I generally agree. The presence of indigenous peoples is implicit in my argument (and explicit in the form of one of the photographs included). The only statement you make that I would take some issue with is your claim that the arrival and long-term presence of indigenous peoples enhanced biodiversity. The arrival of humans in the Americas is actually associated with the extinction of numerous megafauna. That was also the case following the arrival of people in Australia and elsewhere. As is the case any time apex species are eliminated from an ecosystem, this extermination undoubtedly also led to the extinction or significant reduction in numbers of numerous other plants and animals we aren’t even aware of while benefiting others. Therefore, I think it would be more accurate to say that over time something like a new equilibrium was established between indigenous cultures and the land, albeit one achieved at great cost. To be fair, I’m not sure this could have been avoided. Regardless, it still needs to be acknowledged. Furthermore, we can also find many subsequent examples of collapse (e.g. the Anasazi, Toltec, and Mayan cultures) that were, to a significant degree, linked to unsustainable exploitation of local resources.
We need to be careful not to romanticize any culture, be it indigenous or our own. Humanity’s relationship with the environment (and with each other) has always been a complex one with examples of both success and failure to be found in virtually every culture’s history. As has often been pointed out by scholars, defining indigenous cultures as “primitive” or “pure” or as “living in balance with nature” is just another way of removing them from the picture. In this light, indigenous peoples are portrayed as the innocents inhabiting the Garden of Eden (i.e. pristine wilderness) while our “superior” knowledge and technology brings the change that drives them from paradise. Indigenous peoples, accordingly, now become like us in that they too need to be saved from the fall. As William Cronon and others have pointed out, modern environmentalism’s depiction of both wilderness and indigenous people very closely parallels the Biblical tradition of the European culture from which the environmental movement emerged.
Indigenous cultures were and are just as capable of greatness and folly as any other culture ever was or is. Their relationship to the environment was not and is not simple. It has always involved trade-offs, as any relationship with the environment inevitably will. By setting ourselves up as more “advanced” or, alternatively, as more “corrupt” than indigenous cultures we make the same mistake of distancing ourselves from other peoples and from the environment, even if that mistake is being made on behalf of different ends.