Flora and vegetation [ Flora ]
Despite their small area, the Krkonoše Mountains are endowed with a rich flora, and thus are of special importance in the context of the other Hercynid mountains. More than 1,250 taxa of vascular plants have been identified in Krkonoše. This amounts to almost half of the total original flora of the Czech Republic. Many times more taxa of non-vascular plants (sporophytes) - bryophytes, lichens, algae, fungi, cyanophytes, myxomycetes - have been identified, and inventories of these groups are undoubtedly still incomplete.
Four distinct altitudinal vegetation belts can be defined in the Krkonoše Mountains: submontane (400 to 800 m), montane (800 to 1,200 m), subalpine (1,200 to 1,450 m) and alpine (1,450 to 1,602 m). Their structure has been altered to a greater or lesser extent by human activities in recent centuries.
Natural deciduous and mixed forests are formed mainly by European beech (Fagus sylvatica), sycamore (Acer pseudoplatanus), ash (Fraxinus excelsior), rowan (Sorbus aucuparia), and grey alder (Alnus incana). Most of the original forests have been cut down and replaced by single-dominant plantations of Norway spruce (Picea abies) and European larch (Larix decidua). The herb layer is characterized by vernal plants, including ramsons (Allium ursinum), tuber-hollow fumitory (Corydalis cava), wood anemone (Anemone nemorosa), yellow wood anemone (A. ranunculoides), dropping bittercress (Dentaria enneaphyllos), coralwort (D.bulbifera), and Turk’s cap lily (Lilium martagon).
Both native and planted mountain spruce forests are currently under great pressure from industrial air pollution. The herb layer is dominated by ferns - alpine lady fern (Athyrium distentifolium), male fern (Dryopteris filix-mas), and hard fern (Blechnum spicant) - and graminoids, such as villous smallreed (Calamagrostis villosa) and wavy hair-grass (Deschampsia flexuosa). On damp sites, tall-herb vegetation includes hairy chervil (Chaerophyllum hirsutum), white and Kablikova’s butterburs (Petasites albus, P. kablikianus), and large bitter-cress (Cardamine amara).
The origin of enclaves in forests can be traced back to the 18th century mountain farms (see below). These enclaves have species-rich mountain meadows, with Sudetic pansy (Viola sudetica), Bohemian bellflower (Campanula bohemica), hawkweeds (Hieracium spp.), giant cat’s-ear (Achyrophorus uniflorus), mountain arnica (Arnica montana), and many orchids (family Orchidaceae).
The most valuable ecosystems of the Krkonoše Mountains - krummholz stands, virgin and secondary mat-grasslands, and subarctic mires - are concentrated in this belt, around the summit plateaux. The shrub layer is dominated by Swiss mountain pine (Pinus mugo); the herb layer by mat-grass (Nardus stricta), villous smallreed (Calamagrostis villosa), various sedges (genus Carex), and low ericoid shrubs: bilberry (Vaccinium myrtillus), cowberry (V.vitis-idaea), bog whortleberry (V.uliginosum), small cranberry (Oxycoccus microcarpus), and crowberry (Empetrum hermaphroditum). Endemic and relic species, such as hawkweeds (Hieracium spp.), sudetic lousewort (Pedicularis sudetica), and cloudberry (Rubus chamaemorus) are abundant.
After the last Ice Age ended, the isolated summits of the Krkonoše Mountains, elevated far above the Central European woodland, became a unique alpine archipelago. Through genetic processes, as a result of micro-evolution, many new species, subspecies and varieties evolved on these ”islands”: the famous Krkonoše endemics Sudetic rowan (Sorbus sudetica), Bohemian bellflower (Campanula bohemica), basalt musky saxifrage (Saxifraga moschata basaltica), rock burnet saxifrage (Pimpinella saxifraga rupestris), and almost thirty species of hawkweeds (genus Hieracium).
The topmost solitary summits of the Krkonoše Mountains (Snezka, Studnicni hora, Lucni hora, Vysoke Kolo, Kotel) are covered by a scanty but prominent vegetation of herbs, bryophytes, and lichens: such as three-leaved rush (Juncus trifidus), daisy-leaved speedwell (Veronica bellidioides), spiked woodrush (Luzula spicata), endemic alpine hawkweeds (Hieracium alpinum agg.), and the lichens Thamnolia vermicularis and Rhizocarpon geographicum.
The richest flora is found on rocky valley headwalls, which have been called the Krkonoše’s ”botanical gardens.” As described by the theory of anemo-orographic systems, the development of these azonal ecosystems has been influenced over eons by the interaction of many environmental factors and biotic processes, including (1) near-the-ground wind systems, (2) deposition and redistribution of snow and avalanche action, (3) denudation of outcrops of mineral-rich rocks and landslides, (4) deposition of airborne soil particles, seeds, spores and germs, (5) coexistence and competition of plant and animal populations, and (6) micro-evolution producing new varieties and species.
Cirque slopes are covered by a varying pattern of tall-herb and fern meadows, with monkshoods (Aconitum firmum, A.gracile), hedge-garlic adenostyle (Adenostyles alliariae), blue sow-thistle (Cicerbita alpina), and numerous ferns; slope springs, with chives (Allium sibiricum), marsh felwort (Swertia perennis), alpine bartsia (Bartsia alpina), willow-herbs (Epilobium spp.), and least primrose (Primula minima); and bizarre crooked forests, with Carpathian birch (Betula carpatica), Silesian willow (Salix silesiaca), Swiss mountain pine (Pinus mugo), rocky cherry (Padus petraea) and, rarely, Sudetic rowan (Sorbus sudetica). Species diversity is highest in the Sniezne Kotly cirques on the Polish side. On small outcrops of nutrient-rich basalt, one can find endemic basalt musky saxifrage (Saxifraga moschata basaltica) and rock burnet saxifrage (Pimpinella saxifraga rupestris), the relic alpine saxifrage (Saxifraga nivalis), and other rare species, including alpine woodsia (Woodsia alpina), rose root (Rhodiola rosea), and least willow (Salix herbacea).