The Blanice NNM covers an area of 294.68ha and includes the upper reaches of the Blanice river to the east of the town of Volary, within the Šumava PLA and in the Jihočeský kraj (South Bohemian Region). The protected area was declared in 1989 to protect the most significant population of freshwater pearl mussels (Margaritifera margaritifera) in central Europe. The monument is surrounded by a buffer zone of 5962ha which covers the whole of the upper catchment of the Blanice river.
The wide Blanice alluvial plain is formed on a crystalline basement, which is built of basaltic metamorphosed rocks with migmatites and granulites. The Quaternary covering consists of fluvial clayey and sandy deposits, which pass into deluvial slope sediments with a stony admix. Peaty organic soils have formed around the many springs in the protected area.
Notable vegetation communities include wetland communities of sedges and sphagnum mosses, which pass into tall-herb wet meadows. On small raised peatbogs we can find common cotton-grass (Eriophorum angustifolium) and hare’s-tail cotton-grass (Eriophorum vaginatum), accompanied by communities of bog whortleberry (Vaccinium uliginosum), the cranberry Oxycoccus palustris and round-leaved sundew (Drosera rotundifolia). Orchids which grow on these wet meadows include broad-leaved marsh orchid (Dactylorhiza majalis), common spotted orchid (Dactylorhiza fuchsii) and the lesser and greater butterfly orchids (Platanthera bifolia and P. chlorantha). Junipers (Juniperus communis) grow at some localities on the fringes of the wetlands in the northern part of the protected area. The majority of the buffer zone is forest-covered.
The main subject of the protection is the occurrence of the critically endangered freshwater pearl mussel (Margaritifera margaritifera). Other notable aquatic animals living in the Blanice river include the broad-fingered crayfish (Astacus astacus), the brook lamprey (Lampetra planeri) from the cyclostomes and fish such as the minnow (Phoxinus phoxinus) and bullhead (Cottus gobio). Notable birds which live in the Blanice valley include the hazel hen (Bonasa bonasia), black grouse (Tetrao tetrix) and the Ural owl (Strix uralensis), with the rare three-toed woodpecker (Picoides tridactylus) also found here. We may be lucky and see rare butterflies such as the purple-shot copper (Lycaena alciphron), moorland clouded yellow (Colias palaeno) or cranberry blue (Plebejus optilete). Red deer (Cervus elaphus) and otters (Lutra lutra) also live in the valley.