08C2
Karst springs and streams with travertine formations
Relationships with habitat classifications. EUNIS: C2.121 Petrifying springs with tufa or travertine formations; Pal. Class.: 54.121 Middle European tufa springs; HD 92/43: 7220 *Petrifying springs with tufa formations (Cratoneurion).
Conservation status. BDA, BC, HD.
Category. Endangered [EN – A1, 2 E2 F2 G2 H2 L2].
General characteristics. Habitats of this type occur both in mountain areas with deciduous forests and in lowlands with herbaceous and shrub vegetation. They occur in karst (limestone and marble) areas, with active accumulation of travertine. Travertine formations accumulate in springs with high concentration of calcium carbonate in the water but also in places where the water penetrates and runs down rock walls. They occur also in flooded areas along rivers or river thresholds and in these cases the vegetation is submerged or semi-submerged. They cover relatively small areas and the coenoses are patchy or linear-shaped. They are dominated by bryophytes from the genera Cratoneuron and Palustriella that are adapted to calcareous substrates. The vegetation belongs to the alliance Cratoneurion commutatum. As a result of the permanent watering with hard water the moss tufts and “curtains on the slopes or rock walls and the eroded river banks become impregnated with limestone and form hard tufts and porous calcareous cones. The habitat also makes complexes with herbaceous communities on limestone (order Festuco-Brometalia).
Characteristic taxa.
- Vascular plants: Carex flacca, Equisetum telmateia, Eupatorium cannabinum, Phyllitis scolopendrium, Saxifraga aizoides, Silene pusilla; Mosses – Cratoneuron filicinum, Eucladium verticillatum, Hygrohypnum luridum, Palustriella commutata, P. decipiens, P. falcata, Philonotis calcarea.
- Animals: Mollusca – Physa spp., Galba truncatula, Hydrobiidae, Pisidium spp.; Crustacea: Alona spp., Simocephalus spp., Chydorus sphaericus, Paracyclops fimbriatus, Eucyclops serrulatus, Megacyclops viridis, Acanthocyclops vernalis, A. gr. “kieferi”, Diacyclops bicuspidatus, D. languidoides, D. clandestinus, Canthocamptus staphylinus, Echinocamptus pilosus, Elaphoidella spp., Bryocamptus zschokkei, B. typhlops, Moraria poppei, Attheyella crassa, A. wierzeiskii, Asellus aquaticus, Gammarus balcanicus, Niphargus spp.; dominant Crustacea: Gammarus balcanicus; Insecta: Ephemeroptera: Epeorus spp. Ancilus fluviatilis also occurs, particularly in W and C Balkan Range.
Distribution in Bulgaria. Karst areas in Bulgaria: West and Central Balkan Range, Pirin Mts., Rhodopi Mts. (Bachkovo village, along the road to Chudnite Mostove locality), Devetsahko and Shumensko Plateaus, West Frontier Mountains, North Black Sea coast (the area northwards from Balchik town), Iskar gorge (Lakatnik village), Iskrecka river, Zemen gorge, Transka Banya locality, etc.
Conservation importance. The critically endangered species Asplenium lepidum occurs in this habitat type.
Threats. Global warming and aridisation, erosion, infrastructure development, urban development, changes in the hydrological regime of the water bodies, building of water power stations. Human activities such as water catchments, riverbed redirection, watering of arable land, extraction of marble and limestone in stone pits are among the most adverse threats.
Conservation measures taken. The habitat is in Annex № 1 of BDA and is of conservation priority. Parts of the habitat are within protected areas: Shumensko Plato (plateau) Nature Park, Central Balkan National Park, and sites from the European Ecological Network NATURA 2000. However the majority of the localities of this habitat type are outside the existing protected areas in Bulgaria.
Conservation measures needed. Preservation of the existing hydrological regime within the habitat itself and within its water catchment; limitation to their minimum of construction activities, ploughing, flooding, erosion. It is recommended to include this habitat in the National Biodiversity Monitoring System. This will allow a detailed assessment of its state and elaboration of a long-term program for its restoration and conservation.
References. Petkoff 1943; Dierssen 2001.
Authors: Anna Ganeva, Dimitar Kozhuharov
