SM6D Agrostis stolonifera – Juncus gerardii saltmarsh
Vegetation
Juncus gerardii tends to dominate this saltmarsh community, and is accompanied as a constant by Glaux maritima and Agrostis stolonifera. Plantago maritima, Triglochin maritimum and Aster tripolium are all frequent species, while Festuca rubra, Armeria maritima and Leontodon autumnalis occasionally grow within this community. The Juncus can sometimes lodge to form distinctive fan-shaped patterns in the marsh. Mean maximum vegetation height = 52.3 cm, n = 4.
Ecology
This is an upper marsh community that is infrequently inundated. Conditions are circumneutral (mean pH = 6.8, n = 4).
Sub-communities
Two sub-communities are described. The Blymus rufus sub-community (SM6Dii) 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 (SM6Di).
Similar communities
Juncus gerardii is also a prominent plant within the quite similar community SM4B Festuca rubra – Juncus gerardii saltmarsh, but there Festuca rubra is both more frequent and more abundant, while Agrostis stolonifera is somewhat less so.
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 = 7.8, n = 142) that supports several 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.