Wetlands Quiz 3

What wetland type classification is sand dunes?

E - sand, shingle, or pebble shores, includes and bars, spits and sandy islets; includes dune systems and humid dune slacks

Definition

Coastal sand dune are sand deposits within a marine beach system

Formation

Occurs along coastlines

Formed by Eolian processes (wind action) and wave action

Typically composed of fine grains of sand formed from crushed shells and rocks

In a constant state of change and movement due to waves and wind

Sediments are transported to different places by water and wind depending on their size and density

Interaction of sediment, wind, waves, and plant forms

But there are lot of other contributing factors: storms, tides, sand types, freshwater inflow, currents…

Sand Dune Hydrology

subject to waves and salt spray, which leaves salt behind

water rapidly percolates into sand

tidal range determines the area of shore that is exposed at any low

at or above high tide line, the sand may blow inland

currents move sand along shoreline

Intertidal area

sand is subject to the ebb and flow of the tides and sand remains moist

Sand Dune Soil

most beach sand comes from erosion of material (calcium carbonate beaches come from limestone, coral, shells)

water movement and erosion break down rocks or coral fragments into smaller particles

course sand harder to move by wind and water than fine sand

Sand Dune Vegetation

Flexible stems that bend with the wind

Minimize water loss with leathery, small, waxy, thick or hairy leaves

Plants are in low water (sand) and can absorb moisture from the air

Long root systems reach deeper to the moist sand and to provide anchorage

Sand Dune Succession

1. Embryo dunes - small patches of grass - few species and pioneer species

2. Mobile dunes - large areas of bare moving sand but greater cover of marram grass

3. Semi-fixed dunes - smaller patches of bare sand with a greyish tinge, many plants besides marram grass

4. Fixed dunes - almost complete vegetation cover - sparse grass and is only found isolated clumps before ultimately disappearing - many other species of plants are present

5. Dune slacks - sand is eroded so the water table is reached

6. Climax - sand dunes normally develop into scrub then woodland

Sand Dune Inhabitants

Diversity is low for plants and animals compared to other coastal habitats

Numerous stresseos limit the number of species that can live there - shifting sand, temperature, salt, and limited water supply

Sand dune loss

Rising sea level and recreation

Sand removal for beach nourishment

Development preventing natural shifting of dunes

Conservation

beach awareness

illegal to drive on the beach or dunes

beach cleanups