You’re not going to believe this…
All species have limits to the type of habitats they can use, some habitats are too unsuitable for them to occupy. The general rule for koalas is that they occur below 800m in altitude, and prefer forests on richer soil types.
We’re working with koalas in the World Heritage Blue Mountains region, living at over 1000m. Not only that, but they were found on the top of a ridge in what most experts would class as poor quality and highly unlikely habitat.
Sometimes we find male koalas in poorer habitats; they can be forced to use them when they’re pushed out by other males, or they might move high up on a ridge so that their mating bellows carry further. So if it’s a male koala that we find we don’t necessarily assume he is in core koala habitat. The breeding females tend to occupy the best quality habitats to meet their nutritional needs while raising young.
What we found on this ridgeline at over 1000m was a cluster of breeding females all carrying young joeys like Pluto. That makes it core koala habitat. None of us could believe what we were seeing, this is a game changer.
It is good news for koalas. Many koalas are found outside of protected areas on the rich soils that humans also prefer to use, for agriculture and urban development. The koalas we found are within the boundaries of Kanangra-Boyd National Park, north of Jenolan Caves. I’ve always hoped that the massive network of protected areas that makes up the World Heritage Area might be a potential refuge for koalas and other species – as habitats out west become less suitable under climate change and habitats to the east towards the Sydney basin are increasingly lost to development. But I thought there would be a lot of limits to the parts of the Blue Mountains that koalas might be able to use, that many of the habitats would be completely unsuitable.
The more we discover about these koalas, the more these expectations get thrown out of the window. The fact that we are finding koalas in more areas than expected fits in with our recent genetic results, that koalas in this region have the highest levels of genetic diversity in the country. To maintain good diversity you need large numbers of koalas.
We now have a lot more areas that we need to survey, and hopefully many more koalas to find!
You can read more about our Blue Mountains Koala Project here
By Dr Kellie Leigh, Executive Director Science for Wildlife.