First report and distribution of invasive species Actinocyclus normanii f. subsalsa Hustedt in Serbia

Abstract

Actinocyclus normanii f. subsalsa is considered native marine or brackish water species (Baltic Sea, Caspian Sea). The species has spread into common freshwaters, throughout the world, and was considered as invasive or potentially invasive species (Kaštovský et al. 2010, Kipp et al. 2012). Phytoplankton, phytobenthos and epilithic samples were used for this study. In laboratory the field samples were treated with standard method with cold acid by Krammer and Lange-Bertalot (1986). Permanent slides were mounted in Naphrax. In Serbia, Actinocyclus normanii f. subsalsa, was registered in several rivers and canals. In 1997 was found as planktonic species in the Tisza River and in benthic samples (in mud) in the Veliki Bački Canal. In 2002 was found as planktonic species in the Danube–Tisza–Danube Canal (Kajtasovo) and the Ponjavica River (Brestovac and Omoljica). Four years later, in 2006, the species was found in plankton, benthos and epiphytic samples in the Ponjavica River (Omoljica). Actinocyclus normanii f. subsalsa is a cosmopolite, alkalibiontic (pH range from 8.0 – 8.83) and halophytic species. It occurs in waters with high conductivity (348 – 918 µS/cm) and it is indicator of eutrophied, polluted waters. Its spread is probably explained by eutrophication of surface waters. The presence of many diatom taxa could give evidence of a wide scale of the environmental possibilities for their development within the studied area. Identification of invasive algae species in water bodies is possible through the long-term floristic studies and continuous biomonitoring of surface waters. Therefore, we continue to monitoring the occurrence of invasive taxa in the waters of Serbia.