Sand dune ecology
   HOME

TheInfoList



OR:

Sand dune ecology describes the biological and physico-chemical interactions that are a characteristic of
sand dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, fl ...
s. Sand dune systems are excellent places for biodiversity, partly because they are not very productive for agriculture, and partly because disturbed, stressful, and stable habitats are present in proximity to each other. Many of them are protected as nature reserves, and some are parts of larger conservation areas, incorporating other coastal habitats like
salt marsh A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is dominated ...
es, mud flats, grasslands, scrub, and woodland.


Plant habitat

Sand dunes provide a range of habitats for a range of unusual, interesting and characteristic plants that can cope with
disturbed Disturbed may refer to: Books * ''Disturbed'', a 2011 novel by Kevin O'Brien (author) Film and TV * ''Disturbed'' (film), a 1990 film starring Malcolm McDowell * "Disturbed" (''Numb3rs''), a 2009 episode of ''Numb3rs'' * "The Disturbed", a 2 ...
habitats. In the UK these may include restharrow ''
Ononis repens ''Ononis repens'', the common restharrow, is a plant species of the genus ''Ononis''. Description It is a prostrate (maximum height 60cm) woody perennial, spreading by rhizomes. It has hairy stems and small oval leaves with toothed edges. ...
'', sand spurge ''Euphorbia arenaria'' and ragwort ''Senecio vulgaris'' - such plants are termed ruderals. Other very specialised plants are adapted to the accretion of sand, surviving the continual burial of their shoots by sending up very rapid vertical growth. Marram grass, ''
Ammophila arenaria ''Ammophila arenaria'' is a species of grass in the family Poaceae. It is known by the common names marram grass and European beachgrass. It is one of two species of the genus ''Ammophila (Poaceae), Ammophila''. It is native to the coastlines of ...
'' specialises in this, and is largely responsible for the formation and stabilisation of many dunes by binding sand grains together. The sand couch-grass ''Elytrigia juncea'' also performs this function on the seaward edge of the dunes, and is responsible, with some other pioneers like the sea rocket ''
Cakile maritima ''Cakile maritima'', sea rocket (Britain and Ireland)Clive Stace, ''New Flora of the British Isles'' 4th edition 2019, p 441 or European searocket (North America), is a common plant in the mustard family Brassicaceae. It is widespread in Europe ...
'', for initiating the process of dune building by trapping wind blown sand. In accreting situations small mounds of vegetation or tide-washed debris form and tend to enlarge as the wind-speed drops in the lee of the mound, allowing blowing sand (picked up from the off-shore banks) to fall out of the air stream. The pioneering plants are physiologically adapted to withstand the problems of high salt contents in the air and soil, and are good examples of stress tolerators, as well as having some ruderal characteristics.


Inland side

On the inland side of dunes conditions are less severe, and links type grasslands develop with a range of grassland herbs which benefit from the reasonable nutrient status and moderately high pH of the more stable soils, especially when enough humus has accumulated in stabilised soils for water retention to be improved. Species like red fescue and lady's bedstraw are adapted to compete with each other - for nutrients, growing space and light, and are known as CSR plants - i.e. having features of Competitors, Stress tolerators and Ruderals in more or less equal proportions. There may also be areas in old blow-outs where
groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidate ...
is near the surface, and often rises to cause flooding in the winter. Frequent, but intermittent waterlogging of the roots requires adaptations to stress, so the proportions of stress tolerators are increased here. In nutrient-rich water, however there are some plants with very competitive strategies, like the reed (''
Phragmites australis ''Phragmites australis'', known as the common reed, is a species of plant. It is a broadly distributed wetland grass that can grow up to tall. Description ''Phragmites australis'' commonly forms extensive stands (known as reed beds), which may ...
''). This is an example of a plant which makes rapid growth and suppresses other species by monopolising root and shoot space and shading out the opposition. Even its own seedlings are prevented from establishing within the existing population, but seeds are blown for long distances in copious quantities to start new colonies, whilst mature populations extend by rapid vegetative growth of lateral underground shoots - rhizomes.


See also

*
Blowout grass ''Redfieldia'', known as blowout grass, is a monotypic genus in the grass family ( Poaceae). The sole species, ''Redfieldia flexuosa'', is native to sandhills in the western and central United States. The plants grow in small clusters, protecting ...
*
Coastal management Coastal management is defence against flooding and erosion, and techniques that stop erosion to claim lands. Protection against rising sea levels in the 21st century is crucial, as sea level rise accelerates due to climate change. Changes in s ...
*
Ecological succession Ecological succession is the process of change in the species structure of an ecological community over time. The time scale can be decades (for example, after a wildfire) or more or less. Bacteria allows for the cycling of nutrients such as ca ...
*
Psammosere A psammosere is a seral community, an ecological succession that began life on newly exposed coastal sand. Most common psammoseres are sand dune systems. In a psammosere, the organisms closest to the sea will be pioneer species: salt-tolerant spe ...
*
Sand dune stabilization Sand dune stabilization is a coastal management practice designed to prevent erosion of sand dunes. Sand dunes are common features of shoreline and desert environments. Dunes provide habitat for highly specialized plants and animals, including rar ...


References

{{DEFAULTSORT:Sand Dune Ecology Dunes Coasts Ecology