Natural environment of Biebrza Marshes was formatted as result of cooperation of natural processes and human activities. The influence of man on the environment concerned the transformation of hydrographical network as well as different kinds of land use, like agriculture, pasturage and forestry. The valuable ecosystems include not only natural areas of forests and peatlands, but also open areas of meadows which are the result of extensive agricultural use. Discontinuance of any land use forms may bring to disappearance of floristic and faunal values of these areas. In other words, most of areas within BNP require active protection. Principles and main policies of protective activities were laid down according to basic aim of BNP establishment, which is protection of peatlands and wetlands that are found as unique and disappearing in Europe, also protection of rare and vanishing plant communities and species of fauna as well as landscape amenities and biotopes important from the avifauna protection point of view.