The significance of the European beaver (Castor fibre) activity for the process of renaturalization of river valleys in the era of increasing

Abstract Changes in the environment that are caused by the activity of beavers bring numerous advantages. They affect the increase in biodiversity, contribute to improving the condition of cleanliness of watercourses, improve local water relations and restore the natural landscape of river valleys. Rapid increase in the European beaver population in Poland in 21st century determines and accelerates the process of renaturalization of the areas that have undergone partial degradation as a result of anthropopressure. A singular example is the river valleys populated by beavers that have been adapted to people’s needs in the last centuries, which has inevitably exerted an undesirable effect.