SM4A Festuca rubra – Agrostis stolonifera saltmarsh
Vegetation
This vegetation usually comprises a rank sward dominated by Festuca rubra and Agrostis stolonifera, which are the only constants. Glaux maritima and Plantago maritima are both frequent and there are a number of occasional associates, namely Triglochin maritimum, Leontodon autumnalis, Juncus gerardii, Trifolium repens, Atriplex prostrata, Cochlearia officinalis, Armeria maritima and Plantago coronopus. Mean maximum vegetation height = 63.1 cm, n = 6.
Ecology
This is predominantly an upper marsh community that is infrequently inundated. Conditions are circumneutral (mean pH = 6.6, n = 6). Rarely included here are instances of inland Festuca-Agrostis swards.
Sub-communities
No sub-communities have been described for this community
Similar communities
In the other Festuca rubra-rich swards of group SM4, Agrostis stolonifera is usually not as abundant as it tends to be in this community. Agrostis can be plentiful in SM4B but in that community Juncus gerardii is much more frequent than it is here. Both Agrostis and Festuca occur together in swards of SM6D, but Festuca is not so frequent there and again Juncus gerardii will be encountered.
Conservation value
Almost all coastal 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 = 7.7, n = 153) 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.