Quoll

• Across the vast Australian continent, feral pigs, feral deer and European rabbits roam in their millions.
• By different names – wild boar, venison and lapin – these could all be served in a Michelin star restaurant.
• Feral and invasive species are becoming popular meals for native wildlife too.

Of crocs and pigs

• This seems like a much-needed good news story for the environment – a natural way to limit feral pigs, one of Australia’s most widespread and damaging invasive species.
• At present, though, we don’t know for sure that crocs keep pig numbers down.
• Together, this means feral pigs can endure relatively high predation rates and still persist in ecosystems in large numbers.

Of quolls and rabbits

• Unfortunately, quolls are now absent or still declining in many places, due likely to competition or predation with the bigger, heavier predators Europeans introduced: feral cats and foxes.
• As quolls have disappeared, rabbits may have taken advantage of the predatory void and expanded.
• Fast-breeding rabbits are now arguably Australia’s worst invasive alien species.

Dangerous dinners

• Cane toads have devastated some native species such as northern quolls, which naturally prey on native amphibians but cannot survive toad toxin.
• Regrettably, a recent attempt to train quolls not to eat cane toads appears to have failed.
• European house mice and introduced rats can be easy prey for owls, snakes, and many other native predators.

Invasive prey aren’t going away

• As time goes on, invasive prey species can become regular meals for native predators – and part of the food web.
• When we try to remove invasive prey species from ecosystems, we must take a big picture view and proceed with great caution.
• When feral cats were killed off on New Zealand’s Little Barrier island, it was done with the best intentions: protect the seabirds nesting there.
• But with the cats gone, invasive rat populations surged and soon began killing the seabird chicks.

Euan Ritchie receives funding from the Australian Research Council and the Department of Energy, Environment, and Climate Action. Euan is a Councillor within the Biodiversity Council, and a member of the Ecological Society of Australia and the Australian Mammal Society.