Doctoral Dissertation Research Improvement Grant: The Impact Of Colonization On Island Ecology

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

For her doctoral dissertation research and under the direction of Dr. Patrick Kirch, Jillian Swift of the University of California, Berkeley, will study the impacts of prehistorically introduced commensal animals on local environments and human societies (or "socioecosystems"). The introduction of new species can have unintended and irreversible consequences for humans and their surroundings that often remain unrecognized until they have become too large to mitigate. Archaeology affords a unique opportunity to investigate long-term processes of species introductions to understand their impacts and evaluate the success or failure of past animal and resource management strategies. This information has critical implications for present-day concerns over global resource limitations and management. How did past peoples and their commensal animals transform local ecosystems, and what can be learned from their prehistoric strategies for long-term sustainability? Swift will utilize comparative research of four different Polynesian Islands as model systems for understanding species introductions and long-term human-environment interaction: Mangareva, the Marquesas, Hawaii, and Tikopia. The islands of Polynesia provide fruitful grounds for comparative analysis, as their first human inhabitants arrived relatively recently (ca. AD 900-1000) and originate from a shared ancestral Polynesian culture. Tikopia, known as a "Polynesian outlier," provides contrast to the other islands with a prehistory that extends back to 900 BC and includes interactions with both Polynesian and non-Polynesian oceanic populations. These first Polynesian settlers transported a suite of plants, animals, and cultural practices which they subsequently adapted to new islands that varied in key factors such as age, size, climate, and resource availability. The research will utilize stable isotope analysis (carbon and nitrogen) of archaeological bone to reconstruct the diet of two commensal species that arrived to the islands with humans: pig (Sus scrofa) and Pacific rat (Rattus exulans). Reconstruction of pig diet will investigate the past animal husbandry practices of an animal which often competed with humans for food resources in a constrained island environment. The limited home range of Rattus exulans will allow for investigation of environmental conditions on a localized scale, and analysis of rat diet will lead to insight into this species' role in island deforestation, extinctions, and extirpations. The comparative approach will identify key environmental and cultural variables that either hindered or encouraged the long-term sustainability of human populations. The study will be undertaken through collaborative international research with the University of French Polynesia and provide training opportunities for undergraduate students in zooarchaeological laboratory methods and stable isotope analysis at the University of California, Berkeley.