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Fish assemblages have been widely used as ecological indicators for assessing the level of environmental degradation and ecosystem health. Environmental disturbances affect the aquatic community structure in terms of abundance and biomass. Therefore, we tested the utility of abundance/biomass comparison (ABC) method, originally developed for marine ecosystems, to detect the anthropogenic disturbance in lotic systems using fish community data. Electrofishing was conducted in the period between 2003 and 2011 at 35 sites along the Southern Morava River basin. The results indicated that species richness strongly influences the utility of ABC method to detect the anthropogenic disturbance in lotic systems. The Warwick (W) statistic showed the positive correlation and the expected direction of response with some factors defining environmental quality, applying it on the samples with greater species richness. This approach has significant power for detecting environmental quality disturbance but may be limited due to effects of habitat variability in riverine environments.

Freshwater mussels of the Order Unionida provide important ecosystem functions and services, yet many of their populations are in decline. We comprehensively review the status of the 16 currently recognized species in Europe, collating for the first time their life-history traits, distribution, conservation status, habitat preferences, and main threats in order to suggest future management actions. In northern, central, and eastern Europe, a relatively homogeneous species composition is found in most basins. In southern Europe, despite the lower species richness, spatially restricted species make these basins a high conservation priority. Information on freshwater mussels in Europe is unevenly distributed with considerable differences in data quality and quantity among countries and species. To make conservation more effective in the future, we suggest greater international cooperation using standardized protocols and methods to monitor and manage European freshwater mussel diversity. Such an approach will not only help conserve this vulnerable group but also, through the protection of these important organisms, will offer wider benefits to freshwater ecosystems. © 2016 Cambridge Philosophical Society

This paper presents the first checklist of the family Chironomidae (Diptera) in Serbia, based on literature citations in two periods (1981/82 and 2010/11) and the unpublished data as well as material examined by the authors. Our survey ranges over the Central, Eastern, Southern and Southeastern parts of Serbia (Southern Morava River basin). We have listed 110 taxa distributed in following five subfamilies: Chironominae (39), Diamesinae (3), Orthocladiinae (48), Prodiamesinae (2) and Tanypodynae (16).

Based on a literature review, the different approaches in the water quality assessment using fish communities in freshwaters are summarized. Fish assemblage indicators, developed throughout the world, were reviewed and the main differences in methodologies, number of metrics and values are summarized. We have drawn attention to the methods used for designing a fish-based index with a particular focus on original developments in North America and its adaptations in many different regions and habitat types. The main obstacles for ecological assessment are scarce ecological information and the problem with the classification. The lack of knowledge is especially true for species assemblages in the relatively unexplored river basins of Europe, e.g. The Balkans peninsular.

Diet of adult pikeperch Sander lucioperca, Eurasian perch Perca fluviatilis, northern pike Esox lucius and European catfish Silurus glanis as top predators in aquatic ecosystems in Serbia was investigated during 2011, in order to understand their relationship to their prey and to investigate their food consumption, feeding and assimilation rate, cannibalism, and habitat segregation. Northern pike, Eurasian perch, pikeperch and European catfish were collected in three reservoirs in Serbia. Prey items that were found in all four species included fish, mollusks, insect larvae and crustaceans. A total of 11 taxonomic groups were found, but they were not all represented as a prey in all four species. Eurasian perch were present in the diet of all four predatory fish species, mollusks were recorded only in that of European catfish. Roach Rutilus rutilus and bleak Alburnus alburnus were prey to all species, except northern pike. Chub Squalius cephalus, bream Brama brama and Gammaridae were found only in stomach of pikeperch. Analysis of similarity showed that difference for diet between predatory fish species was significant for their due to significant differences existing between northern pike and pikeperch and northern pike and Eurasian perch.

Research into the ichthyofauna of the Vlasina Lake reservoir in south Serbia, which is part of the Danube basin, was carried out in 1993, 40 years after its formation. The results of the research reveal the presence of several species of fish belonging to the Adriatic and Aegean basin, such as Alburnus albidus, Rutilus basak, Scardinius graecus and Pachychilon macedonicus. These findings are of great importance from the aspect of conservation, because the species Scardinius graecus and Alburnus albidus are on the European list of endangered fish species. In the latest study of the Vlasina Lake reservoir ichthyofauna (70 years after its formation), the above-mentioned species were not found. However, the presence of naturalized populations of two species from the Adriatic basin were confirmed: Scardinius knezevici and Alburnus scoranza. These findings represent the first known areal expansion of these species, which are new to the ichthyofauna of Serbia, from the Adriatic into the Danube (Black Sea) basin. Projekat ministarstva br. 43002 i br. 173025

The evolution of e-learning systems put them in almost all areas of human life. E-learning can be considered in context of continuous societal and technological development. Current trends lead to creation of virtual society, alongside the physical world. As new in-formation communication technologies are developed, it is possible to extend the domain and usability of existing e-learning methodologies. E-learning technologies are used and developed by educational institutes, governmental organisations as well as commercial content vendors and large business corporations. This papers briefly reviews the evolution of learning paradigms and methodologies. With focus on modern e-learning tools and platforms, in the second part, different approaches in organising learning delivery are presented. In the third part, characteristics of e-learning tools and platforms are reviewed. According to the ISO software quality measure standards 9126 and 25000 and available assessing methods for learning systems, we propose a set of important characteristics for descriptive evaluation of e-learning systems. Furthermore, we analyse the impact of developing IT areas on selected characteristics. .

The species Helicopsyche bacescui in Europe has a disjunct area that is mainly situated south of 45 degrees N latitude and east of 22 degrees E longitude with an isolated smaller part in southwestern Hungary. Recent investigations on the territory of Serbia documented the presence of H. bacescui at 39 localities south of the Danube. The known area of the species is thereby enlarged by about 30%, while its western boundary is relocated by about 440 km. H. bacescui is primarily found in lowlands at elevations of less than 200 m above sea level, frequently in streams that periodically run dry. In Serbia, on the other hand, it is found in permanent highland streams at localities with average elevation of 467 +/- 35 m above sea level. The highest locality at which this species has been found is the spring of the Obudojevica (Western Serbia), which lies at an elevation of 1060 m above sea level. H. bacescui belongs to specific benthic communities that differ from typical macrozoobenthos assemblages found in similar habitats in Serbia by the pronounced dominance of Gammaridae, significant presence of Pisidium species, and absence of other groups of Trichoptera (above all, members of the family Hydropsychidae).

The aim of the study presented was to define trophic relationships within the benthic community according to functional feeding groups (FFG) in the Vlasina River (Southeast Serbia), with an attempt to use those results to describe the watercourse. In an investigation performed during 1996, a total of 125 macrozoobenthic taxa were identified, 95 of which were included in FFG analyses. Although the investigated part of the river, in its physical and chemical characteristics, as well as characteristics of the benthofauna, generally corresponds to what could be expected, certain variations of faunal composition were observed along the river. Two groups of sites were separated by FFG analysis - sites on the upper section of the river and on a tributary (the Gradska River) comprised one group, while the remaining sites made up the other. Cilj nam je da ovim radom prikažemo trofičke odnose u zajednici makroinvertebrata prema funkcionalnim grupama u ishrani (FGI) u reci Vlasini (jugo-istočna Srbija) i te rezultate upotrebimo za opisivanje vodotoka. U okviru istraživanja obavljenih tokom 1996. godine, od ukupno 125 identifikovanih taksona makrozoobentosa, 95 taksona korišćeno je u FGI analizi. Iako istraživani deo reke, sa njegovim fizičkim i hemijskim karaktristikama, kao i karakteristikama bentofaune uopšte, odgovara srednjem toku reka, istraživane su fine promene u distribuciji bentofaune duž toka. Izdvojile su se dve grupe lokaliteta prema FFG analizi - grupisali su se lokaliteti gornjeg sektora reke kao i pritoka Gradska reka, dok su ostali lokaliteti formirali drugu grupu. null

The mayfly (Ephemeroptera) fauna was studied during investigations of the Vlasina River (Serbia) conducted in 1996. Twenty-six species from 14 genera belonging to eight families were recorded. Compared to similar aquatic ecosystems in Serbia and Europe, the ephemeropteran fauna of the Vlasina River is characterized by high species diversity. Good water quality and habitat heterogeneity led to the observed richness of taxa. Based on fauna distribution, the middle reach of the river can be divided into three different segments - upper, middle, and lower. Distribution of the two dominant families, Heptageniidae and Baetidae, is emphasized. Representatives of Baetidae reach their highest density in July, while Heptageniidae were the most abundant in November. The recorded mayflies represent widely distributed European or Holarctic species. Raznovrsnost efemeroptera proučavana je u reci Vlasini (Srbija) tokom 1996. godine. Dvadeset šest vrsta iz četrnaest rodova utvrđeno je tokom ove obimne studije. U poređenju sa sličnim akvatičnim ekosistemima u Srbiji i Evropi, fauna efemeroptera iz reke Vlasine karakteriše se visokom raznolikošću vrsta. Dobar kvalitet vode i raznovrsnost staništa uslovljavaju i uočeno bogatstvo taksona. Središnji deo reke može se podeliti u tri segmenta - gornji, srednji i donji. Sagledana je distribucija predstavnika dve dominantne porodice Heptageniidae i Baetidae. Predstavnici baetida dostižu najveću gustinu tokom jula, a heptagenida u novembru. Utvrđene vrste efemeroptera predstavljaju evropske ili holarktičke elemente. null