Document ID: chunk:federal_register_of_legislation:F2022L00555:body:0:p81
Version: federal_register_of_legislation:F2022L00555
Segment Type: other
Provision Reference: 
Character Range: 249505–252475

For example, FPCs are toxic and protect the plant from predators. FPC levels differ within a species, on an individual tree basis. Leaf moisture may play a role during times of low rainfall or heat stress (Ellis et al. 2010a). Choice of browse trees is also influenced by physical characteristics including tree size, number of palatable trees nearby, and presence of shelter trees (Crowther et al. 2014; Moore et al. 2010).
The nutritional composition and amount of plant secondary metabolites of Eucalyptus species can vary within and between species (Moore et al. 2010; Wallis et al. 2010) at fine scales. This is also influenced by disturbance history, climate conditions (Au et al. 2019; Moore et al. 2004; Stalenberg et al. 2014; Youngentob 2015) and seasonality (More and Foley 2000), creating a patchy and dynamic distribution of food quality in space and time across landscapes and with corresponding spatio-temporal shifts in tree use by Koalas (Moore et al. 2010). Koalas living in different eucalypt communities therefore contend with different nutritional and toxicological challenges (DeGabriel et al. 2009).
The Koala has a specialised digestive tract with an extremely enlarged caecum to retain food for long periods to break down food to extract nutrients and degrade toxic plant metabolites by gastrointestinal microorganisms (Cork et al. 1983; Shiffman et al. 2017). Gut microbiomes of Koalas vary (Alfano et al. 2015) and appear to be influenced by diet (Brice et al. 2019) suggesting that gut microbiomes of Koalas are finely optimised to digest particular species of Eucalyptus, Corymbia, and Angophora, and dietary selection by individuals may be therefore limited by their microbiome (Blyton et al. 2019).
This relationship between diet and microbiome has ramifications for Koala translocations, the treatment of sick or injured Koalas, habitat restoration, population management and habitat requirements. If Koalas are introduced to new locations, a higher diversity of potential food trees may enable Koalas to find a suitable diet. Sick and injured Koalas treated with antibiotics that deplete gut microbiomes could be inoculated with probiotics to restore functional gut microbiomes, enhance recovery and successful return to the wild. Inoculations of microbiomes optimised for certain species of Eucalyptus, Corymbia, and Angophora could potentially be used to assist in translocations, disease prevention, or shift diets in-situ, preventing the need for translocations when managing population numbers (Blyton et al. 2019). Understanding population-level gut microbiomes could also be used to optimise the selection of tree species in habitat restoration targeted at Koalas, or via inoculations, to assist the plasticity of populations to adapt to changing forest tree composition in the future as the local climate changes.
Species distribution models indicate that the range of Koala browse trees will be impacted in the future by climate