Velká niva National Nature Reserve

A forested peatbog 1 km east of the village of Lenora and 4.5 km west of the town of Volary.

Parish: Volary (Prachatice district – Jihočeský kraj – South Bohemian Region)
Area: 120.31 ha
Elevations: 748 – 775 metres above sea level
Declared: 1989

The subject of the protection is an extensive valley peatbog with stands of bog pines, surrounded by a ring of peaty pine stands and waterlogged spruces around the margins and with a large number of rare and protected peatbog plant and animal species.

The reserve lies on the floor of a smaller flat basin which is part of the Vltava river graben. The basement is of cordierite-biotite migmatites of the nebulite type, with medium-grained cordierite-biotite migmatites (anatexite) in places and passing into pearl gneisses (Moldanubicum). The slope positions are covered with colluvial and solifluctional sandy-loam and stony-loam deposits of predominantly Pleistocene age. The majority of the reserve is covered with fluvial sands and gravels left behind by abandoned meanders of the Vltava river and a large seam of raised bog peat of Holocene age. The soil cover is predominantly of typical organic (peat) soils but on the former river terraces on the margins of the reserve gleyic peaty soils and gleyic podzols can also be found.
Stands of bog pines (Pino rotundatae-Sphagnetum) are at the core of the reserve with bog pine (Pinus rotundata) and small numbers of downy birch (Betula pubescens). The forest stands around this central area are of peaty pines with bog whortleberries (Vaccinio uliginosi-Pinetum) with Scots pines and a mixture of silver birch (Betula pendula) and Norway spruce (Picea abies). Waterlogged spruce stands (Mastigobryo-Piceetum) with bazzania mosses are developed on the margins of the reserve and along small streams. The undergrowth in the bog pine and peaty pine stands includes typical peatbog species as well as bog rosemary (Andromeda polifolia), the cranberry Oxycoccus palustris, round-leaved sundew (Drosera rotundifolia) and common spotted orchid (Dactylorhiza fuchsii). The expansion of common reed (Phragmites australis) in the open bog pine stands is of interest.

The moss layer is dominated by species which are typical of communities of the Sphagnion medii alliance such as flat-topped bog moss (Sphagnum fallax), Magellanic bog moss (Sphagnum magellanicum) and the fork moss Dicranum affine. Under the waterlogged spruces which grow along the streams we can find the leopardsbane Doronicum austriacum, the mountain snowbell (Soldanella montana), interrupted clubmoss (Lycopodium annotinum), the stitchwort Stellaria longifolia and the rare lesser twayblade (Listera cordata).

A number of rare and disappearing fungi species grow here including Vibrissea truncorum on wood in the clear streams. The bracket fungus Phellinus laevigatus on the fallen trunks of dead birches, the shelf fungus Diplomitoporus flavescens on dead bog pine trunks as well as several saprotrophic, gilled fungi such as conifer roundhead (Stropharia hornemannii), the twiglet Tubaria confragosa, and the scalycap Pholiota subochracea or mycorrhizal species such as the brittlegills Russula consobrina and Russsula helodes and the deadly webcap (Cortinarius speciosissimus).
The invertebrate fauna in the NNR is represented by many typical species for peatbogs with bog pines, including some rarer or relict species. Notable invertebrates include the wolf spider Pardosa sphagnicola, the light knot grass moth Acronicta menyanthidis, the tortricid moth Epinotia gimmerthaliana and the geometrid Arichanna melanaria. Research into several phytophagous beetle orders has recorded the presence of the leaf beetles Luperus viridipennis, Longitarsus suturellus, Asiorestia femorata and Minota obesa and the weevils Pselaphorhynchites nanus, Otiorhynchus fuscipes and Notaris acridulus. The bark beetle Pityogenes conjunctus lives on the bog pines. A large number of nests of the ant Formica lugubris are also characteristic for the area.

Common forest bird species inhabit the reserve although the bird fauna is not rich and is of low species diversity. The regular presence of the hazel hen (Bonasa bonasia) and capercaillie (Tetrao urogallus) has been recorded here.
A part of the reserve was probably deforested in the second half of the 18th century and part was also drained by open channels which were renewed in the first half of the 20th century and maintained around the reserve until the end of the last century. Luckily these channels had a minimal drainage effect due to their low gradients but resulted in part of the bog pine stands being lost. However, the most valuable bog pine stands remained unaffected by drainage. The predominant tree species in the reserve area are bog pines with some trees reaching 15 – 20 metres in height but the majority are only around 5 metres high, while many trees are of procumbent form similar to peatbog pine scrub. The stands on the margins of the reserve are predominantly of Scots pines, which form a specific ecotype with tall cylindrical trunks (up to 30 metres) and with a narrow crown which resists competition from the spruces and the loads of wet snow. The reserve is not used for commercial forestry purposes, with the exception of the fallen spruces which were removed in 1997 after a bark beetle infestation.
The reserve is not commercially used. Public access to the reserve is not allowed as there are no suitable access paths.