14F2

F. Shrub communities

Sub-alpine willow (Salix spp.) communities

Relationships with habitat classifications. EUNIS: F2.32162 Balkan Range willow brush, F2.32163 Rhodopide willow brush; PAL. CLASS.: 31.6216 Southeastern alpine willow brush, Balkan Range willow brush, 31.62163 Rhodopide willow brush, 31.621631 Rhodopide Lapland willow brush, 31.621632 Rhodopide small willow brush, 31.621633 Rhodopide tall willow brush; HD 92/43: 4080 Sub-arctic Salix spp. scrub; 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 (Nardeta strictae, Festuceta validae etc.) community, 5 Hygropsychrophilous (peat bog) communities.

Conservation status. BDA, HD.

Category. Endangered [EN – A1, 2 B1 C2 D2 E2 G2 H2 1].

General characteristics. The phytocoenoses typical for this habitat type are dominated by the oligothermal willows Salix appendiculata, S. hastata, S. lapponum, S. silesiaca, and S. waldsteiniana, that grow in peat-bogs, marshes, along streams and rivers. These willows have limited distribution in the Bulgarian mountains and occur separately or together. Salix lapponum is a short shrub, up to 1–1,5 m high, that occurs mainly on Vitosha plateau at about 2000 m alt. Some phytocoenoses reach 1600 m alt. Very rarely Salix lapponum makes small phytocoenoses among the Dwarf pine shrubs in the marshes in the subalpine belt of Rila Mts. at 2300–2400 m alt. A considerable number of species participate in the composition of this habitat type. Main species are Deschampsia caespitosa. Sanguisorba officinalis, Potentilla erecta. More limited in distribution are Alchemilla glaucescens, Baeothryon caespitosum (= Trichophorum caespitosum), Bistorta major (= Polygonum bistorta), Carex cinerea (= Carex curta), C. echinata, C. flava, C. nigra, Carex ovalis (= Carex leporina), C. umbrosa, Cirsium heterotrichum, Eriophorum angustifolium, E. latifolium, Juncus conglomeratus, J. effusus, Molinia caerulea, Potentilla palustris (in Vitosha Mts.), Succisa pratensis, Swertia perennis, etc. In Vitosha Mts. the Lapland willow is accompanied by Salix waldsteiniana, whose shrubs are usually slightly higher. In most cases they are at the periphery of the groups of shrubs of the Lapland willow. In some places they can make monodominant communities. They occur mainly in stony places along streams. The two species, especially the Lapland willow, find optimal conditions for their development in Vitosha Mts. and their areas of distribution increase. In Pirin and Rila Mts. and in the Balkan Range the Waldstein willow makes monodominant shrub coenoses in wet, stony places with different slant above 1500 m alt. Angelica pancicii grows together with Salix waldsteiniana along the streams and rivers.

The oligothermal species Salix hastata is rare for the Bulgarian flora and is known only from Josifovitsa peak in Rila Mts., where its distribution is very limited.

Only Salix silesiaca of all tall willows very rarely forms phytocoenoses alone or together with other willows. Single individuals or small groups occur mainly among the Dwarf pine shrubs and in the coniferous belt. Phytocoenoses mixed with Alnus viridis develop very rarely and in them the Green alder makes a second layer. Abies alba, Acer heldreichii, Betula pendula, Picea abies, and Pinus sylvestris have limited distributions in some areas. The species composition of the ground layers is similar with that of the theDwarf pine and forest coenoses: Campanula rotundifolia, Cirsium appendiculatum, Doronicum columnae, Geranium macrorrhizum, Geum coccineum, Hypericum maculatum, Juniperus sibirica, Luzula luzuloides, L. sylvatica, Rubus saxatilis, Vaccinium myrtillus, etc. The habitats are stony, always humid and with poorly developed soil layer.

Salix appendiculata is very limited in Bulgaria. Single individuals have been found only in Rila Mts., and they do not form phytocoenoses. The syntaxonomy of the communities of the alpine and sub-Arctic willows in Bulgaria has not been studied. The occurance of syntaxa of higher rank like Alnion viridis, Adenostyletalia alliariae and Mulgedio-Aconitetea is possible in Bulgaria.

Characteristic taxa.

Distribution in Bulgaria. Vitosha, Pirin, Rila and Rhodopi Mts. and the Balkan Range; 15000–2500 m alt.

Conservation importance. The hygrophilic communities are a natural reservoir for long preservation of water. They are an irreplaceable regulator of their exploitation in the dry season. Some rare species (e.g. Potentilla palustris) occur as well, thus  increasing their conservation significance.

Threats. The natural succession processes from hygrophilic towards mezophilic vegetation in combination with the climate changes threaten the existence of this habitat type and at the same time reduces the water supply not only in the mountains but also the adjacent and more distant flat areas of the country. The drainage of the areas with the phytocoenoses of the sub-Arctic willows causes transformations into the mezophilic communities and the disappearance of the habitat type under consideration.

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

Conservation measures needed. Termination of the drainage of the hygrophytic habitats, thus stopping the replacement of the hygrophilic communities by mezophilic and xero-mezophilic ones; study, monitoring and conservation of the adjacent shrub and forest communities.

References. Bondev et al. 1982.

Author: Veska Roussakova


Sub-alpine willow (Salix spp.) communities (distribution map)