Koalas are an iconic Australian species and true dietary specialists, surviving on a diet of almost exclusively eucalyptus leaves. While genuine obligate specialists like the koala are exceedingly rare, their narrow ecological niche also limits their ability to adapt to environmental change and places them at risk. Indeed, koalas have declined across most of their historic geographic ranges and have recently been listed as threatened in Queensland, NSW and the ACT. Habitat destruction is the major reason for the decline; since European settlement approximately 80% of Australia’s eucalyptus forests have been cleared. Increasingly, translocation of affected koalas is presented as a viable management action when a known population is under threat. Other threats to koalas include climate change, both directly via heat stress and dehydration and indirectly via changes to the distribution, leaf chemistry and nutritional quality of eucalyptus trees. It is anticipated that digestible protein levels will decrease while tannin and fibre levels and secondary metabolites like cyanogenic glucosides, will increase in eucalypt leaves.
There is an urgent need to understand the role of microbes in koala digestion and their potential to buffer digestive efficiency against the impacts of climate change as well as from translocation to areas with different species eucalyptus trees. The aims of this project are to:
1.Describe the variation in the hindgut microbial community of koalas eating different diets
2.Determine how hindgut microbial communities adapt during exposure to natural leaf toxins and common antibiotics used to treat diseases such as Chlamydia
3.Test whether microbial inoculations from appropriately adapted koalas can alter the gut microbial community and allow koalas to eat unfamiliar leaves in new environments
4.Leverage our sensitive gene and pathway discovery pipelines to characterize new enzymatic functions in the koala’s gastrointestinal tract, particularly terpenoid, tannin and lignin-degrading enzymes