Danube Basin Research Articles

Investigating the scale of herding in Chalcolithic pastoral communities settled along the Danube River in the 5th millennium BC: A case study at Borduşani-Popină and Hârşova-tell (Romania)

Abstract In southeastern Romania, the Gumelniţa culture is characterized by the appearance of tell sites. Whether this phenomenon was accompanied by increasing specialization of the economy may be investigated through the zooarchaeology of pastoral systems. The scale of herding is an important element of this framework. A case study was conducted on the tell sites of Hârsova and Bordusani-Popina situated in the Danube River basin. Both sites, located respectively on a terrace of the river and on the island of Balta Ialomiţei, delivered occupations from the Gumelniţa A2 dated to the second half of 5th millennium cal BC. Their occupants subsisted on an economy focused to a large extent on aquatic resources but also heavily dependent on cattle, pig and caprines husbandry and agriculture. The role of riverbanks resources in herding strategies and the extent to which the island of Balta Ialomiţei may have sustained domestic animal stocks was addressed through stable isotope analysis of animal skeleton remains. At both sites, results revealed local herding for cattle and caprines, reflected in an unexpectedly high contribution of C4 plants to their diet, most likely from ruderal C4 plants that are more abundant around the settlements as well as in cultivated fields. Domestic pigs had a higher trophic status than their wild counterparts, highlighting a significant contribution of animal protein to their diet most likely provided by human activities, suggesting that they were maintained in the settlement. Overall the findings suggest domestic stocks were reared in close proximity to the settlements, rather than in an extensive system. This scheme complements the small-scale cultivation system highlighted from the archaeobotanical analysis. Gumelniţa tell sites have been previously described as being part of larger pastoral systems including locations with complementary functions, although functional complementarity in time was not made explicit in this model. In this regard, the results obtained at Hârsova and Bordusani-Popina are not in favour of large-scale seasonal mobility.

The Alburnus benthopelagic fish species of the Western Balkan Peninsula: An assessment of their sustainable use

In this study, we aimed to assess the population status of bleak (Alburnus spp.) over the Western Balkan Peninsula in terms of its sustainable use. A second objective was to determine key factors important for fishery management planning. Two different basins, continental (the Danube Basin and the Sava River sub-basin) and marine (the Adriatic and the Aegean Sea Basins) were examined. A sustainability assessment and factor analysis were conducted using the adjusted ESHIPPOfishing model, extended with additional socio-economic sub-elements, and the categorical principal components analysis (CATPCA), respectively. The results of the assessment revealed the bleak populations in the Danube Basin and the Sava River sub-basin to be highly sustainable. The population characteristics with abiotic and biotic factors were responsible for this status, while the influence of socio-economic factors was insignificant. The sustainability status of the bleak populations of the Mediterranean basin varied, with the populations from Ohrid and Skadar Lakes showing a high and those from Prespa and Dojran Lakes a medium status. Socio-economic factors with traditional fishing were the most important for the Mediterranean bleak populations.

Assessment of the contamination of riparian soil and vegetation by trace metals — A Danube River case study

The aim of this study was to assess the spatial distribution of arsenic and heavy metals (Cd, Cr, Cu Hg, Ni, Pb and Zn) in a riparian area influenced by periodical flooding along a considerable stretch of the Danube River. This screening was undertaken on soil and plant samples collected from 43 sites along 2386km of the river, collected during the international Joint Danube Survey 3 expedition (ICPDR, 2015). In addition, data on the concentration of these elements in river sediment was used in order to describe the relationship between sediment, riparian soil and riparian plants. A significant positive correlation (Spearman r, for p<0.05) was found for trace metal concentrations in river sediment and soil (r=0.817). A significant correlation between soil and plants (r=0.438) and sediment and plants (r=0.412) was also found for trace metal concentrations. Elevated levels of Cd, Cr, Cu, and Ni were found at certain sites along the Serbian stretch, while elevated concentrations of Hg were also detected in Hungary, of Pb along the Romanian stretch and of As along the Bulgarian stretch (the Lower Danube). These results point to the presence of naturally-occurring metals derived from ore deposits in the Danube River Basin and anthropogenic metals, released by mining and processing of metal ores and other industrial facilities, which are responsible for the entry of metals such as Cu, Ni and Zn. Our results also indicated toxic Cd and Zn levels in plant samples, measured at the Hercegsznato site (Middle Danube, Hungary), which highlighted these elements as a potential limiting factor for riparian vegetation in that area. The distribution of the analysed elements in plant material also indicates the species-specific accumulation of trace metals. Based on our results, the Lower and Middle Danube were found to be more polluted in terms of the analysed elements.

Macroparasites and their communities of the European eel Anguilla anguilla (Linnaeus) in the Czech Republic

This paper summarises the results of parasitological examinations of the European eel Anguilla anguilla (Linnaeus) in the Czech Republic, carried out at the Institute of Parasitology, Czech Academy of Sciences (previously the Czechoslovak Academy of Sciences) within the period of 50 years (1958-2008). Even though this survey is limited to the Czech Republic, it provides extensive data probably incomparable with any other study anywhere regarding the number of eels examined and parasites found. A total of 723 eels was examined from 42 localities that belong to all of the three main river drainage systems in the country, i.e. the Elbe, Danube and Oder river basins. Of the 31 species of adult and larval macroparasites including Monogenea (4 species), Trematoda (3), Cestoda (3), Nematoda (11), Acanthocephala (5), Hirudinea (1), Bivalvia (1), Copepoda (1), Branchiura (1) and Acariformes (1), most of them (30) were recorded from the Elbe River basin. These parasites can be divided into three main groups regarding their host specificity: parasites specific for eels (26%), non-specific adult parasites occurring also in other fishes (61%) and non-specific larvae (13%). The highest number (19) of parasite species was recorded in the Mácha Lake fishpond system in northern Bohemia. The parasite communities in eels from the individual localities exhibited large differences in their species composition and diversity depending on local ecological conditions. The parasite fauna of A. anguilla in the Czech Republic is compared with that in other European countries. The nematode Cucullanus egyptae Abdel-Ghaffar, Bashtar, Abdel-Gaber, Morsy, Mehlhorn, Al Quraishy et Mohammed, 2014 is designated as a species inquirenda.

High sensitive multiresidue analysis of pharmaceuticals and antifungals in surface water using U-HPLC-Q-Exactive Orbitrap HRMS. Application to the Danube river basin on the Romanian territory

The occurrence of 67 pharmaceutical and antifungal residues in the Danube river on the Romanian territory was studied by using solid-phase extraction (SPE) and LC-Q Exactive Orbitrap high resolution MS in both full scan (FS) MS and targeted MS/MS modes. A single-laboratory validation procedure was carried out for the determination of 67 compounds in FSMS mode evaluating selectivity, sensitivity, linearity, precision and accuracy. The method showed satisfactory analytical performance. The evaluation of the recovery concluded that 75% of the compounds show recoveries between 85 and 115% and 10% of the compounds show recoveries between 85% and 65%. The level of detection was lower than 5ngl−1 for 66% of the compounds, between 5 and 10ngl−1 for 22% and between 10 and 25ngl−1 for 14% of the compounds. The coefficients of determination R2 were higher than 0.99 for 79% of the compounds, over a linearity range of 2.5–50ngl−1. Targeted MS/MS analysis, performed in addition to the full scan acquisition was used for confirmatory purpose.Twenty samples of Danube water and three of the main tributaries were collected in May, July, August and October 2014. Analysis of the selected water samples revealed the occurrence of 23 compounds such as diclofenac, carbamazepine, sulfamethoxazole, tylosin, indomethacin, ketoprofen, piroxicam, together with antifungals like thiabendazole, and carbendazim. Carbamazepine was detected in 17 samples, the maximum concentration being 40ngl−1. The highest concentration reached was 166ngl−1 for diclofenac.

The Pre-Mousterian industrial complex in Europe between 400 and 300 ka: Interpreting its origin and spatiotemporal variability

The author discuss data indicating that the non-handaxe (non-Acheulean) tradition of small tools and core-choppers was present in parts of West Eurasia during the early Middle Pleistocene – the period marked by a wide spread of Acheulean in West Asia and West Europe – and survived until 400–300 ka and perhaps later in some areas, beyond the area of the maximum Acheulean distribution, in the Danube basin and the Balkans, and to a limited extent north of the Danube basin in Central Europe, and in the south of Russian plain and Northern Caucasus in Eastern Europe. The author defines these Middle Pleistocene assemblages, which are totally lacking true Acheulean handaxes and debitage resulted from large flake or Levallois knapping technologies, as the “Pre-Mousterian industrial complex”. The assemblages of Pre-Mousterian complex are variable due to their functional differentiation and other reasons, but generally comprise the next three components: (1) simple (mostly primary and orthogonal, and also rare unipolar and centripetal) cores with short reduction sequences, consisting of flaking of 1–3 flakes from one platform, followed by the core rotation or discard; (2) flake-tools, which are made mostly (but not exclusively) on small-sized flakes with beveled platforms and include varieties of simple side-scrapers, denticulates, notches, thick end-scrapers, awls, and convergent pieces, as well as small numbers of tools with flat ventral retouch or bifacial retouched edges; and (3) large-sized tools are always present and include mostly unifacial choppers, and more rare chopping-tools and proto-bifaces (or pointed choppers) with partial bifacial processing. The author discuss that the hominids that produced lithic industries of Pre-Mousterian complex acquired a high behavioural plasticity to settle in most uncomfortable (within Western Eurasia) forested and forest-steppe environments with cold winters in Central and Eastern Europe. The hominids developed tool inventories well suited for bone- and woodworking, made real wooden throwing spears and composite tools with wooden hafts that are found in Schöningen. In contrast to the Acheulean complex in West Europe and West Asia, assemblages of Pre-Mousterian complex do not show a transition (temporally being placed now during MIS 8–MIS 7, between c. 300–200 ka in both the regions) toward the Middle Palaeolithic or Mousterian technology. In contrast to the Acheulean to Middle Palaeolithic transition, which is associated with final neanderthalization of H. heidelbergensis and the origin of H. neanderthalensis, the assemblages of Pre-Mousterian complex disappear with the spread of Early Middle Paleolithic Neanderthals.

O invazi masařky Liosarcophaga aegyptica (Salem, 1935) do střední Evropy a objevu masařky Heliophagella verstraeteni (Lehrer, 1975) na východním Slovensku (Diptera, Sarcophagidae)

The invasion of the subtropical flesh-fly Liosarcophaga aegyptica (Salem, 1935) into South Moravia was observed during late summer 2003. This African insect was known to occur in the maritime habitats of the Black Sea and after World War II sporadically also in eastern Hungary, southern Slovakia and Lower Austria. Its population density increased in the Danube Basin and the first flies were also captured in South Moravia during late summer 2003. Elementary analyses revealed that this flesh-fly prefers habitats with high species diversity and important species similarity and that it might become sedentary in this territory. The flesh-fly Helicophagella verstraeteni (Lehrer, 1975) accompanying very dry and warm habitats of Romania, Hungary and France was discovered in a similar habitat of eastern Slovakia and is new to the fauna of Central Europe. Results of single linkage analyses in communities with Liosarcophaga aegyptica are presented together with the figures of the male genitalia of the two species of flesh-flies treated.

Dietary habits of invasive Ponto-Caspian gobies in the Croatian part of the Danube River basin and their potential impact on benthic fish communities

Invasive Ponto-Caspian (P-C11P-C=Ponto-Caspian; NF=Neogobius fluviatilis; NM=Neogobius melanostomus; PK=Ponticola kessleri; CCA=canonical correspondence analysis; GLM=generalized linear model; n.d.=not determined.) gobies have recently caused dramatic changes in fish assemblage structures throughout the Danube basin. While their presence in the Croatian part of the basin has been noted and distribution studied, their dietary habits and impacts on native fish communities have, until now, been unknown. In 2011, 17 locations in the Sava River Basin were sampled for fish and 15 for benthic invertebrates. Fish population monitoring data, available for nine seasons (2003–2006 and 2010–2014) and 12 locations, were used to analyse the impacts of P-C gobies on benthic fish abundance. Gut content analysis indicates that the monkey goby Neogobius fluviatilis diet is very diverse, but dominated by Trichoptera, Chironomidae, Bivalvia and Odonata. The diet overlaps considerably with the round goby Neogobius melanostomus diet, although Gastropoda are dominant in the latter's diet. Small fish and Gammarus sp. dominate the bighead goby Ponticola kessleri diet. Comparison of gut content with the prey available in the environment indicates that monkey and round gobies exhibit preference for Trichoptera, Megaloptera and Coleoptera, and bighead goby for Trichoptera, Gammarus sp. and Pisces. P-C gobies in the Sava River are spreading upstream, towards the reaches with lower fish diversity. Analyses indicate potentially positive impacts of P-C gobies' presence on some fish populations: round and bighead goby on Balkan golden loach Sabanejewia balcanica and monkey goby on common carp Cyprinus carpio, crucian carp Carassius carassius, burbot Lota lota and Balkan loach Cobitis elongata. However, there are also indications that bighead and round goby could adversely impact the native chub Squalius cephalus and zingel Zingel zingel populations, respectively. As P-C gobies are still in the expansionary period of invasion and the ecosystem still adapting to new circumstances, continued monitoring of fish population dynamics in the Sava basin is needed to determine the outcome and impacts of this invasion.

IthytrichiaEaton, 1873 (Hydroptilidae: Trichoptera): A Genus New for the Entomofauna of Serbia

ABSTRACT: During field work carried out in 2003, 2004, 2007, and 2011, larvae of the genus Ithytrichia (Trichoptera, Hydroptilidae) were identified as part of a benthic macroinvertebrate survey. Specimens of Ithytrichia lamellaris Eaton, 1873 were collected from independent localities in four rivers of Eastern and Central Serbia, namely the Black Timok, Mlava, Morava, and Western Morava. For the fauna of Serbia, three species within the family Hydroptililae were known up to now: Hydroptila vectis, Hydroptila sparsa, and Agraylea multipunctata. This is the first record of Ithytrichia larvae in watercourses of Serbia (Danube basin). Analysis of the environmental data indicates that I. lamellaris is a typical eurythermic species which inhabits slightly alkaline waters rich in dissolved oxygen, with a moderate organic load and abundant aquatic vegetation.

DISTRIBUTION AND VARIABILITY OF PHOSPHATE-MOBILIZING BACTERIA AND PHOSPHOROUS COMPOUNDS IN THE DANUBE COASTAL WATERS

In 2010-2012 on the coastal waters of theDanubeRiverthe character of the distribution and variability of phosphorus compounds, as well as the phosphate and heterotrophic bacteria were analyzed.There is lacks of bioavailable phosphorus compounds in the ecosystem of the coastal waters, which is due to excessive intake of nitrogen compounds from the Danube River basin. The number of heterotrophic and the phosphatemobilising bacteria in the surface layer of the seaside exceeds the value in the bottom layer and increases with distance from the edge of the delta. In the bottom layer at various depths the distribution of the bacteria are mainly homogenous. The number of bacteria, mobilizing phosphate from sparingly soluble compounds made 29-78% of the number of heterotrophic bacteria in the surface layer, and 44-85% in the bottom layer. The content of phosphorus compounds generally positively correlated with quantitative indices of the phosphate and heterotrophic bacteria, due to the leading role of "microbial loop" in the biological cycle of phosphorus in the coastal water ecosystem. Negative correlation of the coefficients between the number of bacteria and soluble inorganic compounds and organic phosphorus compounds (p &lt;0.05) were registered only for the bottom layer in November 2012, which is probably due to the full utilization of phosphorus by bacteria and its accumulation in cells.Abiotic environmental factors - temperature and salinity - have no significant impact on the abundance of bacteria. Microbial degradation of organic matter is related to the saturation of water with oxygen and is characterized by an inverse relationship with the number of bacteria in the warm season, and direct - in the cold. Revealed correlations enhance understanding of the ways of phosphorus transformation in water column and the role of bacteria in these processes.

Spatio‐temporal variability of dryness/wetness in the Danube River Basin

AbstractThe present study focuses on the analysis of dryness/wetness conditions in the Danube River catchment area from 1901 to 2013 based on reanalysis data. The spatio‐temporal variability of dryness/wetness conditions is analyzed by means of the Standardized Precipitation Index (SPI) for an accumulation periods of 6 months. To characterize the spatial variability of SPI6 at monthly time scales, an empirical orthogonal function (EOF) analysis was applied. The leading mode of SPI variability captures in‐phase variability of SPI over the entire catchment area of Danube River. The leading mode of dryness/wetness variability was found to be strongly related to the different phases of the Arctic Oscillation. The second and third modes of variability show a more regional character of the dryness/wetness variability over the Danube River catchment area. Based on a composite map analysis, between the time series corresponding to the first three leading modes of dryness/wetness variability and the geopotential height at 850 mb and precipitation totals, it is shown that dryness (wetness) conditions over the Danube catchment area are associated with an anticyclonic (cyclonic) circulation, transport of dry (humid) air towards the Danube catchment area and reduced (enhanced) number of rain days. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Environmental impact on the antioxidant responses in Corbicula fluminea (Bivalvia: Veneroida: Corbiculidae) from the Danube River

The present study aims to assess the biological effects of different environmental pollution on the Asian clam Corbicula fluminea. Biomarkers indicative of oxidative stress (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GPx; glutathione reductase, GR; and the phase II biotransformation enzyme glutathione-S-transferase, GST) were measured in clams collected within the Serbian sector of the Danube River Basin at three locations: Višnjica, Zemun and Bela stena. Clams from Višnjica exhibited significantly higher SOD, CAT and GST activities than clams from the other two locations (p < 0.05), whereas GPx and GR activities do not have such a marked pattern. An alteration in the activity of SOD, CAT and GST reflects the presence of certain pro-oxidative chemicals that can lead to oxidative stress in clams at the Višnjica site. In conclusion, the noted antioxidant disparities among clam populations from different locations reflected physiological sensitivity of C. fluminea to environmental change, supporting its use as a sentinel organism in biomonitoring investigations.

Landscape as a determinant of dispersal patterns and population connectivity in a newt species

Landscapes and their structure are important in shaping the distribution of species and the composition of communities. Since a landscape contains elements that are less permeable to dispersal, species use corridors of habitat suitable to movements that maintain the genetic flow among populations. Corridors have been widely used in conservation biology, but less often to study the connectivity between species’ allopatric ranges. In this study, we analyzed the distribution and connectivity patterns of the Danube Crested Newt (Triturus dobrogicus), a species found in the Danube river basin and whose range is separated by the Carpathian Mountains in two regions, eastern and western. Despite the geographical barrier and clear morphological differentiation between the populations of the two regions, recent genetic analyses suggest maintenance of genetic flow. The aims of our study were (1) to estimate the dispersal ability of the Danube Crested Newt and the connectivity (via corridors) between populations and (2) to identify possible pathways used by the species to cross the Carpathian Mountains barrier. We found that the landscape facilitates a higher population connectivity in the western range than in the eastern range of the species. Moreover, we identified two major migration pathways, along the Iron Gate Canyon and the Timiş – Cerna Gap, that may connect all known occurrences from the two regions separated by the Carpathian Mountains. As an alternative dispersal hypothesis, we also discussed the possibility that the Danube Crested Newt is passively dispersed by water, down the Danube river flow direction. Our study provides support for the assertion that even when a species’ distribution is separated in two ranges by a geographical barrier, connectivity between populations via corridors can persist.

Genetic and morphological variability of the European mudminnow Umbra krameri (Teleostei, Umbridae) in Serbia and in Bosnia and Herzegovina, a basis for future conservation activities.

As a basis for future conservation activities, the genetic and external body morphology variability of the European mudminnow Umbra krameri, a highly endangered fish species in Serbia and in Bosnia and Herzegovina, was determined for existing populations with the use of molecular markers (mitochondrial and microsatellite DNA) and geometric morphometric methods. Mitochondrial DNA cytochrome b gene analysis revealed two previously undescribed haplotypes: Da1 (the Lugomir population from the Danube River basin) and Sa1 (the Bakreni Batar and the Gromiželj populations from the Sava River system), with a corresponding genetic distance of 0·7%. Paired values of FST and DAS distances for microsatellite marker data show that the difference between the Danube and the Sava populations is seven to nine times higher than the difference between the populations within the Sava River system. Geometric morphometric analyses also support a clear separation of the Lugomir population from the Bakreni Batar and the Gromiželj populations. The analysis of the body shape variation, however, indicates a significant difference between the two genetically indistinguishable Sava populations. The observed genetic and phenetic relationships of the analysed mudminnow populations most probably represent a consequence of historical, geographical and ecological factors. These results will offer guidelines for future protection, conservation and sustainable management of this species in the region.

Information on huchen, Hucho hucho (L.), from historical Polish sources

Abstract This paper presents historical information on the Danube huchen, Hucho hucho (L.), in Polish sources from the sixteenth to early twentieth centuries in the Danube, Prut, Dniester, and Vistula river basins. These accounts concern the historical distribution of the species and its economic importance, culinary value, fishing methods, and artificial reproduction and propagation. The occurrence of huchen in the Dniester River basin until the beginning of the eighteenth century merits special interest, because this river is not mentioned by any modern source on the natural distribution of this species. The extinction of the huchen in this river can likely be attributed to anthropogenic changes in the environment that were associated mainly with agricultural development.

Hot Central‐European summer of 2013 in a long‐term context

ABSTRACTThe European summer of 2013 was characterized by very high temperatures that established a new historical maximum in Austria. The extremity of this summer in Europe is assessed based on the E‐OBS and ECA&amp;D data sets. At the continental scale, it is ranked as the fifth warmest summer since 1951, with large positive temperature anomalies over Central Europe. According to seasonal heat wave characteristics, the 2013 summer was unprecedented in Kremsmuenster and Graz (both Austria) and ranked as the second or third at other stations with at least 100 years of measurements in the Czech Republic, Slovakia, Croatia and Slovenia. The most intense 2013 heat wave over Central Europe in early August was driven primarily by anticyclonic conditions and was probably amplified by the preceding precipitation deficit. In combination with major flooding in the Danube and Elbe river basins in early June and severe convective storms at the end of July, the hot 2013 summer in Central Europe may represent an analogue of a future summer climate that will probably be more prone to both temperature and precipitation extremes.

Biostratigraphy, sedimentology and paleoenvironments of the northern Danube Basin: Ratkovce 1 well case study

Abstract The Ratkovce 1 well, drilled in the Blatné depocenter of the northern Danube Basin penetrated the Miocene sedimentary record with a total thickness of 2000 m. Biostratigraphically, the NN4, NN5 and NN6 Zones of calcareous nannoplankton were documented; CPN7 and CPN8 foraminifer Zones (N9, 10, 11 of the global foraminiferal zonation; and MMi4a; MMi5 and MMi6 of the Mediterranean foraminiferal zonation were recognized. Sedimentology was based on description of well core material, and together with SP and RT logs, used to characterize paleoenvironmental conditions of the deposition. Five sedimentary facies were reconstructed: (1) fan-delta to onshore environment which developed during the Lower Badenian; (2) followed by the Lower Badenian proximal slope gravity currents sediments; (3) distal slope turbidites were deposited in the Lower and Upper Badenian; (4) at the very end of the Upper Badenian and during the Sarmatian a coastal plain of normal marine to brackish environment developed; (5) sedimentation finished with the Pannonian-Pliocene shallow lacustrine to alluvial plain deposits. The provenance analysis records that the sediment of the well-cores was derived from crystalline basement granitoides and gneisses and from the Permian to Lower Cretaceous sedimentary cover and nappe units of the Western Carpathians and the Eastern Alps. Moreover, the Lower Badenian volcanism was an important source of sediments in the lower part of the sequence.

Future water quality monitoring — Adapting tools to deal with mixtures of pollutants in water resource management

Environmental quality monitoring of water resources is challenged with providing the basis for safeguarding the environment against adverse biological effects of anthropogenic chemical contamination from diffuse and point sources. While current regulatory efforts focus on monitoring and assessing a few legacy chemicals, many more anthropogenic chemicals can be detected simultaneously in our aquatic resources. However, exposure to chemical mixtures does not necessarily translate into adverse biological effects nor clearly shows whether mitigation measures are needed. Thus, the question which mixtures are present and which have associated combined effects becomes central for defining adequate monitoring and assessment strategies. Here we describe the vision of the international, EU-funded project SOLUTIONS, where three routes are explored to link the occurrence of chemical mixtures at specific sites to the assessment of adverse biological combination effects. First of all, multi-residue target and non-target screening techniques covering a broader range of anticipated chemicals co-occurring in the environment are being developed. By improving sensitivity and detection limits for known bioactive compounds of concern, new analytical chemistry data for multiple components can be obtained and used to characterise priority mixtures. This information on chemical occurrence will be used to predict mixture toxicity and to derive combined effect estimates suitable for advancing environmental quality standards. Secondly, bioanalytical tools will be explored to provide aggregate bioactivity measures integrating all components that produce common (adverse) outcomes even for mixtures of varying compositions. The ambition is to provide comprehensive arrays of effect-based tools and trait-based field observations that link multiple chemical exposures to various environmental protection goals more directly and to provide improved in situ observations for impact assessment of mixtures. Thirdly, effect-directed analysis (EDA) will be applied to identify major drivers of mixture toxicity. Refinements of EDA include the use of statistical approaches with monitoring information for guidance of experimental EDA studies. These three approaches will be explored using case studies at the Danube and Rhine river basins as well as rivers of the Iberian Peninsula. The synthesis of findings will be organised to provide guidance for future solution-oriented environmental monitoring and explore more systematic ways to assess mixture exposures and combination effects in future water quality monitoring.

Danube cooperation in the field of climate change and position of the republic of Serbia in the water resources management

The paper discusses the thesis that the basic factor that determines the policy of RS on climate change is defined by the possibilities of cooperation between the countries of the Danube basin. In this regard, it is argued that for RS this is the most important route in international activities in the field of climate change and environment in general - the cooperation with the countries located in the Danube basin. This conclusion is based on an estimate of the significance of the Danube River for the RS, as well as the fact that there are already established forms of cooperation between the countries in the basin of this river, in a way that covers the key water resources in RS. At the same time, it is estimated that the institutionalization of the cooperation between the countries in the Drina River Basin, as well as the harmonization of the national with EU legislation would contribute to the further improvement of the water resource system management in the Danube basin.

Prvi nalaz vodenog ora�ka (Trapa natans L., Trapaceae, Myrtales) u Centralnoj Srbiji

Water chestnut (Trapa natans L.) is a floating macrophyte that generates differing views on its role and importance in aquatic ecosystems. It is protected as a rare species in a number of European countries and is an invasive species in some regions of the world. T. natans inhabits stagnant and slow flowing waters that exhibit large fluctuations in water level. Occurrence records are frequently reported from the north of the Republic of Serbia (Vojvodina Province), while there are no relevant data about its habitats in southern parts of the country. The first record of T. natans in Central Serbia was from the Međuvrsje Reservoir on the Zapadna Morava River (the Danube River Basin) in 2011. A marked increase in species abundance in certain sections of the reservoir was observed in 2012. High water temperatures and continuous inflow of nutrients reported in recent years will most likely induce further propagation of this species, potentially leading to further eutrophication of the system and upsetting the ecological balance of the new habitat.