There are several different habitat types in a sand dune system, from early successional stages such as embryo dunes and mobile dunes, to later successional stages like dune heath and fixed dunes.
Use these videos to help you identify the different habitat types, learn more about how they are formed, and find out which species live in them.
Embryo Dunes
Embryo dunes are the youngest sand dunes. They are the earliest stage in a dune’s life. These dunes face the beach, are made up of mostly exposed sand, and are also the smallest dune stage – reaching just up to a few metres tall. Here pioneer species like couch or lime grass are the first to colonise the sand and begin to stabilise it with their long roots. These embryo dunes are often only present in the summer and can be washed away by high tides or winter storms, but will form again each year.
Dune habitats can look different in different locations. To watch a video about Embryo Dunes in Lincolnshire, click here.
Semi-Fixed Dunes
With plant roots now reaching deep into the dune, semi-fixed dunes are pretty stable, but you can still see exposed sand on their surface which is able to move. These dunes will continue to accrete sand from the beach and, the sand on these dunes can be blown over the ridge and inland to grow the dunes behind them. These are also known as yellow dunes because of the colour of the sand.
Dune habitats can look different in different locations. To watch a video about Semi-Fixed Dunes in North Devon, click here.
Dune Slacks
Sand dunes are separated by dips, called dune slacks. Slacks are formed in two ways – either when a new dune ridge forms in front of a low-lying area which cuts it off from the sea, or when a dune blowout forms in an area that's got lots of vegetation, exposing a dip of bare sand. Where these low areas are low enough to meet the dune water table, freshwater pools can form. These slacks are fantastic habitats for dune wildlife such as natterjack toads, which use the pools for breeding.
Dune habitats can look different in different locations. To watch a video about Dune Slacks in in North Devon, click here, or to watch a video about Dune Slacks in Lincolnshire, click here.
Fixed Dune
As you move further away from the beach, the dunes become less yellow in colour and begin to turn grey. This is because these dunes are starting to build up more humus (the broken-down organic plant matter which is found in soil) from the diverse plant life and bacteria which now lives in these stable dunes. These dunes are also better at holding in water, making them able to support larger shrubs. These are also known as grey dunes and can still have sand blowing through them from blowouts, the semi-fixed dunes or even from the beach on a really windy day!
Dune habitats can look different in different locations. To watch a video about Fixed Dunes in Cumbria, click here.
Dune Heath
Dune heaths are found on the more acidic sandy areas where rain has leached out the lime from the sand. These are very rare habitats as they’ve often been lost to plantations or development, but a few locations still have extensive areas - including Studland in Dorset. Here you can find many species of heather, lichens and fine grasses, often with a thin layer of peaty soil.
Saltmarsh
Behind some sand dune systems, salt marshes can form where sheltered estuaries or creeks can deposit fine sediments, or where where gentle tidal waters can deposit sediments. Salt marshes are important habitats for many species of coastal bird. Saltmarshes are exposed at low tide but submerged, or at least partly submerged by saltwater when the tide rises, meaning that only very salt-tolerant species can survive here.