Cape Town Daily Photo

How to kill a dune

We’ve probably all heard about dune conservation, but perhaps we haven’t all understood why it’s important to conserve dunes. Dunes are our shore’s first line of defence against the destruction caused by storms and unusually high tides. Acting as a long barrier, they reduce the chance of flooding, and in the case of severe storms, help to delay flooding. Dunes also help contain the beach sand and salty water spray from being blown inland, thereby protecting vegetation from dying due to excessive soil salinity, and preventing beaches from extending too far inland.

I’d never realised how fragile dunes were before reading this article on dune protection! Beach grass, shown in this photo, is the scaffolding used to build dunes. The grass grows, more sand is deposited, the grass grows above the sand, more sand is deposited, and the cycle continues until we have huge dunes to protect our shoreline.

The beach grass shown in this photo is extremely resilient to the elements. Like a true champ it resists drought conditions, tolerates very high levels of salt in the sand, and flourishes in very infertile soil. However, even though the grass in this photo is extremely hardy, its brittle inner core is extremely vulnerable when stepped on. Even a single person taking a shortcut across a dune kills grass on which they stand. A few people taking a shortcut across a dune will kill enough grass to cause the dune to be eroded by the wind.

Visit this site and follow the links to see the illustrations of how easily dunes erode when people trample the grass. I don’t think I’ll ever walk over a dune again, except by using the designated paths or bridges.