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Dunes of the Gold Coast Why are dune systems important? Dunes are critical to the health of our beaches. They are buffer zones that reduce the impacts of shoreline variability on our city. The major sand deposits of South East Queensland formed 10,000 years ago, but the frontal dunes were formed more recently (2000-3000 years ago). Cover up those dunes! Vegetation is very important to the maintenance of the dune system. It protects the beach from erosive wave action. If the dunes are in a healthy condition, vegetation can regenerate naturally after a storm. Dune vegetation tolerates a hostile environment of high winds, salt spray, sand blast and limited water availability. Within the dune community, plants are dependent on each other for protection and nutrient supply.1 Figure 1. A Gold Coast dune profile What kind of dunes? There are two main types of sand dune formations on the Gold Coast: beach ridges and low dune mobile sand sheets: ♦ ♦ Beach ridges usually sit parallel to the beach. Younger ones (closest to the sea) are all sand, whilst the older (more inland) ridges feature a more fertile soil profile, capable of supporting a more complex vegetation structure Low dune mobile sand sheets usually face the direction of the prevailing wind, and (as their name suggests) are always moving, with sand being blown about by wind. Vegetation on these sand sheets is typically less established Rolling frontal dunes on South Stradbroke Island (Source: GCCC) Where are our dunes? Sandy dunes occur naturally along the coastline of the city, interspersed with rocky headlands. Council undertakes protective works to improve the health of our dunes. Common species on our dunes Gold Coast dune health Name Description Location Spinifex sericeus (Spinifex) ♦ ♦ Leaves silvery-hairy ♦ Many long-pointed bracts form roly-poly Common, primary sand stabilisation species Carpobrotus glaucescens (Pig Face) Casuarina equisetifolia (Coastal She-oak) Banksia integrifolia (Coastal Banksia) Male and female flowers feature on separate plants ♦ ♦ Prostrate, spreading ♦ Edible fruits ♦ Graceful weeping tree up to 10m tall ♦ Fine rigid branchlets are needle-like and jointed with tiny teeth ♦ Seeds found in woody cones ♦ ♦ Up to 15m tall ♦ Yellow flowers, spike cylindrical to 15cm long ♦ Seed cone splits open to release paper thin seeds Common Leaves triangular in crosssection, fleshy Heath and open forest on mid and high dunes Dunes and their vegetation can be damaged by many natural forces such as: ♦ ♦ ♦ ♦ ♦ ♦ Waves generated by cyclones and storms Saltwater inundation Strong winds and sandblast Droughts Fires Insect and parasitic attack Sometimes our activities in the coastal zone can also affect dune health, including: ♦ Beachfront development ♦ Mowing, fertilising and topsoiling of dunes ♦ Pedestrian and vehicular traffic (tramples vegetation) ♦ Weeds and feral animals can disturb native Common ecological communities, reducing their resilience to the harsh conditions of the dune environment Dark green leaves with silver-white underside Rolling secondary dunes on South Stradbroke Island (Source: GCCC) Spinifex (Source: GCCC) Pig Face (Source: GCCC) Looking after our dunes The majority of mainland dunes have been impacted by adjacent development. Gold Coast City Council has extensive dune management programs, working alongside several community groups to minimise the impact of past and future coastal development. For more information, see information sheet Looking after our dunes. Coastal She-oak (Source: GCCC) Coastal Banksia (Source: GCCC) Reference 1. Leaflet from series ‘Coastal Sand Dunes – their vegetation and management’ Beach Protection Authority of Queensland (1975) Importance of dune vegetation (Leaflet No. 3 issue 4)