F. Shrub communities

Subcontinental steppe scrub

Relationships with habitat classifications. EUNIS: F3.2412 Subcontinental peri-Pannonic scrub, F3. 2413 Peri-Pannonic thickets; PAL. CLASS: 31.8B12 Subcontinental peri-Pannonic scrub, 31.8B13 Peri-Pannonic thickets; HD 92/43: 40A0 *Subcontinental peri-Pannonic scrub; Bondev (1991): 126 Shrub (Amygdaleta nanae) and grass (Artemisieta albae, Agropyreta brandsae, Brometa riparii etc.) steppe and xerothermic communities.

Conservation status. BDA, BC, HD.

Category. Endangered [EN – A1, 2 B1 C1 D3 E2 F2 G2 H3 I].

General characteristics. This habitat type encompasses a number of shrub communities distributed mainly in the continental parts of North and West Bulgaria and more rarely in isolated places in South Bulgaria. They occur mainly in dry, stony places, on poorly developed soils (Rendzic and others), mainly on limestone. Some of these shrub communities are parts of the relic steppe vegetation in Bulgaria; others are of secondary origin and develop on eroded ground in rare forests or their peripheries. The domination of shrubs from the family Rosacaceae is typical, but they do not include the widely distributed and almost completely of secondary origin shrub coenoses (replacing strongly destroyed forests) of Carpinus orientalis, Crataegus monogyna, Prunus spinosa, Rosa canina, Syringa vulgaris etc. The subcontinental steppe scrub includes coenoses that are mixed or are dominated by the following species: Amelanchier ovalis, Amygdalus nana, Cerasus fruticosa, Cerasus machaleb, Cotoneaster spp., Rosa myriacantha, Rosa pimpinellifolia and Spiraea media. The largest are the coenoses dominated by Amygdalus nana. It is a small shrub (up to 1 m high) that participates in the composition of the petrophytic steppes and in hasmophytic vegetation in some places. Most widely distributed are the complex shrub-tree coenoses dominated by Amygdalus nana that occur on the slopes of the low mountains West of Sofia (Chepan, Golo Bardo, Lyulin, Lozenska, Konyavska and Zemenska mountains), and more rarely in Dobrudzha plain, along the North Black Sea coast and the Danubian plain, Forebalkan, East Balkan Range and Toundzha Hilly Country (Bakadzhitsi hills). Many shrub and tree species participate in the composition of these coenoses . They occur mainly in poor, eroded, calcareous places with thin soil layers and have low projective cover, usually up to 60–70%. Amygdalus nana flowers in April – May and gives a rose aspect to the areas. In the composition of these communities also occur Achillea clypeolata, Artemisia alba, Astragalus angustifolius, A. onobrychis, Bromus riparius, Carex humilis, Cleistogenes serotina, Daphne cneorum, Festuca valesiaca, Medicago minima, Melica ciliata, Prunus spinosa, Satureja montana, Sesleria rigida, Syringa vulgaris, Thymus ssp., Trifolium alpestre, as well as some ephemeroids such as Adonis vernalis, Allium flavum, Crocus biflorus, C. flavus, Helleborus odorus, Muscari tenuiflorum, Pulsatilla montana.In some places single trees and shrubs occur, including remnants of destroyed forests, such as Acer hyrcanum, A. tataricum, Carpinus orientalis, Fraxinus ornus, Quercus cerris, Q. pubescens.

Phytocoenoses dominated by Rosa pimpinellifolia or Rosa myriacantha are also very typical for the habitat. These roses are small shrubs (0,50–1 m high), with thick, needle-like spines and large, white flowers. Their phytocoenoses cover relatively small areas, mostly several tens of square meters, in dry, eroded, stony places including the peripheries of rare oak forests (more rarely). In some places they participate in coenoses dominated by Amygdalus nana. Although only two associations are known (Rosa spinosissima-Bromus squarrosus and Rosa spinosissima-Festuca pseudovina) that are described in Lozenska Mts. applying the dominant method, they are more widely distributed in the country, particularly in its continental parts: mountains of West Bulgaria, Danubian Plain, Forebalkan, etc. Various herbaceous xerophytes, including some ruderal species, participate in the coenoses of Rosa pimpinellifolia. A community of Rosa myriacantha with a high abundance of Comandra elegans has been described from the region of Pleven. The shrub communities of Cerasus fruticosa are even rarer. Although they have not been described in the Bulgarian phytocoenological literature there are data on their occurrence in the Danubian Plain (Pleven heights, the region of Svistov, the valley of Russenski Lom River, Kabiyushka Mogila locality, Dobrudzha plain, etc.) and possibly in other regions of the country within the distribution range of the species. These coenoses are 1,5 m high, rare scrub that most often covers areas of several tens of square meters on dry and eroded slopes with xerophytic herbaceous vegetation, dominated by grasses (Bothriochloa ischaemum(=Dichanthium ischaemum), Chrysopogon gryllus, Stipa spp. etc.). Cerasus fruticosa participates also in the composition of the coenoses of Amygdalus nana that develop on the rocks of the canyon of Russenski Lom River.

The shrub communities in which the abundance of Spiraea media is high are relatively rare and occur also mainly in the low mountains of West Bulgaria but also in many places in the southern parts of the country. Based on the dominant method, one association has been described in which Spiraea media is a codominant together with Syringa vulgaris. It occurs in Vrachanska Mts. (Tosheva Mogila, Genova Mogila and Babka peaks), at about 1100 m alt. The shrub coenoses are open (cover up to 60%) and occupy eroded, southern slopes on karst limestone. Acer hyrcanum, Achillea clypeolata, Carpinus orientalis, Cerasus mahaleb (= Prunus mahaleb), Corylus colurna, Fraxinus ornus, Lunaria rediviva participate together with the dominants in the coenoses and give white-lilac aspect.Phytocoenoses with significant participation of Spiraea media also occur in other parts of the country throughout the distribution range of the species in the country, e.g. Lyulin, Golo Bardo Mts., etc.

Cerasus mahaleb can occur in Bulgaria as a tall shrub, in some places in Dobrudzha area, often of secondary origin, and as a small tree in the composition of the xerothermic oak and Oriental hornbeam forest along the North Black Sea coast. They are rarely abundant and rarely form coenoses but participate widely in the composition of various shrub communities and forests. The other shrubs from the family Rosaceae that participate in the subcontinental steppe scrub are Amelanchier ovalis, three Cotoneaster species (C. integerrimus, C. nebrodensis and C. niger), etc. With few exceptions these species do not form their own communities (e.g. a shrub community with high abundance of Amelanchier ovalis occur in Borovski Dol locality, Rudina Mts.), but participate in a number of shrub and herbaceous communities.  Amelanchier ovalis prefers rocky places with poor soil and outcrops of calcareous rocks.

Characteristic taxa.

Distribution in Bulgaria. Danubian Plain, Forebalkan, the mountains in West Bulgaria (Ponor plateau, Dragomanski Chepan Mt, Konyavska, Zemenska, Milevska Mts., Rudina Mts., Golo Bardo Mts., southern part of Vitosha Mts., Lozenska Mts., Lyulin Mts., etc.), East Balkan Range, North-East Bulgaria, North Black Sea coast, isolated localities in South Bulgaria: the Bakadzhitsi hills in Toundzha Hilly Country and probably in other places of the country; up to 1100 m alt.

Conservation importance. The coenoses participate in relic steppe complexes in which occur vascular plants of limited distribution in Bulgaria, including some protected plants such as Anemone sylvestris, Astragalus wilmottianus, Daphne cneorum, Eryngium palmatum etc. The fungus species of conservation importance Sarcosphaera coronaria also occurs.

Threats. Ploughing of the steppe habitats, grazing by domestic animals, deterioration of the herbaceous communities, afforestation, fires, extraction of limestone and other inert materials, infrastructure development.

Conservation measures taken. The habitat is in Annex № 1 of BDA and is of conservation priority. The locality in Kabuyshka Mogila locality near Shumen is within a Protected Site. Some of the localities are within sites from the European Ecological Network Natura 2000.

Conservation measures needed. Proclamation of some of the most representative localities of this habitat as protected areas (e.g. the localities in Dragomanski Chepan and Konyavska Mts.), phytocoenological studies, mapping.

References. Achtarov 1955; Velchev 1971; Ganchev 1961; Zhelezova 1955; Jordanoff 1936.

Authors: Chavdar Gussev, Rossen Tzonev

Subcontinental steppe scrub (distribution map)