SD6: Ammophila arenaria mobile dune community

Summary

Synonymy

Ammophiletum arenariae Moss 1906, Tansley 1911, 1939, all p.p.; Elymo-Ammophiletum arenariae Br.-Bl. & De Leeuw 1936; Ammophila arenaria stands Gimingham 1964a p.p.

Constant species

Ammophila arenaria.

Rare species

Allium ampeloprasum ssp. babingtonii, Corynephorus canescens, Euphorbia paralias, E. portlandica, Scrophularia scorodonia.

Physiognomy

The Ammophila arenaria community includes virtually all the vegetation of more mobile coastal sands in which the robust perennial grass Ammophila arenaria plays a dominant role in the dune-building process. In young stands, or where newly eroded surfaces among established dunes are being recolonised, the cover of the plant is often low, with just a few sparse shoots emerging from freshly-blown sand that may be otherwise quite bare. Growth can become very vigorous, however, in activelyaccreting material where Ammophila can spread its horizontal rhizomes far and keep pace with burial of up to 1 m a year, the expanding clones putting up denselybranching tillers that become aggregated into the characteristic tussocks (Gemmell et al. 1953, Greig-Smith 1961, Ranwell 1972). The shoots enhance accretion even more, continuing to proliferate among the upbuilding sand, until they can be packed at 150–200 m⁻². Adjacent tussocks, with their spreading foliage reaching 1 m or more in height, can thus enlarge to form an extensive cover of the grass over stretches of still shifting sand that is being built into often substantial dunes.