10F2
Mountain communities of Dryas octopetala
Relationships with habitat classifications. EUNIS: F2.2915 Carpatho-Balkan Dryas mats, F2.2917 Rhodopide mountain avens mats; PAL. CLASS.: 31.491 Carpatho-Balkan Dryas mats; HD 92/43: 4060 Alpine and Boreal heaths; Bondev (1991): 2 Calciphilous, cryophytous grass (Kobresieta myosuroides, Cariceta kitaibelianae, Seslerieta korabensis, etc.) and dwarf shrub communities (Dryeta octopetalae, Saliceta reticulatae, etc.), 9 Calciphilous shrub, dwarf shrub and grass communities (Festuceta penzesii, Sesleria korabensis, Astragaleta angustifoliae, Dryeta octopetalae, Chamaecytiseta absinthioides, Junipereta sibiricae, Junipereta pygmaei etc.).
Conservation status. BDA, HD.
Category. Endangered [EN – A1, 2 C2 D3 E3 H2 I L1].
General characteristics. Mountain avens (Dryas octopetala) is a chamaephyte, small, evergreen shrub with creeping, strongly branched stems, up to 50 cm long, densely caespitose. It is an arctic-alpine geoelement. It is a mesoxerophyte that is not demanding of temperature conditions. The species is a glacial relic in the Bulgarian flora. It forms small areas of phytocoenoses on the highest mountain ridges subjected to strong winds, on the slopes and in the bottom of the cirques in the alpine belt of the high mountains and on steep, mainly northern slopes in the subalpine belt. The soils vary from shallow rendzina soils to average strong humus-carbonate, stony soils developing on limestone and dolomites. The soils are usually slightly alkaline. Mountain avens exhibits good edificator and dominant features and has high abundance in its communities. The total projective cover is high, 80–100%. In some coenoses the above-ground projective cover is limited, but the roots are well developed, hence the great importance of these plants for consolidation of the screes. The age of the different plant mats can be more than 100 years. The communities are of primary origin. There is no tendency towards an increasing of the areas covered by these coenoses or expanding the distribution of the species and establishment of new coenoses. Most often the composition of the coenoses is very diverse and related to the specificity of the habitat. Two main groups of coenoses exist: typical alpine coenoses at high altitudes and coenoses with the participation of a large number of subalpine species at more moderate altitude. The phytocoenoses that occur in the alpine belt of Rila and Pirin Mts. (similar in composition are also the ones in Slavyanka Mts., although they are at lower altitude), occupy very limited areas. The ecological conditions are very harsh, the soils are shallow and skeletal. The bedrock is limestone. The coenoses occur on the mountain ridges and are subjected to strong winds, or are found on the slopes of the cirques where the snow cover is thick and the vegetation period is very short. The following species participate in these coenoses: Armeria alpina, Artemisia eriantha, Carex atrata, C. bulgarica, C. curvula, C. ericetorum, Cetraria aculeata, C. islandica, Dianthus microlepis, Festuca riloensis, Gentianella bulgarica, Juncus trifidus, Kobresia myosuroides, Oxytropis campestris, Pedicularis verticillata, Primula minima, Saxifraga paniculata, Sesleria comosa, Silene acaulis, Vaccinium uliginosum etc. In the coenoses under consideration there are species typical for Carici rupestris-Kobresietea and Elynetalia such as Carex atrata, Kobresia myosuroides, Oxytropis campestris, Silene acaulis etc. However, the number of species from Seslerietalia comosae (Sesleria comosa, Carex curvula, Festuca riloensis, Juncus trifidus, Gentianella bulgarica, Primula minima, Dianthus microlepis etc.) is also rather high. Therefore, a new association needs to be identifed that is different from the known associations from other mountains in Europe belonging to Elyno-Seslerietea.
The coenoses of the mountain avens that occur in Central Balkan Range at 1600–1700 m alt. occupy the mountain ridges and very steep slopes. They are subjected to strong winds, but the soils are relatively well developed with occasional outcrops. Some of the communities are monodominant. In others a significant role is played by Vaccinium vitis-idaea, Sesleria latifolia, S. rigida,in some places Juniperus sibirica, and to a more limited extent Anthyllis vulneraria, Carex kitaibeliana, Carum rigidulum subsp. bulgaricum, Crocus veluchensis, Daphne blagayana, Festuca balcanica, F. pseudodalmatica, Helianthemum nummularium, Homogyne alpina, Iberis saxatilis, I. sempervirens, Leontopodium alpinum, Linum capitatum, Luzula luzuloides, Rhodax canus, Thymus spp.etc.
The participation of endemics, some of them locally distributed in the Balkan Range, and the participation of species that are more frequent for the lower subalpine belt (some of them occurring even at lower altitudes) are the reasons for the need to determine a local association different from the ones that occur in other European mountains.
Characteristic taxa.
- Vascular plants: Anthyllis vulneraria, Armeria alpina, Artemisia eriantha, Carex atrata, C. bulgarica, C. curvula, C. ericetorum, C. kitaibeliana, Carum rigidulum subsp. bulgaricum, Dianthus microlepis, Dryas octopetala, Festuca balcanica, F. riloensis, F. pseudodalmatica, Gentianella bulgarica, Kobresia myosuroides, Iberis saxatilis, I. sempervirens, Juncus trifidus, Juniperus sibirica, Leontopodium alpinum, Linum capitatum, Luzula luzuloides, Oxytropis campestris, Pedicularis verticillata, Primula minima, Rhodax canus, Saxifraga paniculata, Sesleria comosa, S. latifolia, S. rigida, Silene acaulis, Thymus spp., Vaccinium uliginosum.
- Fungi: Macromycetes – Galerina vittiformis, Inocybe egenula, Laccaria montana, Marasmius epidryas (on the dead parts of Dryas octopetala); Lichens – Cetraria aculeata, C. islandica.
Distribution in Bulgaria. Rila, Pirin, Slavyanka Mts., Central Balkan Range, from 1570 up to 2800 m alt.
Conservation importance. The rare and protected species Alyssum cuneifolium, Asperula capitata, Carex fuliginosa, Daphne blagayana, Gentiana frigida, Potentilla apennina subsp. stojanovii, Rhodax alpestris, Thymus perinicus etc. participate in these coenoses. The coenoses of the mountain avens are relic and rare for the vegetation in Bulgaria.
Threats. Some of the communities are pastures, others are in close proximity to tourist routes and are threatened by trampling or direct destruction.
Conservation measures taken. The habitat is in Annex № 1 of BDA. Significant parts of this habitat are within Rila, Pirin and Central Balkan National Parks, Alibotush Strict Nature Reserve and sites from the European Ecological Network Natura 2000.
Conservation measures needed. Monitoring of the state of the coenoses and effective implementation of the existing legal documents and regimes in the protected areas.
References. Bondev 1959, Ganchev 1963; Kochev 1967; Meshinev et al. 2000; Roussakova 2000.
Author: Veska Roussakova
