Recent studies in Amazonia historical ecology have revealed substantial diversity and dynamic change in coupled natural human systems. In the southern Amazon, several headwater basins show evidence of substantial pre-Columbian landscape modification, particularly in areas historically dominated by speakers of the Arawak language family. The headwater basin of the Xingu River, the easternmost of these areas occupied by Arawak-speaking peoples, has revealed such a complex built environment. This discussion examines settlement pattern and land-use, which have implications for understanding the dynamics of natural-human systems in the Upper Xingu basin and other areas across the transitional forests of the southern Amazon.