Eucalyptus are grown commercially all over the world these days.
They are native to Oz, over 700 species, native to parts of New Guinea and Indonesia too. Although NG and Ind only have a small number of species in secluded pockets.
Koalas will only eat a very small number of these species of Eucalypti , hence Koalas aren't found all over Oz. I fail to see how they arrived here when Noah crashed his boat as they are lazy little *** sleeping 16-20 hours per day. Don't move very quickly when awake either.
But I'm not sure what this has to do with "Doomsday Prophecies", unless Koalas have started migrating north with the intention of ruling the world one day. Imagine that, everyone gets to sleep in and laze around. Sounds like the Greeks and Mexicans ;-).