SM4B Festuca rubra – Juncus gerardii saltmarsh
Vegetation
This community is dominated by a mixture of Festuca rubra and Juncus gerardii, alongside which occur Glaux maritima, Plantago maritima, Triglochin maritimum and Agrostis stolonifera as constants. Frequently found here are Armeria maritima and Aster tripolium, while Cochlearia officinalis, Leontodon autumnalis and Carex extensa are occasional. Mean maximum vegetation height = 44.5 cm, n = 11.
Ecology
This is an upper marsh community that is infrequently inundated. Conditions are circumneutral (mean pH = 6.7, n = 11).
Sub-communities
Two sub-communities are described. The Blymus rufus sub-community (SM4Bii) is a regional variant in which B. rufus is present and can be abundant. It is restricted to Donegal, Mayo and Sligo. This species is absent from the typical sub-community (SM4Bi).
Similar communities
The abundance of Juncus gerardii serves to distinguish this community from the other Festuca rubra swards of group SM4. In SM6D, Juncus gerardii is also a key species, but in that community Agrostis stolonifera usually replaces Festuca rubra as the main grass species.
Conservation value
Almost all examples of this vegetation qualify as EU HD Annex I habitat 1330 Atlantic salt meadows. It is typically a diverse saltmarsh community (species/4 m2 = 8.2, n = 173) that contains some specialist species.
Management
The main immediate threat to this saltmarsh community is probably grazing by livestock. Sea-level rises as a result of climate change will have an impact, particularly in areas susceptible to coastal squeeze.