Australia’s koala paradox: why is the beloved marsupial endangered in parts but overabundant in others?

There are so many koalas in some places that food is the issue – while elsewhere populations are threatened by habitat loss. And there are no easy fixes

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n French Island in Victoria’s Western Port Bay, koalas are dropping from trees. Eucalypts have been eaten bare by the marsupials, with local reports of some found starving and dead. Multiple koalas – usually solitary animals – can often be seen on a single gum.

Koalas were first introduced to French Island from the mainland in the 1880s, a move that protected the species from extinction in the decades they were extensively hunted for their pelts. In the absence of predators and diseases such as chlamydia, the population thrived.

But the island is now struggling with an overabundance, part of a paradoxical threat facing the marsupial across the country: in the north-eastern states, koala numbers are declining, but in parts of southern Australia, the animals are eating themselves out of house and home. What makes saving the celebrated species so difficult to get right?