Distribution data on beaver populations thriving in central Poland are common. We modelled beaver population viability to assess the current status and threats to the beaver in the 135-km-long section of the Vistula valley. We simulated different densities of expanding beaver populations and evaluated the three most significant scenarios of potential developments in the valley with the LARCH habitat model. The model output indicated higher vulnerability of low density populations to the same environmental changes. At present, suitable habitats sustain a large minimum viable population as part of one sustainable network. Hypothetical construction of two dams and removal of riparian forests within dykes would lead toa 25% reduction in population size. In contrast, river renaturalisation would increase beaver numbers by 42%. Based on the population trends we conclude that scenario analysis is beneficial in helping to evaluate future management decisions.