The Zasavica ( sr-Cyrl, Засавица) is a

bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and musk ...

in the region of

Mačva Mačva ( sr-Cyrl, Мачва, ; ) is a geographical and historical region in the northwest of Central Serbia, on a fertile plain between the Sava (river), Sava and Drina rivers. The chief town is Šabac. The modern Mačva District of Serbia is nam ...

, west central

Serbia , image_flag = Flag of Serbia.svg , national_motto = , image_coat = Coat of arms of Serbia.svg , national_anthem = () , image_map = , map_caption = Location of Serbia (gree ...

. It is a major

wildlife refuge A nature reserve (also known as a wildlife refuge, wildlife sanctuary, biosphere reserve or bioreserve, natural or nature preserve, or nature conservation area) is a protected area of importance for flora, fauna, funga, or features of geolog ...

and one of the last authentically preserved

wetlands A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...

in Serbia. In the 2000s it became a popular attraction with the successful

reintroduction Species reintroduction is the deliberate release of a species into the wild, from captivity or other areas where the organism is capable of survival. The goal of species reintroduction is to establish a healthy, genetically diverse, self-sustain ...

beavers Beavers (genus ''Castor'') are large, semiaquatic rodents of the Northern Hemisphere. There are two existing species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers are the second-large ...

, which had become extinct on the same land areas 100 years before.

Location

Zasavica is located several kilometers across the

Sava The Sava, is a river in Central Europe, Central and Southeast Europe, a right-bank and the longest tributary of the Danube. From its source in Slovenia it flows through Croatia and along its border with Bosnia and Herzegovina, and finally reac ...

River from the town of

Sremska Mitrovica Sremska Mitrovica (; sr-Cyrl, Сремска Митровица, ) is a List of cities in Serbia, city in Serbia. It is situated on the left bank of the Sava, Sava river. , the city has a total population of 36,764 inhabitants, while its adminis ...

. The entire Zasavica system is located in the Mačva region and is administratively divided between the province of

Vojvodina Vojvodina ( ; sr-Cyrl, Војводина, ), officially the Autonomous Province of Vojvodina, is an Autonomous administrative division, autonomous province that occupies the northernmost part of Serbia, located in Central Europe. It lies withi ...

(northern part; municipality of Sremska Mitrovica) and

Central Serbia Central Serbia (), also referred to as Serbia proper (), is the region of Serbia lying outside the autonomous province of Vojvodina to the north and the disputed Kosovo region to the south. Central Serbia is a term of convenience, not an administ ...

(southern part; municipality of

Bogatić Bogatić ( sr-cyr, Богатић, ) is a town and municipality located in the Mačva District of western Serbia. As of the 2022 census, it has 24,522 residents. Geography Bogatić is located in the western part of Serbia. The nearest large ...

). It roughly extends between the settlements of Crna Bara, Banovo Polje, Ravnje,

Zasavica I Zasavica I (), also known as Zasavica () or Gornja Zasavica (), is a village in the Sremska Mitrovica municipality, in Serbian province of Vojvodina. The village has a Serb ethnic majority and its population numbering 772 people (2011 census). Ge ...

Zasavica II Zasavica II ( sr-Cyrl, Засавица II), also known as Donja Zasavica (), is a village in the Sremska Mitrovica municipality, in the Vojvodina province of Serbia. The village has a Serb ethnic majority and its population numbering 608 people ...

, Salaš Noćajski, Noćaj and Mačvanska Mitrovica.

Geography

The Zasavica bog is a marshy

lowland Upland and lowland are conditional descriptions of a plain based on elevation above sea level. In studies of the ecology of freshwater rivers, habitats are classified as upland or lowland. Definitions Upland and lowland are portions of a ...

in the

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

of the Sava River. It is a typical elongated

oxbow __NOTOC__ An oxbow is a U-shaped metal pole (or larger wooden frame) that fits the underside and the sides of the neck of an ox or wikt:bullock, bullock. A bow pin holds it in place. The term "oxbow" is widely used to refer to a U-shaped meand ...

(in Serbian: ''mrtvaja'', dead ater. The fossilized, parallel bed of the Sava is so elongated that it actually stretches almost to the

Drina The Drina ( sr-Cyrl, Дрина, ) is a long river in the Balkans, which forms a large portion of the border between Bosnia and Herzegovina and Serbia. It is the longest tributary of the Sava River and the longest karst river in the Dinaric Al ...

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 to almost . The marsh, consisting of several connected bogs, covers an area of . During normal water levels, the bog is deep on average, but it can get up to deep. The marshland's altitude varies from . The entire

biotype {{Short pages monitor