Arctic-alpine rich fen

Fens around springs and small rivers in the alpine belt of European mountains (the Alps, Pyrenees, Scandes, Scotland) and in the northernmost (arctic) part of Europe, including Svalbard and Iceland. They are found on open substrates that are constantly flushed by cold and base-rich water. The sites are extreme with respect to soil and microclimate. Cold water is constantly present in the root horizon and restricts ion uptake of plants. Frequent disturbances, a high amount of oxygen in the soil water as well as low productivity due to low temperature during the short vegetation period prevent any remarkable peat accumulation and peat layer is typically lacking or very thin (< 20 cm). If peat accumulation would increase, other fen habitats would develop. Solifluction and cryoturbation lead to disruption of plant roots and soil surface structures.

The vegetation substitutes at high altitudes and latitudes the Caricion davallianae vegetation of type D4.1. The vegetation consists of small sedges, rushes, small herbs and non-sphagnaceous (brown) mosses and includes many arctic-alpine species. Most characteristic are Carex bicolor, Carex microglochin, Carex maritima, C. norvegica, Carex atrofusca, Carex frigida, Carex saxatilis, Carex vaginata, Carex aquatilis ssp. stans, Kobresia simpliciuscula, Scirpus pumilus, Juncus arcticus, Juncus alpinoarticulatus, Juncus castaneus, Juncus triglumis, Juncus biglumis, Saxifraga oppositifolia, Tofieldia pusilla. Vegetation is usually polydominated. Bryophyte layer consist of hepatics (Aneura pinguis) and different brown mosses such as Amblyodon dealbatus, Bryum pseudotriquetrum, Calliergon richardsonii, Campylium stellatum, C. polygamum, Catoscopium nigritum, Cinclidiun stygium, Paludella squarrosa, Philonotis calcarea, P. tomentella, Scorpidium cossonii, S. revolvens (locally), Tayloria lingulata, Tomentypnum nitens and Warnstorfia exannulata. Within these sites appear species that can be treated as glacial relicts in the European mountains or surviving species during the Pleistocene glaciation in the boreal and arctic refugial areas. In high mountains outside the Alps, Pyrenees and Scandes, these habitats are depauperate and transitional to spring and small-sedge fen habitats.

These habitats exist in high-mountain or arctic areas and are threatened by direct human activities: tourism, construction of small power station, construction that cause erosion or snow slide, capture of springs, channelling of streams (water supply) etc. Global changes might change the precipitation and temperature regime and can change dramatically the species composition.

Indicators of good quality:

• Species richness and presence of diagnostic species
• Absence of human intervention
• Permanent water flow
• Low productivity
• Presence of mosses 

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats