S20 - Scirpus lacustris Ssp. tabernaemontani swamp Scirpetum tabernaemontani Passarge 1964

Summary

Synonymy

Schoenoplectus tabernaemontani nodum Adam 1976; Scirpetum maritimae (Christiansen 1934) R.Tx. 1937 sensu Lee 1977.

Constant species

Scirpus lacustris ssp. tabernaemontani.

Physiognomy

In the Scirpetum tabernaemontani, S. lacustris ssp. tabernaemontani always dominates, its tall shoots forming a dense cover generally 80-90 cm high. S. maritimus occurs occasionally, although it rarely exceeds a cover of 25%. Scattered beneath are occasional plants of a variety of salt-marsh species such as Aster tripolium, Atriplexprostrata, Triglochin maritima, Glaux maritima and Cochlearia anglica and species characteristic of disturbed and/or moist soil surfaces, e.g. Ranunculus sceleratus, Juncus bufonius and Chenopodium rubrum. There is occasionally a mat of algae over the substrate surface and around the bases of the Scirpus stools.

Sub-communities

Sub-community dominated by Scirpus lacustris ssp. tabernaemontani. Here the dominant occurs alone or with a very sparse understorey of salt-marsh or freshwater swamp associates.

Agrostis stolonifera sub-community. Agrostis stolonifera forms an open mat beneath the Scirpus and associates are more frequent and abundant. Eleocharis uniglumis, E. palustris, Carex otrubae and Oenanthe lachenalii are differential occasional.

Habitat

The community occurs most frequently in moist, brackish sites with soft, anaerobic raw gleys of silt or clay. It may be encountered in depressions at various levels on coastal salt-marshes, around flashes in inland saline sites and as emergent vegetation in counter-dikes, warpingdrains and as a fringe around some Scottish sea-lochs.

Although S. lacustris ssp. tabernaemontani appears to be tolerant of salinities similar to those endured by S. maritimus (Packham & Liddle 1970) and will survive surface salt efflorescence (Lee 1977), it is also able to grow in standing fresh water and the Sczr/7ws-dominated sub-community of the Scirpetum tabernaemontani occurs locally inland.

S. lacustris ssp. tabernaemontani is grazed by cattle and Lee (1977) considered that this may play some part in confining the community to wetter, less accessible sites. Large-billed grey geese also eat the shoots as well as digging for roots and rhizomes (Ogilvie 1978).

Zonation and succession

Stands are usually well marked off from the surrounding vegetation by virtue of the bulky physiognomy of the dominant, although scattered shoots of dwarf S. lacustris ssp. tabernaemontani occur widely in a variety of upper-marsh grasslands.