Movement of Southern European Aquatic Alien Invertebrate Species to the North and South

Abstract

Due to globalisation and anthropopressure (intensification of shipping, creation of water corridors connecting seas, cultivation of commercial species), the movement of aquatic species has increased in recent years. The determination of trends in the movement of aquatic species in their geographical distribution over time is important because it may help in the management of a species in aquatic ecosystems. There are also knowledge gaps on the long-term trends in the movements of Southern European aquatic alien invertebrates. The study provides the first evidence of both northward and southward movements of these species based on available observations from 1940 to 2021, using meta-analyses and GAM modelling. To date, the majority (98%) of analysed Southern European aquatic alien invertebrates of Mediterranean and Ponto-Caspian origin have moved to the north. Among them, 61% are Ponto-Caspian aquatic alien invertebrates that moved only to the north, and 4% are Mediterranean aquatic alien invertebrates that moved only to the north; the rest include species that moved to the north and south: 27% are Ponto-Caspian aquatic alien invertebrates, and 6% are Mediterranean aquatic alien invertebrates. The one-way movement to the south was observed only in 2% of Mediterranean aquatic alien species. The study will help in understanding the movement patterns of Southern European aquatic alien invertebrates and in the effective management of aquatic ecosystems that allow for the co-existence of people and the rest of biodiversity.