Vladica Simić

Conservation status of freshwater mussels in Europe: state of the art and future challenges.

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.

Spatio-temporal pattern of the Chironomidae community: toward the use of non-biting midges in bioassessment programs

We employed the self-organizing map (SOM) method to investigate the spatio-temporal pattern of the Chironomidae community in the Southern Morava River basin (Serbia) and to examine to what extent the Chironomidae community is affected by environmental factors. Additionally, this study explores the problems of utilizing chironomids in bioassessment programs. The SOM analysis of the chironomid community data produced 3 groups of sites. The indicator species analysis presented indicator taxa for two groups. Twenty taxa (at species, species group and genus level), according to the Kruskal–Wallis test, showed the most pronounced differences among the temporal units. Out of 15 measured environmental parameters, one-way ANOVA pointed out that 10 significantly differ between the groups. Elevation had the most important influence on the chironomid community, also affecting other environmental parameters. According to our findings, the winter season and the periods with high water level are the main sources of natural variability. To avoid such variability and to successfully incorporate Chironomidae in bioassessment programs, we suggest exclusion of the arguable months from monitoring programs.

Use of the river macrozoobenthos of Serbia to formulate a biotic index

We studied macrozoobenthos of right-hand tributaries of the Danube in Serbia from 1989 to 1996 with special attention to qualitative and quantitative composition, dominance, frequency, elements of α-biodiversity and the following environmental variables: altitude, bottom structure, water flow rate, profile dimensions, water temperature, oxygen concentration, acidity, BOD5 and concentrations of nitrogen, phosphorus and toxic substances. Five categories of streams were isolated by cluster analysis. Frequent taxa (genera, families and subfamilies) were classified within these categories and a matrix of habitat quality was used to derive a biotic index for the investigated region. Because Serbia is central to the Balkan peninsula, it is proposed that this index be designated the BalkaN Biotic Index (BNBI).

Chironomid faunal composition represented by taxonomic distinctness index reveals environmental change in a lotic system over three decades

The widely distributed family of the Chironomidae represents the most diverse and abundant group of macroinvertebrate fauna and potentially provides information on stream water quality and the effect of anthropogenic disturbances. Change in the chironomid faunal composition in the Southern Morava River basin (Serbia) was examined by comparing data from 1981 and 2010. We tested the performance of the parameter “taxonomic distinctness” (delta+) as an indicator of water quality and examined the possible relationship between delta+ and water quality using PCA. The 2010 survey yielded 96 taxa in 28 localities over three seasons. In total, 10,179 specimens represented the five subfamilies. Chironomid diversity was captured with the index delta+ that is based upon taxonomic distinctiveness and purported to be independent of sampling effort. Delta+ was correlated to total species richness and is significantly higher now than it was in 1981. In keeping with PCA results, delta+ was increasing in accordance with water quality increase. We conclude that delta+ is a useful measure for estimating anthropogenic disturbance over time. The linear relationship between delta+ and the water quality gradient gives rise to a novel metric, independent of sampling effort, in the multimetric approaches of analyzing macroinvertebrate assemblage data for bioassessments.

Macroinvertebrates along the Serbian section of the Danube River (stream km 1429–925)

Results of the investigation of the aquatic macroinvertebrate fauna along a 504 km stretch of the Danube River in Serbia are presented. A total of 74 macroinvertebrate taxa were observed during a 2001 survey. Oligochaeta and Mollusca were the principal components of the community with regard to species richness and abundance. Based on data on the qualitative composition of the macroinvertebrate fauna, a correspondence analysis divided the investigated stretch in three sectors — upper (Pannonian), Iron Gate sector and entrance sector to the Iron Gate stretch. The distribution patterns of certain species supported the division of sectors defined by correspondence analysis.

A Report of Orconectes (Faxonius) Limosus (Rafinesque, 1817) [Crustacea: Decapoda: Astacidea: Cambaridae: Orconectes: Subgenus Faxonius] in the Serbian Part of the River Danube

ABSTRACT Spiny cheek crayfish (Orconectes limosus L.) were found in the Serbian part of the River Danube (August 2004, at 1112 km of the water course). A description of the biology, origin and distribution of this species, as well as the potential impact to the aquatic ecosystems is presented and discussed. This is the first record of this invasive crayfish in Serbian part of the River Danube. In addition, our results could indicate that there is potential risk for the expansion of O. limosus in other regional waters in the future.

Model of the assessment of the critical risk of extinction and the priorities of protection of endangered aquatic species at the national level

In the period 1995–2006, the biodiversity of the aquatic habitats in the area of Serbia was explored, with the aim to identify the endangered species of macroalgae, macroinvertebratae and fishes. During the work a data base was formed (Aquatic Ecosystems Diversity in Serbia, AEDSer), containing the data from exploring the biodiversity of the aquatic ecosystems of Serbia since 1860. Based on the data base, classification of the aquatic species was made into categories of endangerment based on IUCN criteria. The following was noted: (1) the global IUCN category assigned to the species often is not identical with the national status of endangerment; and (2) the species that are given a category of endangerment at the national level do not have the same realistic risk of extinction in all their habitats. This remark imposed the need for a model for assessing the critical risk of extinction of the endangered species and determining the priorities of their protection at the national level. Two categories of characters were used to develop the model: the characters that determine the degree of ecological specialisation of the species based on the circumstances of habitat; and the characters suggesting the risk factors from the system: “HIPPO” in the spatial and time dimension. The possibility to apply the model was tested on 10 aquatic species belonging to different categories of endangerment at the national level (macroalgae 2, macroinvertebrates 7, and fishes 1 species). The model based on points determined the level of extinction risk and, that way, the species needing urgent conservation from the same or different categories of endangerment were isolated. The model suggested can contribute to a more efficient defining the conservation priorities.

DISTRIBUTION OF NON-INDIGENOUS TUBIFICID WORM BRANCHIURA SOWERBYI (BEDDARD, 1892) IN SERBIA

ABSTRACT Recently, dispersion of invasive species became an important theme, since the man-aided outspread of the organisms was recognized as one of the major threats to the biodiversity. Aquatic biotopes are, due to its unique features, among the most disposed ecosystems to this kind of disturbance. Non-indigenous species of different origin were found among plants, vertebrates and invertebrates. Aquatic worm Branchiura sowerbyi (Beddard 1892) is obvious example of human induced dispersal of invertebrates. The aim of the study was to contribute to the cognition of the current distribution of this invasive species and to point up, once again, the risk of devastation of aquatic ecosystems caused by distribution of alien species. B. sowerbyi was for the first time observed in Serbia in 1972 in fish pond in Vojvodina. Since that time the worm spread its areal and now it could be found in a lot of ponds, channels, reservoirs and lowland rivers in Serbia. According to our results B. sowerbyi has been well adapted in artificial and modified water bodies in Serbia.

Evaluation of genotoxic potential throughout the upper and middle stretches of Adige river basin

In this study a comprehensive genotoxicological survey throughout the upper and middle stretches of Adige river basin is presented. The study was carried out at 7 sites located along the Adige main course and one the most significant tributaries, the Noce creek, both presenting different levels of pollution pressure. To give an insight into the nature of the genotoxic activity we employed the battery of prokaryotic and eukaryotic assays. Mutagenicity in water samples was evaluated by SOS/umuC test in Salmonella typhimurium TA1535/pSK1002. The level of DNA damage as a biomarker of exposure (comet assay) and biomarker of effect (micronucleus assay) and the level of oxidative stress as well (Fpg - modified comet assay) were studied in blood cells of Salmo cenerinus Nardo, 1847 and Salmo marmoratus Cuvier, 1829. Within the applied bioassays, comet assay showed the highest potential for discriminating the sampling sites which are under lesser extent of pressure (sampling sites 1-Barnes at Bresimo and 4-Noce downstream S. Giustina) from the sites under high pressure (sampling sites 5-Noce at Mezzolombardo and 6/7-Adige upstream and downstream municipality of Trento). Significant correlation between the standard and Fpg - modified comet assay indicated that oxidative stress could be a major contributor to observed DNA damage in collected specimens.

Different aggregation approaches in the chironomid community and the threshold of acceptable information loss

Due to the problem of identification, Chironomidae larvae, although very abundant, are often avoided or not properly used in bioassessment programs. The aim of this work was to test how different aggregation processes—taxonomic resolution and the random aggregation approach (best practicable aggregation of species—BestAgg) affect the analysis of chironomid communities regarding any information loss. The self-organizing map method, together with classification strength analysis and Spearman’s rank correlation, revealed that the genus-level and BestAgg-abundance matrix most accurately approximated the species-level community pattern. The subfamily-level dataset was ineffective at presenting the chironomid community structure, with a substantially lower concordance with the species-level dataset. The biologic environmental gradients analyses presented the same set of important environmental variables for the species-level, genus-level, and BestAgg-abundance matrix. The indicator values analysis showed that indicator genera provide information very close to that gained from species indicators. According to our results, the numeric relationship between species and higher taxa influences taxonomic scaling, limiting Chironomidae family aggregation, with acceptable information loss only up to genus level. In addition, the BestAgg approach, with the maximum level of aggregation, properly assesses the community structure and consequently describes environmental conditions.