Lonja field is part of the valley between the river Sava and moslavachka up next to the river Lonja Lonju. Park Danube nature Park covers an area of 506.50 km2.There is a large variety of flora and fauna, and interesting architecture and Posavina wooden houses, which are noted for their beauty, number of well preserved architectural monument . Somere areas within the Nature Park (ornithological reserve Krapje Đol) are under strict protection. Marshy meadows, forests of ash, willow and poplar are important for nesting ducks, while in the flooded oak forests and meadows nature park rare European animals (white-tailed eagle and short-toed eagle, gray and white egret, black stork, etc.). In the floodplain, where high water remains up to six months, one of the largest carp spawning places in Europe. There are also other animals typical for this area (indigenous pigs, wild boar, horse Croatian posavac, deer, deer, otters, beavers, wild cats).
Region of flooded plains with wet meadows, forests and groves of willow, poplar and common oak, permanent and temporary water channels, flood meadows and ponds. Here resides Natura park Lonjsko polje, most interesting species are several species of heron – (Nycticorax nycticorax), great white egret (Egretta alba), Purple Heron (Ardea purpurea), black stork (Ciconia nigra), white stork (Ciconia ciconia) and spoonbill (Platalea leucorodia), European honey buzzard
(Pernis apivorus), black kite (Milvus migrans), white-tailed eagle (Haliaeetus albicilla) and Lesser Spotted Eagle (Aquila pomarina) and other wetland and forest species such as Little crake (Porzana parva), ginger Crake (Porzana porzana), Common Snipe (Gallinago Gallinago), terns, Whiskered tern (Chlidonias hybrida) and the collared flycatcher (Ficedula albicollis).