09F2
High-mountain communities of Bearberry (Arctostaphylos uva-ursi)
Relationships with habitat classifications. EUNIS: F2.27. Alpine heaths Arctostaphylos uva-ursi and Arctostaphylos alpinus; PAL. CLASS.: 31.47. Alpine bearberry heaths; HD 92/43: 4060 Alpine and boreal heaths; Bondev (1991): 3 Scrub community (Pineta mugi) partly mixed with potential shrubs (Alneta viridis, Saliceta waldsteinianae, etc.) and secondary shrub (Junipereta sibiricae, etc.), dwarf shrub (Vaccinieta vitis-idaeae, etc.) and grass community (Nardeta strictae, Festuceta validae, etc.), 6 Siberian juniper community (Junipereta sibiricae) mostly mixed with secondary shrubs (Chamaecytiseta absinthioides, Vaccinieta myrtilli, Vaccinieta vitis-idaeae, Vaccinieta uliginosi, etc.) and grass communities (Nardeta strictae, Festuceta validae, etc.).
Conservation status. BDA, HD.
Category. Endangered [EN – A1, 2 B1 D2 E2 F2 H2 I L3 K].
General characteristics. Arctostaphylos uva-ursi is a pioneer species in rocky and stony places in the Bulgarian mountains from 1000 up to 2500 m alt. Its optimal development is in the subalpine belt. It participates also in secondary communities in areas with destroyed soil and vegetation cover. The species prefers silicate areas but can also occur on calcareous ground (limestone, dolomites). The localities are flat or slightly slanting, rarely steep. The species is defined as microthermic xeromesophyte. The exposure does not play a significant role for its development – it can occur on mountain ridges, northern and southern slopes. The large vertical range of distribution of Arctostaphylos uva-ursi is a result of its potential to develop on different soil types, Cambisols, Umbrosols, Rendzic, with different acidity and structure.
Being a pioneer species the phytocoenoses of Arctostaphylos uva-ursi occur on rock outcrops and stony places lacking in soil and vegetation. The roots enter small rock crevices where small quantities of fine soil have been accumulated. The development of the soil cover and the formation of phytocoenoses, especially in the upper subalpine sub-belt, has been a long process in harsh ecological conditions. The area covered by most of the phytocoenoses is between several to approx. 100 m2. The projective cover is very high, often 100%. In the early stages of the development of these communities there are no or very few other species, as a rule. The development of the soil cover and dying off of plant parts create conditions for the invasion of other species. The floristic composition of the phytocoenoses in the next successional stages depends very much on the altitude and on the composition of the surrounding vegetation. Most frequent species are Bruckenthalia spiculifolia, Vaccinium myrtillus, and V. vitis-idaea, whose ecological characteristics are similar to these of Arctostaphylos uva-ursi. The abundance of Avenula versicolor, Chamaespartium sagittale, Festuca airoides, Gentianella bulgarica, Juncus trifidus, Poa media, Potentilla ternata, Sesleria comosa, etc. varies in the upper subalpine sub-belt. With the development of the soil cover Arctostaphylos uva-ursi is being gradually replaced by other species and various polydominant phytocoenoses with complex spatial structures develop. They comprise dense, mosaic patches of different shrubs in which most often participate Arctostaphylos uva-ursi (Vaccinium uliginosum, V. myrtillus, V. vitis-idaea and/or Juniperus sibirica). In most places the soil cover is shallow and skeletal, dry or moderately humid. At the conditions of the upper subalpine sub-belt these phytocoenoses show sub-climax features. Their evolution results in the establishment of communities of the dwarf pine. The associations of Arctostaphylos uva-ursi on silicate belong to the order Vaccinio-Piceetalia. In the coenoses of Arctostaphylos uva-ursi on limestone, e.g. Kozya Stena locality in Central Balkan Range the following species participate: Anthyllis vulneraria, Asperula cynanchica, Bupleurum flavum, Carex kitaibeliana, Cotoneaster integerrimus, Daphne blagayana, Dryas octopetala, Leontopodium alpinum, Rhodax canus, Sesleria rigida, etc.
At lower altitudes, and especially in the beech vegetation belt, the primary phytocoenoses of Arctostaphylos uva-ursi are rare. Being a xeromesophyte the species participates, and sometimes plays an important role, in the ground layers of some coniferous phytocoenoses that develop on stony grounds. Most often these are communities of Pinus nigra subsp. palassiana, and more rarely of Pinus sylvestris. In North Pirin Mts. mixed coniferous coenoses of Pinus nigra and Pinus heldreichii also develop with the participation of Arctostaphylos uva-ursi in the ground layers dominated by Festuca penzesii. The soil is of humus-carbonate type, well developed and moderately humid. In West Rhodopi Mts. Arctostaphylos uva-ursi forms patches on the rocks alone or together with Vaccinium myrtillus, V. vitis-idaea and Bruckenthalia spiculifolia. It participates also in the composition of the phytocoenoses of Pinus nigra and Pinus sylvestris together with Chamaecytisus absinthioides, Vaccinium myrthillus, V. vitis-idaea. As a result of overexploitation Arctostaphylos uva-ursi is rare and in small patches.
Characteristic taxa.
- Vascular plants: Antennaria dioica, Anthoxanthum odoratum, Anthyllis vulneraria, Arctostaphylos uva-ursi, Asperula cynanchica, Bellardiochloa variegata (= Bellardiochloa violacea), Bruckenthalia spiculifolia, Bupleurum flavum, Carex bulgarica, C. kitaibeliana, C. ovalis (= Carex leporina), Chamaecytisus absinthioides, Chamaespartium sagittale, Cotoneaster integerrimus, Daphne blagayana, Deschampsia flexuosa, Dryas octopetala, Festuca airoides, F. penzesii, Gentianella bulgarica, Hypericum maculatum, Juncus trifidus, Leontopodium alpinum, Luzula luzuloides, Poa media, Potentilla ternata, Rhodax canus, Sesleria comosa, S. latifolia, S. rigida, Thymus sp.div., Vaccinium myrtillus, V. uliginosum, V. vitis-idaea.
- Fungi: Micromycetes – Phialina lachnobrachya (on dead leaves of Arctostaphylos uva-ursi).
Distribution in Bulgaria. In the mountain belt of Rila, Pirin, Vitosha, Ossogovo, Belasitsa, Slvyanka Mts., Balkan Range, Central and West Rhodopi Mts., and Sredna Gora Mts.; 1000–2500 m alt.
Conservation importance. Arctostaphylos uva-ursi is included in the Red Data Book of R Bulgaria as “rare.” Its phytocoenoses belong to the category of rare plant communities. Rare species such as Bupleurum flavum, Daphne blagayana, D. oleoides, Leontopodium alpinum. Dryas octopetala, Orchis pallens, occur in these communities.
Threats. Trampling, grazing, but above all collection of leaves of Arctostaphylos uva-ursi for medicinal purposes. Arctostaphylos uva-ursi has slow growth and development rates, and eradication of whole plants is inadmissible.
Conservation measures taken. The habitat is included in Annex № 1 of BDA. Part of the localities of this habitat are within the borders of Rila and Central Balkan National Parks, Vitosha Nature Park and Alibotush Strict Nature Reserve and in sites of the European Ecological Network NATURA 2000.
Conservation measures needed. Monitoring of the habitat state and effective implementation of the legal legislation in the protected areas.
References. Genova et al. 1987; Kochev 1967; Meshinev et al. 2000; Russakova et al. 1991.
Authors: Elena Genova, Veska Roussakova
