Embryo Dunes
At
the front of the dunes is the youngest dune called an embryo dune. This
is a hostile environment for plants because of the salinity, lack of humus
and pH of 8-9. The alkaline pH is a consequence of the presence of shell
fragments in the sand. This is also a very dry environment and the rapid
drainage and exposed nature of the site make it difficult for plant growth.
(The term xerosere is sometimes used for plant succession in very dry
environments)
The plant which can colonise here is sand couch grass. This is a smaller version of sea couch grass which in Ireland is not found north of Dublin, on the east coast, and Galway, on the west. Couch is able to survive in the hostile environment by being resistant to salt, and is able to withstand drought, storing water in its succulent leaves. It also thrives on burial by the accumulating sand. The couch grass slows the blown sand from the beach and it gathers among the plants. Vegetation cover is sparse with perhaps 80% of the dune being exposed sand. Winter storms can sometimes wash away this dune but it builds up again in the summer.
Follow the links in the diagram below to explore the dunes.
