If Flame Robins did not eat insects, the plants would be overpopulated with insects. Insects eat the leaves of many plants, including eucalyptus. Too many insects = there are no leaves on the trees for the koalas to eat.
Even butterflies are important to koalas. Butterflies, like the common brown, pollinate native plants when looking for nectar to drink. Unlike bees, which pollinate a small area very effectively, butterflies can carry pollen over great distances, which means they can bring new plants into an area and ensure a uniform distribution of a diversity of plants. The diversity of plants at ground level helps other animals such as kangaroos to thrive.
Caterpillars, the young of butterflies, eat plants. The common brown caterpillar eats herbs like kangaroo grass (Themeda triandra), which has a tendency to become too dominant in one area if left unhandled. Aboriginals used to manage kangaroo grass with regular small fires, but now that is not happening, we are lucky to have common brown caterpillars!
Macropods (kangaroos, wallabies) make footprints through thick undergrowth as they search for food and water. When undergrowth is thick, koalas use kangaroo and kangaroo tracks to move from tree to tree every day. If there are no tracks in the thick undergrowth, a koala is in danger of being preyed upon by dogs and it is much more difficult for them to get through. Too much energy expended means that a koala has less energy to reproduce.
Grass seed eaters, such as long-billed Corellas, spread the seeds of the herbs and help control weeds such as onion grass. Grassy forests are the perfect habitat for koalas as they make it easy to move from one tree to another.
Koalas also benefit other species. Black-chinned honeysuckle is a small threatened bird. They take koala skins to line their nests. Without koalas, whose fur will black-chinned Honeyeaters get? Wallabies don’t sit still long enough, possums only come out at night. Will black-chinned honey babies get too cold in their nests and die?
Some creatures, like the endangered Painted Honeyeater, have all but disappeared from koala habitat. Could this be why koalas are declining? We just don’t know.
The images on this page are from the book “Koala Kingdom” by Eddie Alfaro. For more info about the book, click here.
People often ask us why koalas are declining, even in national parks. The truth is, no one is really sure. Each region has different challenges, but in general, koalas are declining too fast for their long-term survival.
We don’t know the answer to the decline of koalas, but we do know this: everything is connected. When the Gray-crowned Babblers disappeared from the You Yangs, did that affect the koalas? Maybe just a little bit. When the Tasmanian Pafmelons, Eastern Barred Bandicoots, Brush-tailed Wallabies, and Dingoes disappeared, did that affect the koalas?
The fact is, we’ve lost species of insects, birds, reptiles, and plants that koalas depend on from koala forests, but we still hope that koalas will reproduce well (but not too well) and live long, healthy lives. It is surprising that they survive.
This rule applies throughout the world. Nature is an intricate web that we still don’t fully understand. We are part of that network and without it we will not survive either.