Praděd NNR is the largest reserve on the Jeseníky PLA territory with an area of 2031 ha. The reserve includes the highest peak of the Hrubý Jeseník mountain range – Mt. Praděd and its main ridge from Mt. Malý Děd along the Jelení hřbet ridge to Jelení studánka. The reserve lies on the border of the Olomoucký kraj – Olomouc Region and the Moravskoslezský kraj – Moravian-Silesian Region. The subject of the protection is the range of sub-alpine and supra-montane biotopes of the main Jeseníky mountain ridge with numerous significant plant and animal species.
Among the most notable biotopes are the windswept Alpine grasslands with starre sedge (Carex bigelowii), small fescue (Festuca supina), daffodil anemone (Anemonastrum narcissiflorum) and the bearded bellflower Campanula barbata, which only occurs in the Czech Republic in the Hrubý Jeseník range and on Mt. Králický Sněžník. Another significant biotope is the cliff vegetation in the Sudeten cirques, which is especially well-developed in the Velká kotlina glacial cirque. This cirque has the greatest species diversity of vascular plants of any locality in the Czech Republic which is uninfluenced by human activity with more than 400 species. Typical species growing here include the sweetvetch Hedysarum hedysaroides, roseroot (Rhodiola rosea), Alpine aster (Aster alpinus), and the endemic carthusian pink Dianthus carthusianorum ssp. sudetica. Sub-alpine tall-herb vegetation is characteristic for areas around the upper treeline with the dominant species hedge-garlic adenostyles (Adenostyles alliariae) accompanied by the monk’s-hood Aconitum callibotryon, Alpine sow-thistle (Cicerbita alpina) or the leopardsbane Doronicum austriacum.
The rock crevices above the tree line also play host to very interesting flora communities, including the Sudetic bellflower (Campanula rotundifolia subsp. sudetica), bitter-cress Cardamine resedifolia or dwarf willow (Salix herbacea) as well as another Jeseníky endemic species – the endemic meadow-grass Poa riphaea. The endemic Jeseniky mountain bellflower (Campanula gelida) still survives at the foot of the Petrovy kameny rock formation.
In addition to the sub-alpine biotopes, the mountain climax spruce forests are also exceptionally well preserved and are of a primeval nature in places. A unique feature within the realms of central Europe is the upper tree line covers a gradual transition from contiguous forest growths through groups of spruces to an alpine treeless environment. This can be seen in areas where pine scrubs were not planted. This phenomenon is especially well developed on the western slopes of the main ridge and is known as a parkland (diffusive) tree line. This is a sharp contrast from slopes which are regularly affected by avalanches and where the upper tree line is closed and forest growths suddenly change into subalpine treeless communities.
The most fundamental fauna type are the mountain butterfly species with the endemic Sudeten ringlet (Erebia sudetica) and several more relict species including the Tortricid moth Sparganothis rubicundana. The smooth newt (Triturus vulgaris) and Alpine newt (Triturus alpestris) are found at their maximum elevations here. Of great ornitholigical significance is the regular nesting of the peregrine falcon (Falco peregrinus) on rocky ledges above the deep valleys and the water pipit (Anthus spinoletta) nests on the bare mountain slopes and occasionally Alpine accentor (Prunella collaris), the dotterel (Charadrius morinellus) has been recorded here and the ring ouzel (Turdus torquatus) lives along the upper border of the forests. Until recently a small population of black grouse (Tetrao tetrix) inhabited the area.
The most significant mammals species are the glacial relicts such as northern birch mouse (Sicista betulina) and Alpine shrew (Sorex alpinus). Occasional evidence that lynx (Lynx lynx) visited the area has been recorded. Around 150 chamoix (Rupicapra rupicapra) also live in the NNR as descendents of these Alpine animals which were introduced here in 1912.
A major problem for nature protection on the territory are the extensive growths of non-indigenous Swiss mountain pine (Pinus mugo), which were introduced here from the end of the 19th century onwards with the aim of increasing the tree line level which had been lowered by overgrazing and unregulated felling, as well as to prevent erosion and avalanche damage. In the most valuable areas (Velká and Malá kotlina glacial cirque) the pine scrubs have been almost entirely removed but in other places we are unable to agree on their removal with the Forests of the Czech Republic state company.
Downhill skiing in the reserve also causes problems and this activity has been permitted at Ovčárna on the basis of an exception from the Act on Nature and Landscape Protection ever since the declaration of the reserve which preceded the current Praděd NNR in 1955.
Two themed nature trails pass through the NNR – The Bílá Opava trail, which leads visitors through the most beautiful stream valley in Jeseníky and the Velká kotlina trail which informs visitors about the natural development of a glacial cirque. Many more kilometres of hiking trails criss-cross the territory and lead visitors to the most interesting places in the Jeseníky mountain range.