Non-indigenous invasive freshwater crustaceans (Crustacea: Malacostraca) in Slovakia - page 4

C. robustum Sars, 1895 is the newest element to Slovak fauna (Figure 4). It was found on the Hungarian side of the Danube River in 2007 and then later in 2009, representing the first findings for Hungary (Borza, 2011). First record for Slovakia is published by Lipták et al. (2012). The species is spreading downstream from the Upper Danube (Borza et al., 2010) and is known from the Main and Rhine River (Bernerth and Stein 2002; Bernauer and Jansen, 2006).

 

Fig04
Figure 4: Distribution of C. robustum confirmed by Borza (2011) (indicated with diamonds) and recorded in the research in 2011 (Lipták et al., 2012) indicated with triangles.

 

Dikerogammarus haemobaphes (Eichwald, 1841) and D. bispinosus Martynov, 1925 arrived to the Slovak-Hungarian stretch of the Danube River approximately at the same time (Figure 5, Figure 7). The species are listed in the papers like Brtek (1953), Brtek and Rothschein (1964) and Brtek (2001). D. haemobaphes extended its range colonizing the Upper Danube from where it reached the Main-Danube Canal and spread to the Main River in 1993 and later in 1994 to the Rhine River as well (Nesemann et al., 1995; Tittizer et al., 1997; Bij de Vaate et al., 2002). The species also extended its range through the Central corridor where it penetrated into Polish inland waters and spread extensively (Grabowski et al., 2007). Brtek (2001) sets D. haemobaphes as the most widespread amphipod in the Slovakian stretch of the Danube River. However a major decrease of the species population is recorded, comparing our results with the results of Brtek (2001). There were no individuals of D. haemobaphes recorded in the Danube in Slovakia.

 

Fig05
Figure 5: Distribution of D. haemobaphes according to the study of Brtek (2001) (squares) and Elexová et al. (2010) (circles).

 

Dikerogammarus villosus (Sowinsky, 1894) was known from the Hungarian reach of the Danube already in the early 20th century (Nesemann et al., 1995). The original species distribution range reached the river kilometer 1707, near the confluence of the Ipeľ/Ipoly River. The species is absent in the works of Brtek (1954) and Brtek and Rothschein (1964). The first record for Slovakia is presented in a paper by Šporka (1999). The species extended its range through the Southern corridor reaching the Upper Danube in 1992 where it occurs abundantly. The species invaded the Rhine River as well (Nesemann et al., 1995). In the Hungarian stretch of the Danube D. villosus is the most wide-spread amphipod species (Borza et al., 2010). D. villosus can be found throughout the whole Slovak section of the Danube River and in lower parts of the March and Váh River as well (Figure 6).

 

Fig06
Figure 6: Distribution of D. villosus according to results from the research in 2011 (triangles), data from Brtek (2001) (squares) and Elexová et al. (2010) (circles).

 

Fig07
Figure 7: Distribution of D. bispinosus according to results from the research in 2011 (triangles), data from Brtek (2001) (squares) and Elexová et al. (2010) (circles).