01E1

E. Herbaceous communities and communities of lichens and mosses

Pioneer thermophylic herbaceous communities in calcareous, rocky and stony places

Relationships with habitat classifications. EUNIS: E1.111 Middle European stone crop swards, E1.112 Sempervivum or Jovibarba communities on rock debris, E1.113 Middle European rock debris communities; PAL. CLASS.: 34.111 Middle European stonecrop swards, 34.112 House-leek communities, 34.113 Middle European grassy rock debris communities; HD 92/43: 6110 *Rupicolous calcareous or basophilic grasslands of Alysso-Sedion albi.

Conservation status. BDA, BC, HD.

Category. Nearly Threatened [NT – A1, 2 C1 D3 E1 F1 G1 H2 I L1].

General characteristics. This habitat type comprises dry, decomposed surfaces of calcareous rocks – peaks, „cornices”, small terraces and hills, hillocks  from the lowlands up to the mountains (900–1000 m alt.). Most often they cover small areas and form complexes with herbaceous communities of Festuco-Brometea or with open, xerothermic woods and shrubs (mostly Quercus pubescens, Fraxinus ornus, Carpinus orientalis, Palliurus spina-christi).At higher altitudes they are neighbouring more mesophytic woods. These coenoses develop on poor, primitive, sandy or stony, calcareous or neutral soils. The vegetation is of pioneer type, open, thermophyllous, consisting mainly of mosses, lichens, terrophytes and succulents or semi-succulents. The projective cover exceeds 30%, but the ground without vegetation is also not less than 30%.

In steep places, at 1000–1800 m alt., relatively specific vegetation develops with the participation of Jovibarba heuffelii and more often Sempervivum erythraeum together with Agrostis rupestris, Dianthus moesiacus, Thymus vandasii, etc.

At lower altitudes, the coenoses of Sempervivum zeleborii occur rarely and the coenoses of Sedum stefco are even rarer. Phytocoenoses with the participation of Potentilla emilii-popii occur very rarely in NE Bulgaria. Sedum acre, S. annuum, S. dasyphyllum, S. hispanicum, S. maximum, S. tuberiferum occur more often as dominants accompanied by other species from the alliance Alysso alyssoidis-Sedion albi. Arabis recta, Poa badensis, Potentilla cinerea, Saxifraga tridactylites, Scleranthus perennis, S. polycarpos,and Sedum album, sometimes as dominants as well, occur in many places, on open stony areas and rock crevices with small tilt. Common species in these coenoses are Acinos arvensis, Bothriochloa ischaemum (= Dichanthium ischaemum), Convolvulus cantabrica, Eryngium campestre, Festuca valesiaca, Hieracium pilosella, Medicago minima, Minuartia caespitosa, Plantago scabra, P. subulata, Sanguisorba minor, Scilla autumnalis (only in S Bulgaria), Seseli rigidum, Sideritis montana, Stachys recta, Teucrium chamaedrys, Thalictrum simplex subsp. rhodopaeum, Trifolium repens.The diversity of mosses (Syntrichia spp., Bryum spp., Grimmia spp.), and lichens (Xanthoria spp., Cladonia spp., Collema spp.) is also typical. They develop at more favourable hydrological conditions during the autumn and especially in the winter.

Coenoses of Melica ciliata as edificator occur in the whole country, on dry, sunny and stony slopes and rocks (mostly calcareous). They occur mainly up to 1000 m alt. but rarely can appear at higher altitudes. These communities include Achillea clypeolata, Acinos arvensis, Artemisia campestris, Asplenium ruta-muraria, A. septentrionale, A. trichomanes, Cardaminopsis arenosa, Cruciata glabra, Cystopteris fragilis, Erysimum odoratum, Ferula heuffelii, Festuca rupicola, Galium album, Genista januensis, Helianthemum nummularium, Jurinea mollis, Linum tenuifolium, Phleum montanum, Sedum acre, S. album, S. annuum, S. dasyphyllum, S. hispanicum, S. maximum, Stachys recta, Stipa joannis, S. pulcherrima, Teucrium chamaedrys, T. montanum, Veronica austriaca subsp. jaquinii, Vincetoxicum hirundinaria.

The phytocoenoses of the habitat under consideration are floristically very rich, and syntaxonomically are related mainly to the alliance Alysso-Sedion albi from class Koelerio-Corynephoretea,whose diagnostic species often occur – Acinos arvensis, Alyssum alyssoides, Cerastium brachypetalum, C. pumilum, C. semidecandrum, Clypeola jonthlaspi, Geranium rotundifolium, Hornungia petraea, Medicago minima, Saxifraga tridactylites, Sedum album, Sempervivum tectorum, Thlaspi perfoliatum, Veronica praecox, Minuartia hybrida.Many species from Sedo albi-Veronicion dillenii also occur: Cruciata pedemontana, Scleranthus verticillatus, Veronica dillenii, Veronica verna, Viola kitaibeliana, etc.The following species also can be observed: Arabis recta, A. sagittata, Arenaria serpyllifolia, Bromus tectorum, Erophila verna, Geranium rotundifolium, Grimmia pulvinata, Holosteum umbellatum, Hornungia petraea, Jovibarba heuffelii, Minuartia glomerata, M. hybrida, M. setacea, Paronychia cephalotes, Poa badensis, Scleranthus annuus, Syntrichia ruralis, Teucrium montanum, Trifolium scabrum, Veronica praecox.

Characteristic taxa.

Distribution in Bulgaria. From the low karst areas in Bulgaria: Forebalkan, the dry valleys of NE Bulgaria (Ludogorie region), the canyons in the Danubian plain and low mountains of W Bulgaria up to 1800 m alt.

Conservation importance. Pioneer communities with the participation of rare and endangered plants and plant communities: Ferula heuffelii, Festuca rupicola, Minuartia rhodopaea, Potentilla emilii-popii, Sempervivum ciliosum, Seseli rhodopeum, Teucrium botrys, etc.

Threats. Construction activities and infrastructure development, grazing, mining of inert materials, air pollution, development of tourism industry.

Conservation measures taken. The habitat is included in Annex № 1 of the national Biodiversity Act. Some localities are within protected areas: Russenski Lom Nature Park, Studenets Protected Site, Chernelka Protected Site, etc. and in sites of the European Ecological Network NATURA 2000 in Bulgaria.

Conservation measures needed. Complete investigation of the plant communities of this habitat type; development of their syntaxonomy and assessment of their conservation importance.

References. Tzonev 2005a.

Authors: Chavdar Gussev, Veska Rousskova, Dimitar Dimitrov


Pioneer thermophilic herbaceous communities in calcareous rocky and stony places (distribution map)