The Skalky skřítků (Elves‘ Rocks) NNM lie on the western fringe of a Tertiary stratovolcano and covers an area of 8.50ha. The monument can be found to the west of the village of Dubina and in the parish of Bražec u Hradiště near to the spa city of Karlovy Vary and was declared a national nature monument in 1979. The main subject of the protection are the unique preserved pseudokarst formations which can be found in the volcanic breccia on the western edge of the Doupovské hory Mountains.
The pseudokarst formations are cavities with a circular or oval profile. These “caves” are between 1cm and 150cm in diameter and several centimetres to several metres deep. There are several theories to explain the formation of these “elves’ caves”. The three theories which are currently most accepted are as follows. The first explains that the caves formed by weathering of tree trunks, branches and other vegetative remnants which were trapped in the removed volcanic sediments (lahares) during the eruption. The second theory relates to the weathering of the less resistant breccia in the volcanic tuffs. The third theory explains the caves as the result of gas explosions in the hardening lava and the following opening of these closed cavities as a result of exogenic factors, such as water erosion.
The vegetation in the Skalky Skřítků NNM and on the surrounding slopes is typical of the herb-rich beechwoods in the area. Herbs which grow here include hepatica (Hepatica nobilis), lungwort (Pulmonaria officinalis), yellow anemone (Anemone ranunculoides), herb paris (Paris quadrifolia), whorled solomon’s seal (Polygonatum verticullatum), fly honeysuckle (Lonicera xylosteum) and others. The herb layer also includes endangered species such as martagon lily (Lilium martagon), narrow-leaved helleborine (Cephalanthera longifolia) and box-leaved milkwort (Polygala chamaebuxus). The monument is the only locality in north-western Bohemia where the highly endangered Irish saxifrage variety (Saxifraga rosacea subsp. sponhemica) grows.
The fauna in the beechwoods on the slopes around the “Elves’ Rocks” mostly comprises common animals, but we can also encounter many rarer animal species here too. Representatives of the amphibians include numerous common frogs (Rana temporaria) and the highly endangered fire salamander (Salamandra salamandra), which lives in damper areas. Reptiles are represented by the critically endangered adder (Vipera berus), while our largest and rarest snake – the Aesculapian tree snake (Elaphe longissima) lives in the nearby valley of the Ohře river. The Doupovské hory Mountains have a rich birdlife including the black woodpecker (Dryocopus martius), grey-headed woodpecker (Picus canus), red-breasted flycatcher (Ficedula parva), stock dove (Columba oenas) and the honey buzzard (Pernis apivorus). Typical mammals live at the monument and in the surrounding forests.