SM19: Blysmus rufus salt-marsh community: Blysmetum rufi (G. E. & G. Du Rietz 1925) Gillner 1960

Summary

Synonymy

Juncus gerardii-Carex extensa Association Birks 1973 p.p.

Constant species

Blysmus rufus, Agrostis stolonifera, Glaux maritima, Juncus gerardii, Triglochin maritima.

Rare species

Blysmus rufus.

Physiognomy

The Blysmetum rufi is a species-poor association, generally dominated by Blysmus rufus but often with abundant Agrostis stolonifera, Glaux maritima and Juncus gerardii. Triglochin maritima, Festuca rubra, Plantago maritima and Carex extensa are all frequent but rarely present in quantity. Some stands may have an extensive algal mat and certain bryophytes may be abundant: Amblystegium riparium, A. serpens, Calliergon cuspidatum, Campylium stellatum, C. polygamum, Drepanocladus aduncus and Cratoneuron filicinum. Cover may be somewhat open, especially on gravelly or rocky substrates, and stands are usually small (10–20 m²), though at a number of Scottish sites the association covers hundreds of square metres.

Habitat

The association occurs on a variety of substrates but sites are often either poorly-drained or subject to flushing by brackish or fresh-water. The characteristic situation is in small depressions in the upper marsh. In some cases, the Blysmetum may develop in old upper-marsh pans, especially where these have a shingle base, and it is sometimes present along path edges (Gillner 1960, Tyler 1969b, Beeftink 1977a). In west Scotland, small stands are widespread within rocky flushes in the saltmarsh/mire transition on raised beaches and also among coastal rocks (Gillham 1957b, Birks 1973, Adam et al. (1977).