Sand Dunes Flashcards
Name Each dune from start to finish
Embryo dune, fore dune, Yellow dune, grey dune, Dune slack, mature dune (climax)
What condition do the Embryo dunes have
High alkaline (over 8) from calcium carbonate
Rapid drainage as sand does not hold water well
high salinity from seawater (halophytes and xerophytes)
No humus
High wind speeds
Harshes environment
What type of species are found in embryo dunes
Sea rocket Sea couch grass (pioneer species), salt-tolerant species; they stabilise the dune and provide humus for plants of the next seral.
What type of conditions do fore dunes have
Still high salinity and alkaline, now some humus from pioneer species that reduces alkaline
What type of species are found in fore dunes
Lyme grass, sea holly and Marram grass - They are drought resistant and capable of withstanding burial, The roots of the marram grass (ribosomes) help stabilise the dune further as they are very long and can access a new supply of sand
What conditions do yellow dunes have
They have a greater diversity of plant species as the plants that died and decayed built up a layer of humus that can trap water etc. PH is slightly alkaline, and salinity has dropped. dunes may be 5-10 meters high
What type of species are found in yellow dunes
Marrum still dominates, however, other plants are taking a hold of the established surface suchas mosses send sedge creeping fescue.
What conditions do grey dunes have
Ph tends more towards an acidic, with higher levels of Humus (nutrients), ground becomes darker with higher humus content. Shelter from winds. so conditions suit more plant species.
How does age change down a dune
The younger a dune near the sea, the older a dune from land
How does PH change down a dune
PH becomes more acidic towards land as humus from decayed plant matter is acidic
What type of species are found in grey dunes
Rushes, Sedges, Cotton grass, brambles, gorse, buckthorns
What conditions do Dune slack have
Below the water table, found between grey dunes and mature dunes, they have permanent water logging and surface water
What plant species are found in dune slack
rushes, sedges, cotton grass, creeping will
What conditions do mature dunes have (climax vegetation)
High humus content and water content allowing for succession over previous species. They have a developed soil.
What plant species are found in mature dune
Arsh, birch, and eventually oak trees. An oak climax vegitation will develop.
