The geological basis is formed by marlstones from the Mesozoic era. In combination with the terrain configuration (steep slope denuded by an erosion in the Pokratický brook valley) and the dry, warm climate, it creates great conditions for the development of thermophilic grasslands and shrublands with many demanding plant species including protected: snowdrop windflower (Anemone sylvestris) the common ball flower (Globularia elongata), the star gentian (Gentiana cruciata), the golden flax (Linum flavum) and L. tenuifolium. The area is one of the most valuable in northern Bohemia when it comes to the occurrence of representatives of the orchid family: the fly orchid (Ophrys insectifera), the lady's-slipper orchid (Cypripedium calceolus), the lesser butterfly-orchid (Platanthera biofolia), the lady orchid (Orchis purprstea), the fragand orchid (Gymnadenia conopsea) and the common twayblade (Listera ovata).
There are unique and rare invertebrate species, such as the Cepaea vindobonensis. From the beetle family, that is bound to only eat one species of plants, it is epitrix Aphtona atrovirens (to the yellow flax), Longitarsus absinthii (to the Roman wormwood), Argopus ahrensi to (the erect clematis) and weevil Liparus dirus (to the broad-leaved sermountain). The abundance of plant species is associated with the occurrence of thousands of species of butterflies, of which the significant is, for example, the green-underside blue (Glaucopsyche alexis). Rare and endemic species from the sorbus family are an important phenomenon of the White Slopes, for example the Sorbus bohemica, the S. albensis, the S.danubialis, the S. Domestica. These are mostly very rare species known and noted only in the last few decades, which do not usually grow outside the Central Bohemian Uplands The locality Bílé stráně is part of the Natura 2000 system, that is intended for the protection of European thermophilic grasslands, with special emphasis on the lady's-slipper orchid.
Photo gallery
Galerie - Bílé stráně Národní přírodní památka
