Sand Dunes

How Sand Dunes are Formed Sand dunes are formed where the dry sand is blown up the beach by the wind. They then stop being blown when and obstacle blocks it such as wood, vegetation or dead animals – like birds. The best develop where: There is a large beach with lots of sand. The wind blows on shore The area is good for sand to build up

Six Sections of Sand Dunes Embryo dune Fore dune Yellow dune Grey dune Dune slack Mature dune

Embryo Dune This is the first set of dunes. They form in the protected are behind the berm and strand line. They can disappear very quickly but some may grow plants and stabilise. They may reach a maximum of 1m.

Fore Dunes These are a collection of embryo dunes and can hold host to sea couch and marram grass so they become more stable. What does grow catches sand and builds up the dunes to reach 5m.

Yellow Dune A humus layer builds up where plants die and decay. This traps water and nutrients. There is less salt spray as there is more shelter. They can reach heights of 5- 10m. Up to 80% of the sand dunes is covered by vegetation. Animals such as rabbits can help enrich the soil with their droppings.

Grey Dune These are much more stable. Moss and lichens fill what remains without vegetation so that these dunes can reach 100% covering. The humus begins to darken the surface. They are usually 10m high and wider than the dunes before.

Dune Slack These are found between the mature dunes where the water reaches the surface causing waterlogging. Plants that live here are well adapted to the damp conditions. If the decay is slow then the peaty soil could develop.

Mature Dune These are found several metres from the coast. As the humus grows, more plants can be held. They are often left untouched and the can grow shrubs and trees.

Human Uses of Sand Dunes Sand dunes are the least threatened of coastal ecosystems. However they are used for a recreational uses. They can be used for trail biking or horse riding. However sand is delicate so they can be ruined easily.