Vegetated snow patch

The habitat is represented by chionophile vegetation on places that retains late-lying snow (snowfield, snowbed and snow-patch), often on the drift from the melting snow-patches. They are well developed in boreal and arctic mountains and in sub-arctic lowlands. Dominants may be mosses, liverworts, lichens, short graminoids, ferns and small herbs. The species composition depends on the geographical range, the altitude, bedrock (calcareous or siliceous soils) and length of vegetation seasons. On the tops of high mountains in South-Europe snow patches are characterised by the presence of endemic taxa and syntaxa. Often the plant communities are disposed in the depressions of slopes and ridges amongst the dominant acidophilous or caciphilous alpine and sub-alpine grasslands. Soils are poorly developed: Lithosols (1–4 cm), strongly skeletal, often with small stones on the surface. Some of them are rich in fine, organic substances.

The most widespread in mountains throughout the Europe are acidophilous mixed herbaceous-dwarf shrub communities of the class Salicetea herbaceae. The dominant species are Salix herbacea, Ligusticum mutelina, Luzula alpinopilosa many mosses as Polytrichum sexangulare, P. juniperinum, Pohlia commutata, ect. Dwarf willow shrubs belong to shrub not to the snow-patch grasslands, but are included under habitat F2.1. The most widespread acidophilous snow-patch communities in the mountains are dominated from Omalotheca supina, Alopecurus gerardii, Carex spp., Alchemilla spp., etc. But the snow-patch vegetation of Iberian Peninsula is rich in endemics and belongs to the endemic alliance Sedion candollei. The endemic alliance Ranunculion crenatii represents the uncommon, isolated herbaceous snow-patch swards of the southern Dinarides and the Pelagonides. Another endemic alliance Hyalopoion ponticae represent the snow-bed vegetation on acidic soils in the Caucasus Mts.

In Northern Europe (Fennoscandia, the Scottish Highlands, Iceland, Greenland and arctic islands) snow-patch communities are dominated by mosses (Distichium capillaceum, Pohlia spp.), lichens or coarse tussock forming grasses, like Deschampsia cespitosa. On Svalbard some snow-beds over siliceous bedrock are dominated by Dicranoweissia crispula, with Andreaea blyttii, A. obovata and A. rupestris as characteristic species. The northern alliance Cassiopo--Salicion herbaceae is very similar to the alpine Salicion herbaceae, but diagnostic are typical arctic species like Carex bigelowii and Harrimanella hypnoides. Specific are some snowbed communities of Fennoscandian Mountains, Iceland and Scottish Highlands, which are dominated by ferns as Cryptogramma crispa, Athyrium distentifolium (Athyrium alpestre), Athyrium filix-femina, Dryopteris expansa (Dryopteris assimilis) or Dryopteris filix-mas.

Calciphilous boreo-alpine snow patch grasslands (Arabidetalia caeruleae) are rich in small herbs, grasses and mosses. Among the characteristic species are Arabis caerulea, Carex atrata, Saxifraga androsacea and Ranunculus alpestris. Open, herbaceous communities on wet (from melting snow), calcareous stones in Scandinavian mountains belong to the alliance Saxifrago oppositifoliae-Oxyrion digynae (=Ranunculo-Oxyrion digynae). Typical species here are Oxyria digyna, Cerastium cerastoides, Cetraria delisei and Saxifraga oppositifolia.

The vegetation communities mostly cover small areas above the forest belt (alpine and sub-alpine parts) in the high mountains of Central and Eastern Europe: Alps, Pyrenees, Carpathians and Caucasus, and in the Scottish Highlands and Sudeten. In South-European Mountains, they are spread very locally in the Paeonian Mountains, Sierra Nevada, Cordillera Central, Monti Sibillini, Abruzzi, Balkan Mountains as Pirin and Rila Mts. and some of the Dinarides.

In a good condition the habitat is represented by communities in patches with different sizes, within a matrix of the dominant alpine, subalpine and tundra grasslands. The development of these communities depends on the duration of snow cover, amount of snowfall in winter and water supply from melting snow-patches. Moss and lichen communities are very sensitive to any disturbance. Alpine and subalpine communities are threatened by overgrazing and development for tourism (ski tracks, trampling on tourist routes, etc). Global warming is another serious threat, because it reduces the snow-patch size, decreases the duration of snow cover and increases the duration of the vegetation growing season.

Indicators of good quality:

• High amount of snowfall and long-term snow cover
• High species richness
• Presence of rare and/or threatened species (on high mountains also endemic species)
• High cover of lichens and mosses (in some varieties

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats