SM15: Juncus maritimus-Triglochin maritima salt-marsh community

Summary

Synonymy

Juncetum maritimi auct. angl. p.p.; Triglochin-Juncus maritimus nodum Adam 1976.

Constant species

Juncus maritimus, Plantago maritima, Triglochin maritima.

Physiognomy

Tall tussocks of Juncus maritimus are always overwhelmingly dominant in this association and the associates are rather variable. However, Triglochin maritima and Plantago maritima are constant in usually small amounts in the understorey and various Puccinellion species, such as Puccinellia maritima, rayed Aster tripolium, Armeria maritima and Glaux maritima, occur frequently throughout. The association differs from the Juncus maritimus salt-marsh in the relative infrequency of Agrostis stolonifera, Festuca rubra and Juncus gerardii. Commonly the bases of the J. maritimus shoots support a variety of epiphytic algae, notably Bostrychia scorpioides and Catenella repens, and there may be an extensive algal mat, locally rich in dwarf free-living fucoids, on the substrate surface. Stands are often based upon discrete and sometimes large clones of J. maritimus but may also form a distinct zone within the marsh.

Sub-communities

Adam (1977) suggested that there are three centres of variation within the association around which sub-communities might be erected: stands which are very speciespoor, sometimes pure J. maritimus in vigorous, tall and dense patches; stands in which Halimione portulacoides and Limonium cf. vulgare are conspicuous and fairly rich stands lacking these two species.

Habitat

J. maritimus is tolerant of a wide range of salinities and soil moisture conditions (Ranwell et al. 1964, Gillham 1957b) and the association occurs at all levels on saltmarshes and on a variety of substrates.