A dune is often viewed as nothing more than a heap of sand next to the sea. But the next time you climb a dune, remember all these things going on underneath your feet.
Words by Andrea Abbot
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- Hardy vegetation like the pioneer Scaevola plumieri traps windblown sand and allows for a line of small dunes to develop just above the high water mark. As the plants creep further, more sand builds up and dunes grow higher. According to Brian High of KZN Wildlife’s North Durban Honorary Officers, the Bluff south of Durban Bay began life aeons ago as a vegetated baby dune.
- Vegetation stabilises sand dunes. Disturbance of those dunes through trampling, vehicles, and livestock grazing causes erosion and plant destruction and can result in sand shifting inland, and the destruction of the dune.
- Dune development is also aided by driftwood as, like with plants, it helps to trap sand and prevent erosion of foredunes – i.e. those closest to the sea. Basil Pather, manager of Durban’s Beachwood Mangroves Reserve explains that driftwood is not alien to the beach environment and if removed can impede the development of foredunes.
- Dunes create natural barriers between the sea and land and absorb the worst impacts of huge waves and tidal surges, especially in this era of rising sea levels.
- Dunes act as a reservoir of sand. When heavy seas and tidal surges erode beaches, the dunes return sand to the scoured-out areas.
- Vegetated dunes create sheltered nesting sites for birds and turtles.
- In providing shelter from salt-laden onshore winds, dunes allow plant communities to develop on the inland side of the dunes. This is the scrub zone that in KZN is characterised by plants like the Natal Wild Banana (Strelitizia Nicolai,) Coastal Silver Oak (Brachylaena discolour,) and Num-num (Carissa macrocarpa), all providing habitat for many faunal species.
- High, stable dunes function as a screen that protects beachfront properties from the effects of corrosive winds and from windblown sand. They also provide a scenic backdrop to the beach and create a sense of being in the wild, especially in coastal areas transformed by massive beachfront development.
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