Vegetation
The vascular vegetation in this community is chiefly formed of a mixture of Agrostis stolonifera, Potentilla anserina, Carex nigra, Trifolium repens and the circular, fleshy leaves of Hydrocotyle vulgaris. Beneath is a characteristically abundant layer of the pointed shoots of Calliergonella cuspidata. Frequently there is some Carex arenaria, Carex flacca or Ranunculus repens, or some patches of the prostrate shrub Salix repens. Mean maximum vegetation height = 41.0 cm, n = 32.
Ecology
This seasonally-inundated community typically occurs towards the rear of coastal duneland systems where it represents stands from the centre of dune slacks (mean altitude = 4.7 m, n = 26; mean extent of bare sand/soil = 1.3%, n = 26). It may also occur at inland locations where similar hydrology prevails.
Sub-communities
No sub-communities are described.
Similar communities
The combination of abundant Calliergonella cuspidata and high sedge cover separates this vegetation type from most other duneland communities. Where Salix repens is found, DU3A Salix repens – Lotus corniculatus should also be considered, but that occurs on drier areas. Carex arenaria and Salix repens do not occur in the fens of the FE3 Agrostis stolonifera – Carex nigra group.
Conservation value
Most examples of this vegetation correspond to the EU HD Annex I habitat 2190 Dune slacks. Species/4 m2 = 17.7, n = 106.
Management
Grazing livestock have access to this community at many sites. Desiccation due to drainage is a problem in some dune slack systems. Other pressures, which may be linked to the drainage, come from agricultural intensification and recreation.