Bílé stráně National Nature Monument

The Bílé stráně (White Slopes) NNM lie above the town of Litoměřice in the České středohoří PLA and the Ústecký kraj – Ústí nad Labem Region. These white (limestone) slopes are a typical ecosystem for the southern and south-eastern fringes of the České středohoří Mountains. The slopes have been owned and protected by the local heritage society since 1929 and were declared as a national nature monument on an area of 3.24ha in 1954.
 
The protected area covers a part of the steep slopes of the valley of the Pokratický potok Stream which have been denuded by erosion. The geological basement is built of marlites of Cretaceous age. The highest positions in the limestone are silicified and contain many fossils of clams of the Inoceramus order. This rock is called “Ringing Inoceramus Opokas” due to its fossil content and the sound it makes when you tap or knock it. Several landslides have taken place here in the last 10 – 12 000 years and each time the surface layers and vegetation slid into the stream valley and succession took place on the bare rocky slopes. The steepest parts of the slopes with washed out fine soils are covered only with skeletal soils without vegetation, which appear to be a shining white colour from a distance – hence the name “White Slopes”.
 
The geological basement of calcareous marlstones in combination with the terrain configuration (steep west-facing erosional – denudational slopes) and the warm, dry climate have created the ecological conditions for the evolution of thermophilous grassland growths and fringe communities of bushes and shrubs and the occurrence of a range of demanding plant species including protected species such as: snowdrop windflower (Anemone sylvestris), common globularia (Globularia elongata), cross gentian (Gentiana cruciata), golden flax (Linum flavum) and narrow-leaved flax (Linum tenuifolium). The White Slopes are among the most valuable localities for orchids in the North Bohemian region: fly orchid (Ophrys muscifera), lady’s slipper (Cypripedium calceolus), lesser butterfly orchid (Platanthera bifolia), lady orchid (Orchis purpurea), fragrant orchid (Gymnadenia conopsea) and the common twayblade (Listera ovata) all grow here. During inventory research in 1989, a total of 475 vascular plant species were recorded here, of which the helleborine Epipactis muelleri and the leafy spurge Tithymalus tommasianus were recorded in the České středohoří Mountains for the first time.
 
This territory is also of great zoological significance. Rare and unique invertebrate species can be found here, including the snail Cepaea vindobonensis and several monophagous beetle species (species which are bound to one particular plant species) – the flea beetles Aphtone atrovirens (bound to the yellow flax), Longitarsus absinthii (on the Roman wormwood) and Argopus ahrensi (on the clematis), as well as the weevil Liparus dirus (on the lasewort). The richness of the vegetation certainly contributes to the recording of 1 000 butterfly species here including the green-underside blue (Glaucopsyche alexis). Around 60 vertebrate species occur in the monument, of which the most significant are the green toad (Bufo viridis), nightingale (Luscinia megarhynchos), Savi’s warbler (Locustella luscinioides) and the lesser spotted woodpecker (Dendrocopos minor).
 
Around one fifth of the reserve is forested with rich, thermophilous woodland communities with hazel, dogwood, whitebeam, perfoliate honeysuckle and Scots pine.
 
For the development of the territory it is necessary to restrict the expansion of the ash trees from the alluvial plain of the Pokratický potok stream. Another negative influence is the vicinity of the town of Litoměřice, the inhabitants of which use the slopes for recreation and sport. The Bílé stráně has been included on the National list of Natura 2000 sites as a Site of Community Importance to protect the thermophilous grasslands with special emphasis on the lady’s slipper.