Distribution of snakes of the vipera family Viperidae in Kazakhstan and modeling of their potential ranges

For three species of snakes of the viper family - the eastern steppe viper (Vipera renardi), common european adder (Vipera berus) and Halys pit viper (Gloydius halys), an analysis of literary sources, collection materials, electronic resources, as well as personal and survey information was performed. Based on these data, the potential range of species was calculated using the maximum entropy method in the Maxent program. The data for extrapolation were a number of bioclimatic variables, maps of altitude and vegetation, as well as humidity and soil types. To minimize the bias of the model towards the most explored areas, the collected points of finds for each species were thinned with a radius of 25 km. At the first stage, the simulation was performed using all environmental factors, after which the correlation of these factors was evaluated and their contribution to the construction of the model was assessed. At the second stage, repeated modeling was performed with the exception of highly correlating factors and factors that made zero contribution to the construction of the first model. The raster models of the probability of the presence of species obtained as a result of the calculation were transferred to monochrome mode with clipping off areas with habitat suitability indices below the threshold. Based on the initial data of the actual location of each of the species and their comparison with the obtained models, the consensus ranges of the steppe viper, common adder and common muzzle Halys pit viper were constructed for the territory of Kazakhstan and the nearest adjacent territories.