DWS Hydro Okologie GmbH

Vienna, Austria

DWS Hydro Okologie GmbH

Vienna, Austria
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Poikane S.,European Commission - Joint Research Center Ispra | Van Den Berg M.,Center for Water Management | Hellsten S.,Finnish Environment Institute | De Hoyos C.,Center for Hydrographic Studies | And 8 more authors.
Procedia Environmental Sciences | Year: 2011

The Water Framework Directive (WFD) has been published in 2000 and the process of its implementation has created a new paradigm in the understanding of ecological status of water bodies in Europe. The Directive explicitly requires that ecological status is assessed through the analysis of various characteristics of aquatic flora and fauna. An Intercalibration exercise is foreseen to identify and resolve significant inconsistencies between the ecological quality classifications of EU Member States to ensure that the obligation to reach good status has the same meaning throughout Europe. The results of the first Lake Intercalibration exercise (2003-2008) are the setting of reference conditions and class boundaries for phytoplankton biomass metrics for all lake intercalibration types and all geographical regions of the EU. Work on macrophyte assessment methods has been carried out in the Alpine, Central/Baltic and Northern region, while only Alpine and Mediterranean countries have succeeded to develop and harmonize phytoplankton composition assessment methods. The aim of the second phase of intercalibration (2008-2011) is to close these gaps and improve the comparability of the results in time for the second river basin management plans due in 2015. © 2011 Published by Elsevier Ltd.


Poikane S.,European Commission - Joint Research Center Ispra | Birk S.,University of Duisburg - Essen | Bohmer J.,Bioforum GmbH | Carvalho L.,UK Center for Ecology and Hydrology | And 16 more authors.
Ecological Indicators | Year: 2015

The Water Framework Directive is the first international legislation to require European countries to establish comparable ecological assessment schemes for their freshwaters. A key element in harmonising quality classification within and between Europe's river basins is an "Intercalibration" exercise, stipulated by the WFD, to ensure that the good status boundaries in all of the biological assessment methods correspond to similar levels of anthropogenic pressure. In this article, we provide a comprehensive overview of this international comparison, focusing on the assessment schemes developed for freshwater lakes. Out of 82 lake ecological assessment methods reported for the comparison, 62 were successfully intercalibrated and included in the EC Decision on intercalibration, with a high proportion of phytoplankton (18), macrophyte (17) and benthic fauna (13) assessment methods. All the lake assessment methods are reviewed in this article, including the results of intercalibration. Furthermore, the current gaps and way forward to reach consistent management objectives for European lakes are discussed. © 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND.


Pilotto F.,University of Rome La Sapienza | Free G.,U.S. Environmental Protection Agency | Cardoso A.C.,European Commission - Joint Research Center Ispra | Wolfram G.,DWS Hydro Okologie GmbH | Solimini A.G.,University of Rome La Sapienza
Fundamental and Applied Limnology | Year: 2012

Invertebrate communities inhabiting different lake zones are expected to respond differently to natural environmental variation and anthropogenic stressors. We used multivariate statistical methods in order to quantify the effects of eutrophication and morphological pressures on the spatial structure of the invertebrate benthic communities at two depth zones (profundal and sublittoral) in subalpine lakes in Italy, Germany and Austria . In both lake zones, environmental variables related to eutrophication pressures (mid-lake total phosphorus and chlorophylla) were significant in structuring the invertebrate community (permutation test: p < 0.01). Three variables relating to morphological pressures (diversity of macrophyte growth forms, sum of pressures in the lake shore, and percentage of natural land cover within a 200 m stretch from the lake shore) were significant (permutation test: p < 0.01) in the sublittoral zone, while in the profundal zone none of the variables included in the analysis related to morphological pressures were significant in structuring the invertebrate community. Variance partitioning analysis showed that profundal communities were mainly affected by eutrophication (8.6 % of total variance; p = 0.005), while in the sublittoral zone eutrophication accounted for only 0.5 % (p = 0.04) of total variance. The effects of morphological pressures could be tracked only in the sublittoral zone, where it accounted for 0.8 % of total variance (p = 0.015). The spatial component was responsible for a large part of the total variance (58.7 % in the profundal, p = 0.005; 44.2 % in the sublittoral zone, p = 0.005) and had interactions with stressor variables in both lake zones. Therefore the analysis of spatial patterns should be included in assessment systems relating invertebrate assemblages to pressures. © 2012 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.


Lopez-Doval J.C.,University of Barcelona | Grossschartner M.,DWS Hydro Okologie GmbH | Hoss S.,Ecossa | Orendt C.,WaterBioAssessment | And 3 more authors.
Limnetica | Year: 2010

The Llobregat is a highly-perturbed Mediterranean river affected by a wide range of pollutants. High concentrations of soluble reactive phosphorus and chloride are the clearest indicators of pollution in this basin. Seven sites in the mid and lower Llobregat basin were sampled in June 2005 to examine the invertebrate community inhabiting the soft sediments along this pollution gradient. Spatial distribution analysis revealed differences in chemical parameters, and in the composition and biomass of the invertebrate community. Most of the taxa found are opportunistic and reflect low or unacceptable biological water quality. Nevertheless, changes in their abundance, biomass and diversity reflect the longitudinal pollution gradient in the river.


Wolfram G.,DWS Hydro Okologie GmbH | Hoss S.,Ecossa | Orendt C.,Orendt Hydrobiologie | Schmitt C.,University of Antwerp | And 13 more authors.
Science of the Total Environment | Year: 2012

The aim of this study was to combine different lines of evidence on the impact of chemical pollution on benthic invertebrate communities in three European river basins (Elbe, Scheldt, and Llobregat). The study integrates chemical analyses, a battery of different sediment toxicity tests, and field data from soft-sediment meio- and macrobenthic fauna within a sediment-quality triad in which chironomids, oligochaetes, and nematodes are identified on the species level. The use of TU (toxic units) and msPAF (multi-substance potentially affected fraction) in an approach assessing the chemical impact as well as the integration of sediment toxicity tests with bacteria (Vibrio fischeri), benthic invertebrates (Caenorhabditis elegans, Potamopyrgus antipodarum, Lumbriculus variegatus, Chironomus riparius), and fish embryos (Danio rerio), together with univariate and non-parametric multivariate statistical analyses of the biological data revealed significant differences between unpolluted and polluted sites in all three river basins. To combine the different results obtained in the sediment-quality triad, a scoring system was successfully developed based on a simple algorithm. This system provides an easily understandable scheme for non-experts among decision makers and water managers. © 2012 Elsevier B.V..


Adamek Z.,Academy of Sciences of the Czech Republic | Orendt C.,Orendt Hydrobiologie | Wolfram G.,DWS Hydro Okologie GmbH | Sychra J.,Masaryk University
Biologia | Year: 2010

Benthic macroinvertebrates are an important indicator of river health. However, their response upon water quality development downstream the pollution outlets considerably depends on the environmental habitat characteristics. Three successive stretches, each of them providing three different mesohabitats in stillwater (S), torrential (T) and riparian (R) zones were selected for evaluation of the impact of altered metapotamal river bed morphology (channelization) and chemical determinants of water quality on the Upper Elbe River. In downstream direction, the stretches are separated by weirs and characterized as a low polluted low modified natural stream (N), a low polluted channelized stream (C) and a channelized polluted stream (CP). Altogether, 111 benthic macroinvertebrate taxa were recorded in the Pardubice hotspot between Němčice and Přelouč. Despite different levels of stream bed and water quality degradation, micro- and mesohabitat characteristics appeared to be the most important factors determining the diversity of macrozoobenthos in riffle (substrate size structure) and in shoreline (macrophyte community composition and structure) mesohabitats. The diversity of macroinvertebrate communities was highest in riparian mesohabitats compared to stillwater and torrential ones. Saprobic indices increased in downstream direction, thus indicating the decline of water quality. © 2010 Institute of Zoology, Slovak Academy of Sciences.


Niedermayr R.,DWS Hydro Okologie GmbH | Schagerl M.,University of Vienna
Fundamental and Applied Limnology | Year: 2010

The phytobenthos community of a carbonate headwater and its springs were studied in the Kalkalpen National Park (Austria). The investigated rivulet Almbach is located at a traditionally farmed mountain pasture. Two springs, one of them fenced in to prevent livestock access, and two more sites from the headwater were sampled from May to October 2005. Whereas diatoms dominated the fenced spring, chlorophytes reached highest biomass at the spring with livestock access. A Discriminant Analysis revealed three functions based on nitrate, phosphorus and channel width, which classified 100% of the sites correctly. Indicator taxa - regarded as highly indicative of a particular site when they are mainly found at that site and are present in a large number of its sample units - were mainly detected at the cattle-free sites. Both springs differed significantly from the rivulet sites and from each other concerning physico-chemical parameters, algal community structure, biomass and seasonal development. Canonical Correspondence Analysis was used to analyze the phytobenthos community pattern along environmental gradients. Phosphorus, benthic ash-free dry mass and pH had the highest influence on the first two axes, which explained 78 % of taxa-environmental variation. A negative impact of pasturing on the sensitive high mountain headwater system was detected because of reduced bank stability through trampling, decreased canopy cover and increased nitrogen input. These factors caused an atypical, chlorophyte- dominated phytobenthos community with both low algal diversity and evenness. © 2010 E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany.


Orendt C.,Orendt Hydrobiologie WaterBioAssessment | Wolfram G.,DWS Hydro Okologie GmbH | Adamek Z.,Academy of Sciences of the Czech Republic | Jurajda P.,Academy of Sciences of the Czech Republic | Schmitt-Jansen M.,Helmholtz Center for Environmental Research
Biologia | Year: 2012

Macroinvertebrate communities were investigated along a gradient of heavy industrial and municipal pollution in the highland Bílina River (Czech Republic). Physico-chemical determinants and ions were monitored and community analysis performed focusing on taxonomic composition, ecological functioning (feeder and dweller guilds) and water quality metrics, including saprobity index, BMWP and diversity. Impacted sites differed significantly from reference and from recovered stretches. Chemical data revealed two main pollution factors, (1) a "salinity determinant", described best by conductivity and SO42-, and (2) an "organic pollution determinant", represented best by O2 concentrations and NO2-, all varying locally and temporally. Some metrics and taxa showed significant correlations to abiotic parameters. Functional communities showed a stronger relationship to the "organic pollution determinant", suggesting that elevated organic pollution had a dominating influence on functional community metrics; though other variables may also have an influence in this multistress environment. On the other hand, there were indications that the taxonomic community was more influenced by ion concentrations ("salinity determinant"). The gradient from reference sites to polluted sites was weaker in the final sampling campaign. The results presented here can be used as a reference for assessing future changes in environmental impact from pollution, being finer and more detailed than assessment according to the EU's WFD. © 2011 Versita Warsaw and Springer-Verlag Wien.


Dokulil M.T.,Nationalpark Neusiedlersee Seewinkel | Herzig A.,Nationalpark Neusiedlersee Seewinkel | Somogyi B.,Balaton Limnological Research Institute | Voros L.,Balaton Limnological Research Institute | And 3 more authors.
Estonian Journal of Ecology | Year: 2014

This review summarizes winter conditions from six polymictic European shallow lakes. The lakes range from oligotrophic to hyper-eutrophic. Four of the lakes freeze regularly while ice cover is absent or rare in the two others. Ice duration and timing of ice-out are significantly influenced by climate signals in three of the lakes. Winter water temperature remains higher in non-ice-covered lakes. No long-term trend in temperature is detectable except for one lake where winter water temperature began to increase in 1986. Secchi depth in winter is equal or greater than summer values in all six lakes indicating relatively better light conditions in winter. Total phosphorus concentration in winter ranges from 10 to 130 µg L–1, which is equal or lower than summer values and is unrelated to chlorophyll a in five of the sites. Phytoplankton species composition during winter differs largely at the six sites. The winter assemblages largely depend on the trophic level and the conditions during the previous season. Winter chlorophyll a and phytoplankton biomass are usually lower than summer values because of reduced photosynthetic rates. Bacterial production often exceeds primary production. Epipelic algal assemblages tend to proliferate during winter in both ice-covered and non-ice-covered lakes. Primary production is low during winter because of insufficient light. Zooplankton abundances and biomass critically depend on conditions during the previous season and the winter situation and are quite variable from year to year, but their values correlate with the trophic status of the lakes. As a result, winter conditions are important to understand seasonal and annual changes in shallow lakes. © 2014, Estonian Journal of Ecology. All rights reserved.


PubMed | DWS Hydro Okologie GmbH
Type: | Journal: The Science of the total environment | Year: 2012

The aim of this study was to combine different lines of evidence on the impact of chemical pollution on benthic invertebrate communities in three European river basins (Elbe, Scheldt, and Llobregat). The study integrates chemical analyses, a battery of different sediment toxicity tests, and field data from soft-sediment meio- and macrobenthic fauna within a sediment-quality triad in which chironomids, oligochaetes, and nematodes are identified on the species level. The use of TU (toxic units) and msPAF (multi-substance potentially affected fraction) in an approach assessing the chemical impact as well as the integration of sediment toxicity tests with bacteria (Vibrio fischeri), benthic invertebrates (Caenorhabditis elegans, Potamopyrgus antipodarum, Lumbriculus variegatus, Chironomus riparius), and fish embryos (Danio rerio), together with univariate and non-parametric multivariate statistical analyses of the biological data revealed significant differences between unpolluted and polluted sites in all three river basins. To combine the different results obtained in the sediment-quality triad, a scoring system was successfully developed based on a simple algorithm. This system provides an easily understandable scheme for non-experts among decision makers and water managers.

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