according Wikipedia
are natural big Eucalyptus forrest next to Australia:
on Papua New Guinea, the island group of Timor, the island of Sulawesi and Philippines island of Mindanao.
introduce Eucalyptus into area and now consider as invasive species
California and Hawaii in USA, Uruguay, Portogal, Spain, Greece, italy (the islands of Sardinia and Sicily)
All of this site the climate is good for a Koalas population
so someone could bring Koalas to have cute furr balls in the tree for tourist or some source for meat and Fur
on Predators so long they sit in a tree is not problem for it, only if move on ground between there problem...
...for that what try to attack a koala
contradictory on believing Koala are cute harmless creature,
they use sharp claws to attack
there another thing that worry me some of species introduce to new habitat start become very aggressive and expand radical.
try to imagine highly aggressive Koalas attacking tourist and hikers...