biotic Index does not meet all the requirements of the Water Framework Directive, a new index, the Multimetric Macroinvertebrate Index Flanders (MMIF) for evaluating rivers and lakes was developed and tested. This index was developed in order to provide a general assessment of ecological deterioration caused by any kind of stressor, such as water pollution and habitat quality degradation. The MMIF is based on macroinvertebrate samples that are taken using the same sampling and identification procedure as the Belgian Biotic Index. The index calculation is a type-specific multimetric system based on five equally weighted metrics, which are taxa richness, number of Ephemeroptera, Plecoptera and Trichoptera taxa, number of other sensitive taxa, the Shannon–Wiener diversity index and the mean tolerance score. The final index value is expressed as an Ecological Quality Ratio ranging from zero for very bad ecological quality to one for very good ecological quality. The MMIF correlates positively with dissolved oxygen and negatively with Kjeldahl nitrogen, total nitrogen, ammonium, nitrite, total phosphorous, orthophosphate and biochemical and chemical oxygen demand. This new index is now being used by the Flemish Environment Agency as a standard method to report about the status of macroinvertebrates in rivers and lakes in Flanders within the context of the European Water Framework Directive.

Classification of nutrient impact on lakes using the chironomid pupal exuvial technique

The European Union Water Framework Directive (WFD) aims to achieve Good ecological status of its waterbodies by 2015 through the determination of reference state to provide a measure of perturbation by human impacts based on taxonomic composition and abundance of aquatic species. Collections of floating pupal exuviae discarded by emerging adult midges (Diptera: Chironomidae) provide a cost-effective method for obtaining representative ecological data from lakes. Chironomid and environmental data were collected from 178 lake surveys (4 samples from each lake) of all WFD types found in Britain. Canonical Correspondence Analysis (CCA) provided species optima and niche breadths in relation to mean nutrient (nitrogen and phosphorus) concentrations. A nutrient impact score derived from species optima was produced for each lake survey and compared with the lake's reference score based on its physical characteristics. A range of reference lake types provided a model of physical characteristics for their observed chironomid species-derived nutrient scores. The Ecological Quality Ratio (EQR) of observed to reference scores were classified into WFD quality bands based on the relative frequency of sensitive to tolerant chironomid species. Sampling errors based on EQR variation were used to determine the confidence of each lake survey classification. Species-based EQR provided a sensitive measure of a lake's perturbation from high ecological status. Analyses were repeated with genus-level data obtained in much less time and with less taxonomic expertise. Precision obtaining EQR from generic data was lower but still acceptable for providing a high confidence of lake ecological classification.

Assessment of eutrophication pressure on lakes using littoral invertebrates

Until the E.U. Water Framework Directive listed benthic invertebrates as a biotic element to be used for ecological classification of lakes, techniques for the assessment of the response of littoral invertebrates to anthropogenic pressures were extremely limited compared with those of rivers and lake profundal zones. We describe here the development of an ecological classification model based on changes of littoral invertebrate assemblages across a gradient of eutrophication, which is the most widespread anthropogenic pressure on lakes across Europe. The model comprises three derived parameters, two of which were developed from taxon-specific optima along a total phosphorus gradient calculated using canonical correspondence analysis, and the third based on invertebrate abundance. Combining the parameter metrics, we can estimate the ecological quality ratio (EQR), relative to those from paleolimnologically-confirmed reference lakes. The model was tested using independent samples collected from both hard and soft substrata and across two seasons from 45 lakes, comprising three alkalinity groups (n = 15 in each), and across gradients in water column total phosphorus concentrations. For hard substrata, EQRs were related consistently and highly significantly to water column concentrations of total phosphorus, accounting for the majority of the variance in every alkalinity group. For samples taken from soft substrata, a significant relationship was found only for high alkalinity lakes, accounting for a moderate proportion of the variability in water column total phosphorus concentrations. Our results compare highly favourably with those from other aquatic ecological assessment methods, irrespective of the faunal or floral group upon which they are based, demonstrating that littoral invertebrate assemblages can provide a statistically robust prediction of nutrient status when samples are collected from hard substrata. While the method was developed specifically to assess nutrient pressures on littoral invertebrates, many lakes are subject to multiple pressures. The development of classification models that incorporate multiple pressures presents a particularly significant challenge for the implementation of the Water Framework Directive, requiring both reliable identification of minimally-impacted reference states and incorporation of pressures that are unlikely to interact in predictable ways.