Polynesian Subsistence, Nutrient Flows, and Long-Term Socio-Ecosystem Dynamics: Insights from Stable Isotope Analysis of the Pacific Rat (Rattus exulans) in Island Foodwebs By Jillian Amy Swift A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Anthropology in the Graduate Division of the University of California, Berkeley Committee in charge: Chancellor’s Professor Emeritus Patrick V. Kirch, Chair Professor Christine Hastorf Professor Anthony D. Barnosky Spring 2016 Polynesian Subsistence, Nutrient Flows, and Long-Term Socio-Ecosystem Dynamics: Insights from Stable Isotope Analysis of the Pacific Rat (Rattus exulans) in Island Foodwebs Copyright © 2016 by Jillian Amy Swift Abstract Polynesian Subsistence, Nutrient Flows, and Long-Term Socio-Ecosystem Dynamics: Insights from Stable Isotope Analysis of the Pacific Rat (Rattus exulans) in Island Foodwebs by Jillian Amy Swift Doctor of Philosophy in Anthropology University of California, Berkeley Chancellor’s Professor Emeritus Patrick V. Kirch, Chair This dissertation applies stable carbon (δ13C) and nitrogen (δ15N) isotope analysis to archaeological specimens of the human-transported Pacific rat (Rattus exulans) to investigate prehistoric patterns of subsistence, site use, and long-term socio- ecosystem dynamics on Polynesian Islands. The Pacific rat is a small commensal species characterized by low dietary selectivity and a limited home range. Its close association with past Polynesian peoples—and ubiquity in Polynesian archaeological sites—suggests that dietary change in this species can provide insight into changing island landscapes and human subsistence regimes. Pacific rat bone collagen δ13C and δ15N values were compared across three contrastive island socio-ecosystems: Mangareva, the Marquesas, and Tikopia. Spatiotemporal trends in Pacific rat stable isotope ratios are related to localized changes in human activity and subsistence practices, as well as global ecosystem processes which include avifaunal extinctions, resource depression, and soil nutrient cycling. On Mangareva, temporal variations in δ13C and δ15N values were assessed from three sites: the Onemea site, Taravai Island (TAR-6), Nenega-iti Rockshelter, Agakauitai Island (AGA-3), and Kitchen Cave Rockshelter, Kamaka Island (KAM-1). Declining δ15N values through time at all three Mangarevan sites reflect archipelago-wide socio-ecosystem changes related to site activity and avifaunal population declines. At the Hane dune site, Ua Huka Island (Marquesas), shifts in rat diet provide insight into changing Marquesan settlement and subsistence practices. On the Polynesian Outlier of Tikopia, a 650-year period of stability in rat bone collagen δ13C and δ15N values during the Kiki Phase (800- 160 BC) suggests that mechanisms for long-term socio-ecosystem sustainability have been in place on the island for over 2000 years. These results demonstrate the capacity for stable isotope analysis of the Pacific rat to provide a new, low- impact line of evidence towards reconstructing localized patterns of site use, subsistence practices, and island ecology. 1 Table of Contents List of Figures and Tables ............................................................................................................. ii Acknowledgements ........................................................................................................................ iii Chapter 1: Introduction .............................................................................................................. 1 The Human Colonization of the Pacific ............................................................................. 1 Transported Landscapes: Polynesian Subsistence and Ecosystem Change ....................... 2 Islands as “Model Systems”............................................................................................... 4 Pacific Rats as Proxies for Nutrient Flows in Island Socio-Ecosystems ........................... 5 Preparation and Analysis of Bone Collagen for C and N Stable Isotope Ratios ............... 6 Carbon an Nitrogen Stable Isotope Analysis in Oceania ................................................... 9 Dissertation Outline ......................................................................................................... 12 Chapter 2: Stable Isotope Analysis of Pacific Rats from Mangareva ................................... 13 Introduction ...................................................................................................................... 13 The Pacific Rat in Polynesian Ecosystems ...................................................................... 15 Materials and Methods ..................................................................................................... 16 Results .............................................................................................................................. 21 Seabird Population Decline and Nutrient Flows on Mangareva ...................................... 25 Conclusion ....................................................................................................................... 27 Chapter 3: Coastal Subsistence and Settlement at the Hane Dune Site, Marquesas .......... 28 Introduction ...................................................................................................................... 28 Subsistence and Settlement in the Marquesas Islands ..................................................... 29 Materials and Methods ..................................................................................................... 32 Results .............................................................................................................................. 33 Discussion ........................................................................................................................ 36 Conclusions ...................................................................................................................... 38 Chapter 4: Pacific rat diet as proxy for human-ecosystem dynamics on Tikopia ............... 40 Introduction ...................................................................................................................... 40 Long-Term Human Ecodynamics on Tikopia ................................................................. 41 Materials and Methods ..................................................................................................... 44 Results .............................................................................................................................. 46 Socio-Ecosystem Dynamics and Pacific Rat Stable Isotope Ratios ................................ 49 Conclusions ...................................................................................................................... 52 Chapter 5: Conclusions ............................................................................................................. 54 Mangareva, the Marquesas, and Tikopia in Comparative Perspective ............................ 54 Future Directions for Stable Isotope Studies of the Pacific Rat ...................................... 56 References ................................................................................................................................... 58 i Figures Figure 2.1. Map of the Mangarevan archipelago and labeled study sites 14 Figure 2.2. Pacific rat δ13C and δ15N values from all three Mangarevan sites 23 Figure 2.3. Rat δ13C and δ15N values from Mangarevan sites with potential food sources 24 Figure 2.4. Avifaunal remains from all three Mangarevan sites 26 Figure 3.1. Map of the Marquesas Islands with Hane dune site labeled 30 Figure 3.2. Pacific rat δ13C and δ15N values from the Hane dune site 36 Figure 3.3. Rat δ13C and δ15N values from Hane with potential food sources 37 Figure 4.1. Map of Tikopia with study sites labeled 41 Figure 4.2. Pacific rat δ13C and δ15N values from Tikopia by cultural phase 49 Figure 4.3 Rat δ13C and δ15N values from Tikopia with potential food sources 51 Figure 5.1. Mean Pacific rat δ13C and δ15N values from all study sites 55 Tables Table 2.1. Results of bone collagen stable isotope analysis from all three Mangarevan sites 19 Table 2.2. Mean Pacific rat δ13C and δ15N values by layer from each Mangarevan site 22 Table 3.1. Results of bone collagen stable isotope analysis from the Hane dune site 34 Table 3.2. Mean rat bone collagen δ13C and δ15N by cultural phase from Hane 35 Table 4.1. Revised chronology for Tikopia’s prehistoric cultural phases 42 Table 4.2. Results of bone collagen stable isotope analysis from Tikopia 47 Table 4.3. Descriptive statistics for Pacific rat δ13C and δ15N values by cultural phase 48 ii Acknowledgements I am immensely grateful to a number of people for their support in making this dissertation possible. This work is the culmination of years of collaborations, friendships, and inspirations, and I apologize if I have overlooked any of those here. First to my dissertation committee, I thank you all for sharing your knowledge, your support, and your time with me over the years. Foremost to Pat Kirch, who is an endless font of knowledge about the cultures and prehistory of the Pacific Islands, and to whom I will be forever indebted for his mentorship and encouragement. To Christine Hastorf, who has a remarkable knack for challenging me to find new ways to think about my research, and whose intellectual rigor has vastly improved