FW3H Cladium mariscus – Phragmites australis swamp
Vegetation
This community comprises typically rather species-poor, dense stands of Cladium mariscus. Phragmites australis is also a constant species here but is usually clearly subordinate to Cladium. No other species is frequent, but careful searching between the saw-toothed leaves may occasionally reveal some plants of Equisetum fluviatile, Menyanthes trifoliata or Mentha aquatica. Infrequently, tussocks of Molinia caerulea and Schoenus nigricans may occur. There is usually very little in the way of a bryophyte layer.
Ecology
These stands occur in rather nutrient-poor but strongly alkaline conditions, in a variety of habitats, including lake margins, fens and flushed areas of bog.
Sub-communities
No sub-communities are currently described.
Similar communities
This is a distinct community which should be easily recognised.
Conservation value
Open, diverse stands of Cladium mariscus swamp and denser stands occurring adjacent to other types of fen, fen-meadow or tall-herb swamps, correspond in Ireland with the priority EU HD Annex I habitat 7210 Cladium fen*. Low diversity, closed stands occurring in isolation are not deemed to correspond. Species/4 m2 = 7.0, n = 73.
Management
These stands are typically unmanaged. The main threats are from peat extraction, infilling, drainage and reclamation.