Gornje Podunavlje Special Nature Reserve is a large protected area of wetland in the northwest of Serbia (Vojvodina province). It comprises two big marshes along the left bank of the Danube River - the Monostor and Apatin marsh, including 66 km (41 mi) of the Danube course (1366 – 1433 km).
Parts of the nature reserve are subject to the Croatia–Serbia border dispute; Croatia claims some areas under Serbian control on the eastern side of the river.
Gornje Podunavlje Wikipedia
The first designation as a protected area dates back to 1955, when an area of 10 square kilometres (3.9 sq mi) was proposed as an important habitat for the white-tailed eagle and the black stork. Since then, the area included and the level of protection has been gradually increased. Gornje Podunavlje was designated as a Special Nature Reserve in 2001, with a total size of 19,648 ha (48,551 acres).
Within the reserve, there is a three-level zonation system established: protection regimes of category I (1.3%), II (24.7%) and III (74.0%). There is a huge biodiversity of Gornje Podunavlje Reserve. More than 150 bird species occur regularly in the reserve, amongst which a lot of threatened ones. It is an area of important aquatic and semi-aquatic vegetation, wet meadows and native lowland forests composed of willow, poplar, ash and oak trees. The area is rich in fish species, as one of the most important spawning areas along the Danube River.
Gornje Podunavlje is also an important trans-boundary area, creating a vast Central Danube Floodplains, the large trans-boundary floodplain in the middle Danube, along the route of the southern European Green Belt. It is one of the best preserved wetlands in the Danube River Basin area. A natural complex of more than 700 square kilometres (270 sq mi) embraces three protected areas: the Kopački rit Nature Park in Croatia, the Danube-Drava National Park in Hungary and the Gornje Podunavlje Special Nature Reserve in Serbia.
As one of the last integral floodplains of the Danube, it contains some of the most valuable wetland habitats and therefore is a sanctuary for many species, which with their lifecycles, is inherently connected to the river. Natural poplar, oak and willow forests and occasionally flooded wet meadows or numerous oxbow lakes and swamps, which were once widespread in the Danube wetlands, are today rare and fragmented habitats.
The area is home to some important species such as white-tailed eagle (Haliaeetus albicilla) or black stork (Ciconia nigra), numerous fish species which find ideal spawning conditions in the oxbows and shallow shoals of the emanated river or rare and endangered mammals like European otter (Lutra lutra) and wild cat (Felis silvestris). Although suffers a certain pressure from numerous human activities, this area still remains an unspoilt natural environment for the many species which inhabit it.