The spatio-temporal distribution of the Ponto-Caspian polychaete in the Lower Sector of the Danube River and in Danube Delta

Abstract

Several Ponto-Caspian species, such as dreissenid and mud shrimp species have become massive invaders in freshwater ecosystems of Europe and North America. In order to understand the ability of other Ponto-Caspian groups to expand and invade other regions, their occurrence and adaptation within areas that can act as a vector need to be understood. Several Ponto-Caspian polychaete species might be capable to become invasive as well. Understanding their ecological tolerances and distribution dynamics in waterways that link them to other regions is therefore imperative to acknowledge their invasive potential. In this study we examine the distribution patterns of three PC polychaete species in the Danube River and delta area in order to assess whether the region might be a corridor for these species to spread into central Europe and beyond. The results revealed that the three studied species greatly vary in distribution and environmental tolerances, but that two of the three show ecological tolerances and distribution range extensions that make them potentially very invasive. Our study provides a baseline for further distribution studies of PC polychaetes and details their habitat requirements. The possibility that the two Ponto-Caspian polychaete species could use the Danube corridor to realise a massive range extension is new and raises several conservation concerns. It is imperative to understand invasive potential and distribution dynamics in order to prepare effective measurements to limit spread of potentially harmful species, such as Ponto-Caspian mussels, mud shrimps and in this case polychaete.

Keywords

• Danube River
• Danube Delta
• Ponto-Caspian Polychaeta