The Drbákov – Albertovy skály NNR was declared in 1997 on a territory of 64.3 ha in the central Vltava river valley, on the right bank of the river on the Smilovice meander, between the Oboz side valley and the side valley by the Častoboř recreational area, in the south of the Středočeský kraj - Central Bohemian Region. The NNR includes the ‘Tisová’ locality on the northern slopes of Drbákov hill ‘Bílé skály’ – White cliffs and ‘Farský les u Častoboře’ forest. The subjects of the protection are near-natural forest communities, especially talus and ravine forests with abundant yew trees and rocky and rocky steppe communities with rare thermophilous plant and animal species.
The majority of the territory consists of very steep valley slopes with small areas on the tilted plateau above the edge of the river valley. The steep, rocky slopes with overhangs in places were modelled by erosional activities of the Vltava river and lies at elevations between 270 and 460 metres and the valley is 150 metres deep on average. The lower sections of the slopes were flooded by the Slapy Reservoir. Due to the meandering course of the river the slope orientations range from north through north-west do west-south-west.
The territory is geologically and geomorphologically varied. The slopes are divided by rocky ribs and gulleys filled with rock talus. The prevailing rocks are metabasites of the Jílové Zone, with the occurrence of acidic rocks such as paleorhyolites, biotite granites but also minerals which are richer in calcium in places (calc-silicate rocks). This geological variety allows the development of a varied composition of plant communities.
The northern and southern sections of the NNR are forested. Only scattered trees and groups of trees grow on the forest-free central section of the reserve. On these very steep, forest-free slopes there are a number of vertical and overhanging rock formations, tens of metres high (the Bílé skály – White Cliffs), with rocky steppe communities.
The vegetation communities vary considerably according to the slope form, orientation, depth of soil cover and mineral basement. The sunny slopes and rocky cliffs are the home of communities with the distinctive yellow-flowering basket of gold (Alyssum saxatile), the knapweed Centaurea rhenana, the woodruff Galium glaucum, the sand cinquefoil Potentilla arenaria, the moon carrot Seseli osseum, yellow woundwort(Stachys recta)and the woody species wild cotoneaster (Cotoneaster integerrimus). Protected plant species include St. Bernard’s lily (Anthericum liliago), the cornflower Cyanus triumphettii, Bohemian small pasque flower (Pulsatilla pratensis subsp. bohemica), the feather-grass Stipa joannis and the aster - Aster amellus.
In areas with deeper soils we can find thermophilous grasslands with the tor-grass Brachypodium pinattum with characteristic species the yellowhead Inula hirta, spiked speedwell (Pseudolysimachion spicatum) and large self-heal (Prunella grandiflora). Thermophilous growths of dwarf oaks with swallowwort (Vincetoxinum hirundinaria) are found on the shallow soils on the gentler slopes and accompanying herbs are xerophilous species such as the St. Bernard’s lily (Anthericum ramosum), angular Solomon’s seal (Polygonatum odoratum), sickle hare’s-ear (Bupleurum falcatum). The shrub layer consists of whitebeam(Sorbus aria), wild service tree (Sorbus torminalis) and juniper (Juniperus communis). Relict pine communities with the typical hawkweed Hieracium schmidtii can also be found on the territory.
The deeper soils in the northern half of the reserve are forest with oak-hornbeam growths with typical grove species including wood stitchwort (Stellaria nemorosa), hepatica (Hepatica nobilis), spring pea (Lathyrus vernus), cowslip (Primula veris) and martagon lily (Lilium martagon). Other forest types found on the territory are stands of dwarf acidophilous oaks, acidophilous oak stands with the rare greater butterfly orchid (Platanthera chlorantha) and oak-hornbeam stands with beechwood elements such as purple lettuce (Prenanthes purpurea) and baneberry (Actaea spicata). Talus and ravine forests grow at the lower elevations and comprise large-leaved lime (Tilia platyphyllos), small-leaved lime (Tilia cordata), sycamore (Acer pseudoplatanus), Norway maple (Acer platanoides) and wych elm (Ulmus glabra) but often with silver firs (Abies alba) in the mixture. Large numbers of yews (Taxus baccata) grow here and several of these trees are hundreds of years old.
The invertebrate fauna is of special significance and we can find sensitive species here which indicate the natural character of the forest growths such as the gastropods: the door snail Ruthenica filograna, the disc snail Discus perspectivus, the door snailsClausilia parvula and Macrogastra plicatula and the snail Helicodonta obvoluta as well as the ground beetle Carabus irregularis. In addition to the forest species we can also find rare thermophilous and xerophilous species such as the cicada- Cicadetta montana, the leaf beetles Psilloides instabilis and Cassia pannonica, the weevils Apion formaneki, Otiorhynchus geniculatus and the Curculionid weevil Trachyphloeus angustisetulus. Abundant populations of emerald lizards(Lacerta viridis) and smooth snakes (Coronella austriaca) live on the rocks, eagle owls (Bubo bubo) nest on the rocks and collared flycatchers (Ficedula albicollis) nest in the forest.
The Bílé skály – White Cliffs were a renowned landmark or orientation point in the past when rafts of timber where floated down the Vltava river from the Šumava mountains to Prague. On the flat plateau above the river valley there are numerous small quarry pits left behind after mineral extraction in times past.
We can reach the area by bus from the Na Knížecí bus station in Prague 5 by catching a bus in the direction of Sedlčany and getting off at Nalžovice. We follow the yellow trail through Nalžovické Podhájí to the carpark where we will find a crossroads of tourist trails. The themed nature trail is 7.35 km long and leads through the magnificent natural scenery of the Bílé skály – White Cliffs. The trail is physically demanding with frequent steep climbs and descents on the rock formations. We will be rewarded for our physical efforts by wonderful views into the Vltava river valley and over the Sedlčany region. We can return to Nalžovice the same way we came.