Evaluating Rapa Nui (Easter Island) Prehistoric Resource Degradation

Earthwatch Institute, Boston MA

Investigators

Abstract

This project National Science Foundation brings together a highly qualified group of international investigators led by Dr. Christopher M. Stevenson to conduct archaeological research on Rapa Nui (Easter Island), Chile. Team members from Rapa Nui New Zealand and the United States will focus on climate change, environmental degradation, and dramatic subsistence changes to develop an empirical assessment of how these may, or may not have, influenced pre-European contact societal collapse on Easter Island. The island is an ideal study area for documenting the dynamic nature of these processes. It is a relatively small isolated island where environmental variables (e.g., rainfall, elevation, temperature, levels of physical erosion, age of volcanic substrates, and soil nutrients) vary significantly over space and time. The archaeological landscape is very well preserved due to low modern population densities. The short period of pre-European contact occupation (ca. AD 1100-1722), and relatively low levels of inter-island contact, facilitate an understanding of why society might have changed with time. This program of paleo-ecological, landscape and archaeological investigations will develop a highly resolved cultural time-line. The team will use geomorphology and geochemistry to assess the history of Rapa Nui soils and determine the impacts of erosion and sustained agriculture. The morphological and functional variation of various classes of gardens will be addressed through an analysis of environmental setting, remotely sensed satellite data, and precise geographical locations. We will Obsidian hydration dating in conjunction with radiocarbon dating will be used to determine the age of agricultural activities. Using a series of GIS and ecodynamic models these data will be analyzed to achieve a robust and comprehensive understanding of how, when and why Rapa Nui terrestrial resources changed through time and the impact that this might have had on prehistoric societal change. The research focuses on Rapa Nui, yet the issues addressed are global. Rapa Nui is often depicted as a model for global environmental degradation. Relatively simplistic linkages have been made between agricultural activities and processes of deforestation, physical erosion, and societal collapse. Utilizing an interdisciplinary team with innovative theoretical and methodological approaches allows scientists to advance understanding of change on Rapa Nui and the suitability of this isolated small island as a model of the world. The research involves empirically measuring a limited number of variables to facilitate complex modeling of the island ecology. This effort will establish whether changes in terrestrial resources were a critical factor in a pre-European contact societal collapse. The Rapa Nui context provides an excellent comparison to continental, large archipelago, and small Pacific island settings and fills a critical gap in understanding the linkages and relationships between social and natural processes. The research will contribute to the development of the dynamic modeling of past human activity. These findings will enable social scientists to understand the impact of people both on the local island level and the wider global scale.