Europeans in their migrations changed all the lands they migrated too (Australia, Africa, India, North and South America, etc)-but to be fair if it wasn't them it would be somebody else. Like the US is nothing like pre-colonization. Mentioned here is the loss of the Great Plains prairie grasses due to John Deere inventing the steel plow so they could plow the deep fertile soils of the tall grasses (that pic with deep roots shows why LOL) then later mechanized farming after WWI and that was the end of the prairies (mostly still some tall grasses and short grass areas)-then growing wheat (rather than corn like natives) it took more land to produce a decent crop. Since farming and drought has depleted parts of Ogallala aquifer (under the Great Plains) the risk of another dust bowl is a real concern. I think it's ironic early colonist thought the prairies desert so kept going west to Oregon, which had less fertile soil. We harvested all the pristine forest in US and sold the wood globally and then often replaced with European species-we Europeanized the US. But before Europeans indigenous natives changed the landscape also-they used fire to burn the grasses to prevent succession with woody plants (the plains offered food in bison and farming grasses and grains), grew specific grasses and grains, etc. Humans have been introducing non-indigenous species for thousands of years-just look how Rome changed the world with plants and animals. There have been trade routes all of recorded history exporting plants, animals, and diseases too. War and slavery all recorded history. Nothing is the same from 60,000 years ago when a warming climate allowed humans to occupy new lands and mold the environment. My understanding of Australia is it has been occupied by humans for 60-80K years but only small populations lived in certain areas along Murray River -so most was pristine with little human intervention? It's a unique ecosystem but also doomed for change because change is inevitable. The US was already occupied and already experienced human intervention-so more intervention was inevitable. It's gene flow-and you can argue yes it may lead to extinction of some species but it can also develop into a new ecosystem (have more genetic potential to address climate changes) and the diversity from gene flow and hybridization can make new species over time. It's what life has done over and over again with big and small extinction events sometimes natural but the last 60k human driven. And yes the humans of today are nothing like 60k ago-we have all kept evolving too. The same gene pool population seeded Europe, China, and North and South America during migration and all evolved with their environments, however gene flow/migration has kept introducing admixtures to all ancestries. Like Haiti has more African ancestry (it still has some admixture) than Africa of today because the huge amount of admixture of other ancestries in all African populations now. It's what humans have always done like an alien species changing an environment to their liking on sci-fi movies. All recorded history humans have waged war against each other, enslaved each other, and migrated to new lands-always in competition, seen as a threat, and bringing their own influence to introduce elsewhere. We still are doing that as 9-14 million people still live in slavery in Africa. (it was legally banned but has never stopped). Heck we are talking about going and doing it to Mars. Poor planet is doomed LOL. Humans are vile creatures-we do a terrible job trying to act otherwise but that isn't our true nature. Blessed be the meek they shall inherit the earth-nope not by a long shot. We go boldly where no man has gone before-and mess it all up. In my best James T, Kirk voice. ROFL.