A FIFTH of World Heritage-listed Fraser Island foredunes have been destroyed by four-wheel-drive vehicles, prompting a call for limits to be set.

At least 235 vehicle tracks have been cut across Fraser’s dunes, with most related to camping.

Because dunes were the first defence against storms, vehicle-induced damage was likely to accelerate erosion and shoreline retreat, researchers said.

Of the island’s 124km of ocean beaches, 122km  are open to vehicles.

Thomas Schlacher, associate professor of marine science at the University of the Sunshine Coast, said the bare sand of inter-tidal areas was often regarded as being more resilient to vehicles than sensitive dunes – but this was wrong.

“What is generally not known – or at least appreciated – is that beaches are diverse ecosystems in their own right,” Professor Schlacher said. “Contrary to popular belief, beaches are not marine deserts.”

A beach could contain dozens of invertebrate animal species in the sand. If smaller species were counted, this rose to hundreds.

Drivers who thought they did not damage beaches because they drove on the hard sand at low tide were wrong, Professor Schlacher said.

“They don’t realise they are driving over little animals underneath the surface,” he said.

“The tide washes over their tracks and makes everything nice and smooth again but the damage has been done.”

Sunshine Coast Four Wheel Drive Club vice-president Paul Dickson said he was sick of people who had nothing better to do with their time than attack 4WD owners.

“Why don’t they get a life?” he said. “They want to put all humans to death so animals can inherit the earth.”

Tip:

Diff Locks<br> There are two types of 4x4 diff locks- manual and full time. Manual Diff Lock<br> A number of different manufacturers make this type of lock which is actuated manually by switch whenever extra traction is required. The beauty of the manual system is that it can be switched off when slippery side slopes want to send the back of the 4x4 sliding off the track. Full Time Diff Lock<br> Again a number of manufacturers make full time difflocks. With these there is absolutely no driver intervention required to lock them, as these units are engaged and working all the time. However, to unlock a full time unit to turn corners a slight change in driving technique is required. Simply back off the accelerator when first entering a corner and the locker will start to ratchet and allow differential action around the corner. As the vehicle straightens up the locker once again resumes its locked position. One problem with the full time unit is when a 4x4 is on a slippery side slope. It cannot be unlocked and could force the rear of the 4x4 to slide off the track because both wheels are driving.