There is, of course, another part to the question of the continued existence of koalas.  How can they survive in the wild when their wilderness has disappeared? 

Over 80% of the natural eucalyptus groves in Australia have been cut down.  Most of the remaining eucalyptus grows on private land.   The continued existence of koalas depends on the marsupial’s ability to adapt to a suburban environment.  But one estimate says that every year 4,000 koalas are killed by cars, dogs, and feral cats.  The species is teetering on the edge of that swift slide into extinction, and the biggest threat to koalas is human carelessness.  Sound familiar?  We are such a selfish species.   https://www.savethekoala.com/deborahtabartsdesk.html