The area has long been used ectively for agriculture. Historical data show that up to 150 singing male Aquatic Warblers occupied the area as recently as last century. The presence of this species was the reason for OTOP BirdLife Poland to purchase and protect the site. Thanks to funding from a LIFE project, part of the land in the area was purchased in 2009 and to date OTOP owns 20ha of land.

Krajnik lies on the right bank of the Oder River. It is located close to the German Lower Oder National Park and borders directly on the neighbouring Lower Oder Valley Landscape Park. In this area Oder splits off into two branches, between which the Międzyodrze interfluve shapes, where the above-mentioned parks are located.

Krajnik is mainly extensively used grassland predominantly by small farmers as well as by the OTOP. The site is drained by means of numerous ditches and a pumping station, which eventually pumps water back into the river. The soil is alluvial, with a layer of peat fragmentarily covering the mineral soil. In some parts of the site there are fluvioglacial sands with vegetation different from the rest of the site, where numerous orchid species are found. The intensity of land use in the polder is very low. The polder is overgrown with wet meadows dominated by sedges and grasses. Some areas are still mown by local farmers, while others are used as pastures. Many plots are used infrequently or not at all.