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Bundesamt für Naturschutz

Hard oligo-mesotrophic waters with benthic vegetation of Chara spp.

Oligotrophic to mesotrophic calcareous waters of all zones hosting submerse stonewort communities (Charetalia order). The vegetation is mostly species-poor and strongly dependent on the water chemistry and nutrient content (from oxygen-rich substrates to sapropel formation, or saline influence).

The European Commission has clarified that - depending on the definition of the term 'natural' - this habitat type may be primary or secondary (e.g. ponds) if its occurrences are subject to (semi-)natural development.

Natura 2000-Code

Notes on habitat mapping

Apart from the presence of the relevant vegetation this habitat is further characterized by the prevailing oligotrophic to mesotrophic conditions and the calcareous water.

The entire waterbody in which vegetation of the syntaxa given above has been recorded is to be included. Apart from the open water the amphibious zone with its reedbeds, tall herb fringe communities, and sedge swamps is to be included. Stands of the plant communities given above which occur outside of oligo- or mesotrophic waters are excluded. Stands in non-environmental waters are excluded. However, older lakes which have formed in extraction sites and are subject to natural development are to be included as important secondary habitats.

Stonewort communities of brackish waters should be considered under estuaries (1130), lagoons (1150) or shallow inlets and bays (1160). Shallow bog hollows with Chara species in calcareous fen complexes should be considered under habitat type 7230 alkaline fens). Vauclusian springs with Chara species and tufa formation are to be considered under habitat type 7220.


All waters (including siliceous ones which do not currently fall into this category) containing submerse stonewort communities should be protected.

Various Chara species occur sporadically in newly created lakes and ponds (e.g. gravel extraction). Secondary waters (e.g. flooded gravel pits) are not normally recorded as they are man-made habitats, or are excluded on account of being still actively worked. An exception are older such waters which have been left undisturbed for some time, especially in physiographic regions where natural examples of this habitat type are now lacking.

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