Poloniny National Park (hereafter NP) and Východné Karpaty (East Carpathian Biosphere Reserve (hereafter BR) is situated in eastern-most Slovakia at the junction of the political boundaries of three European countries – Poland, Slovakia and Ukraine. In terms of geography and ecology, its territory corresponds wiht the important transition between the West Carpathian and East Carpathian geosystems and ecosystems, which is clearly reflected in the distribution of plant and animal populations and in the overlapping biotic communities. The transboundary interconnection of the Carpathian scenery found adequate expression in the establishment of large-scale conservation areas in all countries concerned, and later led to unification of these areas under the umbrella of UNESCOś biosphere reserves.
The bedrock of the NP and BR is formed almost entirely by flysh rocks of the Dukla Unit of Upper Cretaceous and Palaeocene age. Sandstones and claystones of various grain sizes and colors create a complex of strata more than 5.000 m deep. Much of the flysh bedrock is covered by Quaternary sediments. Most of the slopes of the area are covered by deluvial clay and clay-sandy loams and talus deposits. Their depth varies, with the gratest accumulation in the foothills. The valley bottoms of larger streams are covered by fluvial sandy loams and gravels. Where brooks meet main valleys, there are alluvial cones of proluvial deposits. In addition to these recent river sediments, there are also old river terraces in the region. A prominent example is the terrace at the confluence of the Ulička and Hlboký potok streams.
Although the flysh bedrocks differ in their resistance to longterm erosive-denudation processes, the region generally has a typical smooth flysh relief. The border ridge with Poland, mostly along the Bukovské Hills, dominates the landscape. Its altitude ranges between 797 m and 1.208 m along the boundaries between Poland, Ukraine and Slovakia. From the main west-east ridge, several smaller mountain ridges stretch southwards. Veľký Bukovec (1.012 m) is the highest of these. The variety of elevations and relief of the Bukovské Hills is emphasized by several more or less distinct ridges – such as Malý Bukovec (830 m), Príkry (952 m), Stinská (1.092 m), Kučalatá (917 m) – separated by valleys (Ruské, Runina, Nová Sedlica, Ruský Potok and Ulič). The lowest point of the NP and BR (200 m) is in the Ulič valey where the Ulička River flows out of Slovakia. The western part of the NP and BR is within the Laborecké Highlands (600 to 800 m). Their relief reflects their relatively late development and the resistance and structure of their bedrock.
Cambisols and luvisols on flysh sandstones and claystones are dominant in the NP and BR. Below 700 m they are base saturated, while at higher elevations they are unsaturated, loamy to clay-loamy. Brown and illimeric soils prevail on the agricultural land at lower altitudes. On a few sites, there are agriculturally unsuitable anaerobic waterlogged soils, predisposed to paludification. Most of these soils are acid to very acid. The mean value of pH decreases as altitude increases: from 5,2 to 4,9 between 250 and 500 m, down to 4,6 to 4,8 between 500 and 900 m, and still lower to 4,0 to 4,3 between 900 and 1000 m altitudes.
As the flysh bedrock weathers rapidly, the soils are endangered by erosion, particularly water erosion. The mean potential soils loss in the NP and BR is 32,7 m3/ha/yr. Landslides are common, particularly on slopes with clay bedrocks. They generally derived from the tendency of the weathering products of flysh bedrock to swell in wet conditions and subsequently slide.
The Polish border ridge is the European watershed between the Baltic and Black Seas. The Slovak section of the East Carpathian BR is drained by the fan-shaped Ulička, Ublianka, Zbojský potok, Cirocha and Udava basins, whose streams feed into the Bodrog river. The flysh bedrock is barely permeable, with little groundwater, so that spring discharges are low. The region has a very low accumulation capability despite abundant woodland. Short heavy showers and snowmelt often result in short periods of rapid runoff, with high flood discharges. In contrast, some streams dry out during drier periods. To minimize flood peaks and permit the use of surface waters, the Starina reservoir was constructed on the Cirocha river in 1987. It has a volume of 60 milions m3, and supplies drinking water to the large towns of East Slovakia.
The climate reflects the diversity of the relief. Three of the zones of the Slovakia climatic classification can be recognized. The warm zone, with a mean annual temperature of 7 to 8°C and a mean annual precipitation total of 800 mm, is found in the lowest parts of the Cirocha and Ublianka valleys. The moderately warm zone extends from 400 to 800 m, and has a mean annual temperature of 5 °C and a mean annual precipitation of 900 mm. The highest parts of the region are in the cold zone, with a mean annual temperature of 4 to 5 °C and a mean annual precipitation above 1000 mm.
Highest temperatures usually occur in July, when the maximum mean temperature ranges from 20,2 to 24,2 °C, depending on elevation. The coldest month is January, with minimum mean temperatures between –8,6 and –8,2 °C. Precipitation occurs throughout the year, and generally exceeds evaporation. Prevailing winds are northwest and southwest, following the direction of the mountain ridges. Winds blow along the valleys, and turn perpendicularly to ridges at saddles and passes.
The flora of the NP and BR is species-rich and biogeographically outstanding. The Bukovské Hills are a botanical frontier between the East and West Carpathians. This is reflected particularly by the occurrence of several East Carpathian endemics that reach their western limit in the NP and BR. Other species, such as flax (Linum trigynum) and traveller´s joy (Clematis vitalba) reach their northern limit here. Other notable species are medium nipplewort (Lapsana intermedia) and epipactis hacquetia (Hacquetia epipactis) from the nortwest. A detailed inventory of vascular plant has identified about 1.200 species in the Slovak section of the East Carpathian BR, many of which are endangered to some extent. The floristic richness of the reserve is further underlined by the know occurrence of 1.200 species of higher fungi (Ascomycetes and Basidiomycetes), more than 350 of musci (Bryophyta) and more than 200 of lichenes.
Forests are the most common type of vegetation. The dominance of beech (Fagus sylvatica) is reflected by the name of the Bukovské Hills: the Beech Hills. The diverstiy of forest types reflects differences in mesoclimatic conditions over the altitude range of more than 1.000 m in the reserve. Oak-beech forests are found on the lowest and warmest sites. In addition to the dominant species, namely oaks (Quercus robur, Q.petraea) and hornbeam (Carpinus betulus), these forests also include maples (Acer platanoides, A. campestre) and lime (Tillia platyphylla, T.cordata). The herb layer is dominated by hairy sedge (Carex pilosa), accompanied by species found at lower elevations, such as blue cowwheat (Melampyrum nemorosum), sweet woodruff (Galium odoratum), yellow archangel (Galeobdolon luteum) and the rare species, such as squil (Scilla kladnii), epipactis hacquetia (Hacquetia epipactis), Polish buttercup (Ranunculus cassubicus) and European scopolia (Scopolia carniolica).
Most of the region is covered by beech forests with characteristic species, such as coralworts (Dentaria bulbifera, D. glandulosa), purple rattlesnake root (Prenanthes purpurea), wood barley (Hordelymus europaeus), mountain fescue (Festuca drymeia) and wood speedwell (Veronica montana). Fir (Abies alba) occurs at higher and wetter locations. On sites with more humus and on talus, there are significant numbers of valuable deciduous trees, such as Scotch elm (Ulmus montana), ash (Fraxinus excelsior), sycamore (Acer pseudoplatanus) and lime (Tillia cordata). These habitats also have a different herb layer, dominated by perennial honesty (Lunaria rediviva), dog´s mercury (Mercurialis perennis) and, in the upper parts of depressions, by white butterbur (Petasites albus). Various ferns are also common.
Maple-beech forests occur at the highest elevations (between 1000 and 1190 m), just below the timberline. Near the summits, harsh conditions limit tree growth. The banks of mountain brooks are lined by various willows (e.g., Salix aurita, S.silesiaca), with butterburs (Petasites hybridus, P.kablikianus), pendulous sedge (Carex pendula) and shiny chervil (Anthriscus nitida) in the herb layer. Similar habitats are occupied by communities dominated by grey alder (Alnus incana). The rarest of these communities include huge ostrich fern (Matteucia struthiopteris) and heart-leaved oxeye (Telekia speciosa) with yellow flowers.
Deforested sites at lower and middle elevations are usually overgrown by secondary shrub formations dominated by blackthorn (Prunus spinosa) or hazel (Corylus avellana), accompanied by black-fruited honeysuckle (Lonicera nigra), southern dogwood (Swida australis), guelder rose (Viburnum opulus), spindle tree (Euonymus europaeus) and other shrubs. Typical herbs include greater stitchwort (Stellaria holostea), cock´s foot (Dactylis polygama), Polish buttercup (Ranunculus cassubicus), ground ivy (Glechoma hederacea) and, at middle elevations, purple hellebore (Helleborus purpurascens), a Carpathian endemic. Characteristic woody species are birches, without which one can hardly imagine the countryside of the East Carpathians Mts. From the viewpoint of silviculture and genetics, the occurrence of rare varieties and growth forms in birch species and birch hybrids is notable.
There is a great range of non-forest communities, each characteristic of a specific environment: flushes, soaks, mires, meadows, pastures and, in particular, polonina grasslands. Poloninas, mountain grasslands at timberline, are a species-rich and representative formation of the East Carpathian mountains. Most are secondary communities that arose due to cattle grazing on mountain ridges. They are distinguished by grasses and rushes-mat-grass (Nardus stricta), tufted hair-grass (Deschampsia caespitosa) and woodrush (Luzula luzuloides) – and also by willow gentian (Gentiana asclepiadea), Carpathian sorrel (Acetosa carpatica) and betony (Betonica officinalis). Poloninas also include species recognized as Dacian migro-element, such as bellflower (Campanula abietina), monkshood (Aconitum lasiocarpum) and compact pink (Dianthus compactus). Acid soils are occupied by heath communities dominated by cowberry (Vaccinium vitis-idaea). Since grazing ended on the poloninas, their species richness has decreased because of the expansion of smallreed (Calamagrostis arundinacea).
In recent years the polonina grasslands on the summits have undergone prominent floristic and faunistic changes due to lacking grass cutting and pasture of domestic animals. The low tussocks of mat-grass and associated forbs disappear under the invasion of the before mentioned Calamagrostis arundinacea whose large tussocks outcompete even the small shrublets of cowberry and billberry. Generally, the flower-rich polonina grasslands lose their human-induced biodiversity and thus create a problem for future management of the NP and BR.
Meadows and pastures of low and middle elevations are characterized by two subdominant species: sweet vernal-grass (Anthoxanthum odoratum) and common bent-grass (Agrostis tenuis). These are quite species-rich communities which also include mountain St.John´s wort (Hypericum maculatum), lesser stitchwort (Stellaria graminea), bellflower (Campanula patula), brown-headed knapweed (Jacea vulgaris), Siberian marguerite (Leucanthemum ircutianum), meadow buttercup (Ranunculus acris), fragrant orchid (Gymnadenia conpsea) and other orchids (Orchis ustulata, O. coriophora, O. morio). The floristic composition of wet mesic to eutrophic meadows is different. These often include marsh marigold (Caltha palustris), rushes (Juncus effusus, J. conglomeratus), meadow-sweet (Filipendula ulmaria) and tufted hair-grass (Deschampsia caespitosa).
Many biotopes of sloping fens and flushes are characterized by the occurrence of broad-leaved cotton-grass (Eriophorum latifolium) and sedges (Carex flava, C. panicea) with various rare species such as marsh helleborine (Epipactis palustris), marsh orchid (Dactylorhiza majalis), jersey orchid (Orchid laxiflora), meadow orchid (Dactylorhiza incarnata) and spotted orchid (Dactylorhiza maculata).
Sprins have a specific flora, with large bitter-cress (Cardamine amara), alternate-leaved golden saxifrage (Chrysosplenium alternifolium), twin-flowered violet (Viola biflora), marsh marigold Caltha laeta, hairy chervil (Chaerophyllum hirsutum) and wood stitchwort (Stellaria nemorum).
The location of the BR at the junction of the East and West Carpathians is also mirrored by a unique range of animal species and communities. the well-preserved vegetation – beech forests, cut meadows, pastures, and poloninas – predetermines the natural diversity of biocenoses. So far, about 3.600 animal species have been found, including about 3.300 species of invertebrates.
Invertebrates include representatives of almost all principal systematic groups, among which the most numerous is the class of insects (Insecta) – about 3.000 species. Most of the invertebrates are found in specific biotopes in broad-leaved forests. Several species of earthworms (Lumbricidae) live in forest soils. One of the most conspicuous is Eisenia lucens, found in rotting logs and moss carpets in wet mountain forests. Communities of molluscs (Mollusca) are species-poor, lacking West Carpathian endemics as well as other species frequent in the Carpathians. The only characteristic East Carpathian species is the slug Trichia bielzi, found in valley groves with a luxuriant herb understorey. Beech-fir woods have a remarkable diversity of centipedes (Chilopoda), ispodos (Isopoda) and millipedes (Diplopoda), including Leptoiulus Baconyensis stuzicensis, a subspecies described from the Stužica primeval forest.
Broad-leaved forests have a multitude of beetles (Coleoptera), particularly from the families of ground and longicorn beetles (Carabidae, Cerambydae). One of the rares is a longicorn beetle (Strangalia thoracica) that lives only in rotting wood in primary beech forests in the East Carpathians. Among the most abundant is the longicorn beetle Rosalia alpina. Females of this species lay eggs in slots of freshly logged timber, and the larvae live in old beeches. Near the village of Nová Sedlica, entomologists have found several rare species of rover beetles (Staphylinidae), such as those living beneath dead beech leaves (Rugilus mixtus, Stenus ludyi and S. maculiger).
Many butterfly species (Lepidoptera) are found in the region. The beech saturnid (Aglia tau) is a typical species of beech forests. Other butterflies – notably Fabriciana aglaia, Papilio machaon and Parnassius mnemosyne – are particularly conspicuous in meadows. Interesting communities of invertebrates, including several endemics, are found in biotopes along rivers and brooks and around springs.
From 2-winged insects (Diptera) altogether 2.254 species are listed 437 species are indicated as new to the fauna of Slovakia. Nine of them have been desribed from the area as new species. A number of species were found reaching their distributional limits in the Bukovské Hills, including East Carpathian endemics, montana Alpine-Carpathian species, Eurosiberian geoelements, species of southern or southeastern origin, Boreo-alpine and/or Boreo-montane geoelements, etc.
The distribution of vertebrates depends on the degree of preservation and disturbance in particular ecosystems. Many species from non-fores, mostly steppe-forest formations have settled in the recent cultural landscape.
In original brook communities, a lamprey (Eudontomyzon danfordi) lives with 19 other native and introduced fish species. these communities also include aphibians, reptiles, birds, and mammals. These species include fire salamander (Salamandra salamandra), grey wagtail (Motacilla cineerea), dipper (Cinclus cinclus) and European water shrew (Neomys fodiens), all characteristic of mountain streams and adjacent shore habitats. River banks in the foothills are occupied by tesselated snake (Natrix tessellata), kingfisher (Alcedo atthis), white watail (Motacilla alba), and sand martin (Riparia riparia). Whitethroat (Sylvia communis), thrush nightingale (Luscinia luscinia) and reed warbler (Acrocephalus palustris and A.schoenobaenus) nest in natural shore thickets. Since the establishment of the Starina Rerevoir, species of waterbirds (generally Anser, Cygnus, Aythya, Mergus) previously unknown in the region have appeared. Otters (Lutra lutra) live year-round in streams with adequate water.
Dry meadows and pastures have been colonized by sand lizard (Lacerta agilis), smooth snake (Coronella austriaca), hoopoe (Upupa epops), long-eared owl (Asio otus) and many other tiny birds that nest in scattered trees and shrubs. Yellow-bellied toad (Bombina variegata), crested newt (Triturus cristatus), common toad (Bufo bufo), common tree frog (Hyla arborea) and grass snake (Natrix natrix) live or reproduce in water-filied depressions. Snipe (Gallinago gallinago), lapwing (Vanellus vanellus) and corncrake (Crex crex) commonly nest in wet meadows. The intensification of agricultral production has led to the decline of a number of native species, such as commpon hare (Lepus europaeus) and partidge (Perdix perdix), which have been replaced by introduces species, such as pheasant (Phasianus colchicus).
Despite their small area, poloninas have a distrinct fauna. Among the most important species are water and tree pipits (Anthus spinoletta and A. trivialis), whinchat (Saxicola rubetra), viviparous lizard (Lacerta vivipara) and northern birch mouse (Sicista betulina).
Among the many forest-dwelling species, birds of prey ar of special note. While buzzard (Buteo buteo) is the most common, kites (Milvus milvus and M.migrans) and eagles (Aquila pomarina and the rare A.chrysaetos) also nest in the reserve. Another important nesting bird is an eagle owl (Bubo bubo). Small carnivores – marten (Martes martes), wild cat (Felis sylvestris) and badger (Meles meles) – are quite abundant. Game animals are common, and serve as a nutritional basis for the large predators, such as bear, wolf and lynx.
Populations of vertebrate herbivores and predators very much changed after World War II which enhanced immigration from the large forested mountains in Ukraine and Romania. More recently, the mammalian fauna in the Polish Bieszczady National Park has been enriched by human-induced introduction of European bison (Bison bonasus), which