The nature park Lonjsko polje, as a wetland, is considered to be the most endangered habitat in the world. It is the largest protected wetland area, not only in Croatia, but in the entire Danube tributary area. It is included in the list of so called Ramsar sited of international importance, especially as a habitat of wetland birds. According to the criteria from the European Union Birds Directive, this area is an Important Bird Area – IBA. It is mostly made up of three fields (polje): Lonjsko, Mokro, and Poganovo polje.
The rivers Sava, Una, Kupa, Lonja, and Strug meet in the nature park. Due to their very complex dynamics, flooding in this area is very unpredictable, so it must be considered as a possibility throughout the year. The water level of Sava downriver from Sisak can rise up to 10 m! If the water level in all the mentioned rivers rises suddenly, large amounts of water meet and cause flooding. The central Posavina area can accept an enormous amount of two billion cubic metres of water. So the water rules over Lonjsko polje and even the local population have accepted its rule.
The activities of the Nature Park Lonjsko polje are primarily focused on the protection, preservation, and promotion of the basic natural and cultural values of the Park. The first educational programmes for children have been designed, and the Park also offers professional tours for its visitors. Professional and scientific research takes place in the Park, along with educational and professional workshops, meetings, and other events.
In the old days, the inhabitants of the villages along the Sava lived a different life and they made traditionally great wines in the vineyards located on the grape hills of Moslavačka gora. Lonjsko polje was much easier to traverse. They would cross the several kilometres to their vineyards across fields, work in the vineyards, and come back to their life along the Sava.
A thematic trail has been designed as a reminder of the old way of life, and it connects the northern part of Lonjsko polje with its living environment, the wine growing hills of Moslavina, and the river Sava.
The thematic trail emphasizes the differences between the past and the present, because most of the trails across the fields no longer exist, the bridges over the rivers are worn, the main watercourses have been regulated, but the inlets and the seductive places along the Lonja have been preserved. It connects the two areas in a new way and, accompanied by romantic tales from history, leads to the replicas of frontier forts where the frontier guards spent most of their lives.
The entire area is a mixture of very different cultures and peoples who used to live here, and who met and sometimes fought in a very complex historical context. All of them called Lonjsko polje and the grape hills of Moslavina their home, for a short, or sometimes a long time.