Reserve "Vratsa Karst" was declared in August 1983 and covers an area of 1467.6 hectares. According to the categorization of the International Union for Conservation of Nature (IUCN) reserve relates to Category I - strict reserve. Covers the northern, mainly rocky slopes of the Vratsa Mountain near Bazovski and Stresherski shares. Situated between the end of the quarry near the village Pavolche cave Zmeyuva hole at the foot of Bivolarsky and Karnov peak in Vratsa Mountain. Divided almost symmetrically from Leva River into two parts. From quarry to Vrattzata extends Bazovski share of reserves, and the second - Stresherski extends from Vrattzata to Karnov peak. The altitude ranges from 250 to 850 m.
The protected area was established to preserve scenic and distinctive local karst terrain with various geomorphological formations, unique cave fauna sub-Mediterranean flora and many relict species. The appearance of forest plantations is determined by oriental hornbeam, common hornbeam, beech, field maple, pine and others.
The distinctive geological and morphological structure of part of the reserve - the availability of space occupied by sheer limestone and siliceous rocks and scree, determined and relatively widespread chasmophytic (skalolyubivi) plant associations and groups. This vegetation is xerophytic, heli-Ofili and prefers limestone terrain. It includes a number of species are "rare" and "endangered" - Neychev broom ( Chamaecytisus neichefii (Urum.) Rothm .), scaly heather ( Asplenium lepidum preSl .), maslinopodobno laurel ( Daphne oleoides L .), laurel laurel ( Daphne laureola L .), alpine campion ( Silene Alpina ) and others.
In general geomorphological characteristics of the area, and separate plant ecosystems are a prerequisite for the development of rich and diverse fauna. The area is rich in karst terrain, rock crevices and caves that favor the development of specific petrophyllous fauna. Forest ecosystems in the region are based on the existence of species entirely dependent on these habitats. The species composition of amphibians and reptiles occurring in the reserve, not distinct from the total number of species identified for Vratsa Mountain as a whole. The reserve can be seen the following types of amphibians, green toad ( Bufo viridis ), forest leggy frog ( Rana dalmatina ), Tree Frog ( Hyla arborea ), yellow-bellied toad ( Bombina variegata ), salamander ( Salamandra Salamandra ), great crested newt ( Triturus Crista-TUS ) and reptiles - Coronella austiaca ( Coronella austriaca ), viper ( Vipera amodytes ) and others.
The species richness of the representatives of the class Birds is significant as typical of the reserve are the Peregrine falcon ( Falco peregrinus ), Egyptian vulture ( Neophron perc- nopterus ), golden eagle ( Aquila chrysaetos ), black stork ( Ciconia nigra ), Common Kestrel ( Falco tinnunculus ), rock swallow ( Ptyonoprogne rupestris ), Pallid swift ( Apus melba ) and others.
Great interest in terms of mammals are found in Reserve Bats: Greater horseshoe bat ( Rhinolophus ferrumequinum ), lesser horseshoe ( Rhinolophus hipposideros ), Mediterranean horseshoe bat ( Rhinolophus blasii ) and others.