An basin of a large or medium river is a large biogeosystem, shaped by the history and natural processes, that is an integrated functional unit with its own hydrological balance, circulation of elements and energy. The author deals with the nature of ecological corridors on the basis of river San, a medium-size river in European terms, and it’s ecological functions. He focuses on the threats and lists ways of preventing degradation of the ecological macrosystem.
Ecological islands are patches of isolated, adjacent, often contrasting, ecosystems. Small forested areas, tree stands, shrub lands in a rural or urban areas are often classified as ecological islands. In Wielkopolska, many parks located around palaces, castles and mansions, e.g. park-arboretum in Gołuchów have such a status. The author presents the related problems using the Koszuty mansion and park as an example.