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.”

If you're like the majority of 4x4 Drivers, you won't be able to change the diff oil until you get home, because you won't have spare oil and a sump pump to change it. If you suspect contaminated oil (a deep water crossing without extended diff breathers or perhaps you have leaking diff seals) then you can try and remove the water by draining the diff until only oil comes out the drain hole. Do not drain too much and leave your diff short of lubrication. Collect this oil and water emulsion as you should never dispose of oil into the environment. Save it till you get back home and dispose of it properly. Its not only diffs that can have water contamination, but also your gearbox, transfer case and engine oil. However, it is usually only when a vehicle is stationary in deep water that these components are contaminated.