Ransko NNR is an extensive forest complex which covers an area of 695.4 ha at elevations of 540 – 673 metres above sea level approximately 1 km south of the town of Ždírec nad Doubravou in the kraj Vysočina – Bohemian-Moravian Highlands Region. The reserve lies in the parishes of Havlíčková Borová and Staré Ransko and was declared relatively recently in 1997. The subject of the protection is the extensive complex of varying forest ecosystems on the Ransko massif with autochthonous populations of forest trees and the occurrence of numerous protected and endangered plant and animal species.
The territory lies on the southern edge of the Henzlička passing into the Dářská brázda depression and a spur of the Přibyslavská pahorkatina hills. Long and predominantly south-facing slopes stretch from the frost-riven cliffs shaped by cryoplanation on the peak of Ranský Babylon hill down to the Doubrava river valley. Small rocky outcrops and redeposited boulders are found on some parts of the slopes and these pass into flattened terrain depressions which are waterlogged as a result of the strata-bound and talus springs which flow into left-side tributaries of the Doubrava river. The Ransko massif is built of basic plutonic rocks – predominantly olivine and hornblende-pyroxene gabbros which are rare in this area and in places they display considerable sulphidic mineralization. This basement is covered by clay-loam to clay-dominated weathering products of elluvial origin which are up to several metres thick in places. A wide range of soil types are found here, from shallow ochric soils with weak humic horizons on the rocky outcrops through typical cambisol to plano-gleyic luvisols and muddy gleysols in waterlogged depressions.
The rich mosaic of location conditions in the extensive NNR is reflected in the wide range of preserved natural communities which are found here. On the peridotite-rocky outcrops of Mt. Ranský Babylon communities of serpentinite pinewoods of the Dicrano-Pinion alliance are found with Scots pine (Pinus sylvestris) and the unusual presence of the serpentine spleenwort (Asplenium cuneifolium) and the endemic Bohemian subspecies of field scabious (Knautia arvensis subsp. serpentinicola). Fragments of communities which are close to beechwoods with wood-rush of the Luzulo-Fagion alliance can be found on the poor stony soils on the ridges. Lower down the slopes on the richer gabbro basement these pass into herb-rich beechwoods of the Dentario enneaphylli-Fagetum and Festuco altissimae-Fagetum associations. In these stands the main edaphic indicator is beech (Fagus sylvatica). Fragments of fir stands of the Luzulo pilosae-Abietum association have been preserved in a few wetter localities where the bedstraw Galium rotundifolium can also be found. Silver fir (Abies alba) now only occurs in the tree mix but not as a dominant species. Predominantly Norway spruce (Picea abies) stands are found on waterlogged or gleysoils in poorer areas. Exceptionally large areas of stream and spring ash-alder stands of the Carici remotae-Fraxinetum association are found in richer, waterlogged areas. In these stands we can find alder (Alnus glutinosa), ash (Fraxinus excelsior) and the largest population of F4002 spring snowflake (Leucojum vernum) in the Bohemian-Moravian Highlands Region. Other herbs which can be found in the Ransko forests are the trefoil cress (Cardamine trifolia), variegated monkshood (Aconitum variegatum), martagon lily (Lilium martagon), mezereon (Daphne mezereum), oxlip (Primula elatior), nine-leaved toothwort (Dentaria enneaphyllos), common centaury (Centaurium erythraea), Alpine enchanter’s nightshade (Circaea alpina), upland enchanter’s night shade (Circaea × intermedia), pendulous sedge (Carex pendula), common spotted orchid (Dactylorhiza fuchsii), greater butterfly orchid (Platanthera chlorantha), trailing St. John’s wort (Hypericum humifusum), the stitchwort Stellaria longifolia, Alpine rose (Rosa pendulina), ramsons (Allium ursinum), lesser periwinkle (Vinca minor) and the coralroot orchid (Corallorhiza trifida), which was first recorded here in 1990.
Numerous ground beetle species inhabit the reserve, including Carabus auronitens, Carabus coriaceus, Carabus cancellatus, Carabus convexus, Carabu linnei, Abax carinatus and the spiders Agyneta cauta, Gonatium corallipes, Maro minutus, Notioscopus sarcinatus, Walckenaeria kochi and others. Wet and waterlogged localities are the biotope of amphibians and stable populations of Alpine newt (Triturus alpestris), common frog (Rana temporaria), common toad (Bufo bufo) and common tree-frog (Hyla arborea) are all found here. The most common reptile in the reserve is the viviparous lizard (Zootoca vivipara), while the slowworm (Anguis fragilis) and smaller numbers of adder (Vipera berus) can also be found here. Birds which nest in Ransko NNR are many but a few examples are goshawk (Accipiter gentilis), woodcock (Scolopax rusticola), pygmy owl (Glaucidium passerinum), Tengmalm’s owl (Aegolius funereus), black woodpecker (Dryocopus martius), stock dove (Columba oenas), nutcracker (Nucifraga caryocatactes), red-breasted flycatcher (Ficedula parva), dunnock (Prunella modularis), raven (Corvus corax) and occasionally the black stork (Ciconia nigra). Mammals include common shrew (Sorex araneus), pygmy shrew (Sorex minutus), southern water shrew (Neomys anomalus), field vole (Microtus agrestis), stoat (Mustela erminea), pine marten (Martes martes) and badger (Meles meles). A permanent population of red deer (Cervus elaphus) lives in the Ransko forests and occasionally a lynx (Lynx lynx) wanders into the area.
A varied complex of forest stands with the representation of autochthonous tree populations has formed at Ransko and in connection with trophic and hydratic conditions in each part of the territory. In places the non-indigenous European larch (Larix decidua) had been planted here. The unstable spruce stands on waterlogged localities are often uprooted. The previous overpopulation of red deer caused considerable damages to the forests by grazing, gnowing and bark stipping. In summit areas the exposed forest stands are also affected by air pollution, wind damage and hoar frosts. The forest stands in the reserve are legally classified as special purpose forests and the intensity of management is graded according to their composition and physical condition. The most valuable forest stands with a natural composition – the serpentinite pinewoods, fir-beech stands and ash-alder stands are left to natural processes. Only minor management measures are carried out in the predominant stands with a near-natural composition. In the stands around the margins of the reserve which differ considerably from the natural composition a gradual renewal must be carried out, with the aim of creating a mixed-age forest with a natural tree species composition.
The territory was influenced in the past by logging to supply the Ransko ironworks, and later by the planting of spruce monocultures, drainage of wet areas and also the use of heavy forestry machinery and intensive forestry methods. Finds of effusive rocks containing sulphide ores led to test drillings being made on the territory and a seam of nickel-copper-cobalt ore was found here. Deep mining of zinc-copper ore was carried out near the reserve but came to an end in 1990. Such environmentally damaging activities as mineral extraction, modifying the water regime, application of chemicals and use of heavy machinery are all forbidden here now. Forestry, hunting and other activities in the NNR are also regulated with the aim of maintaining and improving the natural condition of this unique mosaic of forest ecosystems on the Ransko massif, whilst maintaining all of the forests functions and protecting the animal and plant gene fund on the territory of Ransko NNR.