Diploma thesis analyzes the viability of the selected species populations in the Czech Republic. The thesis is divided into two main parts. The first part contains a stochastic model simulating possible scenarios of the Eurasian lynx population size in the Czech Republic. For this model program Vortex was used. The second part is focused on Time series analysis of the Grey Partridge and the Common Kingfisher population, where data was obtained from the Czech Society for Ornithology. This analysis aims on identification of factors that may affect the viability of the two bird species.