Velká Pleš National Nature Reserve

The Velká Pleš NNR was declared in 1984 on an area of 95.7 ha and lies in the west of the Středočeský kraj - Central Bohemian Region. The national nature reserve predominantly covers the slopes and summit areas of two distinctive hills above the valley of the Berounka  river, which were named Velká Pleš and Malá Pleš (Large and Small Bald Hills) thanks to their forest-free summits withrocky steppe and forest steppe areas. The slopes fall steeply into the river channel at an elevation of 244 metres above sea level, whereas the summit of Velká Pleš hill lies at nearly 500 metres above sea level. The main subject of the protection is the natural forest-free areas on the summits, known as „pleše “ or “bald hills” with a mosaic of communities of rocky crevices, primitive soils, xerothermal grasslands and thermophilous fringes, which pass into open oak stands with wild service tree and dwarf oak stands with wood-rush. Talus and ravine forests, oak-hornbeam stands and lime-beech stands with firs grow on the slopes. The pleš or bald hilltops are the localities where many relict plant and animal species, especially invertebrates occur.
 
The NNR covers a part of the Vlastecká vrchovina Hill Country with isolated rocks and frost-riven cliffs as well as the left-bank slope of the Berounka river. The geological basement is predominantly built of Upper Cambrian volcanics of the Křivoklátsko – Rokycany Belt – predominantly andesite, with rhyolites, dacites and tuffs in the southern section. The most northerly section is built on greywackes and shales of Neoproterozoic age. The Quaternary covering of loamy and stony-loamy slope deposits is especially shallow in the north-western part of the reserve and the soils are mostly of the Ranker type.
 
The vegetation has developed under the combined influences of the river and summit phenomena with a notable inversion of the normal altitudinal levels. Talus and ravine forests and beechwoods with the occurrence of submontane and montane species have developed on the slopes and at the foot of the hills, whereas on the hilltops we can find open xerothermal oak stands and grass-herb communities with the extrazonal occurrence of species which aremore abundant in warmer parts of central and northern Bohemia. However, these areas are negatively influenced by the large population of non-native mouflon and the presence of non-native “weeds”, such as shepherd’s purse (Capsella bursa-pastoris) and others. Even here we can easily distinguish the communities on the rocky outcrops with the rare fern Woodsia ilvensis and the communities on the shallow skeletal soils with sheep’s fescue (Festuca ovina), perennial knawel (Scleranthus perennis), the hawkweed Hieracium pilosella and others. Heather (Calluna vulgaris) and wavy hair-grass (Avenella flexuosa) advance to cover the nutrient-poor areas. On the outcrops which are richer in minerals we can find communities with the fescue Festuca pallens, the sandy cinquefoil Potentilla arenaria and other species which indicate the transition to thermophilous grassland communities with the fescue Festuca valesiaca, and tor-grass (Brachypodium pinnatum), accompanied by the St.Bernard’s lily Anthericum ramosum, the St.Bernard’s lily Anthericum liliago and the spiked speedwell (Pseudolysimachion spicatum). The dominant woody species of these biotopes is the low bush of wild cotoneaster (Cotoneaster integerrimus). The deeper soils play host to forest fringe communities with bloody cranesbill (Geranium sanguineum) and mountain zigzag clover (Trifolium alpestre). In these positions we can find permanent tree species, especially hardy oaks which form open of oak stands with wild service tree (Sorbo torminalis-Quercetum) and dwarf oak stands with wood-rush (Luzulo albidae-Quercetum) on poorer soils. On the slopes above the Berounka river talus and ravine forests (Aceri-Carpinetum) have developed, which pass into lime-beech woods (Tilio cordatae-Fagetum), where the herb layer includes nine-leaved toothwort (Dentaria enneaphyllos) and coralroot (Dentaria bulbifera). The warmer slopes are covered with oak-hornbeam stands (Melampyro nemorosi-Carpinetum). Around 340 species of vascular plants grow in the reserve. Rare fungi species can also be found here, including the wood-rotting fungus Vararia cremeoavellanea.
 
Velká Pleš NNR, and especially the bald hilltops – “pleš” are important localities for thermophyte invertebrate species. Two relict weevil species – Apion oblivium and A.hoffmanni have beenrecorded on the large thyme (Thymus pulegioides). The rocky steppe and forest steppe growths are inhabited by the relict weevil Coenorhinus interpunctatus, while the occurrence of the significant snout beetle Bagous diglyptus is bound to the meadow saxifrage (Saxifraga granulata). The weevil Trachyphloeus angustisetulus is an example of the wingless insects (Apterigota) which lives here, while Asiorestia nigritula represents the leaf beetles. The jewel beetle Acmaeodera degener only lives at two localities in Bohemia – Velká Pleš NNR and the nearby Týřov NNR. Significant populations of rare thermophyte spiders also live atVelká Pleš, including several species of ground spiders, such as Gnaphosa lucifuga, the purse web spider Atypus affinis , and large numbers of the eye-catching ladybird spider Eresus sandaliatus, which can be seen on sunny days in June.

In the talus and ravine forests we can find cryophilous spider species, suchas the dwarf spider Gongylidium edentatum, and the daddy longlegs Platybunus bucephalus and Trogulus nepaeformis. Here we can also find significant species of (mostly) montane beetles, including  the ground beetles Pterostichus burmeisteri and Carabus irregularis, the phytophagous leaf beetle Chrysolina rufa staphylaeoides, the fungus weevil Dissoleucas niveirostris from the Anthribidae, and others such as the weevil Phloeophagus thomsoni (which lives in old wood) and the weevil Acalles hypocrita, which is a species indicating the continuity of the forest cover.

Atotal of 65 butterfly species have been recorded in theNNR, of which 15 are classified as rare in the Czech Republic, including the lasiocampyd moth Phyllodesma tremulifolia or the geometrids Ecliptopera capitata, Petrophora chlorosata and Idaea deversaria. Commonly seen species also include the Jersey tiger moth (Euplagia=Callimorpha quadripuctaria) and the nine-spotted Syntomis phegea. Dice snakes (Natrix tessellata) and the marsh frogs (Rana ridibunda) live by the river, while fire salamanders (Salamandra salamandra) lives throughout the reserve. The rocky steppe and steppe grasslands are the biotopes of the smooth snake (Coronella austriaca). Birds which are common here include the small songbirds (tits and flycatchers) as well as those which are bound to hollow trees such as the stock dove (Columba oenas) and black woodpecker (Dryocopus martius) and also the woodcock (Scolopax rusticola). Small mammals in the reserve include the harvest mouse (Micromys minutus).
 
The long-term problem in the reserve is the high concentration of game animals, especially of mouflon, which prevent the natural rejuvenation of the vegetation communities. Therefore it is necessary to support targeted renewal, including planting new firs and cutting back the expansively-spreading ash stands. Velká Pleš NNR is not open to the public and no marked tourist trails lead to it.