|Location||Mačva region, Vojvodina province (partially)|
|Primary inflows||Zasavica River|
|Primary outflows||Zasavica River|
|Max. length||33 kilometres (21 mi)|
|Max. width||300 metres (330 yd)|
|Surface area||11.5 square kilometres (4.4 sq mi)|
|Average depth||2.5 metres (8.2 ft)|
|Max. depth||10 metres (33 ft)|
|Surface elevation||76-82 m (250-270 ft)|
The Zasavica (Serbian Cyrillic: Засавица) is a bog in the region of Mačva, west-central Serbia. With Obedska bara and Carska Bara one of the major wildlife refuges and one of the last authentically preserved wetlands in Serbia. In the 2000s became a popular attracton with the successful reintroduction of the beavers, which became extinct hundred years ago.
- 1 Location
- 2 Geography
- 3 Human history
- 4 Preservation
- 5 Wildlife
- 6 Special residents of Zasavica
- 7 See also
- 8 References
- 9 External links
Zasavica is located just several kilometers across the Sava river from the town of Sremska Mitrovica. The entire Zasavica system is located in the Mačva region and is administratively divided between the province of Vojvodina (northern part; municipality of Sremska Mitrovica) and Central Serbia (southern part; municipality of Bogatić. It roughly extends between the settlements of Crna Bara[disambiguation needed], Banovo Polje, Ravnje, Zasavica I, Zasavica II, Salaš Noćajski, Noćaj and Mačvanska Mitrovica.
The Zasavica bog is a marshy lowland in the floodplain of the Sava river. It is a typical elongated oxbow (in Serbian: mrtvaja, dead [water]). The fossilized, parallel bed of the Sava is so elongated that it actually stretches almost to the Drina river. In time, Zasavica river was formed from the subterranean waters from the Drina and from several streams, most notably, Duboka Jovača and Prekopac canal  (gravitationally, from the Cer mountain. The final section connecting Zasavica and Sava has been channeled (Bogaz canal). The river slowly meanders into and through the bog, widening from 50 metres (55 yd) meters to almost 300 metres (330 yd). The marsh, consisting of several connected bogs, covers an area of 11.5 square kilometres (4.4 sq mi). During normal water levels, the bog is 2.5 metres (8.2 ft) deep on average, but it can get up to 10 metres (33 ft) deep. The marshland's altitude varies from 76 to 82 meters (250 to 270 ft). The entire biotype includes also the Batar stream and several other canal-tributaries to Zasavica, and consists of an ecological row of water and marsh systems with fragments of flooded meadows and forests. Through the rivers Sava and Danube, the Zasavica biotype belongs to the Black Sea drainage basin.
Remains show that humans were already settled the marshy areas of Mačva in 5000 BCE. They made canals and water alleys in the marsh, using them both for irrigation and drainage. That way, they participated in the volatile process of constant change of the Sava and Drina rivers directions, creation of meanders, change of the landscape, etc. Time erased memories of the first recorded settlers and the remains of their work was attributed by the later settlers as the work of giants, creating one of two popular legends in Zasavica. Other legend connected to the area is that of winged dragons. Ancient Celtic maps show area of Zasavica as one of 8 dragon-inhabited places in the Balkans.
From recent history, Zasavica is known as both the hiding place and a battle ground of Zeka Buljubaša, one of the heroes of the First Serbian Uprising. He was finally defeated and killed by the Ottomans in Zasavica in 1813.
Special reservation of nature of Zasavica was formed in 1997 and placed under the state protection as the category I natural treasure of exquisite value. It includes the bog and surrounding terrains, with a total area of 18.25 square kilometers. Of that, 6.75 square kilometres (2.61 sq mi) or 37% is placed under the level I of protection and the rest is in levels II and III. The majority of the protected area covers the water surfaces of the rivers and canals Zasavica, Jovac, Prekopac and Batar. Zasavica has a priority nomination to become a Ramsar site. It is proclaimed an Important Bird Area and since 2001 it is a member of the Europark Federation, federation of the national parks od Europe.
There are over 600 species of plants are recorded in the reservation. Several of them are endangered natural rarities and listed in the Serbia's Red Book of Endangered Species: European white water-lily, yellow waterlily, water soldier, fringed water-lily, marsh nettle, sweet flag, aquatic bladderwort, triangular club-rush, Common Mare's Tail, water violet, greater spearwort and the endemic Pannonian plain species of Pannonian cornflower. In the Valjevac section of Zasavica a rare and endangered marshland bio-community Acoro-Glyceretum maximae is found.
150 species of Fungi has been widely distributed in the entire reservation, in every eco-system (ground, trees, logs, meadows, pastures, etc.). Many are edible, including the rare species of morel. Poisonous mushrooms are rare and few, including panther cap, death cap and yellow-staining mushroom.
Though dozens of species of trees are found, forests, which make 16.74 % of the reservation, are mainly made of narrow-leafed ash and to the lesser extent of white poplar, willow or black alder. Alluvial slopes are inhabited by Pedunculate Oak, European hornbeam, linden and European Turkey oak. Since 1962 a 1.1 square kilometres (270 acres) plantations of willow and hybride poplars were planted. White orchid also lives in Zasavica.
Phytoplankton is represented with 234 species and zooplankton with 220. Representatives of the first group are the Batrachospermnum algae, fresh water sponge (Spongilla lacustris) and fresh water jellyfish (Craspedacustra sowerbii). Out of the second group, 21 taxa are new and recently discovered in Serbia.
250 species of insects live in Zasavica and 15 of them are protected. There are several rare species of longhorn beetle (out of 35 living in Zasavica) and endemic Balkan species including three recently discovered in Serbia: Syrian longhorn beetle (Arhopalus syriacus), Morimus asper and Agapanthia lais. Species of Cerambyx cerdo and Morimus funereus are protected. Endemic and rare cricket Zeuneriana amplipennis, living only in Serbia, is also found.
In Zasavica live 23 species of fish, categorised in 8 families and 20 genera. The most common are members of the carp family. Of those, 20 species ar autochthonous and three are imported (two from North America, one from China), though even the common carp had been introduced by Romans. Seven species are protected: Umbra krameri, Rhodeus sericeus amarus, loach (Misgumus fossilis), Cobitis tenia, etc. Six species are classified as endangered, five as vulnerable and six as rare. As part of the "Return of the autochthonous species of fish" project, wels catfish has been reintroduced into Zasavica.
Zasavica hosts 27 species of reptiles and amphibians, of which all 12 amphibian and 4 reptilian species are protected and some of them are on the preliminary list to be included into the Red Book. Six amphibian and seven reptilian species are also classified as the endangered species by the Bern Convention. Two endemic Balkan species live in Zasavica: Danube Crested Newt and eastern sub-species of the sand lizard, Lacerta agilis bosnica, which is European Protected Species.
There are 185  species of birds in the reservation, of which 120 are resident birds. Because of such large number of birds, including rare ones like night heron and spotted crake, Zasavica is included in the list of IBA, important bird areas. Since 1998, 20 artificial nesting platforms are placed throughout the reservation. Other species include common moorhen, little grebe, Eurasian coot, great reed warbler, little bittern, mallard, common quail, white stork, black stork, Eurasian bittern, white-tailed eagle, Western marsh harrier, common kestrel, mute swan, northern lapwing, etc.
So far, 45 species of mammals are found in Zasavica. It is ideal for the water-bound species like Eurasian otter or wildcat, which are protected all over Europe. Otters were not spotted for years though. Recent but unconfirmed sightings of otters recently prompted the ecology organisations from Sremska Mitrovica to announce an award for those who capture otter on camera. Fur animals also live in Zasavica, most notably muskrat. Eurasian Shrew, striped field mouse, fat dormouse and several species of bats are listed as rarities in Serbia.
Special residents of Zasavica
Umbra krameri or in Serbian mrguda ("frown fish") in Serbia lives only in Zasavica. It has been classified as an endangered species in the entire of Europe and placed under the strict protection by the Bern Convention. In Serbia it has been protected in 1993. In March 2008 the fish has been discovered in the village of Bački Monoštor, near town of Sombor, almost 150 kilometers north of Zasavica.
In 1998 the cattle of the Podolian breed was introduced in Zasavica. First animals arrived in the spring of 1998 from Mionica, in western Serbia. Pasture "Valjevac", near the small Goransko-ribolovačko lake was chosen as their home. The pasture has an area of 3 square kilometers and today numbers 50 cattle. Breeding of Podolian cattle is being part of the program for the preservation of the animal species, developed by the Serbian Ministry of agriculture.
Mangulica is the only surviving autochthonous Serbian breed of domesticated pig. Other two, Šiška and Šumadinka died out. A breed, also known as "woolen pig", due to its good qualities, is considered a "noble", but it almost died out in the 1980s. Its fat has up to 80% less cholesterol and triglycerides than a common, white pig. In 1998 Mangulica was introduced in Zasavica, but unlike Podolian cattle, they are left to roam free in the reservation, becoming feral since then. A cases of breeding with wild boar are known.
The main attraction in the reservation are the reintroduced beavers. Extinct in the early 1900s, four families with five members each, plus 11 single animals (31 in total) were reintroduced in 2004 with the help from the Bavarian Science Society. From Serbian side, project is conducted by the Biology Faculty of the Belgrade University. Each animal has a subdermal tracking microchip implant. Initial fears that the beavers will not adapt proved to be groundless as very soon first dam was spotted and the animals began to reproduce. A dam is 30 metres (33 yd) long and 1.8 feet (0.55 m) tall (of that, 0.8 metres (2.6 ft) above the water) and located at the Batar's mouth into Zasavica. In the late 2006 a dam in the canal Glušci, which flows into the Zasavica, was discovered and the beavers, though not the dams, are spotted in the river of Jadar some 35 kilometres (22 mi) to the south down the Drina. As the area surrounding the Zasavica is entirely agricultural, farmers don’t share the excitement of the biologists as they claim the beavers ruin their crops saying that was the original reason for their extinction a hundred years ago 
- (Serbian) Marković Jovan Đ (1990). Enciklopedijski geografski leksikon Jugoslavije. Sarajevo: Svjetlost. ISBN 86-01-02651-6
- (Serbian) Mangulica, dabar i lokvanji = Politika (in Serbian). 2008-04-30. p. 41.
- (Serbian) Zasavica site
- (Serbian) Mala enciklopedija Prosveta. Vol. II (I ed.). Belgrade: [[Prosveta (publisher)|]]. 1959. p. 562.
- (Serbian) Službeni glasnik Republike Srbije. 1993-07-09. pp. br. 50.
- (Serbian) "Mrguda pronađena u Bačkom Monoštoru". Retrieved 2008-05-27.
- (Serbian) "Dabrovi oglodali mnoga imanja". Retrieved 2008-05-27.