Medník National Nature Monument

At Medník NNM we can find hornbeam-oak woods and beechwoods with the occurrence of the critically endangered dog’s-tooth violet.
 
The monument lies in the parish of Hradišťsko pod Medníkem to the south of Prague and near the confluence of the Sázava and Vltava rivers. Medník NNM was declared in 1933 on an area of 19.02ha at elevations of 220-398 metres above sea level.
 
The geological basement is built of Proterozoic rocks which are more than 500 million years old. These are predominantly basic effusive rocks of the gold-bearing Jílové Belt. The area with the richest occurrence of the dog’s-tooth violet is the place where gold was mined at the beginning of the historical period. Remnants of the sand and gravel terraces of the Sázava river of Quaternary age are preserved on the slopes of Medník hill. Stony slope deluvia with small boulder fields have also formed on the slopes.
 
The territory of the national nature monument is covered with beechwoods and oak-hornbeam stands, with a shrub layer in some areas. Enclaves of spruce monoculture can be found in the eastern and western parts of the protected area. The Sub-Mediterranean dog’s-tooth violet (Erythronium dens-canis) grows in the undergrowth of the deciduous beech and hornbeam stands alongside typical central European deciduous forest herbs such as coralroot (Dentaria bulbifera), hepatica (Hepatica nobilis), spring pea (Lathyrus vernus), greater stitchwort (Stellaria holostea), tuberous comfrey (Symphytum tuberosum), the lungwort Pulmonaria obscura, asarabaccum (Asarum europaeum) and dog’s mercury (Mercurialis perennis). The sedge Carex pilosa also grows at this locality in isolation from its predominantly Sub-Mediterranean distribution. This sedge also accompanies the dog’s-tooth violet at its nearest locality in the Slovakian Karst region which lies more than 500 kilometres to the east of Medník. The population of dog’s-tooth violets on Medník hill is estimated at around 5,700 individual plants.
 
The questions concerning the origin of the dog’s-tooth violets at this locality have never been fully answered because there is no direct evidence. The most popular version is that the violets were planted here by monks from the Strahov Monastery. It is also possible that the violets are a relict population left over from a wider distribution of this species in the older stages of the Quaternary period.
 
The fauna at the locality which has been studied in detail are predominantly the molluscs, which form a species-rich forest community with the occurrence of certain cryophilous and montane elements. A relatively strong population of fire salamanders (Salamandra salamandra) lives in the protected area.
 
The dog’s-tooth violet would benefit from a gradual opening up of the forest stands, which could be achieved by transforming the neighbouring spruce stands into deciduous forest. The dog’s-tooth violets grow very early in the springtime when the deciduous forest is still without leaves, whereas the neighbouring spruces carry their needles all year round.