Sand Dunes

• What is our example

  Formby Point, Sefton Ciast (located in North of Liverpool)
• Embryo dunes


  • Initial stages of dune very sandy, little vegetation (can't survive in dry conditions)
  • Sandwort & Lyme grass pioneer species in psammosere succession they have waxy leaves to retain moisture & long roots to collect water
  • Sand being blown into system
  • To begin psammosere succession sand blown onshore needs to e trapped by an object
• Foredunes


  • When vegetation starts to grow
  • Sparse, not much veg
  • Embryo dunes that started to become colonisedby increased number of pioneer species
  • pioneer plants trap sand in their leaves & root consolidate the sand. Once they die, they increase the amount of humus (organic matter) in sand dune therefore making it possible for less specialist plants to grow
• Yellow dunes


  • Above level of highest spring tide, similar amount of humus & are less exposed to strong winds. These factors mean that plants don't have to be as specialised as pioneer species to colonise
  • Still areas of exposed sand
  • Plants more grass-like. Lack of leaves help reduce moisture loss therefore allowing plants to colonise quickly. Have larger root systems in order to obtain as many nutrients as possible. These roots help stabilise dunes reducing their mobility
  • Red fescue and marram grass
• Grey dunes


  • Named bc of their colour they are grey bc of the significant increase in humus (dead plant matter) within them
  • Complete veg coverage which enables a range if plants to exist. pH also decreases therefore biodiversity can increase
  • Plants here establish themselves quickly & tend to be widespread as there is more competition e.g heather, harebells and creeping willow
• Plagioclimax


  • Dunes can reach the climax veg for the UK (mixed oak woodland) the soil here is acidic due to the increased nutrient content
  • However in UK, it's difficult to find sand dunes that have reached their climatic climax veg. As sand dunes area is a fragile environment, most are managed so that they only reach a plagioclimax (usually heathland)
• What does psammosere succession mean


  succession in sand dunes is called a psammosere succession bc it's succession occurring on sand
• What is the formation of a blowout

  • Created if there's a gap in the veg e.g from a rabbit burrowing or a dog digging.
  • They can occur at any stage of the succession
  • Once the gap in veg has been created, the sand is blown out from underneath the veg creating a bare patch of sand. It's difficult for plants to colonise the area as it lacks nutrients
• What is the formation of a dune slack

  • Created if there's a low point in the dunes. This could be bc when the dunes were initially created, a new embryo dune developed a significant distance away from the foredunes
  • If the bottom of the dune slack is below the water table, or if the height of the water table rises e.g in winter, then there will be a pool in the dune slack
  • Niche species such as natersack toads found here
• Stores of sediment

  • Sand dunes require a constant supply of sediments. This is provided by the River Mersey and the River Dee
  • Low energy environment is required. This is provided by short fetch (max 200km) and the relative protection of sediment cell 11
• What are Formby sand dunes managed by

  • The National Trust and therefore they only reach a plagioclimax due to their fragile nature.
• What management is put in place

  At Formby Dunes, old Christmas trees can be donated to help regenerate the dunes. They act as the barrier to trap the sand and therefore start the process of sand dune development.

  • 15000 old Christmas trees have been 'planted' in past 5 yrs