SD5: Leymus arenarius mobile dune community

Summary

Synonymy

Ammophiletum arenariae Tansley 1911, 1939 p.p.; Elymo-Ammophiletum arenariae Br.-Bl. & De Leeuw 1936 p.p.; Leymus arenarius consocies Bond 1952; Ammophila arenaria stands Gimingham 1964a p.p.; Potentillo-Elymetum arenariae (Raunkiaer 1965) Tx. 1966 sensu Birse 1980.

Constant species

Leymus arenarius.

Physiognomy

The Leymus arenarius community consists of open to locally dense stands of dune vegetation dominated by the tall and tussocky perennial grass Leymus arenarius. It is a rhizomatous plant, able to colonise and fix mobile sand and keep pace with substantial accumulation by upward and outward extension of its stout buried stems, such that the robust glaucous shoots, often well over 1 m high, can be found emerging from dunes that have grown to several metres tall (Trail 1904, Bond 1952).

No other species is constant throughout, but Elymus farctus is locally common, invading foreshore sand ahead of or together with the Leymus and sometimes remaining as a subsidiary and shorter element to the cover here, though only thickening up in vegetation which is best regarded as transitional to Elymus farctus foredunes. Ammophila arenaria is likewise never a prominent feature here, but it is a characteristic colonist of wind-blown sand along with or subsequent to Leymus and can be found as an occasional in the community, going on to exceed the lyme grass in frequency and abundance among the various kinds of Ammophila dunes. Then, in some stands, Festuca rubra is quite common with Elymus repens sometimes marking out places where there has been incorporation of organic detritus.