sand dunes Flashcards
1
Q
what 5 conditions are needed
A
- plentiful load of sand
- strong winds
- flat land
- low gradient beach
- wide beach
2
Q
how do they form
A
wind blows across and the drier sand deposits o the beach and takes material inland
3
Q
what is on an embryo dune
A
- pioneer species take root e.g sea rocket
- plants add organic matter which aids water retention
4
Q
what is on an yellow dune
A
- little organic matter
- highly mobile
- marram grass
5
Q
what is on an grey dune
A
- fixed
- high humus
- dying veg
- creeping willow
6
Q
what is a blow out
A
when strong winds and human trampling give rise to dune collapse
7
Q
what is a dune slack
A
depressions within the dunes
8
Q
what is a wasting dune
A
when the supply of sand is low, creatinf small dune features
9
Q
what threats are there to sand dunes`
A
- over grazing
- recreation
- sea level change
- afforestation
