Psammoseres

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.