Sand Dunes
About Sand Dunes
Sand dunes are accumulating mounds of sand which are formed when sand blows inland from the beach. The mounds get larger overtime as they are out of reach of the tidal zone. The unique habitat is a home for rare beachgrasses such as marram grass, which stabilise the dunes with their deep roots. These highly adapted grasses have rolled up leaves so that they do not dry out in the harsh conditions. Grasses and vegetation become more abundant and mature, moving inland.
Sand Dune Lifecycle and Vegetation
Embryo dunes are the youngest and smallest of the dune lifecycle. They are found nearest to the ocean and are mostly loose sand. There is very little plant life here, other than pioneer species including beachgrasses which help stabilise the dunes.
Fore dunes are found behind the embryo dunes and are slightly taller, with more grasses including marram grass. These dunes are more stable and weather resistant than embryo dunes due to increased number of roots binding the sand together.
Dune slacks are the dips found between the dunes, such as behind the fore dune. This is a sheltered area where freshwater ponds can form, if the dip is below the water table, providing a habitat for amphibians and birds.
Semi-fixed and fixed dunes are found slightly further inland. They have a greater density of vegetation meaning that the more complex root systems provide greater stability to the dune. Some visible plants may include clover, pyramidal thistle, lady’s bedstraw and sea rocket. There is still some loose sand visible on the surface which has blown inland from the beach. Grasses are abundant on the fixed dune and some vegetation can be found.
Mature dunes are found furthest from the beach and there is very little loose sand. Due to their maturity and greater water availability, shrubs and trees begin to colonise on mature dunes.
Dune heath is a rare habitat found further inland where you can find heath species such as heather and grasses. Often there is no dune heath in the sand dune lifestyle due to human activity and land-use change such as urban development.
Wildlife
Dunes are made up of loose sand so make a good habitat for burrowing bees and wasps. Sheltered areas of dune with a variety of plants, near sunny open areas provide habitat for invertebrates and reptiles which like to bask in the sun.
Some birds to look out for amongst the dunes include:
- Skylark (Alauda arvensis)
- Stonechat (Saxicola rubicola)
- Linnet (Linaria cannabina)
- Wheatear (Oenanthe)
- Buzzard (Buteo buteo)
- Kestrel (Falco tinnunculus)