Temperate high-mountain siliceous scree

This habitat consists of siliceous, mostly acidic screes, moraines or stone rivers of high altitudes (mainly over 1000 m above sea level) and cool sites in mountain ranges of the nemoral zone of Europe, including the Alps, Pyrenees, Carpathians, central and eastern parts of Balkan Peninsula, Apennines, etc.. Scree habitats consist of rock fragments with different forms and sizes covering the frost-shattered summits of mountains or accumulating on slopes below siliceous cliffs. Siliceous screes are made up of siliceous rocks, such as quartzite, granite and sandstones.

The screes are colonised by a range of mostly perennial plant species. The vegetation consists of assemblages of mostly acidophilous or neutrophilous species. The composition is strongly influenced by altitude and geographical ranges. Siliceous screes are habitats which contain many relic and local endemic species, but less than calcareous screes. The diversity of vegetation units is also smaller compared to calcareous screes. A widespread alliance in the Alpine and Carpathian mountain systems is the Androsacion alpinae. In the Pyrenees, where the habitat is more common, two specific alliances occur: Senecionion leucophylli and Dryopteridion oreadis. The plants grow tufted between the scree stones, in places with a little soil. Typical species include Androsace alpina, A. wulfeiana, Saxifraga bryoides, Silene acaulis and Festuca picta. Another widespread species of this habitat in most European mountains is Oxyria digina.

The siliceous screes are more humid than the calcareous ones, because they have larger water-retention characteristics. The humid, humus-rich siliceous screes of the Alps, on slopes long-covered with snow, are carpeted by Luzula alpinopilosa, and accompanied by species that constitute an ecological variant of the snow patch communities. There are also communities of ferns and low semi-shrubs, including Gymnocarpium dryopteris, Cryptogramma crispa, Athyrium distentifolium, Dryopteris dilatata, Cystopteris fragilis, Vaccinium spp. colonizing non-stabilized screes on shady places, often with a high proportion of large blocks. The scree vegetation in the Caucasus Mountains., outside the range of the EU 28+, is represented by the endemic alliances Scrophulario minimae-Symphyolomion graveolens and Chaerophyllion humilis. Those screes are outside this habitat type’s definition.

Indicators of quality:

•    Occurrence of natural erosion processes.

•    Presence of rare, relict or endemic species.

•    Absence of human activities, including grazing.

•    Absence of alien species.

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats