The study was carried out from 2007 to 2010 in two ecoregions: the Carpathians and the Central Highlands. The objectives of our survey were to test the existing biological index metric based on benthic macroinvertebrates at reference conditions in the high-and mid-altitude mountain streams of two ecoregions according to the requirements of the EU WFD and to determine which environmental factors influence the distribution of benthic macroinvertebrates. Our results revealed statistically significant differences in the values of the physical and chemical parameters of water as well as the mean values of metrics between the types of streams at the sampling sites. RDA analysis showed that the temperature of the water, pH, conductivity, the stream gradient, values of the HQA index, and altitude were the parameters most associated with the distribution of benthic macroinvertebrate taxa and the values of the metrics. The values of biological indices should be considered according to the stream typology including altitude and geology. At the reference conditions, the suggested border values of biological indices are very harsh. The values of the biological indices of most sampling sites did not correspond to the requirements of the high status in rivers. The streams at altitudes above 1,200 m a.s.l. should be treated as another river type and new reference values should be established.

Pollution of the water environment by mining waters is a problem not only in Poland, but worldwide. This study investigated the mollusc communities in seven mining subsidence reservoirs affected by coal mine output (the Katowicka Upland, Upper Silesia, Southern Poland). The objective of the survey was to determine the relationship between the molluscs and their environments and to evaluate the ecological-conservation value of freshwater habitats which support rare and vulnerable molluscs. From 1993 to 2005, 23 mollusc species were recorded. Our result confirmed an invasion by Potamopyrgus antipodarum (Gray, 1843), whose density varied from 2 to 2422 individuals/m 2 in the waters of the Katowicka Upland. A few rare and vulnerable species were found, e.g. Acroloxus lacustris (Linnaeus, 1758), Hippeutis complanatus (Linnaeus, 1758), Ferrissia wautieri (Mirolli, 1960), Anodonta anatina (Linnaeus, 1758), Musculium lacustre (O.F. Mu¨ller, 1774) or Pisidium casertanum (Poli, 1791). Principal component analysis showed a positive correlation between mollusc density and pH, the concentration of chlorides, the total hardness, alkalinity and total dissolved solids, and a negative correlation between the number of species and phosphates. Because of the distinctive environmental features of the mining subsidence reservoirs in Czu"o´w, the research area has provided a refuge for wildlife.

The composition of the diatom assemblages was analysed in four rivers of Upper Silesia, Poland in 2017. The diatom assemblages studied were found to reflect anthropogenic salinization caused by mining activities. The assemblages in those rivers characterised by the highest salinity (Bolina and Mleczna) showed a relatively low taxonomic richness. The diatom assemblages were dominated by species typical of brackish or marine waters. The rivers with a minimal or weak anthropogenic impact (Centuria and Mitręga) supported taxonomically richer diatom assemblages typical of mid-altitude siliceous or calcareous streams (respectively), that have a fine particulate substratum. The presence of a new species, Planothidium nanum sp. nov., was revealed. The new species shows a unique set of morphological characters, including small size; its elliptical outline as well as very widely-spaced central striae on the sternum valve (sinus) and widely-spaced central striae on the raphe valve allow to separate it from other similar Planothidium.

We analyzed the biomass, density and age structure of S. woodiana populations in relation to different environmental factors at new sites of its occurrence in southern Poland. The highest recorded biomass was 4,413 g m–2. Mussel density was 19 individuals m–2. The age structure was formed by juveniles as well as by specimens more than 8 years. The rapid expansion of S. woodiana in European countries is believed to be the result of accidental introduction of fishes bearing glochidia of this species. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

The aim of the study was to identify the vegetation pattern in the different types of watercourses basing on survey in reference conditions in a wide geographical gradient, including mountain, upland and lowland rivers. We tested relationship between composition of macrophytes to environmental variables including: altitude, slope, catchment area, geology of valley, land use, hydromorphological features, water physical and chemical measurements. Analysis based on 109 pristine river sites located throughout major types of rivers in Central Europe. Qualitative and quantitative plant surveys were carried out between 2005 and 2013. Based on TWINSPAN classification and DCA analysis, six macrophyte types were distinguished. The lowland sites were divided into the following three types: humic rivers and two types of siliceous rivers depending on the catchment area, including medium-large and small rivers. The mountain and upland rivers were divided into three geological types: siliceous, calcareous and gravel. We found that the variation of macrophyte communities was determined by several habitat factors (mainly altitude, flow type, riverbed granulometry, conductivity and alkalinity), whereas the spatial factor was rather limited; further, the plant diversity was not reflected accurately by the European ecoregion approach.

The objectives of the survey were to analyse the structure of the mollusc communities in the mining subsidence reservoirs that were created as a result of land subsidence over exploited hard coal seams and to determine the most predictive environmental factors that influence the distribution of mollusc species. The reservoirs are located in urbanised and industrialised areas along the Trans-Regional Highway, which has a high volume of vehicular traffic. They all have the same sources of supply but differ in the physical and chemical parameters of the water. In total, 15 mollusc species were recorded including four bivalve species. Among them Anodonta cygnea is classified as Endangered according to the Polish Red Data Book of Animals and also as Near Threatened according to the European Red List of Non-marine Molluscs. Eleven of the 15 mollusc species are included on the European Red List of Non-marine Molluscs as Least Concern. Conductivity, pH and the concentration of calcium were the parameters most associated with the distribution of mollusc species. Canonical correspondence analysis showed that Potamopyrgus antipodarum, Radix balthica, Physella acuta, Gyraulus crista and Pisidium casertanum were associated with higher conductivity and lower pH values. A. cygnea, Anodonta anatina and Ferrissia fragilis were negatively influenced by these parameters of the water. The results of this survey showed that the mining subsidence reservoirs located in urbanised and industrialised areas provide refuges for rare and legally protected species and that they play an essential role in the dispersal of alien species as well.

Anthropogenic freshwater habitats may provide undervalued prospects for long‐term conservation as part of species conservation planning. This fundamental, but overlooked, issue requires attention considering the pace that humans have been altering natural freshwater ecosystems and the accelerated levels of biodiversity decline in recent decades. We compiled 709 records of freshwater mussels (Bivalvia, Unionida) inhabiting a broad variety of anthropogenic habitat types (from small ponds to large reservoirs and canals) and reviewed their importance as refuges for this faunal group. Most records came from Europe and North America, with a clear dominance of canals and reservoirs. The dataset covered 228 species, including 34 threatened species on the IUCN Red List. We discuss the conservation importance and provide guidance on how these anthropogenic habitats could be managed to provide optimal conservation value to freshwater mussels. This review also shows that some of these habitats may function as ecological traps owing to conflicting management practices or because they act as a sink for some populations. Therefore, anthropogenic habitats should not be seen as a panacea to resolve conservation problems. More information is necessary to better understand the trade‐offs between human use and the conservation of freshwater mussels (and other biota) within anthropogenic habitats, given the low number of quantitative studies and the strong biogeographic knowledge bias that persists.

Anthropogenically elevated nutrient concentration occurs in both ground and surface waters and cause grave environmental problems which are responsible for the degradation of water quality on a worldwide scale. The progressive anthropogenic pressure caused by prolonged agricultural activity has a negative effect on most water ecosystems including rivers and reservoirs. Freshwater molluscs, which are hololimnic organisms, have a limited mobility; therefore, they are good bioindicators of changes in their habitats. They reflect the abiotic or biotic state of water habitats, which represents the impact of environmental change on the habitat, community as well as on the ecosystem. A long-term survey of mollusc communities revealed the occurrence of 44 species including some rare, vulnerable, threatened or legally protected species, e.g. Borysthenia naticina, Unio crassus, Anodonta cygnea, Pseudanodonta complanata or Sphaerium rivicola, in the Wkra River, its tributaries and selected oxbow lakes. In the Wkra River catchment area, the mollusc communities, including U. crassus (Habitats Directive Natura 2000), are under a combined effect of several environmental factors. Conductivity, hardness, current velocity, river width, temperature, nutrient concentration and the size of sediment particles were the parameters most associated (statistically significant according to the forward selection results) with the distribution of mollusc species. The forward selection results showed that the concentration of dissolved oxygen and the occurrence of macrophytes also exerted a significant influence on the distribution of Mollusca. Among environmental factors, anthropogenically elevated concentrations of nitrites and nitrates in the water were the most predictive parameters that negatively influenced (stressors) the structure of mollusc communities. The novel findings of this survey showed that some mollusc species could tolerate wider ranges of some environmental factors and higher concentrations of nutrients than had been expected. U. crassus is more tolerant of a relatively high concentration of nitrates in the water than was previously expected, as well as of nitrites and phosphates, and it can survive in rivers with relatively high nutrient concentration. The present results confirm both the field and the toxicological research on the negative effect of nitrites and nitrates, which is caused by their toxicity to freshwater molluscs. The number of individuals, number of mollusc species and density decreased dramatically within the last year of the survey in the Wkra River and its tributaries. This phenomenon seems to be a direct result of the nutrient enrichment in the Wkra River catchment area, the regulation of riverbeds or an indirect result, e.g. lack of primary or appropriate host fishes for unionid species. The declining trend in the global mollusc population has probably begun to occur in the Wkra River catchment area.