Bithynia Tentaculata Research Articles

Differences in Natural Infections of Two Mortality-Related Trematodes in Lesser Scaup and American Coot

Populations of North American waterbirds, particularly lesser scaup, have been declining due to habitat disturbance, changing food resources, contaminants, bad water quality, and competition. However, epizootic diseases, including parasitism, may also play an important role in further decline. Trematode-associated mortality of migrating waterbirds, mainly American coot and lesser scaup, has been occurring in the Upper Mississippi River National Wildlife and Fish Refuge since 2002. We examined the levels of infective stages of Cyathocotyle bushiensis and Sphaeridiotrema globulus in the invasive, intermediate host snail, Bithynia tentaculata, during the fall of 2005 and compared these to infection levels in moribund or dead bird hosts. Our results show different infection levels of these 2 parasites in the 2 bird species; C. bushiensis is found more frequently in coot, and S. globulus is more common in scaup. This result is interesting because both bird species are presumed to forage on the same snail population and thus should be experiencing the same extent of exposure. These differences in infections could be attributed to differences in resources of gastrointestinal tracts of coot and scaup, or host resistance. Alternatively, differences in feeding behaviors of coot and scaup may also contribute to differential infections of the 2 trematodes.

Effects of abiotic factors (temperature, pH, heavy metals) on activities of glycosidases in invertebrate animals

We have established differences in amylolytical activity in the whole organisms of several invertebrate animals (larvae of chironomids Chironomnus plumosus, pond snail Limnaea stagnalis, orb snail Planorbis corneus, faucet snail Bithynia tentaculata, and zebra mussel Dreissena polymorpha)--potential objects of nutrition of fish benthophages under separate and combined actions of temperature (0, 10 or 20 degrees C), pH (5.0, 7.4 or 8.3), and ions of heavy metals (copper, zinc at a concentration of 10 mg/l) in vitro. The strongest inhibitory effect on the amylolytical activity in tissues of the studied animals was produced by a combination of the low temperature, acidic pH values, and the presence of the heavy metal ions. Enzymes of chironomids were more resistant to action of the studied agents as compared with mollusks.

The role of Jakara dam in the transmission of schistosomiasi

Fresh water bodies around the Jakara dam in Wasai town of Minjibir Local Government Area of Kano state were investigated for the presence of potential snail intermediate host. Five sites ,one stream, one burrow pit , one pond and two locations on the Jakara dam were investigated . Five species of snails, Bulinus globosus Morelet, the intermediate host of Schistosoma haematobium Bilharz, Biomphalaria pfeffeiri Krauss, the intermediate host of S. mansoni Sambon and Lymnea natalensis Krauss, the intermediate host of Fasiola gigantica Cobbold , P..conica and Bithynia tentaculata were encountered and investigated for trematode infections. B. globosus was the most frequently encountered in the two dam sites (Fako and Kwata) and was the only species shedding schistosome cercariae. Fishermen, children, female child hawkers were also found at the dam site. This clearly indicates Jakara dam is playing a role in the transmission of schistosomiasis. Keywords : Schistosomiasis , snails, Jakara dam, Kano state

Development and characterization of 17 polymorphic microsatellite loci in the faucet snail, Bithynia tentaculata (Gastropoda: Caenogastropoda: Bithyniidae)

Bithynia tentaculata (Linnaeus, 1758), a snail native to Europe, was introduced into the US Great Lakes in the 1870’s and has spread to rivers throughout the Northeastern US and Upper Mississippi River (UMR). Trematode parasites, for which B. tentaculata is a host, have also been introduced and are causing widespread waterfowl mortality in the UMR. Waterfowl mortality is caused by ingestion of trematode-infected B. tentaculata or insects infected with parasites released from the snails. We isolated and characterized 17 microsatellite loci from the invasive faucet snail, B. tentaculata (Gastropoda: Caenogastropoda: Bithyniidae). Loci were screened in 24 individuals of B. tentaculata. The number of alleles per locus ranged from 2 to 6, observed heterozygosity ranged from 0.050 to 0.783, and the probability of identity values ranged from 0.10 to 0.91. These new loci provide tools for examining the origin and spread of invasive populations in the US and management activities to prevent waterfowl mortality.

The life-cycles and growth of some comb-branchial mollusks (Gastropoda: Pectinibranchia) in the ponds of the European part of Russia

The life-cycles of three mollusc species, Bithynia tentaculata, Contectiana listeri, and Viviparus viviparus (Gastropoda: Pectinibranchia), from the different freshwater bodies of the European part of Russia were studied. The growth rates were determined from the analysis of morphometric characteristics of their shell. The maximum duration of the life-history of comb-branchial molluscs is larger, than that of freshwater pulmonate snails. The life-cycle of Bithynia tentaculata (Bithyniidae) may last 4 years. The duration of life of large molluscs of the family Viviparidae (Contectiana listeri and Viviparus viviparus) is 5–6 years. The structure of the life-cycles of different populations of the same species depends on the temperature regime in the waterbody.

Variation in Sr uptake in the shell of the freshwater gastropod Bithynia tentaculata from Lake Arreo (northern Spain) and culture experiments

The Sr uptake features in Bithynia tentaculata aragonite shells from monthly collections in Lake Arreo (northern Spain) over a two-year period are compared with those from the same species grown in culture experiments with similar waters under controlled temperature. The shell aragonite of B. tentaculata from Lake Arreo formed in isotopic equilibrium with the lake water. A comparison of the stable oxygen isotope values ( δ 18O) from the shells and waters allowed the selection of suitable shells for Sr uptake studies. The Sr/Ca molar ratio in B. tentaculata shells (Sr/Ca shell) from the lake and from the culture experiments positively correlate with some chemical parameters like conductivity and solute composition. Some environmental factors such as pH and T have minor influence on Sr incorporation into shells, as reported from other aragonitic mollusks. The Sr/Ca shell exhibits a good positive correlation with the Sr/Ca of the water (Sr/Ca w) using linear regression. However, a polynomial function equation better fits the Sr/Ca shell and the Sr/Ca w ( R 2 = 0.890, p = 2.923e−11). Above a value of 0.0025 for Sr/Ca w, the ratios of Sr/Ca shell present small changes. This pattern reveals a noticeable variation of the partitioning coefficient (KdSr) with Sr/Ca w. The KdSr for B. tentaculata shell aragonite obtained in this study is 0.290 ± 0.078 ( n = 25) and it is close to the mean values obtained for other non-marine aragonitic mollusks. KdSr values in B. tentaculata are influenced by the variations in Sr/Ca w that mask the T effect. This feature, together with the influence of physiological processes on the trace element incorporation, may explain the observed KdSr pattern.

Effects of snail grazers and light on the benthic microbial food web in periphyton communities

AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 61:163-178 (2010) - DOI: https://doi.org/10.3354/ame01449 Effects of snail grazers and light on the benthic microbial food web in periphyton communities Tanja Burgmer1, Julia Reiss1,2, Stephen A. Wickham3, Helmut Hillebrand1,4,* 1Erken Laboratory, Department of Limnology, Evolutionary Biology Centre, Uppsala University, Norr Malma 4200, Norrtälje 761 73, Sweden 2Department of Life Sciences, Roehampton University, London SW15 4JD, UK 3Organismal Biology, Institute for Zoology, Hellbrunnerstr. 34, Salzburg 5020, Austria 4Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl-von-Ossietzky University Oldenburg, Schleusenstr. 1, Wilhelmshaven 26382, Germany *Corresponding author. Email: hillebrand@icbm.de ABSTRACT: Periphyton harbours a complex microbial food web with different trophic levels, but little is known about trophic interactions within this food web and its response to factors that potentially control the entire community. We used natural periphyton communities from Lake Erken (Sweden) in 2 experiments manipulating grazer presence. In addition to an ungrazed control, we included natural densities of either of 2 snail species (Theodoxus fluviatilis and Bithynia tentaculata) in order to test how generalist consumers affect different components of the periphyton. In the second experiment, we additionally manipulated light supply to alter the heterotroph–autotroph ratio in the periphyton and thus potentially the trophic interactions. In both experiments, grazer presence decreased algal biomass immediately and shifted the community composition from dominance of large filamentous forms to dominance of prostrate and motile unicellular species. Biomass of bacteria, heterotrophic nanoflagellates, ciliates and meiofauna also decreased with grazing, but with differentiated temporal dynamics and effect strength. In the ungrazed control, first heterotrophic protists and later meiofaunal biomass increased, indicating strong bottom-up and top-down propagation of trophic interactions in the microbial food web. High light increased the biomass of mixotrophic ciliates and nanoautotrophs but not total algal biomass. Grazer presence decreased algal richness in the second experiment, but increased evenness of the algal community under high light conditions. We conclude that grazer presence puts different pressure on the components of the periphyton, which are further linked by direct or indirect internal trophic processes. KEY WORDS: Periphyton · Microbial food web · Protozoa · Algae · Grazer · Light Full text in pdf format PreviousNextCite this article as: Burgmer T, Reiss J, Wickham SA, Hillebrand H (2010) Effects of snail grazers and light on the benthic microbial food web in periphyton communities. Aquat Microb Ecol 61:163-178. https://doi.org/10.3354/ame01449 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 61, No. 2. Online publication date: October 20, 2010 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2010 Inter-Research.

Doplněk k poznání vodních měkkýšů Labe mezi Hřenskem a Střekovem a srovnání s malakofaunou Labe v jiných úsecích [A supplement to the knowledge on aquatic molluscs of the Elbe River between Hřensko and Střekov and a comparison with molluscan communities in other parts of the Elbe River (Czech Republic)

This paper completes knowledge on aquatic molluscs of the free flowing part of the Elbe River between Hřensko and the weir with lock in Ústí nad Labem – Střekov. Altogether, 21 species of aquatic molluscs (9 gastropods, 12 bivalves) were found in 2009. Viviparus viviparus, Potamopyrgus antipodarum, Bithynia tentaculata, Ancylus fluviatilis, Unio pictorum, Anodonta anatina, Corbicula fluminea, Sphaerium corneum and Pisidium supinum were the most frequently occurring molluscs found during this research. The occurrence of two endangered bivalves Pseudanodonta complanata and Pisidium moitessierianum was recorded. No significant difference from the previous author’s research was found. Molluscan communities of this part of the river were compared with those of the upper canalized part of the Elbe River which contain more species (especially gastropods) living predominantly in stagnant or slowly flowing waters e. g. Stagnicola palustris, S. corvus, Lymnaea stagnalis, Planorbis planorbis, Bathyomphalus contortus, Anisus vortex, Hippeutis complanatus, Ferrissia fragilis.

Seasonal Dynamics of Two Mortality-Related Trematodes Using an Introduced Snail

Seasonal dynamics of 2 trematode species, Cyathocotyle bushiensis and Sphaeridiotrema globulus, were assessed in relation to life history traits of the parasites and their hosts, as well as abundance of host species and abundance of infective stages. Both of these trematodes are associated with recurrent mortality of migrating waterbirds on the Upper Mississippi River National Wildlife and Fish Refuge. An invasive snail species, Bithynia tentaculata, serves as intermediate host for both trematode species. In total, 2,970 snails were collected at 2 study sites. Prevalence and mean abundance of the 2 trematode species varied among dates and was attributed to several factors, including migration patterns of definitive hosts, snail population dynamics, and seasonal changes in temperature. The surge of new infections of both parasites seems to be due to avian hosts foraging at this site during spring migration. The high prevalence and abundance of metacercariae among the snail population promote mortality among molluscivorous birds by increasing the probability of ingestion of a lethal dose. Additionally, mortality of non-molluscivorous birds can be explained by accidental ingestion of a couple of highly infected snails resulting in a lethal dose.

Malacofauna of two hydrologically different habitats in the near-shore zone of the Włocławek Dam Reservoir (Vistula River, Poland)

1. Shallow-water benthic macroinvertebrate community of the limnic part of a lowland Polish dam reservoir Małgorzata Poznańska, Jarosław Kobak, Norbert Wolnomiejski, Tomasz Kakareko Limnologica CrossRef

Assessing the potential for using biogenic calcites as dosemeters for luminescence dating

Calcium carbonate emits an intense thermoluminescence (TL) signal and previous work has explored the potential of using this signal to date both inorganic carbonates such as limestones and stalagmites and biogenic calcite produced by marine organisms. Luminescence analysis of biogenic calcites directly dates the secretion of the mineral by the organism and is therefore not reliant upon exposure of the sample to daylight. A method is outlined for using the TL signals from slug plates, from the Limacidae family, and opercula from the snail Bithynia tentaculata to construct a single-aliquot regenerative-dose growth curve. Analysis of slug plates from a number of Quaternary sites show that the equivalent dose ( D e) of a late Holocene sample is close to zero and that the D e increases with age over the last 500 ka. The TL signal from snail opercula is shown to increase up to doses over 4000 Gy. Replicate measurements from 16 opercula from a site ∼220 ka show a broad distribution. Potential causes of this scatter are discussed along with recommendations about how it could be reduced. The major challenge which remains to be solved before slug plates or snail opercula could be used to calculate ages is to develop methods for calculating the dose rate received during burial.

Survival of the Faucet Snail after Chemical Disinfection, pH extremes, and Heated Water Bath Treatments

AbstractThe faucet snail Bithynia tentaculata, a nonindigenous aquatic snail from Eurasia, was introduced into Lake Michigan in 1871 and has spread to the mid‐Atlantic states, the Great Lakes region, Montana, and most recently, the Mississippi River. The faucet snail serves as intermediate host for several trematodes that have caused large‐scale mortality among water birds, primarily in the Great Lakes region and Montana. It is important to limit the spread of the faucet snail; small fisheries equipment can serve as a method of snail distribution. Treatments with chemical disinfection, pH extremes, and heated water baths were tested to determine their effectiveness as a disinfectant for small fisheries equipment. Two treatments eliminated all test snails: (1) a 24‐h exposure to Hydrothol 191 at a concentration of at least 20 mg/L and (2) a treatment with 50°C heated water for 1 min or longer. Faucet snails were highly resistant to ethanol, NaCl, formalin, Lysol, potassium permanganate, copper sulfate, Baquacil, Virkon, household bleach, and pH extremes (as low as 1 and as high as 13).

Resistance to ship‐induced waves of benthic invertebrates in various littoral habitats

Summary1. Ship‐induced waves disturb benthic invertebrate assemblages colonizing littoral zones of lakes and rivers. However, the impact of ship‐induced waves on invertebrates has rarely been quantified, and the influencing factors have not been addressed.2. In an experimental wave tank, five benthic invertebrate species, Bithynia tentaculata, Calopteryx splendens, Dikerogammarus villosus, Gammarus roeseli and Laccophilus hyalinus, were exposed to waves of increasing shear stress (0.43–2.19 N m−2). Mean number of detached individuals was recorded for five littoral habitats [coarse woody debris (CWD), reeds, sand, stones and tree roots], representing different levels of structural complexity as quantified by their fractal dimensions (FD).3. Results showed that detachment of invertebrates was significantly related to shear stress in all habitats except tree roots. Detachments averaged for the five species were significantly lower in habitats with a high degree of structural complexity, decreasing in the habitat sequence: sand, CWD, stones, reeds and tree roots.4. Consistent with their different morphologies and methods of attachment to substrates, the five species displayed differences in their response to hydraulic stress that were dependent on habitat.5. The increasing sheltering effect of structural habitat complexity was mirrored by increasing dissipation of the kinetic energy of waves; i.e. the FD of the habitat was positively correlated with shear stress reduction due to the flow resistance of the habitat.6. Network habitats such as tree roots provided the best sheltering conditions against hydraulic disturbance, because they combined good refuge availability for all studied invertebrate species and maximal dissipation of kinetic wave energy. Consequently, persistent anthropogenic impacts, such as lakeshore modification or long‐term exposure to ship‐induced waves, which cause disappearance of complex littoral habitats such as tree roots or dense reed belts, will drastically increase the adverse effects of boating and ship traffic on littoral invertebrate assemblages.

Testing the aminostratigraphy of fluvial archives: the evidence from intra-crystalline proteins within freshwater shells

Until recently few studies of amino acid racemization of fossil bivalves and gastropods collected from river terrace deposits in Europe were based on the analysis of the intra-crystalline fraction. Instead they were based on the epimerization (racemization) of a single amino acid, isoleucine, and its inter-conversion to alloisoleucine. This paper presents data from the analysis of the intra-crystalline fraction of the shells, using a preparation technique of sample bleaching to remove the leachable matrix, thus leaving a component that exhibits closed-system behaviour. Reverse-phase HPLC separation with fluorescence detection allows the interpretation of four amino acids in detail: aspartic acid, glutamic acid, alanine and valine. The intra-crystalline fraction offers greater potential for improved resolution, especially when combined with the analysis of multiple amino acid d/l values, which racemize at different rates. This is explored using three species of freshwater gastropods (Bithynia tentaculata and troschelii, Valvata piscinalis) and the bivalve Corbicula. Sites of different ages within the Lower Thames river terrace sequence are used as a stratigraphical framework, with samples from other southern UK sites providing supplementary evidence. The results indicate better resolution using the intra-crystalline fraction over that obtained using unbleached shells, with differentiation possible at sites of up to MIS 7 age. However, for older sites, although values are always higher, the separation is less successful. A species effect has been identified between the gastropod shells. Despite the analysis of intra-crystalline protein, amino acid data from Corbicula remain problematical. Preliminary data on the opercula from Bithynia indicate that better resolution is possible, particularly at older sites.

Closed-system behaviour of the intra-crystalline fraction of amino acids in mollusc shells

When mollusc shells are analysed conventionally for amino acid geochronology, the entire population of amino acids is included, both inter- and intra-crystalline. This study investigates the utility of removing the amino acids that are most susceptible to environmental effects by isolating the fraction of amino acids encapsulated within mineral crystals of mollusc shells (intra-crystalline fraction). Bleaching, heating and leaching (diffusive loss) experiments were undertaken on modern and fossil Corbicula fluminalis, Margaritifera falcata, Bithynia tentaculata and Valvata piscinalis shells. Exposure of powdered mollusc shells to concentrated NaOCl for 48h effectively reduced the amino acid content of the four taxa to a residual level, assumed to represent the intra-crystalline fraction. When heated in water at 140°C for 24h, only 1% of amino acids were leached from the intra-crystalline fraction of modern shells compared with 40% from whole shell. Free amino acids were more effectively retained in the intra-crystalline fraction, comprising 55% (compared with 18%) of the whole shell after 24h at 140°C. For fossil gastropods, the inter-shell variability in D/L values for the intra-crystalline fraction of a single-age population was reduced by 50% compared with conventionally analysed shells. In contrast, analysis of the intra-crystalline fraction of C. fluminalis does not appear to improve the results for this taxon, possibly due to variability in shell ultrastructure. Nonetheless, the intra-crystalline fraction in gastropods approximates a closed system of amino acids and appears to provide a superior subset of amino acids for geochronological applications.

Anthropogenic Pressure on a Molluscan–Trematode Community over a Long-term Period in the Basingstoke Canal, UK, and Its Implications for Ecosystem Health

A long-term study of a molluscan–trematode community in the Basingstoke Canal, UK, was undertaken over the period 1970–2003 which coincided with a significant restoration program involving substantial anthropogenic changes to the canal’s ecosystem. The aim of this study was to correlate these changes with alterations in the molluscan–trematode community, focusing on fluctuations in the prevalence and species richness of the trematode population as a good indicator, in terms of biodiversity, of ecosystem health. Molluscs were sampled at four time periods (1970, 1982, 1983, 2003) and examined for trematode parasites. The molluscan population over the sampling period demonstrated a limited stability with few species being present during all time periods. During 1982 and 1983, when restoration of the sampling site was being undertaken, Lymnaea stagnalis dominated the molluscan fauna, possibly because it was best able to take advantage of the disturbed conditions, while other species such as Bithynia tentaculata were absent. In the trematode population, the prevalence and diversity of both cercarial and metacercarial infections was high in 1970 prior to the period of restoration work. However, during 1982 and 1983, the trematode community was significantly reduced with cercarial prevalence declining to less than 1%. By 2003, more than 12 years after restoration had been completed, the trematode population had shown only a modest recovery. Trematodes use a wide range of different host species for completing their life-cycles and may be used as bioindicators of ecosystem diversity and health. An interpretation of the structure of the molluscan–trematode community over the sampling period suggests that the restoration project had an initial negative effect on ecosystem health, in terms of biodiversity, but this has subsequently only shown modest signs of recovery suggesting continuing problems in ecological functioning and stability.

Holocene environmental changes of Lake Geneva (Lac Léman) from stable isotopes (δ13C, δ18O) and trace element records of ostracod and gastropod carbonates

Stable isotopes and trace-element contents of ostracod (Candona neglecta) valves mostly from the Holocene portion of two assembled cores from Petit Lac (Lake Geneva, Switzerland-France) were analysed in order to depict the geochemical record of post-glacial environmental changes of this lake. Additional stable isotope and trace element data from the gastropod Bithynia tentaculata (shells and opercula) from some intervals of these cores, as well as previous data from bulk carbonate from the lower part of the studied intervals were also considered. Mg/Ca and Sr/Ca molar ratios for the Holocene lake water have been estimated from evaluations of the partitioning coefficients for Mg and Sr for C. neglecta and B. tentaculata taking into account the modern-lake water composition. This study shows an overall gentle trend to higher δ18O values in C. neglecta valves from the Boreal interval (mean −8.44‰) to the upper part of the core (mean −8.11‰). This trend is superimposed to higher frequency oscillations of stable isotope values and trace element ratios, especially through the upper Older Atlantic and the Subboreal. The overall isotopic oxygen trend includes several shifts in δ18O of about 1‰. These shifts are interpreted as major regional-global climate changes that have also been observed in other coeval δ18O and pollen records which reflect the Holocene climate variability in other European basins. Especially well-defined peaks in some episodes like Older Atlantic (~8200 yr BP), Younger Atlantic – Subboreal transition (~5600 yr BP) and early Subatlantic (~ 2500 yr BP) correspond to well-recognized events in globally-distributed records. Some of these shifts are correlated with pulses in the lake-level curve of the Lake Geneva.

Food quality of algae and cyanobacteria for the freshwater gastropodBithynia tentaculata:the role of polyunsaturated fatty acids

(2006). Food quality of algae and cyanobacteria for the freshwater gastropod Bithynia tentaculata: the role of polyunsaturated fatty acids. SIL Proceedings, 1922-2010: Vol. 29, No. 3, pp. 1235-1240.

Terrestrial mollusc succession and stratigraphy of a Holocene calcareous tufa deposit from the Fyledalen valley, southern Sweden

A Holocene calcareous tufa deposit in the Fyledalen Valley in southern Sweden was investigated with respect to molluscs, pollen, plant macrofossils and Coleoptera remains. The investigation recovered four mollusc species that today are severely threatened and included in the Swedish Red List of Endangered Species and/or the European Community's Natura 2000 programme. These include Vertigo genesii (Gredler), Vertigo geyeri Lindholm, Cochlicopa nitens (Gallenstein) and Vertigo moulinsiana (Dupuy). Tufa formation was initiated in the early Preboreal (after 11 500 cal. BP), when an open birch-pine forest dominated the area and stopped in the late Boreal (after 8800 cal. BP) when deciduous trees had become established. The presence of the molluscan species Vallonia pulchella (Müller), Columella columella (Martens), Vertigo genesii, Pupilla muscorum (L.) and Euconulus alderi (Gray), coupled with an almost complete lack of shade-demanding taxa, suggests an open marsh environment throughout the time of tufa deposition. The mollusc succession shows evidence of increasing temperature. Columella columella, commonly associated with open arctic-alpine habitats is present at the base of the profile in the early Preboreal, whilst Vertigo genesii, which commonly is associated with open arctic-alpine habitats or calcareous springs, persists until the mid-Boreal (∼ 8800 cal. BP). The tufa deposition ends when the regional groundwater levels rise, approximately 8800 cal. BP, more thermophilous molluscs, such as Vertigo moulinsiana and V angustior Jeffreys and the aquatic Bithynia tentaculata (L.), Radix peregra (Müller) and Planorbis planorbis (L.) colonize the site. Stratigraphic correlations, as well as faunal and floral comparisons, are made with nearby sites.

Vodní měkkýši Labe mezi Pardubicemi a Hřenskem [Aquatic molluscs of the Elbe River between Pardubice and Hřensko (Czech Republic)

Aquatic molluscs of the Elbe River between Němčice (near Pardubice, Eastern Bohemia, Czech Republic) and Hřensko (Northern Bohemia, Czech Republic) at 27 localities were investigated from 1994 to 2004. Altogether 40 species (24 gastropods, 16 bivalves) from 77 species known on the territory of the Czech Republic were found at sites under study. A gradual invasion of 6 non-native species (Potamopyrgus antipodarum, Physella acuta, Menetus dilatatus, Ferrissia clessiniana, Corbicula fluminea) and an extinction of another species (Theodoxus fluviatilis, Planorbis carinatus, Unio crassus, Pisidium amnicum) were documented in comparison with historical records. Rare mussel Pseudanodonta complanata and rare pea mussel Pisidium moitessierianum were found at several localities under study and these finds document survival of these bivalves in the Elbe River. Molluscan communities of particular localities were most often usually compounded from species Viviparus viviparus (downstream of loc. 9), Bithynia tentaculata, Radix auricularia, Radix ampla, Unio pictorum, Anodonta anatina, Corbicula fluminea (downstream of loc. 8), Sphaerium rivicola (downstream of loc. 7), Sphaerium corneum s. lat., Pisidium supinum, Dreissena polymorpha.