The Vůznice NNR was declared in 1984 on an area of 231.22 ha and lies to the north of the town of Nižbor in the Středočeský kraj- Central Bohemian Region. The protected area includes the deep valley of the Vůznice stream on the left bank of the Berounka river within an extensive complex of forest types and communities which are typical for a hilly country. The reserve lies at elevations between 250 and 410 metres above sea level.
The geological basement is built of rocks of Neoproterozoic age - fine, medium and coarse-grained greywackes and shales with bodies of lydite. A dyke of granite porphyry is the only representative of Paleozoic rocks found here. Quaternary colluvia lie on the slopes and at the foot of them. Numerous frost-riven cliffs, rocky outcrops and steep slopes can be found above the deeply-incised stream valley. Talus accumulations lie at the foot of the rocky outcrops. The stream alluvial plain is partially modified as a fish-breeding station with water supply channels and a water supply reservoir were built here but now they are practically abandoned. The soils consist of a mosaic of transitional types, oligotrophic and mesotrophic Cambisols, Rankers to Lithosols, with Gleysols in wetter areas.
Vůznice NNR includes a complete network of forest ecosystems which are typical for a central European hill country. Alder stands with chickweeds (Stellario-Alnetum glutinosae) and with perennial honesty (Lunaria rediviva) and ash stands (Pruno-Fraxinetum) grow in the valley, passing into species-rich oak-hornbeam stands (Melampyro nemorosi-Carpinetum) on the gentler slopes which conceal a carpet of fumitories in April and a range of thermophilous species including greater stitchwort (Stellaria holostea), hepatica (Hepatica nobilis) and Isopyrum thalictroides. On the steeper slopes the forest stands pass into hornbeam-maple stands (Aceri-Carpinetum) which stabilize the mobile scree. Subxerophilous oakwoods with cinquefoils (Potentillo albae-Quercetum) grow on the plateaux and the gentler slopes and the rocky outcrops are covered with oak stands with catchflies (Viscario-Quercetum association). Larger areas on the dry plateaux and gentler slopes are also covered with oakwoods with wood-rush (Luzulo albidae-Quercetum). In the herb layer we can find wavy hair-grass (Avenella flexuosa), sheep’s fescue (Festuca ovina), the wood-rush Luzula luzuloides and others. The dwarf oak stands on the ridges are accompanied by sheepsbit scabious (Jasione montana) and the hawkweed Hieracium pilosella. Remnants of relict pine stands can be found above the Pinvička valley with xerophilous communities of the Hieracio pallidi-Pinetum association with basket of gold (Aurinia saxatilis). Small areas in the reserve are covered with cultural stands of Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). Spring area communities with alternate-leaved golden saxifrage (Cardamino-Chrysosplenietum alternifolii) are found at several places in the reserve. Botanical research has identified more than 450 vascular plant species in the reserve, of which 14 are specially protected. These species include spring snowflake (Leucojum vernum), wolfsbane (Aconitum vulparia), narrow-leaved helleborine (Cephalanthera ensifolia), dark-red helleborine (Epipactis purpurata), burning bush (Dictamnus albus) and perennial honesty (Lunaria rediviva). The bulbous corydalis Corydalis cavais commonly part of the herb layer in the humus-rich forest stands in springtime. Very rich fungi populations are found in the reserve, especially of fungi growing on wood, such as thescarlet elfcup (Sarcoscypha austriaca) with its eye-catching red cup-shaped fruit bodies.
The fauna in Vůznice NNR is also of very high species diversity thanks to the wide range of biotope types which are found here. Molluscs which live here include the “hairy snail” Perforatella bidentata and the door snail Bulgarica nitidosa which only lives in Český kras and Křivoklátsko PLAs in the whole world. Aquatic species recorded here include button ram’s-horn snail Anisus leucostoma and the shiny peaclam snail Pisidium nitidum. The spiders are represented by a number of thermophilous species, but we can also find many cryophilous species in the damp forests, such as the sheet-web spider Helophora insignis and the Cybaeid spider - Cybaeus angustiarum. Among many butterfly species it is possible to observe the poplar admiral (Limenitis populi), spotted fritillary (Melitaea didyma) or the Jersey tiger moth (Euplagia quadripunctaria). Until the 1950s the clouded apollo (Parnassius mnemosyne) lived at Vůznice, but it is now extinct in the area. Significant species are also represented among the phytophagous beetles, including the leaf beetle Chrysolina rufa staphylaeoides, the weevils Apion opeticum and Trachodes hispidus, and the continuity of these forests are shown by the presence of the weevils Acalles camelus and Acalles commutatus. From the species which are bound to rotting leaves and wood, small rove beetles from the Pselaphidae and ant-like stone beetles from the Scydmaenidae orders live here. Notable ground beetle species which have been recorded here are Trechus rubens and Dromius angustus.
Amphibians in the reserve include fire salamander (Salamandra salamandra), alpine newt (Triturus alpestris) and yellow-bellied toad (Bombina variegata). The smooth snake (Coronella austriaca) represents the reptiles. Large numbers of birds live in the reserve and include the black stork (Ciconia nigra), kingfisher (Alcedo atthis), grey heron (Ardea cinerea), green woodpecker (Picus viridis), grey woodpecker (Picus canus), flycatchers and many others. Fish which live in the Vůznice stream include the minnow (Phoxinus phoxinus), bullhead (Cottus gobio), brown trout (Salmo trutta) and non-native species which were left behind by the fish breeding station. Mammals are represented by the fat dormouse (Glis glis)and the whiskered bat Myotis alcathoe, which has recently been discovered for the Czech Republic in South Moravia and in Křivoklátsko.
The mission of nature protection activity in the reserve is to renew the natural composition and structure of the forest stands. The majority of the area is left to natural development. In recent decades the most effective natural regeneration has been with the hornbeams and ashes, while the natural regeneration of fir, maple, oak and beech is limited by the high deer populations in the reserve. In dry years there are regular infestations of geometrids, oak leaf roller moth (Tortrix viridana) and gypsy moth (Lymantria dispar) on the oaks, bark beetles on the spruces and root-boring pine beetles and weevils (Pissodes) on the pines. The valley meadows are being overgrown by opportunist and ruderal species and for this reason the most valuable localities must be cut regularly.
In historic times an important trading route passed through the Vůznice valley, which is illustrated by the Jenčov castle ruins at the northern edge of the reserve. Currently this is the only locality in the reserve which is accessible for the public, as a tourist trail leads to the ruins. The rest of the reserve is closed to the general public.