Coastal Dune Grassland

 

All plants on the dune system are low in height and salt tolerant, and are able to withstand the harsh environment and dry infertile soil. Where hairy spinifex (Spinifex sericeus) abounds, a gentle dune is formed as the prevailing winds blow in from the sea. Spinifex grows on long runners that extend further and further into the softly blown dune. Compaction of the dune kills the plant or seriously impedes its growth. Spinifex is a dioecious plant which means that male flowers grow on separate plants to the female flowers. The flowers are fertilized when the pollen is dispersed via the wind. The resulting seed heads are then pushed by the wind along the dune where they may then germinate. A single plant can cover a huge area. So on both counts, the survival of the species in a very harsh environment is assured. An excellent example of a dune covered in hairy spinifex is just north of the Frankston Yacht Club. Here, the gently angled dune has formed due to the nature of the spinifex growing via long runners towards the beach.

Another tough plant adapted to the salty winds and blazing north west sun is the Coastal salt bush (Atriplex cinerea). Like the hairy spinifex, male and female flowers are found on separate plants, with the striking beetroot coloured flowers dwarfing the tiny female flowers hidden at the base of the leaf axils (where the leaves attach to the stalk).

A plant that was once considered extinct exists quite happily in amongst the spinifex. This is Actites megalocarpa, the Dune Thistle (also known as the Coast Sow Thistle).

Another plant to be found on the front dune is the Prickly spear grass (Stipa stipoides).
 

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Hairy Spinifex (male)

Hairy Spinifex (female)

Dune Thistle

Coastal Salt Bush

Prickly Spear Grass

 

Note: Marram grass (an introduced species of grass) has a growing characteristic that changes the very nature of the dune system. Because of its clumping root system, steep sides are formed on the dune, and this discourages natural grasses to grow.
 

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Marram Grass