06B1
Over-wet and flooded dune slacks
Relationships with habitat classifications. EUNIS: B1.81 Dune-slack pools; B1.85 Dune-slack reed beds, sedge beds and cane beds; PAL. CLASS.: 16.31 Dune-slack pools, 16.35 Dune-slack reed beds, sedge beds and cane beds; HD 92/43: 2190 Humid dune-slacks; Bondev (1991): 147 Psammophytous grass communities with a prevalence mostly of Leymeta racemosi, Ammophylleta arenariae, Galileeta mucronata, Centaureeta arenariae, Trachomitum venetum and shrub communities with a prevalence of Cionureta erectae and others mostly on the coastal sands.
Conservation status. BDA, BC, HD.
Category. Critically endangered [CR – A1, 2 C3 D3 E2 F2 G3 H3 I].
General characteristics. This habitat type occurs in the lower parts of the white and grey dune systems. In Atlantic Europe, with more humid climatic conditions, this habitat type is more diverse and is represented by different subtypes, including marshes, mires and communities of prostrate willows (Salix spp.), etc. In the conditions of a more arid climate of the Bulgarian Black Sea coast only two subtypes of this habitat can be distinguished depending on whether the coenoses develop in permanent water bodies in the dunes or in over-wet (wet) sands. These communities consist of typical hydro- or hygrophytes.
1. Permanent fresh water bodies in the dunes. This habitat in Bulgaria is unique to the Kamchiyski Pyasatsi locality, where Kamchia River has left old riverbeds and estuaries called “azmatsi” in the dunes. They are several permanent, eutrophic swamps, with an average depth of approx. 1,5 m. Typical hydrophytic communities of Ceratophyllum demersum, Lemna minor, L. trisulca, Myriophyllum spicatum, Potamogeton crispus, P. pectinatus, etc. occur. There is a belt of high grasses (reed, sedges, common at their periphery and sometimes in spring these places are flooded. Probably such water bodies existed in the past at the present Sunny Beach tourist complex. A contact zone existed between the dune complexes and the former Indzhekjoy (Nesebar) swamp, where in spring Hadzhiyska River flooded the dunes. This locality of the habitat is now completely destroyed.
2. Communities of high hygrophytes in over-wet lower places in the dunes. The communities occur together with the transitional habitat subtype, in the grey and white dunes and often make transition complexes with it. This habitat type occurs in the Shablenska Tuzla locality, near Shkorpilovtsi village – Kamchia River, Gradina and Zlatna Ribka camping places, near Nessebar and Sunny Beach tourist complex. Phytocoenoes of high hygrophytes such as Juncus littoralis (= Juncus acutus subsp. tommasinii), Phragmites australis, Scirpus lacustris (= Schoenoplectus lacustris), Typha angustifolia develop mostly on the over-wet sands, along small rivulets flowing close to the dunes and flooded areas beside them. The coenoses of Cladium mariscus (Shablenska Tuzla and Sunny Beach localities near Hadzhiyska river) that cover small areas occur very seldom. Transitional (mixed) coenoses with communities from the alliance Molinio-Holoschonion (see Mediterranean tall-grass communities beside rivers and dune slacks) develop in places with lower humidity.
Characteristic taxa.
- Vascular plants: Ceratophyllum demersum, Cladium mariscus, Juncus littoralis (= Juncus acutus subsp. tommasinii), Lemna minor, L. trisulca, Myriophyllum spicatum, Phragmites australis, Potamogeton crispus, P. pectinatus, Scirpus lacustris, Typha angustifolia.
- Fungi: Micromycetes – Anthracoidea subinclusa (on Carex melanostachya), Puccinia cancellata (on Juncus acutus), P. cladii (on Cladium mariscus), P. phragmitis, Ustilago grandis (on Phragmites australis).
- Animals: Mammalia – Chiroptera: Myotis daubentonii, Nyctalus noctula. Pipistrellus pipistrellus, P. pygmaeus, P. nathusii.
Distribution in Bulgaria. Black Sea coast, but restricted to Shablensko and Durankulashko lakes, Kamchia River – Shkorpilovtsi village, Nesebar – Sunny Beach resort, Gradina and Zlatna Ribka camping places.
Conservation importance. As a result of its restricted distribution and very specific way of formation the habitat type is threatened by extinction. The hydro- and hygrophytic coenoses themselves are unique and of conservation value although their species composition is mainly of widely distributed species. This is the main habitat of the protected species Cladium mariscus along the Black Sea coast. The imagos of water insects (mainly from family Chironomidae) are a very important food resource for the numerous bat communities in the warm months of the year.
Threats. Intensive development of tourism, building of mega-tourist complexes will most probably completely destroy the habitat. The changes in the hydrological regime of the water bodies near the beach, general aridisation and degradation of the dunes as a consequence of the anthropogenic activities, entering of ruderal and alien invasive species (Amorpha fruticosa, etc.) also have negative impact on the habitat.
Conservation measures taken. The habitat is included in Annex №1 of the national Biodiversity Act. Some of the localities are within protected areas (Kamchiyski Pyasatsi Protected Site, Pyasachni Dyuni Nature Monument between Gradina and Zlatna Ribka camping places) and protected sites from the European Ecological Network NATURA 2000.
Conservation measures needed. Termination of construction activities, urbanization and degradation of the still remaining dunes and beaches along the Black Sea coast; minimization of the tourist impact; termination of activities that contradict the protection regimes of the protected areas; designation of new protected areas and restoration of the natural water regime in the lower areas among the dunes.
References. Meshinev et al. 1994.
Author: Rossen Tzonev
