A local ecologist says Australians should deal with booming kangaroos numbers by eating them.

Associate Professor David Paton from the University of Adelaide says eating more roo meat would ensure that culled carcasses are not wasted.

A/Prof Paton has conducted a long-term experiment in plots of fenced-off bushland at Sandy Creek Conservation Park in the Barossa Valley.

He found that the ever-increasing numbers of hungry kangaroos were unable to get into the plots, which had allowed the vegetation to return to levels not seen since the 1970s. The smaller animals and birds that the vegetation supports have risen in number too.

He said that if communities got behind kangaroo culls in other key areas, similar results could be achieved.

“If you don't cull the kangaroos or don't reduce their populations in some way, then you're going to lose a lot of other biodiversity,” A/Prof Paton said.

“It's not the kangaroos' fault they're overabundant, it's probably we've just been too reluctant to take a stick to them, remove them out of the system sooner, to actually prevent the damage being caused.

“If we're going to cull these animals we do it humanely, but we also perhaps should think about what we might use the animals that are killed for.

“We shouldn't just simply leave them out in paddocks to rot or leave them in the reserves to rot.”

The SA Department for Environment, Water and Natural Resources estimates there are about 4.7 million kangaroos in the state’s commercial harvesting zone across rural South Australia.

Regional director Brenton Grear said it was important for the community to know that kangaroos are being destroyed sensitively.

“We use competent shooters to actually ensure that animals are killed humanely,” he told reporters.

Animal Liberation SA wants non-lethal means to be investigated.

“There is some talk of sterilisation, but I think that's a while off, the best way to do it would be to relocate kangaroos,” Animal Liberation spokesperson Sally Sutton said.

“I know that they're supposed to be shot with a headshot, but whether that's the actual case, particularly because a lot of culls are done at night, how are they going to see to do a headshot, and also what happens to the joeys, that are in pouch or at foot.”

A/Prof Paton said the exploding numbers of the emblem species certainly created a “conundrum”.

“Is it just about kangaroos and is that the only thing, or is it about managing to keep kangaroos in the landscape at levels where they don't take out much of the rest of our biodiversity?”