S17 - Carex Pseudocyperus Swamp

Summary

Constant species

Carex pseudocyperus, Juncus effusus, Sparganium erectum.

Physiognomy

Carex pseudocyperus can form dense pure stands of emergent vegetation over 1 m tall but it often occurs intermixed with some Juncus effusus and Sparganium erectum, patchy Typha latifolia or Phragmites australis, swamp and fen herbs such as Mentha aquatica, Lycopus europaeus and Scutellaria galericulata and Arrhenatherion species in fragmentary jumbles along water margins.

Habitat

This vegetation is most typical of shallow, mesotrophic to eutrophic, standing or sluggish waters around lowland ponds, in dykes, canals and slow-moving rivers.

Zonation and succession

C. pseudocyperus swamp may form a zone in open water adjacent to Phragmitetum australis and occur as a raggy fringe between pasture and streams or ponds. It is also sometimes found in association with the rich-fen vegetation of the Peucedano-Phragmitetum.

Distribution

C. pseudocyperus swamp has a patchy distribution through the central and southern English lowlands and seems to be most characteristic of the Midlands. In East Anglia, C. pseudocyperus usually occurs as a component of rich fen rather than as a swamp species.

Affinities

This often fragmentary vegetation has rarely been noted as a distinct community but a separate category is retained here to include the swamp occurrences of C. pseudocyperus as distinct from those in fens such as the British Peucedano-Phragmitetum and similar communities described from The Netherlands (e.g. Westhoff & den Held 1969). C. pseudocyperus swamp has affinities with the freshwater vegetation dominated by C. otrubae and with the Sparganietum erecti.