Modeling the effects of climate change on the distribution of bighead goby Ponticola gorlap (Iljin, 1949) in the southern basin of the Caspian Sea

The phenomenon of climate change due to the expansion of human industrial activities is rapidly advancing, and via disrupting ecological processes and destroying the habitats, has caused extinction of many fishes and reducing the biodiversity of aquatic ecosystems. This study predicts the distribution of Ponticola gorlap under two climate scenarios (RCP 2.6 and RCP 8.5) for the years 2050 and 2080 using the MaxEnt model. Five climatic and environmental variables, including annual mean temperature, annual precipitation, annual temperature range, flow accumulation, and slope, were utilized for forecasting. The model demonstrated excellent performance (AUC criterion: 0.969) in predicting species distribution. Annual temperature range identified as the most influential variable (importance score: 57/5) in determining the species' distribution. Moreover, the study forecasts a significant decrease in the distribution of P. gorlap under both optimistic and pessimistic scenarios for the years 2050 and 2080. As climate change intensifies and suitable habitat ranges diminish, the species faces an elevated risk of extinction in the future. Hence, experts and policy-makers should focus more on conservation measures.