Analysis of the environmental factors affecting the distribution of the Loach (Oxynoemacheillus bergianus) in Kordan River-Iran

In order to sustainable exploitation and conservation of biodiversity of riverine ecosystems، which have been exposed to considerable modifications caused by anthropogenic activities، it is necessary to understand the habitat requirements of the species inhabiting these ecosystems. Kordan River of the Namak Lake basin، originates from the highlands of the Alborz Province، and is one of the environments inhabited by the native Angora loach، Oxynemacheilus bergianus. This river has been exposed to anthropogenic activities such as agriculture، dam construction and ecotourism. Habitat requirements of this species and the impacts of anthropogenic effects were determined in 68 stations along the Kordan River. According to the best model selected based on the Akaike Information Criterion (AIC)، the variables including altitude، river width، flow rate and the size of the substrate material were determining factors for the presence of this species. Other models which were، also، suitable based on AIC values، showed that the altitude and river width are the most important independent variables affecting the presence of the species. Therefore، the anthropogenic activities being held in Kordan River and bringing up the changes in river width، depth، substrate and the flow rate، can affect the presence and distribution of Oxynoemacheilus in the mentioned river.