Biotic Homogenization of Inland Seas of the Ponto-Caspian

Comparative analysis of patterns of species invasion, dispersal, and impact on ecosystems in the Ponto-Caspian seas has been ongoing since 1900. The Black Sea is an important international shipping destination. High shipping intensity has facilitated species invasions into the Black Sea. Many species have successfully established because of Black Sea disturbances. The Black Sea serves as a hub for species that then spread further to the Sea of Azov, the Caspian Sea, the Sea of Marmara, and in some cases the eastern Mediterranean Sea. The Black Sea has thus become the main recipient for non-native species and acts as a donor to the seas of Eurasia. Native biodiversity has declined and invaders now dominate the Ponto-Caspian seas. This process has caused biotic homogenization of the Ponto-Caspian, as the same invaders determine community structure and in some cases ecosystem functioning in the different seas. Among these invaders, gelatinous species have become the main drivers of ecosystem functioning. The invasion rate of new species is accelerating.