Potential habitats of an alien species (Asterias rubens Linnaeus, 1758) in the Black Sea: its current and future distribution patterns.

The Atlantic common starfish, Asterias rubens, has arrived firstly at the Marmara Sea in 1996 and to the Black Sea in 2007. In this study, we have exhibited the possible potential distribution of Asterias rubens throughout the Black Sea. For this, we predicted and determined the present and future distributions, and habitat preferences of this starfish in the Black Sea using environmental variables. The ecological niche modeling was used to detect the suitable habitat of A. rubens. In the current model, shallow areas seem to be the suitable habitat for A. rubens. However, this trend may change in the future distribution pattern. For the future projection, two representative concentration pathways (RCPs) that are a greenhouse gas concentration was used: RCP2.6 that is likely to keep global temperature rise below 2 °C by 2100 and RCP8.5 that will happen approximately 5 °C in range of global mean temperature increase in 2100 from pre-industrial baseline. According to RCP2.6 scenarios as well as the RCP8.5 scenario in 2040-2050, the suitable habitats in the Black Sea will probably decrease due to climate change. The most suitable habitats in these scenarios will remain the western and southern coasts of the Black Sea because these areas will be less affected by the change in the climate. In contrast, for the 2090-2100 periods of the RCP8.5, there will likely be a significant unsuitable habitat throughout the Black Sea. Therefore, the suitable habitat for A. rubens will be restricted to the western and southern coasts of the Black Sea.