Classification Of Ecological Status Research Articles

DNAqua-Net or how to navigate on the stormy waters of standards and legislations

Several national and international environmental laws require countries to meet clearly defined targets with respect to the ecological status of aquatic ecosystems. In Europe, the EU-Water Framework Directive (WFD; 2000/60/EC) represents such a detailed piece of legislation. The WFD that requires the European member countries to achieve an at least ‘good’ ecological status of all surface waters at latest by the year 2027. In order to assess the ecological status of a given water body under the WFD, data on its aquatic biodiversity are obtained and compared to reference status. The mismatch between these two metrics then is used to derive the respective ecological status class. While the workflow to carry out the assessment is well established, it relies only on few biological groups (typically fish, macroinvertebrates and a few algal taxa such as diatoms), is time consuming and remains at a lower taxonomic resolution, so that the identifications can be done routinely by non-experts with an acceptable learning curve. Here, novel genetic and genomic tools provide new solutions to speed up the process and allow to include a much greater proportion of biodiversity in the assessment process. further, results are easily comparable through the genetic ‘barcodes’ used to identify organisms. The aim of the large international COST Action DNAqua-Net (http://dnaqua.net/) is to develop strategies on how to include novel genetic tools in bioassessment of aquatic ecosystems in Europe and beyond and how to standardize these among the participating countries. It is the ambition of the network to have these new genetic tools accepted in future legal frameworks such as the EU-Water Framework Directive (WFD; 2000/60/EC) and the Marine Strategy Framework Directive (2008/56/EC). However, a prerequisite is that various aspects that start from the validation and completion of DNA Barcode reference databases, to the lab and field protocols, to the analysis processes as well as the subsequently derived biotic indices and metrics are dealt with and commonly agreed upon. Furthermore, many pragmatic questions such as adequate short and long-term storage of samples or specimens for further processing or to serve as an accessible reference need also be addressed. In Europe the conformity and backward compatibility of the new methods with the existing legislation and workflows are further of high importance. Without rigorous harmonization and inter-calibration concepts, the implementation of the powerful new genetic tools will be substantially delayed in real-world legal framework applications. After a short introduction on the structure and vision of DNAqua-Net, we discuss how the DNAqua-Net community considers possibilities to include novel DNA-based approaches into current bioassessment and how formal standardization e.g. through the framework of CEN (The European Committee for Standardization) may aid in that process (Hering et al. 2018, Leese et al. 2016, Leese et al. 2018. Further we explore how TDWG data standards can further facilitate swift adoption of the genetic methods in routine use. We further present potential impacts of the legislative requirements of the Nagoya Protocol on the exchange of genetic resources and their implications for biomonitoring. Last but not least, we will touch upon the rather unexpected influence that the new General Data Protection Regulation (GDPR) may have on the bioassessment work in practice.

HeLM: a macrophyte-based method for monitoring and assessment of Greek lakes

The Water Framework Directive (WFD) requires Member States to develop appropriate assessment methods for the classification of the ecological status of their surface waters. Mediterranean region has lagged behind in this task, so we propose here the first developed method for Greek lakes, Hellenic Lake Macrophyte (HeLM) assessment method. This method is based on two metrics, a modified trophic index and maximum colonization depth Cmax that quantify the degree of changes in lake macrophytic vegetation, as a response to eutrophication and general degradation pressures. The method was developed on the basis of a data set sampled from 272 monitoring transects in 16 Greek lakes. Sites from three lakes were selected as potential reference sites by using a screening process. Ecological quality ratios were calculated for each metric and for each lake, and ecological status class boundaries were defined. For the evaluation of effectiveness of the method, the correlations between individual metrics and final HeLM values and common pressure indicators, such as total phosphorus, chlorophyll a and Secchi depth, were tested and found highly significant and relatively strong. In addition, the ability of HeLM values and its individual metrics to distinguish between different macrophytic communities’ structure was checked using aquatic plant life-forms and found satisfactory. The HeLM method gave a reliable assessment of the macrophytic vegetation’s condition in Greek lakes and may constitute a useful tool for the classification of ecological status of other Mediterranean lakes.

The role of alkalinity in setting water quality metrics: phosphorus standards in United Kingdom rivers.

UK implementation of the European Union Water Framework Directive (for the 2015-2021 cycle) Ecological Status (ES) classification for river phosphorus is based on the calculation of reference conditions for reactive phosphorus (RP) using river alkalinity measurements. Underpinning this approach is that the alkalinity is primarily from rock weathering and is free of anthropogenic influences. However, the potential contribution of anthropogenic alkalinity needs to be considered and, if possible, quantified. In the rural South West River Basin District of England, 38 river sites were examined with respect to river alkalinity loads in order to test this consideration. At river base flow when RP can cause enhanced algal growth, 9 sites (24%) had effluent alkalinity contributions amounting to 25-49% of the total riverine alkalinity load, while 11 (29%) of the sites received ≥50% of their alkalinity load from effluent. When flows increased above base flow to Q95 flow at these 11 sites, catchment diffuse run-off became the largest load of alkalinity at 9 of the sites, and that at the Q95 flows, combined effluent and diffuse alkalinity loads contributed 68-100% of the total alkalinity load. Anthropogenic alkalinity is likely to be present in diffuse run-off, but it is difficult to apportion alkalinity loads between natural and contaminant sources. It is likely that diffuse loads of alkalinity will dominate on the annual timescales used to assess WFD compliance, even at sites where ground water alkalinity dominates at base river flows. In principle, inclusion of anthropogenic alkalinity in the calculation of ES boundary concentrations for RP may lead to a relaxation of the standards. In practice this may not follow. It is likely that at the river sites used initially to develop the algorithms now used for P standard setting, anthropogenic alkalinity was present, to varying and unknown degrees, and that this alkalinity would have influenced the measured and reference RP and biological metrics on which the P standards are based. Apart from RP, alkalinity is also used to underpin water quality metrics for additional chemical and biological parameters, and for this reason, understanding the complex factors determining river alkalinity loads should be an important task for water quality regulators.

Diatom diversity and ecological status of the Lasovacka and Lenovacka streams near Zajecar: Consideration of WFD implementation in Serbia

The development and improvement of the monitoring system of rivers according to the requirements of the Water Framework Directive (WFD) is essential for all European states because assigning a wrong ecological status class (misclassification) to a water body can have significant economic consequences. In order to point out some of the key issues of WFD implementation in Serbia, we conducted a one-year study of the composition and abundance of diatoms in the phytobenthos in two streams, the Lasovacka and Lenovacka, in eastern Serbia. The physicochemical quality elements were also used in the assessment of their ecological status. The diatom community exhibited a higher species richness in the Lasovacka (88 taxa) than in the Lenovacka stream (63 taxa). Such a detailed study enabled us to record some of the rare taxa, e.g. Caloneis budensis in the Lasovacka, which was the first finding of this species in Serbia. The Lasovacka and Lenovacka streams were downgraded to moderate and poor ecological status, respectively, because of the high nitrogen load. Since the monitoring results based on the diatom indices resulted in the assignment of two streams to a good ecological status, the possible reason for the mismatch between the biological and physicochemical quality elements could be due to the lack of analysis of benthic invertebrate fauna or the application of diatom indices that are insufficiently sensitive to the specific environmental pressure. The results of this study show that conducting a comprehensive ecological investigation of rivers within the framework of the WFD in Serbia is urgently needed.

Pesticides in agricultural headwater streams in southwestern Germany and effects on macroinvertebrate populations

Pesticides are a major burden for stream ecosystems in the central European cultivated landscape. The objective of the present study was to investigate the applicability of ecological indicator methods in relation to toxicity of pesticides under the specific hydro-morphological conditions in small water bodies. Thus, an association of toxicity evaluating methods with different ecological indicators was to be attempted. Based on three random samples taken within the 2016 vegetation period, 23 headwater areas in the Saarland were investigated to test for pesticides and their metabolites. The macroinvertebrate population was also surveyed in 16 of these streams. Evidence was found of 41 substances in total. Most dominant substances include atrazine, isoproturone, quinmerac and tebuconazol as well as metabolites of dimethenamid, chloridazon and metazachlor. At 9 of the 23 sampling points, over 10 plant protection products and metabolites were found. Only 17% of the water bodies investigated contained fewer than 5 substances. Around half of the bodies of water investigated show noticeably high concentrations of metabolites of plant protection products. Maximum concentrations exceeding environmental quality standards or the Health-oriented Guideline Values were measured for 13 substances at individual sampling points.Analysis of the biological data for only 4 of the water bodies investigated resulted in the Ecological Status Class (ESC) “good”. All others fell short of the quality target, although they were classified as “good” or “very good” according to the Saprobic index. SPEARpesticides as a measurement of the sensitivity of the biocoenosis to pesticides shows their influence in a few water bodies. Likewise, high toxic unit values have also been calculated, indicating the presence of toxic substances at relevant concentrations. However, an actual correlation between SPEARpesticides and toxic unit could not be derived. Clearly in these very headwater streams other habitat-determining hydromorphological factors overlay the toxic impact of pesticides.

Assessing the ecological status of Italian lagoons using a biomass-based index

We compared the performance of abundance- and biomass-based M-AMBI in the 13 major Italian lagoons, using a benthic dataset constituted by 208 sampling sites. The relative importance of ecological groups changed when using abundance or biomass, sometimes leading to an improved ecological status classification. Being biomass more ecologically relevant than abundance, the adoption of a biomass-based index may better describe the ecological status of lagoons, where the community is naturally disturbed and dominated by tolerant and opportunist species.

The typology of Polish lakes after a decade of its use: A critical review and verification

The abiotic typology of Polish lakes, compliant with the requirements of the EU Directive 2000/60/EC (Water Framework Directive), was developed in 2004 under the commission of the Ministry of the Environment. Based on the combination of the obligatory typological criteria from Annex II of the WFD and one additional factor, all Polish lakes larger than 0.5km2 were assigned to 13 abiotic types. This typology reflected the diversity of abiotic conditions and was assumed to be tested and validated for its ecological relevance on the basis of biological data obtained thereafter. The first ten years of its application proved the high usability of this typology for lake classification of ecological status on the one hand, while on the other hand, it allowed to gather experiences and to detect deficiencies and errors considered in the verification process. In 2015, the abiotic typology of Polish lakes was verified. Above all, verification involved an analysis of the justification of lake eco-regional division and refinement of water stratification criteria, as these two issues have been questioned in the current typology. Data on physicochemical properties, phytoplankton, macrophytes and benthic diatoms obtained from the state lake monitoring conducted in the years 2007–2013 were used to verify the ecological relevance of the typological criteria. Typological criteria used in the verified lake typological scheme were essentially the same as those used in 2004. However, the number of lake types has been reduced from the previous 13 to seven, mainly due to the withdrawal from the lake division based on eco-regions. Moreover, the more specific criteria for determining the water mixing type were established. The new lake typology is expected to be implemented in routine monitoring and water management in Poland in the forthcoming River Basin Management Plan 2021–2027.

Effectiveness of Posidonia oceanica biotic indices for assessing the ecological status of coastal waters in Saronikos Gulf (Aegean Sea, Eastern Mediterranean)

Biotic indices are considered key assessment tools in most national and European policies aimed at improving the quality of coastal waters. At present, several Water Framework Directive (WFD)-compliant biotic indices based on the marine angiosperm Posidonia oceanica have been developed and applied in the Mediterranean Sea. In this study, we investigated the effectiveness of four different P. oceanica indices (POMI, PREI, Valencian CS, and BiPo) in evaluating the ecological status of coastal waters in a case study area of Greece. The evaluation, comparison, and validation of the Ecological Status Class (ESC) assessments obtained by each index were based on a set of eight common sites that encompasses the maximum range of environmental quality in the study area. Four sampling sites separated by tens of km were chosen in each of the two water bodies (WBs) studied. The spatial variations of the features of P. oceanica meadows were examined according to a hierarchical sampling design across four spatial scales, ranging from metres to tens of km, using independent nested analysis of variance. Except for the BiPo index, the reference values for each metric/index were defined by the dataset available for the study area. All biotic indices classified the WBs of the study area in Good ESC category. Only three of the four indices (PREI, Valencian CS, and BiPo) showed high comparability in the assessment of ESC at study site level. It is assumed that the differences found in the remaining index (POMI) are due to the different type of metrics taken into consideration and the different weighting given to them. Our findings suggest that all indices can provide an overall view of the cumulative impact of multiple environmental stressors existing in the study area, and can thus help raise awareness of ecosystem degradation.

An attempt to assess the ecological status of a lake based on historical and current maps of submerged vegetation

AbstractThe possibility of doing a back assessment of the ecological status of a lake based on archival bathymetric maps indicating areas overgrown with rushes and aquatic vegetation was verified. This assessment was assumed to be in accordance with that performed with the official Polish macrophyte-based method for lake assessment (Ecological State Macrophyte Index, ESMI). The study was conducted on Lake Dobrąg located in the Warmian-Masurian Voivodeship (surface area - 108 ha, maximum depth - 27.9 m, mean depth - 11.6 m). It included the hydroacoustic distribution of submerged macrophytes along 85 evenly distributed belt transects (perpendicularl to the shore line), creating a bathymetric chart and maps of vegetation occurrence and identifying areas occupied by hydrophytes (Cmax) and the maximum depth of lake colonization (Z). Analogous data were read from archival bathymetric chart dating from 1964-1968. The values obtained were compared with the means (and their confidence intervals) of 83 stratified lakes in Poland in different ecological status classes. Analysis of changes indicated that the ecological status of the lake had deteriorated. In the mid-1960s, the status of the lake was less than “very good” while the current status borders between “good” and “moderate.” The results indicate that the proposed method could be useful when attempting to assess changes in ecological status using archival bathymetric charts showing areas overgrown with vegetation and the distribution of it in lakes.

Improved retrieval of Secchi depth for optically-complex waters using remote sensing data

Water transparency is one of the ecological indicators for describing water quality and the underwater light field which determines its productivity. In the European Water Framework Directive (WFD) as well as in the European Marine Strategy Framework Directive (MSFD) water transparency is used for ecological status classification of inland, coastal and open sea waters and it is regarded as an indicator for eutrophication in Baltic Sea management (HELCOM, 2007). We developed and compared different empirical and semi-analytical algorithms for lakes and coastal Nordic waters to retrieve Secchi depth (ZSD) from remote sensing data (MERIS, 300m resolution). The algorithms were developed in water bodies with high coloured dissolved organic matter absorption (aCDOM(442) ranging 1.7–4.0m−1), Chl a concentration (0.5–73mgm−3) and total suspended matter (0.7–37.5gm−3) and validated against an independent data set over inland and coastal waters (0.6m<ZSD<14.8m). The results indicate that for empirical algorithms, using longer wavelengths in the visible spectrum as a reference band decreases the RMSE and increases the coefficient of determination (R2). The accuracy increased (R2=0.75, RMSE=1.33m, n=134) when ZSD was retrieved via an empirical relationship between ZSD and Kd(490). The best agreement with in situ data was attained when ZSD was calculated via both the diffuse and the beam attenuation coefficient (R2=0.89, RMSE=0.77m, n=89). The results demonstrate that transparency can be retrieved with high accuracy over various optical water types by the means of ocean color remote sensing, improving both the spatial and temporal coverage. The satellite derived ZSD product could be therefore used as an additional source of information for WFD and MSFD reporting purposes.

Robustness of the biotic indicators used for classification of ecological status of lotic water bodies: A testing method when the data series are short

Successful implementation of the Water Framework Directive and achieving its objective of good ecological status of all water bodies depend on the power of the set of monitoring indicators to capture the change in the ecological status of aquatic systems. In this context, testing the robustness and sensitivity of ecological indicators currently used for assessing the status of lotic water bodies is instrumental for the adaptation and further development of assessment methods. This is also a prerequisite for an effective, context-based monitoring system and for improving the quality of the decision making for water bodies. This is particularly challenging in regions where the sets of indicators are under development, the data series are relatively short and data which addresses the individual error sources are lacking. Here we show that hierarchical clusters and ordination analysis provide appropriate tools with which the validity of the ecological status of water bodies set up based on biological multimetric monitoring indices in a small water basin could be tested. We hypothesize that robust and informative monitoring methods classify all water bodies belonging to a single ordination grouping in the same quality class (high, good, moderate, poor or bad). In our case study multimetric biological indicators failed to discriminate between the good and moderate ecological status. Community structure as well as water conductivity and nitrate load were primarily responsible for the observed difference between ordination groupings. Inconsistencies shown in our case study are likely to be induced by insufficient refinement of monitoring schemes and by the constraints existing in the data series and available metadata. We show that multiplication of indicators leads to discrepant interpretation and problematic application. Proposed ordination analysis proves to be a simple and useful tool to detect such discrepancies and support further progress in indicator development. Integrated and longer data and metadata series are needed to refine context-based monitoring methods.

A new paradigm for biomonitoring: an example building on the Danish Stream Plant Index

Summary Despite intensive efforts for more than a decade to develop Water Framework‐compliant assessment systems, shortcomings continue to appear. In particular, the lack of reference conditions has hindered the development of assessment systems capturing the heart of the Water Framework Directive (WFD) – that ecological status should be set as the deviation from the natural, undisturbed condition. Recently, the Danish Stream Plant Index (DSPI) was developed. This system contrasts existing systems in that it builds on an expert interpretation of the normative definitions of ecological status classes in the WFD without taking pressure–impact relationships into account. Here, we substantiate the approach taken in the development of DSPI and examine whether the DSPI class decreases with increasing level of anthropogenic stress and, additionally, whether the deviation from the natural undisturbed condition increases with decreasing DSPI class sensu WFD using trait composition of plant assemblages from Danish streams around year 1900 as a reference. We furthermore examine the trait composition of the vegetation in sites classified into different DSPI status classes to explore whether predictable patterns exist that can be used to identify the ultimate cause(s) of failure to meet ecological goals and help guide the selection of appropriate mitigation measures. We observed that DSPI declined with several parameters indicative of environmental stress in Danish streams and, furthermore, that the deviation from the natural undisturbed condition regarding the trait composition of plant communities declined with increasing DSPI, implying that the trait composition of plant communities in the high DSPI status class was most similar to those occurring in Danish streams around year 1900. We also found that trait characteristics capable of disentangling important stressors in Danish streams varied consistently among sites classified into different DSPI classes. Based on our findings, we call for new thinking. We suggest that more effort should be directed at describing reference conditions and interpreting the normative definitions of good, moderate, poor and bad instead of focusing solely on developing assessment systems using pressure–impact frameworks. We find this particularly important with respect to streams as these are seldom impacted by only a single stressor.

Habitat use and tolerance levels of macroinvertebrates concerning hydraulic stress in hydropeaking rivers – A case study at the Ziller River in Austria

Artificial flow fluctuations due to the operation of hydropower plants, frequently described as hydropeaking, result in a constant decrease of biomass of specific macrozoobenthos (MZB) taxa. For the presented case study, we assessed three reaches in the Ziller River catchment. At each sampling reach we performed the Multi-Habitat-Sampling (MHS) method with a Water Framework Directive (WFD) compliant AQEM/MHS net according to the Austrian guideline. Additionally, a hydraulic-specific sampling was conducted with a modified Box (Surber) sampler. As a basis for predictive habitat modelling of the MZB fauna, we measured abiotic parameters like mean (v40) and bottom-near (vbottom) flow rate or water depth respectively, for each box sample. In addition, the choriotope type, representing grain size classes, was determined. One of the main results is, that the national status assessment was not capable to reflect the impact of pulse release at the investigated river stretches on the basis of status classes. Moreover, we figured out that 1) habitats of stagnophilic macroinvertebrate taxa are minimized in channelized stretches affected by hydropeaking, leading to heavy quantitative losses for populations, becoming apparent in significant decreases in total individual numbers and biomass for many taxa. 2) The minor respond of the ecological status class in affected stretches by applying the WFD compliant national assessment method for macroinvertebrates owes to the tolerance of rheobiont or rheophilic taxa commonly classified as indicators for good conditions regarding saprobity or degradation score. 3) A development of a stressor-specific sampling design is required as the MHS method largely ignores vulnerable habitats. 4) The habitat suitability of selected species provides efficient expertise for impact assessment and mitigation measure design in terms of predictive habitat modelling.

How do low-abundance taxa affect river biomonitoring? Exploring the response of different macroinvertebrate-based indices

The contribution of rare taxa to aquatic bioassessments remains a subject of debate, and generates contrasting positions among researchers. Very little is known about the effect of low-abundance taxa (LAT) for calculating both single and multimetric macroinvertebrate-based indices, as well as the ecological status classification. In this study, we aimed to: i) identify the aquatic macroinvertebrates that need special attention during index applications given their low abundance; ii) analyse the effect of excluding LAT on single (IBMWP and IASPT) and multimetric (STAR_ICMi) biological indices; and iii) investigate the influence of LAT on river ecological status assessments. To this end, two different river basins in SE Spain and N Italy with contrasting climatic conditions and river types were selected. Our results showed that almost all the taxa at the family level can act as low-abundance taxa. In particular, the LAT belonged mainly to orders Diptera, Trichoptera, Coleoptera, Gastropoda and Hemiptera. The IndVal analysis stressed Tabanidae, Cordulegasteridae and Hydroptilidae as the most characteristic low-abundance families in the Spanish data set, while Dryopidae and Athericidae were identified mostly in N Italy. Excluding LAT affected the studied index values and the resulting bioassessment classification, except for the IASPT index. Loss of the entire LAT pool reduced the ecological status for 78% of the samples for the IBMWP index. Changing took place in 41% of the samples when considering the STAR_ICM index. Relevant changes were detected even when considering loss of 50% of the LAT, especially with the IBMWP index. Similar values and patterns were obtained in each considered quality class and river type. Our results provide useful information about controversial taxa and stress the significance of LAT in river biomonitoring. Excluding LAT is discouraged, although different responses according to the considered index were detected. The IBMWP index always obtained lower values (coupled mainly with an underestimation of ecological classes), while STAR_ICMi and, especially the IASPT index, were less affected by excluding LAT. Paying special attention to all the protocol application stages is recommended, with emphasis placed when using the IBMWP index.

Exploring the ecological response of fish to flow regime by soft computing techniques

Ecosystem integrity has become a focus of watershed management. Recently much attention has been paid to the analysis of eco-hydrological data for developing a better understanding of how flow regimes influence the structures and functions of riverine ecosystems. This study explores ecosystem integrity in Taiwan rivers through characterizing the relationship between flow regimes (long-term continuous hydrological observational datasets) and fish communities (non-continuous ecological monitoring datasets) using soft computing techniques (self-organizing feature map (SOM) and clustering methods). The analysis is driven by the Taiwan Eco-hydrologic Indicator System (TEIS) statistics and biodiversity measures, in which data sets consist of 74 long-term monitoring records of flow and fisheries at 38 locations in 12 rivers in Taiwan. Results indicate that: (1) flow regimes of the 12 rivers can be related to watershed locations, namely upstream, midstream and downstream regions; (2) fish diversity is significantly higher in midstream regions than in up- and downstream regions; and (3) a consistent relationship between flow regime and fish community can be obtained when using presence–abundance data. Flow regime characteristics are consistent with respect to the hydro-geographical and ecological characteristics of streams, especially for midstream reaches, which provides further evidence of the importance of natural flow regimes in sustaining ecological integrity. These analysis results offer valuable insights into management options that support decision-makers in evaluation and classification of ecological status and provide further analyzed evidence to address ecological flow regime issues in water resources management.

Satellite-based products for monitoring optically complex inland waters in support of EU Water Framework Directive

The need to restore and protect waterbodies from further degradation has resulted in formulation of the European Union Water Framework Directive 2000/60/EC (WFD). The directive aims to harmonize European legislation on water; and member states shall establish a programme for monitoring the status of all waterbodies larger than 0.5 km2, in order to ensure future quality and quantity of inland waters. The biological and physical–chemical status and ecological potential should be assessed and action plans for a sustainable management and protection of freshwater resources should be established. In practice, this means that extensive and expensive sampling programmes are needed. The ecological status of a waterbody can be described by various biological and physical–chemical quality elements, and several of these important ecological parameters can be monitored by space-based instruments: (1) phytoplankton biomass; (2) chlorophyll-a concentration; (3) water transparency; and (4) frequency and intensity of blooms. The objective of this article is to demonstrate how Environmental Satellite/Medium Resolution Imaging Spectrometer and future Sentinel-3/Ocean Land Colour Instrument data can be effectively used to complement traditional water monitoring programmes by adding information with significantly improved spatial coverage and temporal detail to support the WFD status assessment process. Examples are provided for five large European lakes (Peipsi, Võrtsjärv, Vänern, Vättern, Mälaren). Time series based on satellite data and data collected within national and regional monitoring programmes were compiled and compared, to demonstrate good agreement between the two techniques, but also to discuss natural differences and limitations. Furthermore, the ecological status class based on satellite and in situ data for each waterbody was calculated and analysed.

The Foram Stress Index: A new tool for environmental assessment of soft-bottom environments using benthic foraminifera. A case study from the Saronikos Gulf, Greece, Eastern Mediterranean

Saronikos Gulf, including the industrial zone of Elefsis Bay and the Port of Piraeus, is one of the most anthropogenically impacted coastal regions of Greece. Distinct assemblages of benthic foraminifers in sediment samples, collected from this gulf in February 2012, defined three zones that reflect abiotic parameters of the sediments (e.g., organic carbon, metal content). A low-diversity assemblage, dominated by stress-tolerant Ammonia tepida and Bulimina spp., was characteristic of samples from Elefsis Bay. Samples from the western and central part of Saronikos Gulf were the most variable with respect to both abiotic parameters and the foraminiferal assemblage, characterized by a mix of stress-tolerant and more sensitive taxa, especially Bolivina spp. and Nonion fabum. Samples from the coast of Salamis and at the eastern sector of the gulf were characterized by a diverse assemblage that included Peneroplis pertusus, miliolids, and a variety of small, epiphytic rotaliid taxa. A new biotic index, the Foram Stress Index (FSI), is based on the relative percentages of two ecological groups of benthic foraminiferal species, grouped according to their tolerance/sensitivity to organic matter enrichment and weighted proportionately to obtain a formula to define five ecological-status classes. The FSI produced three rankings for these samples (Poor, Moderate and Good), that strongly correlate with the macroinvertebrate-classification tool known as the BENTIX Index. The FSI provides a new tool to assess sediment or substrata quality based upon the benthic foraminiferal assemblages, which are a significant component of living meiobenthic communities that are generally not considered in most biotic benthic indices.

The performance of biomass-based AMBI in lagoonal ecosystems

We studied the performance of the AZTI Marine Biotic Index AMBI manipulating input data collected from lagoonal ecosystems. Our data set consisted of macrofaunal abundance and biomass counts gathered at a variety of sites at which the disturbance status was known. Input data were also manipulated using a set of transformations of increasing severity. Biotic indices were calculated using raw and transformed abundance, biomass and production. Among the three categories of AMBI-based indices, medium transformation of data gave the highest correlation with pressures. However, increasing the severity of transformation generally resulted in a decrease of the correlation with environmental factors. The relative importance of ecological groups changed when using abundance or biomass, sometimes leading to an improved ecological status classification. Being biomass and production more ecologically relevant than abundance, using them to derive AMBI-based new indices seems intriguing, at least in lagoonal waters, where the community is naturally disturbed and dominated by opportunists.

Tributyltin pollution biomonitoring under the Water Framework Directive: Proposal of a multi-species tool to assess the ecological quality status of EU water bodies

The Water Framework Directive (WFD) is a key legislative action developed by the European Union in order to protect aquatic ecosystems. One of the concerning pollutants, listed in this directive as a priority hazardous substance, is tributyltin (TBT), a biocide largely used in antifouling paints and identified as a causative agent of imposex/intersex in gastropods. In order to integrate TBT pollution monitoring within this legislative framework, a practical exercise is here proposed to assess the evolution of surface water ecological status in Ria de Aveiro (NW Portugal). Three bioindicators – the caenogastropods Nucella lapillus, Nassarius reticulatus and Littorina littorea – were used under the general WFD benthic invertebrate quality element, and the vas deferens sequence index (VDSI) and the intersex index (ISI) were selected as biomarkers for the purpose of assessing the condition of this quality element regarding the impact of TBT pollution. Levels of VDSI in N. lapillus and N. reticulatus, and ISI in L. littorea, were surveyed in 2013 and compared with previous data available for the same species and study area in 1998 and 2005, providing a time lapse for a period of 15 years. VDSI and ISI values were converted into Ecological Quality Ratios (EQR) and EQR boundaries were set for each species in order to define the five ecological status classes (High, Good, Moderate, Poor and Bad). We propose N. lapillus as key bioindicator, however the combined use of further species is very useful to cover a wider study area. Based on the proposed method, it is concluded that the ecological status of the surface waters surveyed in Ria de Aveiro, concerning the impact of TBT pollution on the above benthic invertebrate taxa, improved considerably since 1998 and achieved a Good Ecological Status in 2013, thus meeting the WFD environmental objectives for this priority hazardous substance even before 2015.

El estado ecológico de las pequeñas cuencas de cabecera en las serranías béticas húmedas (parque natural Los Alcornocales, sur de España) según la Directiva Marco del Agua: ¿su aplicación garantiza la conservación?

In compliance with the European Water Framework Directive, member states have had to develop a method to assess the quality of aquatic ecosystems by comparing the current situation regarding near–natural reference conditions for each river type. In 2008, the Spanish Ministry of Environment approved the Order of Water Planning Statement. This statement sets out reference conditions and ecological status class change limits for the different types of rivers in Spain for which sufficient data are available. In the presentstudy, we established reference conditions and quality class thresholds for streams classified as wet Betic mountain rivers from 24 reaches of streams located in the Los Alcornocales natural park, using two qualitative indices based on macroinvertebrates (IBMWP and IMMi–L). The results for the IBMWP index indicate that from the standpoint of management of the ecological state, the watercourses studied show more affinity with the types of the Spanish Atlantic siliceous slope than with those of the Mediterranean siliceous slope when we consider EQR values. Considering the threshold values, the index resembles siliceous low Mediterranean mountain rivers (type 8). However, the EQR values do not match those calculated in this study. These results suggest that it is necessary to use an index adapted to the characteristics of these watercourses. Application of the quality criteria contained in the Guadalete–Barbate and Mediterranean–Andalusian Basin Plans to the management of these waterways is discussed, because it is unlikely that they ensure the maintenance of good ecological status. We thus propose a new calibration of the IBMWP index that ensures the maintenance of good environmental status of watercourses in this natural area, and the use of the IMMi–L index as an effective management tool. However, as our study area represents only a part of the wet headwaters in the southern Iberian peninsula, analysis of other basin types is necessary to complete such information.