Relationships with habitat classifications. EUNIS: E4.121 Alpine acid small herb calcicolous snow-patch communities; PAL. CLASS.: 36.121 Alpine small herb calcareous snow-patch communities; HD 92/43: 6170 Alpine and subalpine calcareous grasslands; Bondev (1991): 2 Calciphilous, cryophytous grass (Kobresieta myosuroides, Cariceta kitaibelianae, Seslerieta korabensis etc.) and shrub (Dryeta octopetalae, Saliceta reticulatae, etc.) communities.
Conservation status. BDA, HD.
Category. Critically endangered [CR - A1, 2 B1 C3 D3 E3 H3 I J].
General characteristics. This habitat type occurs mainly on the bottom of the glacial cirques but other shapes of the mezorelief cannot be excluded. The herbaceous coenoses developing near snow patches on limestone are of very limited distribution. They develop on schists and marble. A typical snow association Gentiano-Plantaginetum atratae has been described from the cirques in Pirin Mts. and the foothills of the neighboring peaks. It occurs between 2400 and 2600 m alt. The duration of the snow cover is relatively small, only 6–7 months. The territories are flat or slightly slanting and receive relatively much sun radiation but are also exposed to strong winds. The soils are rendzhinas, strongly skeletal, with numerous small stones on the surface. At these relatively favourable conditions the projective cover of the vegetation varies between 70 and 90%. The main parts of the plants are small, 3–5 cm high, suppressed by the big snow mass. Species include Arenaria biflora, Dianthus microlepis, Draba scardica, Galium demissum subsp. stojanovii, Gentiana verna, Gnaphalium supinum (= Omalotheca supina), Oxytropis urumovii, Plantago atrata, Potentilla crantzii, P. ternata, Ranunculus carinthiacus, Sedum atratum, etc. Some of these species are more typical on acidic substrates. Taller species (up to 15 cm height) are less abundant: Alopecurus gerardii, Carex kitaibeliana, Poa pirinica, and Sesleria coerulans. The phytocoenoses under consideration include a number of rare species; some are local endemics. There are two subtypes of habitats with specific groups of plants. The first group is defined by the marble bed rock and includes mainly calcicoles. The second group occurs on schists rich in calcium and have transitional characteristics towards phytocoenoses of silicate; hence, many species typical of acidic soils also occur: Alopecurus gerardii, Campanula alpina subsp. orbelica, Dianthus microlepis, Euphrasia minima, Potentilla ternata, Sedum atratum, Trifolium repens subsp. orbelicum, etc.
Distribution in Bulgaria. This habitat type occurs mainly in Pirin Mts. and is very limited in Rila Mts.
Conservation importance. Rare phytocoenoses with species protected by law: Alyssum cuneifolium subsp. pirinicum, Arabis ferdinandi-coburgi, Empetrum nigrum, Galium demissum subsp. stojanovii, Gentiana frigida, Papaver degenii, Pedicularis oederi, Potentilla apennina subsp. stojanovii, Pulsatilla vernalis, Saxifraga ferdinandi-coburgi, Viola grisebachiana.
Threats. The increase of the tourist flow; construction of tourist facilities.
Conservation measures taken. The habitat is included in Annex № 1 of BDA. The localities of this habitat are within the borders of Rila and Pirin National Parks. Some of the most representative localities are in sites of the European Ecological Network NATURA 2000 in Bulgaria.
Conservation measures needed. Monitoring of the habitat state and strict implementation of the regulations in the National Parks.
References. Mucina et al. 1990; Roussakova 2000; Simon 1958.
Author: Veska Roussakova