Are the Australian and Amazonian ecosystems in fact manmade? The case of Australia is somewhat stronger, as fire adapted communities, although of course present before Aboriginal settlement, expanded dramatically afterwards at the expense of other Australian vegetation types, and it is known that Aboriginals knew very well the use of fire in order to change the ecosystem and obtain food. The case of the Amazon isn’t so credible. It is said that a large percentage of the basin (I don’t remember the exact number) is covered by the so called terra preta, a human-made soil and coal mixture which can retain nutrients for a long time. It is said that once the human population was much greater, and there were more advanced civilizations there. How much of science and how much of pseudoscience these claims carry?

Also, I have read a minority view that the Amazon rainforest is in a transitional state. That at the last ice age it was mostly grassland with fragmented rainforest, and that when temperatures started to rise, forests expanded and isolated species from different communities mixed, giving rise to the extreme biodiversity of today, which will sort itself out in the future with some species prevailing and others going extinct leading to a more homogenious flora and fauna. How much true is that?

sorry no-one seems to know the answer to your question.