Well actually, aborigines have been stomping around for more like 120,000 years - probably more, but they just can’t prove it. In any case, its not solely due to them but let’s say they gave the theory of evolution a bit of a kick up the arse.
Australia was once covered by thick rainforest and had a vast inland sea -the very inland sea many explorers died hunting for. Obviously climactic conditions shifted and some vegetation benefited while others perished. Animals too.
Fact remains, many Australian trees require fire to seed and the pattern is for the grass and shrubs to to dry out in summer setting the stage for rapid but fairly low intensity fires.
Aborigines were mostly migratory hunter gatherers, not slash and burn farmers. They’d torch a whole area as they moved off to encourage fresh growth and to attract certain animals for their next visit.
The Australian CSIRO is currently looking at these tradional burn-offs and actually employing aborigines to do controlled burns in certain areas to stave off the likes of the big fires hitting California now.
Essentially a combined factor of climactic shift, possibly in some way related to the arrival of the aborigines, in addition to evolution led to hard arsed trees and shrubs that like a good roasting. Those that don’t disapeared. The idea is cautiousluy accepted in Australai because some environmentalitst are concerned that re-introducing these big burns will upset the apple cart.
(in extreme haste)