23E4

E. Herbaceous communities and communities of lichens and mosses

Alpine and sub-alpine closed calcareous grasslands

Relationships with habitat classifications. EUNIS: E4.41721 Rhodopide pungent fescue grasslands, E4.4173 Balkan oligophile closed calcicolous grasslands; PAL. CLASS.: 36.41721 Rhodopide pungent fescue grasslands, 36.4173 Balkan oligophile closed calcicolous grasslands; HD 92/43: 6170 Alpine and subalpine calcareous grasslands; Bondev (1991): 9 Calciphilous shrub, dwarf shrub and grass communities (Festuceta penzesii, Sesleria korabensis, Astragaleta angustifoliae, Dryeta octopetalae, Chamaecytiseta absinthioides, Junipereta sibiricae, Junipereta pygmaei etc.), 31 Shrub (Junipereta sibiricae, Chamaecytiseta absinthioides) and grass (Festuceta penzesii, Festuceta pirinensis, Festuceta hirtovaginatae etc.) replacing Pinus heldreichii forests.

Conservation status. BDA, HD.

Category. Vulnerable [VU - A1, 2 B2 F2 G2 H2].

General characteristics. The alpine and sub-alpine closed calcicolous grasslands occur in some mountains, especially in the subalpine belt. They are almost closed phytocoenoses dominated mainly by medium-high to high caespitose perennial grasses that cover rather large areas. The exposure is mainly southern, with western or eastern components. The slope in most cases is 30–45°. Most of the habitats are on shallow to medium-strong humus-carbonate soils, more or less skeletal, aerated and very dry throughout almost the whole vegetation period. The soils are neutral to alkaline. The projective cover of the phytocoenoses varies between 70% and 90%.

Although the main characteristics of the habitat vary within certain limits, the floristic and phytocoenotic diversity of the vegetation is very rich. Most of the species are Bulgarian or Balkan endemics but many rare and endangered species also occur. Xerophytes mainly dominate. Apart from the obligate calcicoles, facultative calcicoles also participate in the phytocoenoses (the abundance of some of them can be high). The altitude has a significant impact on the composition of the different phytocoenoses. Therefore the phytocoenoses that represent this habitat type are not only rich in species but have also very diverse species composition. Almost each high mountain has its specific group of phytocoenoses. Most diverse are those in Pirin and Slavyanka Mts. Some of them have very limited distribution.

The coenoses of the Balkan endemic Festuca penzesii (F. pungens gr., F. pungens var. penzesii) are among the most representative ones. These coenoses are typical for the two southwestern mountains of Bulgaria, Slavyanka and Pirin Mts. These phytocoenoses are endemic also for the Balkan Peninsula. In Bulgaria they occur at (1600) 1900–2500 m alt., where they cover large areas and are a main element of the calcicolous vegetation in these mountains. Generally, the areas covered by these coenoses are relatively dry, calcareous places. The calcareous bed rock often is cracked and broken and in many places reaches the surface. As a rule, the slopes are steep and mainly with a south, eastern or western exposure. The bulging forms of relief are preferred. The soil is shallow, very skeletal, eroded, and in some place, where the places are not very steep, forming patches among the rocks or the broken pieces of rocks. The herbaceous layer is with different projective cover depending upon the degree of development of the soil layer. In some places this layer is very thin and these coenoses can be transitional forms to the calcareous habitats with open phytocoenoses. The dominating role of Festuca penzesii is not always strongly expressed. In some places sub-dominants or co-dominants can be one or more species such as Astragalus angustifolius, Bellardiochloa variegata (= Bellardiochloa violacea), Festuca dalmatica, F. nigrescens, Sesleria caerulea, S. korabensis, etc. One of the most widely distributed polydominant phytocoenoses are these with Sesleria coerulans. The group of these phytocoenoses as a whole, and each phytocoenosis in particular, has a very rich floristic composition with mainly calcicoles. More typical species are Achillea ageratifolia, Alyssum cuneifolium, Androsace villosa, Carex kitaibeliana, Cerastium alpinum subsp. lanatum, Festuca pirinensis, Gentiana verna, Linum capitatum, etc. It is possible that coenoses of this species occur in Rhodopi Mts. as well.

The coenoses of Festuca pirinensis (= Festuca bosniaca subsp. pirinensis) occur mainly on the slopes of Vichren peak and more rarely on Sinanitsa peak. The species is the endemic to Pirin Mts. where the habitats are very stony. Alyssum cuneifolium subsp. pirinicum, Bellardiochloa variegata, Bromus lacmonicus, Carex kitaibeliana, Cerastium lanatum, Koeleria eriostachya, Onobrychis pindicola subsp. urumovii, Scutellaria alpina, Sesleria coerulans participate in these coenoses.

In Pirin and Slavyanka Mts., on the steep slopes, and rarely on the mountain ridges in the woody part of the subalpine belt, the phytocoenoses of the relic Balkan endemic Festucopsis sancta occur. These localities have a southern exposure (or with southern component). The soils are developed on marble limestone, belong to the “rendzhik” type and are relatively strong with much skeletal material. They are well drained, aerated and dry. The phytocoenoses are monodominant or with the high participation of Sesleria korabensis, S. rigida, and Stipa pennata.

Most of the coenoses in the lower parts of the subalpine subbelt are of secondary origin and replace destroyed forests of Pinus heldreichii, P. nigra,and Ostrya carpinifolia. This group of phytocoenoses belong to the class Elyno-Seslerietea. In the subalpine belt of the West and Central Balkan Range communities dominated by Festuca balcanica subsp. balcanica and (very rarely) Festuca balcanica subsp. neiceffii) occur on shallow soils on the steep calcareous slopes. Some of the phytocoenoses of Festuca balcanica subsp. balcanica are monodominant, others have co-edificators or sub-edificators. Achillea ageratifolia,Deschampsia flexuosa, Festuca nigrescens, Juniperus sibirica, Luzula luzuloides, Saxifraga rocheliana, Sesleria caerulea, etc. also participate. Festuca balcanica is not an obligate calcicole and can occur also on silicate soils. Therefore, only part of the coenoses of this species can be considered as part of this habitat type, and are widely distributed in the Balkan Range (western and central). Similarly, the phytocoenoses of Carex kitaibeliana can be considered as such. Anthyllis vulneraria, Asperula capitata, Minuartia verna, Rhodax canus, Sesleria rigida, etc. also participate in these coenoses on limestone. The coenoses dominated by Festuca xanthina and Bromus erectus in the Balkan Range also belong to this habitat type. They have a very limited distribution in the western and central parts of the mountain. The communities of Festuca xanthina (a rare species in the Bulgarian flora) develop on steep, rocky and eroded places at and above 900 m alt. They are very rare and cover limited areas. The soils are shallow rendzhinas. Their floristic composition (Alyssum repens, Asperula capitata, Aster alpinus, Carex kitaibeliana, Dianthus petraeus, Draba lasiocarpa, Minuartia verna, Primula veris, Seseli rigidum, Sesleria rigida, etc.) is of particular interest because this habitat type is very rare in the neighbouring countries (Serbia and Romania). Its phytocoenoses belong to various associations  from the alliance Seslerion rigidae. The syntaxonomy of the Bulgarian phytocoenoses, including their affiliation to higher taxa, has not been studied.

Bromus erectus, a very polymorphic species, makes phytocoenoses very rarely and in small areas on primary calcareous terrains. These are mainly of southern exposure and on stony soils. Their floristic composition is similar to that of Festuca xanthina. Festuca paniculata makes phytocoenoses on limestone, mainly in the West Balkan Range (in Serbia as well), but the soils are not always shallow and alkaline. In some places these coenoses cover considerable areas and the fescue clearly dominates.

Characteristic taxa

Distribution in Bulgaria. Pirin and Slavyanka Mts., the Balkan Range and limited areas in Rila Mts.; at 1500–2500 m alt.

Conservation importance. Many Balkan and Bulgarian (some local) endemics participate in the composition of the phytocoenoses (some of which endemic) under consideration: Alyssum cuneifolium subsp. pirinicum, Arctostaphylos uva-ursi, Asperula capitata, Betonica bulgarica, Campanula transsilvanica, Carex parviflora, Carum rigidulum subsp. bulgaricum, Chondrilla urumoffii, Daphne oleoides, Draba athoa, Erysimum slavjankae, Galium rhodopeum, Laserpitium siler, Lathyrus linifolius, Leontopodium alpinum, Minuartia bulgarica, Verbascum humile, Veronica austriaca subsp. neiceffii, etc. The fungi Hygrocybe murinacea is of conservation importance.

Threats. All phytocoenoses are used as pastures despite their low forage value. Overgrazing may cause negative changes in the vegetation and habitats.

Conservation measures taken. The habitat is included in Annex 1 of BDA. Some of the localities are within the borders of Rila, Pirin and Central Balkan National Parks, Alibotush Strict Nature Reserve and in sites of the European Ecological Network NATURA 2000.

Conservation measures needed. Monitoring of the habitat state. Regulation of grazing –  moderate grazing is necessary for the maintenance of the floristic composition and structure of the phytocoenoses and the specificities of the habitats.

References. Meshinev et al. 2000; Simon 1958.

Author: Veska Roussakova


Alpine and sub-alpine closed calcareous grasslands (distribution map)