That’s the time scale it took place over, not the time scale it took to take place as I’m aware.
That said, native peoples have also played strong roles in maintaining the ecology of grasslands in e.g. the Great Plains through... fire.
But at the same time, those same natives who propagated breadfruit throughout the Amazon were also present as it transitioned from being partly savannah to full on rainforest again.
> Over thousands of years, native people played a strong role in molding the ecology of this vast wilderness