County: Tauragė Municipality: Jurbarkas distr.; Tauragė distr. Latitude Longitude 59º 09' N 22º 27' E

Physical - geographical features

Viešvilė strict nature reserve is located in the Karšuva wood in Karšuva lowland, which has formed during retraction of last glacier. In those times it was flooded by shallow post-glacial basin and covered with the sandy deposits of ancient delta of the Nemunas river. Later on, the lower eastern area transformed into mire complex and in the higher and drier western part the wind drifted sand into dunes. Nowadays Viešvilė strict nature reserve is established to protect the mire complex and Kaskalnis geomorphologic reserve - to protect the highest continental dunes in Lithuania. Mires occupy almost 60% of the Viešvile strict nature reserve territory. Artoji, otherwise called Didžioji plyne (i.e. Great plain) is a 1072 ha mire massif of complex configuration where raised-bog covers the largest area, but transitional mire, as well as fen complexes, still occupy significant plots. Medium thickness of the Artoji peat layer is 3,6 m., and the thickest reaches up to 9,8 m. In some places under the peat there lies the lake mud layer of 4 m. In the eastern part of the reserve there is the Glitis mire (455 ha) with the largest (19 ha) in this reserve Glitis Lake. Two more small raised bogs of 43 and 57 ha lie in the south-western part of the strict nature reserve near the Sakaline Village.

The main "core" of Viešvilė strict nature reserve is the small Viešvilė River (length - 21,4 km). It flows through the reserve for 15 km. This is one of the most natural rivers, getting its waters from the forested areas. The source of the river is the small Buveinis Lake (6 ha) stretching in the north of Artoji bog. In the upper reaches the river quietly winds for 6,5 km only through the mires. In the middle reaches it is filled up from rich springs and through the small valley crosses the sandy plain studded with dunes. However right outside the strict nature reserve boundary there are built two dams, which stop the natural flow of the river and block up the waterway for the fish.

Biological diversity

There are found various types of mires in Viešvilė reserve. One can see open or covered with thin or dense forest raised-bogs, transitional mires and fens. The prevailing types of forest in the mires are: thin pinewood with marsh tea shrubbery (in the raised bog) and alder, birch groves (in the fens). Mires have never been drained, thus they preserved primary naturalness and many rare plant species are found there. Most of those species, such as: marsh saxifrage (Saxifraga hirculus), fen orchid (Liparis loeselii), green coralroot (Corallorhiza trifida) concentrate in the open and semi open mires of intermediate type. Many rare species of mushrooms, lichen and moss grow in the old woods of alder and spruce stretching along the mire. Many of them are rare all over the Europe and few of them are found only in this place in Lithuania.

A distinguishing feature of the Viešvilė strict nature reserve is its great variety of habitats. Even in a short distance, there can be observed a wide spectrum of mires, woods, meadows and water bodies.

The strict nature reserve is abundant of insects. For old woods are characteristic: stag beetle (Ceruchus chrysomelinus), chafer (Gnorimus variabilis).

Viešvilė river is populated by brown trout (Salmo truta fario), brook lamprey (Lampetra planeri), abundant of bullhead (Cottus gobio).

Forests provide safe shelter for timid hollow birds grey-head woodpecker (Picus canus), white backed woodpecker (Dendrocopos leukotos) and predator birds, like: lesser spotted eagle (Aquila pamarina), tengmalm's owl (Aegolius funereus). Crane (Grus grus) is abundant in the mires, very rare golden plovers (Pluvialis apricaria) constantly breed there. In the autumn and spring time abundant in fish mire lakes provide good resting and feeding ground for numerous flocks of migratory birds.

Old gloomy forests hide large beasts of prey - wolf (Canis lupus) and lynx (Lynx lynx). Numerous beavers (Castor fiber) and otters (Lutra lutra) inhabit the Viešvilė River.