Splitting Australia’s koala in two
CONSERVATIONISTS HAVE SPENT years debating whether or not the koala should go on the national threatened species list, but a government ruling this week may have solved the problem.
The koala is clearly in trouble in some places. In Queensland, for example, populations in the fragmented habitats of the southeast are afflicted by disease and assailed by dogs and motor vehicles, while in more remote areas populations have been declining for reasons that are not always clear.
In Victoria and South Australia, however, the problem is not that koala populations are dwindling, but that they have grown too large and are wrecking their own habitat.
Koala plight in Queensland
Alarmed biologists from Queensland and New South Wales have long urged the Commonwealth government to recognise the plight of their koalas by listing the species as threatened, regardless of what is happening in Victoria and South Australia.
But the difficulty with that is that the Commonwealth uses a strict set of rules to test whether a species should be classed as threatened. The rules were developed by the World Conservation Union (the IUCN) to decide which species should be entered on the Red List, which is a global roll call of threatened species.
These rules have stipulations, such as that for a species to be classed as vulnerable, its population must have declined by more than 30 per cent over the last three generations or 10 years. When a rule like that is applied to koalas as a whole, the Victorian boom offsets the Queensland bust, and the species stays off the list.
Accurate threatened species listing
But we want koala populations to flourish throughout their geographic range, and if major sections of the population are suffering we want the threatened species list to record that.
This is especially important when one considers that northern koalas are different to southern ones. They are smaller, for example, and they contain genetic variation not represented in the south. If we lost them, we would have lost a significant chunk of koala-ness, regardless of how many koalas survived down south.
The Commonwealth Environment Minister has responded to this dilemma with what I think is a sensible decision. This is to create a split listing: koalas from New South Wales, the ACT and Queensland are now officially Vulnerable; those from Victoria and South Australia are not considered threatened (as was formerly the case for the species as a whole).
Split listing for koalas
This means that the differing problems faced by koalas throughout their range are officially recognised, and especially there is proper legal acknowledgement by the Commonwealth of the fact that northern koalas are facing serious problems.
The decision has had some criticism. For example, Senator Larissa Waters was reported in the Sydney Morning Herald as arguing the Commonwealth should have gone further and included Victorian and South Australian koalas in the new listing, as a precaution against future declines in the south.
But lumping southern and northern koalas together would make it impossible for the Commonwealth Threatened Species Scientific Committee, to recommend placing the koala on the threatened species list at all. In this case, at least, the Commonwealth Environment Minister should be congratulated for getting it right.
Professor Chris Johnson is a mammal ecologist and conservation biologist at the University of Tasmania in Hobart. He is also an adjunct professor at James Cook University in Townsville, Queensland.