Assessing charcoal and phytolith signals for pre-Columbian land-use based on modern indigenous activity areas in the Upper Xingu, Amazonia

The nature and extent of past indigenous transformations in the Amazon basin is an actively debated topic, and one that has important implications for both conservation policy and the cultural heritage of its indigenous and traditional populations. The use of charcoal and phytoliths to measure past human impacts in non-lacustrine settings has become especially influential in this debate but has also generated disagreement among scholars regarding the possible limits of these proxies for detecting ancient land-use. To contribute empirical data to this issue, our paper presents the first attempt to study charcoal and phytolith signals from areas of modern indigenous land-use, in the Xingu Indigenous Territory, southern Amazonia. Our findings show that, while charcoal and early successional herb phytoliths are good indicators of land-use intensity, certain types of land-use leave subtler traces in the phytolith record that can hinder their detection. We demonstrate how using finer sampling resolution and comparing local proxy data on their own terms are necessary steps in order to identify trends in human land-use across time and space.