Psammoseres

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Psammoseres (sand dunes):

A sere is a stage or sequence of events

Psammo means that we are talking about a sequence of events on sand

Wind moves them

Act as a natural coastal defence

Made up of coarse sediments

Transported and deposited by strong winds

Sediment can only stay in the same place if it is stabilised by vegetation

Sand dunes are very sensitive to human disruption

Conditions needed for sand dunes to form:

Regular onshore winds

Regular, plentiful supply of sand

Wide sandy beach

Adequate vegetation to stabilise dunes

Protection from humans and storms

Vegetation type changes in a transect across a sand dune because of the PH. The PH decreases the further away from the sea you get. Different plants have adapted to different acidities. For example lyme grass can survive in alkaline conditions so forms closer to the sea whereas heather can survive in PH 6.5-7 so forms further away from the sea. Height of sand dunes also changes. This is because if they are further away from the sea, there is less damage to them.