Everyone thinks the water as the focus of a coastal ecosystem, but visiting this boardwalk you will see the huge variety of habitats, flora and fauna living in close quarters to each other. The coastal dunes are essential to shaping the land and providing unique habitats. furthermore, each beach has unique dune systems, the result of different wind patterns, and the presence or lack of vegetation on the ground.
Types of Dunes
The crescentic dune also called the barchand dune, is the most common type of sand dune. As its name suggests, this dune is shaped like a crescent moon with points at each end, and it is usually wider than it is long. Crescentic dunes form when winds blow from one direction.
The linear dune is straighter than the crescentic dune with ridges as its prominent feature. Unlike crescentic dunes, linear dunes are longer than they are wide -- in fact, some are more than 160 kilometers long. The ridges are long and snakelike, and these dunes usually occur in parallel sets separated by other sand, gravel or rocky corridors.
The star dune has arms that radiate out from a center pyramid-shaped mound, hence the descriptive name. Star dunes grow upward instead of outward and are a result of multidirectional winds. They tend to show up around topographic barriers. They're among the tallest sand dunes on Earth
The dome dune is rare, oval- or circular-shaped and has no slip face. Dome dunes sometimes appear at the ends of crescentic dunes. Most dome dunes are low -- only a few feet high.
The parabolic dune is U-shaped, but differs from the crescentic dune because its crests point upward, with elongated arms that follow behind. A parabolic dune's trailing arms are typically anchored by vegetation.
The Coolum coastal dune ecosystem can be broken down into 5 major zones - forest, woodland, foredune, beach and ocean.
The forest zone - representing the mature state of coastal vegetation development, established in the area behind the foredune and far enough inland to be protected from strong winds. Soil conditions are improved in this zone with accumulated leaf litter providing nutrients and increased water holding capacity. The forest zones primary function is to stabilise the hind dune.
Woodland zone - situated behind the foredunes the woodland zone represents the second step in coastal vegetation development. Pioneer plants found in this zone provide shade, reduce wind movement and start the soil development process through leaf litter breakdown. This creates more favourable conditions for secondary plants to establish and increase the stability of the dunes.
Foredune - located immediately facing the beach the foredune is the most important part of the dune system and the most fragile. Vegetation traps sand preventing it from being blown inland, where the vegetation cover is lost the beach becomes susceptible to erosion from wind and waves.
To claim this earthcache as a find, please send the answers to the following questions to the CO. Please do not post the answers online.
Q1. Please compare the vegetation of Wp2 and Wp3, how has the size and coverage changed between these zones, how would the change in vegetation affect the stability of the dunes?
Q2. Compare the texture and soil make-up, and vegetation (eg. sand, dirt, leaf) between WP 2 and 4. Please suggest what would cause these differences?
Q3. At Wp4 what dune types can you see (you may see more than one), how did you identify these dunes?
Q4. Imagine you were to visit these dunes shortly after a large storm with high wind speeds, do you think this would change the dune types observed, if so how?