FW3C Carex rostrata swamp
Vegetation
This community consists of glaucous, usually dense beds of Carex rostrata. No other species is more than occasional in the community as a whole, therefore further details on the vegetation are described under sub-communities.
Ecology
This vegetation type occurs around the margins of mesotrophic and slightly dystrophic lakes and pools. Stands have also been recorded in turloughs. It may also be found in poor fens and in upland flushes amongst blanket bog and wet heath.
Sub-communities
Two distinct sub-communities are described. In the Phragmites australis – Equisetum fluviatile sub-community (FW3Ci) of mesotrophic lakes, Carex rostrata, growing in standing water, may be the only species present. Some sparse cover of Phragmites australis or Equisetum fluviatile is occasional. Less often found are Typha latifolia, Mentha aquatica, Menyanthes trifoliata and Schoenoplectus lacustris. In the rarer Sphagnum subsecundum agg. – Potamogeton polygonifolius sub-community (FW3Cii) of acidic fens and flushes, Carex rostrata grows through a quaking carpet of Sphagnum.
Similar communities
Sub-community FW3Ci is related to the FE2D Carex rostrata – Menyanthes trifoliata mire community. In that assemblage, however, Menyanthes trifoliata and other marsh and fen species, such as Galium palustre, Potentilla palustris, Agrostis stolonifera and Hydrocotyle vulgaris, are more likely to be recorded. Some confusion could arise between FW3Cii and the FE2E Menyanthes trifoliata – Sphagnum recurvum agg. mire, which also combines Carex rostrata with high Sphagnum cover, but in the present community Menyanthes and Sphagnum recurvum agg. are typically absent.
Conservation value
This is a swamp community of medium species richness in terms of plants (species/4 m2 = 7.8, n = 36). Some examples of sub-community FW3Ci form part of the priority EU HD Annex I habitat 3180 Turloughs*. Stands of FW3Cii are likely to correspond to habitat 7140 Transition mires. In addition, the EU HD Annex II species Desmoulin’s whorl snail (Vertigo moulinsiana) has been recorded from multiple stands of this vegetation.
Management
This community is typically unmanaged. Threats include eutrophication and drainage.