Pristine and natural North America had mammoth, horses, and many other megafauna which were rapidly hunted to extinction. But somehow the American Indian evolved culturally, adapting to their environmental niches and cultivating the land to maintain a lifestyle dominated by hunting, with some farming. This involved more-or-less extensive changes to the landscape.
America before the White man came wasn't pristine or natural. It was bountiful.
Erm, no? Seems kind of racist to say otherwise? The plains indians entire culture revolved around preserving and respecting nature. And I'm pretty sure it's only theorized that the paleo-indians wiped out the mammoths, and I'm not sure how that's the problem of the white man or even the native americans of the mid 19th century.
Extending your argument to its logical absurdity, no environment can be considered "pristine" unless it's the literal primordial sludge the first life emerged from. Very odd nitpickery.
There are many records of large pre-Columbian settlements exhausting resources (like game and trees) and abandoning entire areas.
There is nothing racist about it. They were humans. They consumed resources and grew their population as aggressively as their technology permitted.