27E4

E. Herbaceous communities and communities of lichens and mosses

Subalpine acidophilic xerophytic grasslands

Relationships with habitat classifications. EUNIS: E4.391 Oro-Moesian Festuca paniculata grasslands, E4.3921 Oro-Moesian Festuca valida grasslands, E4.3922 Oro-Moesian Festuca balcanica grasslands, E4.393 Oro-Moesian Poa violacea grasslands; PAL. CLASS.: 36.391 Oro-Moesian Festuca paniculata grasslands, 36.3921 Oro-Moesian Festuca valida grasslands, 36.3922 Balkan Festuca balcanica grasslands, 36.393 Oro-Moesian Poa violacea grasslands; HD 92/43: 62D0 Oro-Moesian acidophilous grasslands; Bondev (1991): 3 Scrub community (Pineta mugi) partly mixed with potential shrubs (Alneta viridis, Saliceta waldsteinianae, etc.), and secondary shrubs (Junipereta sibiricae etc.) dwarf shrub (Vaccinieta vitis-idaeae, etc.) and grass (Nardeta strictae, Festuceta validae, etc.) communities, 8. Acidophilous psychrophytous grass communities (Nardeta strictae, Festuceta validae, Bellardiochloeta violaceae, Agrostideta capillaris, etc.).

Conservation status. BDA, HD.

Category. Vulnerable [VU – A1, 2 B2 C1 G2 H2 I J].

General characteristics. This group of habitats and the coenoses related with them occur mainly on steep slopes, sometimes up to 60°–70°, between 1900 and 2500 m alt. (exclusively below and above this vertical range). In cases when the forest vegetation is destroyed this group of phytocoenoses can reach down to 1700–1600 m alt. (rarely more below). The exposure is southern, eastern or with southern component. The bedrock is silicate. The soils are shallow or medium strong, more rarely deep, always very stony and sandy, but with high humus content. During most of the vegetative season they are dry; the snow melts early in the year and stays longer in the autumn compared to other areas in the subalpine regions. Often there is very fine gravel on the surface with rock outcrops in some places where the coenoses under consideration develop. The different stages of the development of the vegetation can be well traced in Rila Mts. The dominant species are grasses, often with large tufts. The grass layer is high, often reaching 60–80 cm. Depending on the succession stage of the phytocoenoses or other factors part of the communities are open and different species can freely enter these communities. In other cases, especially during the optimal stage of development of the coenoses dominated by Festuca valida, and in some places of Festuca balcanica, the tufts are very dense, covering the whole surface and other species manage to develop only on the tufts themselves. The floristic composition in most of the phytocoenoses is rich.

Most representative for this group of habitats are the coenoses of Festuca valida, Festuca paniculata, Bellardiochloa variegata (= Bellardiochloa violacea) and Festuca balcanica subsp. balcanica (the latterendemic for the Balkan Range). The coenoses of the Balkan endemic Festuca valida play a basic role in the xerothermic subalpine herbaceous subalpine vegetation in Rila, Vitosha, and Pirin Mts., and they are more limited in other Bulgarian mountains. Their habitats, compared to those of the other two fescue species generally occur on better developed and humid soils. The natural vertical distribution of the coenoses dominated by this species is located in the upper part of the subalpine subbelt. Only in some areas of the lower part of the alpine belt which are warmer and more protected by the wind, Festuca valida forms communities of limited area. In the lower parts of the subalpine belt these communities most often replace the destroyed forests. The slope varies from 5 to 70° but is mostly between 30 and 45°. The exposure most often is southern or eastern. In the relief depressions these coenoses occupy, as a rule, the buldging, stony places, and they avoid the high mountain ridges. In most cases these coenoses are among the floristically richest ones in the Bulgarian mountains, although Festuca valida is a strong edificator in them. A significant part of the species in the subalpine and alpine belt occur in these coenoses, except for the hygrophytes. Rare species, some of which are treated as characteristic for this group of coenoses, also occur: Centaurea kernerana subsp. georghieffii, Dianthus tristis, Hypericum richeri subsp. grisebachii, Jovibarba heuffelii, Viola balcanica, etc. The wide vertical range has its impact on the species composition but as a rule a large number of species are constant. At lower altitudes the abundance of Brachypodium sylvaticum, Calamagrostis arundinacea, Deschampsia flexuosa, Luzula luzuloides, L. sylvatica, Poa nemoralis, Rubus idaeus, Senecio nemorensis, Vaccinium myrtillus is high. Overgrazing causes the wide distribution of Nardus stricta even on steep slopes. At high altitudes species typical for the alpine coenoses also occur: Carex kitaibeliana, Juncus trifidus, Poa media, Potentilla ternata, Scleranthus neglectus, Sesleria comosa  etc. In some of the coenoses of Festuca valida the abundance of F. paniculata is also high.There are conenoses in which the two species are co-dominants.

On less developed, dry and skeletal soils, where the grazing is more limited, especially in the upper part of the subalpine vegetation belt, the herbaceous layer is dominated by Festuca paniculata. The edificator capacity of this species is smaller but the environment is less favourable and the floristic composition in some of the coenoses is poorer and the projective cover is lower (70–80%) compared to the coenoses of Festuca valida.In general the floristic composition of the two groups is very similar. Sometimes, together with the herbaceous species, the participation of Genista depressa, Juniperus sibirica, Pinus mugo, Vaccinium myrtillus is also high.. Recently, Chamaecytisus absinthioides has replaced the herbaceous coenoses. Stipa pennata is the second dominating species together with Festuca paniculata in the phytocoenoses in Rila and Pirin Mts. Very often together with the two fescue species, Bellardiochloa variegata (= B. violacea) has relatively high abundance. In Rila and Pirin Mts. this species plays a less dominating role compared to the other two, but in the Balkan Range in particular its coenoses play an important role in the composition of the vegetation cover above the timberline. The coenoses of Bellardiochloa variegata (as well as Festuca paniculata) develop both on silicate and limestone but the latter belong to a different habitat type. Most of the coenoses of Bellardiochloa variegata develop on sunny places such as the southern slopes with slants of 45° and more. They also occur in places with eastern and western exposures, sometimes on the mountain ridges and in the colines (e.g. in the Balkan Range). However the soil is always well aerated and very dry because it is stony and shallow to medium-strong and the rains are the only source of humidity. The rock outcrops are not an exception. Sometimes the erosion is strong. Similar to the whole group of xerothermic herbaceous coenoses on silicate rocks, the coenoses of Bellardiochloa variegata have a rich floristic composition. Apart from the monodominant coenoses, coenoses with high participation of Agrostis capillaris, Carex caryophyllea, C. kitaibeliana, Festuca dalmatica, F. rubra, Deschampsia flexuosa, Nardus stricta, Thymus vandasii also occur. Other frequently occurring species are Festuca nigrescens, Hieracium hoppeanum, Nardus stricta, Thymus longicaulis, Verbascum longifolium, etc.

The coenoses of the Balkan endemic Festuca balcanica subsp. balcanica rarely occur on acidic rocks or the steep, stony slopes of (1300) 1600 and 2200 m alt.They also belong to the group of the xerothermic phytocoenoses. The soils are shallow to well developed, moderately humid, and well aerated. Their floristic composition is very diverse. Some of the coenoses are monodominant while others are mixed with Achillea ageratifolia, or Agrostis rupestris, Antennaria dioica, Bellardiochloa variegata, Bruckenthalia spiculifolia, Calamagrostis arundinacea, Genista depressa, Hieracium hoppeanum, Koeleria eriostachya, Poa media, Saxifraga rocheliana, Sesleria caerulea. Agrostis rupestris, Antennaria dioica, Bruckenthalia spiculifolia, Calamagrostis arundinacea, Genista depressa, Hieracium hoppeanum, Koeleria eryostachia, Sesleria coerulans also occur. Although the communities of Carex kitaibeliana prefer limestone they also occur on silicate. Their composition is similar to those of the already-mentioned coenoses and thus they belong to the habitat type under consideration.

Another group of phytocoenoses also occur more often in the medium high mountains than in Rila and Pirin Mts. In some places they are of primary origin but more often they are of secondary origin. These are the coenoses of Calamagrostis arundinacea, Deschampsia flexuosa, Luzula luzuloides. The abundance of Agrostis capillaris, Anthoxanthum odoratum, Bellardiochloa variegata, Festuca airoides, Hypericum maculatum, Poa media, Vaccinium myrtillus is high. Two coenoses of the Balkan endemic Festuca amethystina subsp. kummeri, have been described from Rila Mts., where a dominant or a second dominant can be Bellardiochloa variegata. The syntaxonomic status of the considered coenoses is related to the alliance Poion violaceae.

Characteristic taxa.

Distribution in Bulgaria. This habitat type covers considerable areas on the southern and eastern mezo- and macro-slopes of Rila and Pirin Mts. Phytocoenoses belonging to this habitat are widely distributed in West and Central Balkan Range, Vitosha, Ossogovo and Belasitsa Mts.; (1350) 1600–2500 m alt.

Conservation importance. The habitat plays a significant soil formation and anti-erosion role. Some of its coenoses are typical only for SE Europe, hence are of national and European value. They have a rich biodiversity as well. Many species of the subalpine and alpine belts find favourable conditions in this habitat, including some protected species: Centaurea kernerana subsp. georghieffii, Dianthus tristis, Festuca amethystina subsp. kummeri, Jovibarba heuffelii, Lilium jankae, Viola balcanica.

Threats. Although the dominant species have bad foraging characteristics almost all mentioned above coenoses are used as pastures. Until 15 years ago, as a result of overgrazing, these coenoses were being replaced by the coenoses of Nardus stricta. After the intensity of the grazing decreased the abundance of Nardus stricta also decreased and in some places a revival of the shrub vegetation can be observed. Erosion is also a threat.

Conservation measures taken. The habitat is included in Annex № 1 of BDA. Parts of the phytocoenoses are within protected areas: Rila, Pirin and Central Balkan National Parks, Vitosha Nature Park, etc., and in protected sites of the European Ecological Network NATURA 2000.

Conservation measures needed. Regulation of grazing, monitoring of the habitat state and implementation of the regulations for the national parks.

References. Meshined et al. 2000, Roussakova 2000.

Author: Vesska Roussakova


Subalpine acidophilic xerophytic grasslands (distribution map)