Modeling habitat requirements of riverine stone loach, Paracobitis hircanica (Teleostei: Nemacheilidae) in the Zarin-Gol River, Caspian Sea basin, Iran

For sustainable exploitation and conservation of biodiversity in riverine ecosystems which have been exposed to considerable modifications by human activities, it is necessary to understand the habitat requirements of the species inhabiting these ecosystems. The Zarin-Gol River in the east of Alborz Mountains, Golestan province, is one of the environments inhabited by the native Hircanian stone loach, Paracobitis hircanica. This stream has been exposed to human activities such as rural discharges, agriculture, fish farm effluents and ecotourism. Habitat requirements of this species and the impacts of human activities were determined in 17 stations along the Zarin-Gol River. Binary Logistic Regression was implemented to develop the distribution model of P. hircanica according to habitat variables. Finally, according to the best model selected by the Akaike Information Criterion (AIC), stream surface width, depth, vegetation cover, altitude and discharge were determined as the most significant parameters for the presence of P. hircanica. Also, other suitable models according to AIC values showed that the stream surface width and depth are the most important independent variables affecting the presence of this loach. Therefore, it was concluded that most significant factors affecting the presence and distribution of P. hircanica are stream surface width, depth, substrate and flow rate.