Changes of malacofauna in a small lowland river in eastern Poland

In 2016, the species composition and the structure of the dominance of molluscs in the Muchawka River (left-bank tributary of the Liwiec River) were assessed. The occurrence of 19 species of molluscs were recorded, including 11 species of snails and 8 species of mussels. The eudominant was Pisidium casertanum, which, only in the last two sites, constituted 43.1% of all molluscs. Two other species of molluscs from the Sphaeriidae family were also eudominants – Pisidium subtruncatum (22.8%) and Sphaerium corneum (10.3%). Snails were most frequently represented by the dominant Bithynia tentaculata, constituting 5.4% of all molluscs, and the subdominant Bathyomphalus contortus at 2.8%. Sixteen years after the first malacological analysis, an increase in species richness and differences in the dominance of molluscs were found in the Muchawka River. Clams from the Sphaeriidae family invariably dominated but with a different species composition. The disappearance of the protected Anodonta cygnea and Sphaerium rivicola has been noted, and the occurrence of the protected Unio crassus has also been noted.

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.

Recent distribution of Sphaerium nucleus (Studer, 1820) (Bivalvia: Sphaeriidae) in the Czech Republic

Recent data about the distribution of Sphaerium nucleus in the Czech Republic are summarized and used in an attempt to evaluate its conservation status. During the last ten years, this species was found at 40 sites, mostly shallow small water bodies situated in lowland river alluviums. These types of habitats are generally endangered due to the huge human impact and exploration of these areas. The revision of voucher specimens of Sphaerium corneum s.lat. deposited in museum collections yielded a further 22 old records of S. nucleus.

Vodní měkkýši přehradní nádrže Slapy (Česká republika) [Aquatic molluscs of the Slapy Reservoir (Czech Republic)]

This paper brings a review of a malacological survey of the Slapy Reservoir (Central Bohemia, Czech Republic). This dam water reservoir was built in 1957 on the Vltava River with area 1392 ha, length 44 km, max. deepness 58 m and altitude 270.6 m. Aquatic molluscs at 22 sites were studied from 2005 to 2006. Altogether, 30 species of aquatic molluscs (21 gastropods, 9 bivalves) which represent nearly 40% of the total Czech aquatic mollusc fauna were found despite the absence of littoral vegetation. Bithynia tentaculata, Radix auricularia, R. cf. ampla, Gyraulus albus, Hippeutis complanatus, Sphaerium corneum, Anodonta anatina and surprisingly also vulnerable Anodonta cygnea belong to most frequent molluscs found during this research. Record of near threatened gastropod Viviparus viviparus fill in long gap among its occurrence in the Vltava River downstream of the Slapy Reservoir (last of the dam water reservoirs on the Vltava River) and in tributaries of the Vltava River in Southern Bohemia (Lužnice, Nežárka). Occurrence of four non-native species (Potamopyrgus antipodarum, Physella acuta, Menetus dilatatus, Ferrissia fragilis) were documented.

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.

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.