Small-sedge base-rich fen and calcareous spring mire

This habitat includes calcareous fen vegetation of the lowlands and mountains of the European nemoral zone, and it also occurs more rarely in the boreal zone where calcareous substrates and the influence of base-rich water are scarce. Calcareous fens occur at sites with a permanently high water table, often near springs, and they are particularly common in areas with calcareous bedrock, especially in the mountain systems of central Europe. Water is rich in calcium, magnesium and bicarbonates and precipitation of calcium-carbonate and tufa formation is common, and also accumulation of organic matter due to permanently wet conditions which reduce decomposition processes. The soil has a high proportion of organic matter and is base-rich, but with limited availability of nutrients.

The vegetation of base-rich fens is dominated by small sedges such as Carex davalliana, C.  flava, C. hostiana, C. lepidocarpa and other short or medium-tall Cyperaceae such as Blysmus compressus, Eleocharis quinqueflora, Eriophorum angustifolium and E. latifolium. In some places these species typical of fens grow together with species characteristic of wet meadows on mineral soil such as Anthoxanthum odoratum, Briza media, Caltha palustris, Cirsium palustre, C. rivulare, Cynosurus cristatus, Festuca rubra agg., Holcus lanatus, Lychnis flos-cuculi, Plantago lanceolata and Ranunculus acris. Bryophytes are common, in some stands reaching a cover close to 100% and, in the moss layer, species of fens (e.g. Bryum pseudotriquetrum, Campylium stellatum, Hamatocaulis vernicosus, Palustriella commutata and Scorpidium cossonii) can grow together with species typical of mineral soils (e.g. Cirriphyllum piliferum, Climacium dendroides, Plagiomnium affine agg., Rhytidiadelphus squarrosus), although the latter may be absent at some sites, especially in primary fens.

Small-sedge calcareous fens can be primary habitats developed around springs and seepages of calcium-rich water. Some of them can be several thousand years old and the long-term habitat continuity can be indicated by the occurrence of species such as Primula farinosa, Salix rosmarinifolia or Triglochin maritimum. At some sites, however, fens can be natural but only a few centuries old, and in other sites they can be secondary, developed on formerly forested land and be dependent on regular mowing. Many of them have been mown once a year without input of fertilizers for several centuries. Export of nutrients with hay has led to partial elimination of nutrient-demanding tall-growing species of wet meadows. Many of these species are still growing in these grasslands but their competitive ability is too weak to outcompete short-growing fen species. Small-sedge fens are most common and most diverse in the limestone massifs of the central European mountain systems, especially the Alps and the Carpathians.

In many places calcareous fen meadows have been damaged or destroyed by artificial drainage, which has caused mineralization of nutrients in the fen sediment and the spread of nutrient-demanding species of wet meadows or species of strongly-drained mesic meadows. To some extent they can be negatively influenced by livestock grazing as well.

Indicators of good quality:

In general, primary fens without species of wet meadows are more valuable than secondary fens. However, in some areas, especially in the lowlands, primary fens may not occur and in that case the secondary fens with meadow species have the highest conservation value.

·      Stable hydrological regime

·      Continued traditional management at secondary habitats

·      Absence of overgrazing

·      No encroachment of trees or shrubs

·      No spread of tall-growing nutrient-demanding herbs

·      Absence or low incidence of neophytes

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats