Overabundant koalas in South Australia prompt fertility program and call for culling in 2019
Koalas in the Adelaide Hills and Mount Lofty Rangers were targeted with a fertility program in 2019.
Image courtesy Brett Jarrett
A koala fertility program in the Adelaide Hills and Mount Lofty Ranges and a cull proposed for Kangaroo Island were responses in 2019 to South Australia’s booming population of koalas, while to World Wildlife Fund pushed for it to be listed as an endangered species on Australia’s east coast.
Surveys found about 150,000 koalas in the Mount Lofty Ranges and Adelaide Hills, and 27,000 on Kangaroo Island. This is having severe effects in overbrowsing.
Natural Resources Adelaide and Mt Lofty Ranges agency reported 13 koalas per hectare in one area of manna gum woodland in the central hills against an optimal number of around one per hectare. This made the koala population one of the greatest food threats to the koala population in parts of the Mount Lofty Ranges. Under the fertility program started in 2019, trained staff captured a set amount of koalas one at a time, administered hormone implant within 10 minutes, and released them.
This followed a program on Kangaroo Island operating for more than 20 years. But the state’s natural resources committee in 2019 told a South Australian parliamentary inquiry that koala numbers on Kangaroo Island needed to be culled.
Koalas were introduced to Kangaroo Island in 1920 as part of a plan to stop the endangered species from becoming extinct on the Australian mainland. The marsupial population flourished. Different management techniques have been introduced to control or accommodate koalas, including planting manna gums that they eat.
A koala cull was previously suggested for Kangaroo Island but the idea was dumped after it created community uproar. Koalas are listed as a vulnerable species by the International Union for the Conservation of Nature. The natural resources committee recommended the state’s environment minister assume the power to declare koalas and other certain species as overabundant, with councils given the jurisdiction to cull them.