06C1
Dystrophic lakes
Relationships with habitat classifications. EUNIS: C1.4 Permanent dystrophic lakes, ponds and pools. PAL. CLASS.: 22.14 Dystrophic water bodies. HD 92/43: 3160 Natural dystrophic lakes and ponds.
Conservation status. BDA, HD.
Category. Endangered [EN – A1, 2 C2 E2 F2 G2 H2].
General characteristics. The lakes and swamps that belong to this habitat type have brown water due to the peat and high quantity of humus acids. The acidity is low (pH 3–4,8). Their natural development is towards the establishment of peat bogs. Phytoplankton and zoobenthos are absent. Zooplankton complexes of rotifers and cladoceran crustaceans develop periodically thus replacing the detritus that accumulates and is not subjected to degradation as a result of the low acidity of the water. After the plankton bloom is over the zooplankton enters into the egg-stage of its development until the next quantity of detritus is accumulated. When the dystrophic lakes are in coniferous forests (spruce forests with fir or dwarf pine communities), their acidity is influenced by the needles accumulated on the surface. The coenoses belong to the alliance Sphagno-Utricularion. They make complexes with oligotrophic, poor in limestone, temporary water bodies and temporary dystrophic water bodies.
Characteristic taxa.
- Vascular plants: Carex rostrata, Sparganium minimum, Utricularia minor; mosses – Calliergon spp., Drepanocladus spp., Sphagnum inundatum, S. subsecundum.
- Fungi: Macromycetes – Galerina sphagnorum;Micromycetes – Anthracoidea inclusa (on Carex rostrata), Rhizophydium pollinis-pini (onpollen of Pinus sylvestris and P. mugo).
- Animals: frequent plankton organisms: Rotifera: Adineta vaga, Keratella cochlearis, Polyarthra dolichoptera; Dicranoporus forcipatus, Lecane sympoda; Cladocera: Daphnia obtusa, Chydorus sphaericus; Copepoda: Macrocyclops fuscus, M. albidus, Eucyclops serrulatus.
Distribution in Bulgaria. This habitat type includes the mountain lakes where vegetation development and accumulation of peat have started. Such are Skakavitsa lakes and the lakes in the forests below Skakavitsa chalet (Belichki Mochuri lakes). They are temporary water bodies in the glacier valley of the Seven Rila Lakes and Chakangyol lakes in NW Rila Mts., part of the lakes in Popovska glacier valley in Pirin Mts., Chairski and Smolyanski lakes in Rhodopi Mts.
Conservation importance. The habitat is important for the conservation of Utricularia minor, a protected species from Annex № 3 of BDA as well as for the protection of a fungal species of conservation importance, Galerina sphagnorum.
Threats. Global warming and aridisation, changes in the hydrological regime of the lakes, atmospheric pollution, eutrophication due to tourism and stock breeding.
Conservation measures taken. The habitat is included in Annex № 1 of BDA. A significant part of the lakes are in Rila and Pirin National Parks, and sites from the European Ecological Network NATURA 2000.
Conservation measures needed. Preservation of the existing hydrological regime in the areas of the lakes; maximum limitation of construction activities, waste pollution, and drainage. The inclusion of these lakes in the National Biodiversity Monitoring System will make it possible to elaborate and implement a long-term program for their restoration and conservation.
References. Ivanov et al. 1964; Dierssen 2001; Kozuharov 2006; Naidenov 2000; Naidenov & Beshkova 2000.
Authors: Anna Ganeva, Dimitar Kozhuharov
