Sand dunes

What is a Psammosere

An ecological succession that began on newly exposed sand

What is plant succession

Change in types of plant species that occupy a given area through time

What is climax vegetation

Dominant mix of vegetation species that characterise an environment given time for colonisation to occur and reach stability

What is a sand dune

Hills of sand of that form on coast when there is enough sand exposed at low tide to dry and be blown inland

What conditions are needed for a sand dune to form

• Large flat beach

• Large supply of sand

• Large tidal range

• Onshore wind

• Obstacle for dune to form against

How is sand transported by the wind

• 1% by suspension fine particles are carried high in the air

• 75% by saltation grains are lifted and bounced along the ground by the wind

• 24% by creep particles roll or slide along the ground after being hit by saltating grains

What is the process of sand dune succession

• Embryo dune

• Fore dune

• Grey dune

• Dune slack

• Mature dune

What is an embryo dune

• Form at back of beach, requires an obstacle such as driftwood to form for sand to accumulate

• Pioneer plants such as sea rockets help build and stabilise dune

What is a fore dune (yellow dune)

• Sand continues to accumulate and dune grows

• Marram grass dominates as its deep roots bind the sand

• Called yellow dune as little humus so relatively yellow

What is a grey dune

• Found further inland

• More plant species establish such as lichens and moss

• Dead vegetation decomposes adding humus to soil making it more fertile and better at retaining moisture

• Grey in colour due to increased organic matter

What are dune slacks

• Low lying depressions between dunes

• Water table may reach surface

• Conditions wetter, allowing other moisture-loving plants to grow such as reeds

What is a mature dune

• Furthest inland

• Soil is thick, nutrient-rich, and moisture-retentive

• Shrubs and eventually woodland may develop

• Represents the climax stage of succession