Vliv migračních bariér na šíření vydry (Lutra lutra) na vodních tocích [The effect of migration barriers on expansion of the common otter (Lutra lutra) on watercourses]
On selected watercourses, 528 potential barriers to otter migration were documented of which 30 most important were identified. The influence of different parameters of the barriers on otter expansion was subjected to statistical analysis. Type of the barrier was the only variable with a significant influence, the weir + channelled river being the critical type which could not be overcome by the otter in 75% of cases. It is obvious that a combination of factors has a stronger effect on the otter while a channelled river has a particularly strong effect (proportion of impassable barriers being 72%).