HE4F Molinia caerulea – Myrica gale flush
Vegetation
Dense tussocks of Molinia caerulea dominate this peatland community, accompanied by a good cover of the twiggy shrub Myrica gale with its distinctive resinous smell. Amongst the tussocks, there are usually stems of Potentilla erecta and some sparse patches of Erica tetralix. Frequently encountered are Succisa pratensis, Schoenus nigricans, Carex panicea, Calluna vulgaris and Eriophorum angustifolium. The bryophyte layer is somewhat unimpressive, normally formed of Sphagnum palustre, Sphagnum subnitens or Sphagnum subsecundum agg. In western Mayo and Galway, Erica erigena may be present and can be co-dominant.
Ecology
Myrica gale is an indicator of flushing and this vegetation occurs in flushed areas of wet heaths, blanket bogs and raised bogs. The peaty substrate is infertile and acidic. Mean altitude = 77 m, n = 34; mean slope = 2.2°, n = 31; mean extent of bare peat = 3.1%, n = 36.
Sub-communities
No sub-communities have been described for this community.
Similar communities
This is the wettest of the HE communities. The presence and usual abundance of Myrica gale serves to differentiate the HE4F community from the other Molinia-dominated communities of group HE4.
Conservation value
Stands of this community may be part of broader areas corresponding to EU HD Annex I habitats 4010 Wet heaths or 7130 Blanket bog (active)*. Stands within raised bog complexes could be considered as 7120 Degraded raised bog depending upon the results of hydrological modelling. It is a rather species-poor community (species/4 m2 = 15.4, n = 92).
Management
This community, which often forms parts of commonages, may be used as rough grazing land (typically for sheep); overgrazing may be a problem. Burning may be periodically used across large areas to suppress the dwarf shrubs and encourage grass growth. Other threats are afforestation, agricultural improvement, drainage and peat extraction.