Barry V. Rolett

Phylogeny and ancient DNA of Sus provides insights into neolithic expansion in Island Southeast Asia and Oceania

Human settlement of Oceania marked the culmination of a global colonization process that began when humans first left Africa at least 90,000 years ago. The precise origins and dispersal routes of the Austronesian peoples and the associated Lapita culture remain contentious, and numerous disparate models of dispersal (based primarily on linguistic, genetic, and archeological data) have been proposed. Here, through the use of mtDNA from 781 modern and ancient Sus specimens, we provide evidence for an early human-mediated translocation of the Sulawesi warty pig (Sus celebensis) to Flores and Timor and two later separate human-mediated dispersals of domestic pig (Sus scrofa) through Island Southeast Asia into Oceania. Of the later dispersal routes, one is unequivocally associated with the Neolithic (Lapita) and later Polynesian migrations and links modern and archeological Javan, Sumatran, Wallacean, and Oceanic pigs with mainland Southeast Asian S. scrofa. Archeological and genetic evidence shows these pigs were certainly introduced to islands east of the Wallace Line, including New Guinea, and that so-called “wild” pigs within this region are most likely feral descendants of domestic pigs introduced by early agriculturalists. The other later pig dispersal links mainland East Asian pigs to western Micronesia, Taiwan, and the Philippines. These results provide important data with which to test current models for human dispersal in the region.

Environmental predictors of pre-European deforestation on Pacific islands.

Some Pacific island societies, such as those of Easter Island and Mangareva, inadvertently contributed to their own collapse by causing massive deforestation. Others retained forest cover and survived. How can those fateful differences be explained? Although the answers undoubtedly involve both different cultural responses of peoples and different susceptibilities of environments, how can one determine which environmental factors predispose towards deforestation and which towards replacement of native trees with useful introduced tree species? Here we code European-contact conditions and nine environmental variables for 81 sites on 69 Pacific islands from Yap in the west to Easter in the east, and from Hawaii in the north to New Zealand in the south. We thereby detect statistical decreases in deforestation and/or forest replacement with island rainfall, elevation, area, volcanic ash fallout, Asian dust transport and makatea terrain (uplifted reef), and increases with latitude, age and isolation. Comparative analyses of deforestation therefore lend themselves to much more detailed interpretations than previously possible. These results might be relevant to similar deforestation-associated collapses (for example, Fertile Crescent, Maya and Anasazi) or the lack thereof (Japan and highland New Guinea) elsewhere in the world.

Voyaging and Interaction in Ancient East Polynesia

The origins of East Polynesian culture are traced to a regional homeland that was centered on the Society Islands but which also included neighboring archipelagoes. Archaeological evidence suggests a fall-off through time in the frequency of opensea voyaging within this homeland, with marked declines in voyaging and interaction after a.d. 1450. A range of social and environmental factors may have contributed to these declines. The regional distribution of terrestrial resources is significant because the smallest islands often suffered the most acute consequences of human-induced environmental change. Tahiti, in the Society Islands, is unique in terms of the unparalleled scale of its resource base and its high degree of voyaging accessibility. If Tahiti and the Societies played the role of a regional hub in early interaction spheres, developments in Tahiti may have influenced inhabitants of the outer archipelagoes. Specifically, if circumstances restricted the flow of timber and canoes from the Societies to outlyingar chipelagoes, and this coincided with the depletion of forest reserves on the smaller outlyingislands, these developments could help explain the contraction of early central East Polynesian interaction spheres. It is likely that voyaging patterns in the Marquesas and the Pitcairn Islands, comparatively isolated archipelagoes, were little affected by internal developments in the Societies.

Modern pollen assemblages from cultivated rice fields and rice pollen morphology: Application to a study of ancient land use and agriculture in the Pearl River Delta, China

Pollen from a series of surface soil samples collected along a transect spanning southeast China was investigated to better understand palynological signals of ancient agriculture and other human activity. The transect surface samples consist of pairs taken inside and outside rice paddy fields. Pollen assemblages from these samples are valuable as modern analogs of human-altered environments and rice agriculture. Our measurements of Poaceae pollen grains from inside the modern rice fields discovered that 34–40 µm is the statistically significant size range for identifying domesticated rice in fossil pollen samples. This conclusion is also based on a size comparison of raw and chemically treated modern pollen grains from the plants. Pollen measurements for local wild grasses show that most native weeds have pollen grains less than 30 µm in size. The modern analogs and our study of the influence of chemical treatment on pollen grain size made it possible to examine a sediment core from the Pearl River delta for evidence of anthropogenic influence, including rice farming. Pollen assemblages from around 2200 cal. yr BP are highly similar to those of our modern analogs representing disturbed landscapes outside modern rice fields. The pollen spectra reveal abrupt increases in Poaceae, Dicranopteris, Artemisia and Pinus indicative of rice farming and forest clearance, at around 2200 cal. yr BP. Major factors associated with this abrupt transition were the rapid formation of the deltaic flood plain and massive increases in the Pearl River delta area population during the Qin Dynasty.

Taiwan, Neolithic seafaring and Austronesian origins

New evidence for the movement of Neolithic basalt adzes across the Taiwan Strait may indicate the beginnings of regular Austronesian voyaging. This seafaring tradition culminated in the Polynesian colonization of the Pacific.

Geological Sourcing of Volcanic Stone Adzes from Neolithic Sites in Southeast China

This study uses XRF (X-ray fluorescence) and ICP-MS (inductively coupled plasma mass spectrometry) analyses to determine the chemical composition of raw material used in stone tool production. The goal is to identify where stone adzes, which are common in Neolithic sites on the coast of Mainland China, were produced and if they were transported from the production areas to other places. Our study focuses on adzes from three Neolithic sites located on the Fujian coast of Mainland China, opposite Taiwan. The sites date to between 6500 and 3500 b.p. All of the adzes we sampled are made of volcanic rock. A diverse selection of raw materials, including basalts, andesites, and dacites, was used in manufacturing the adzes, indicating that they are made of rock deriving from many di¤erent geological formations. None of the adzes have identical chemical signatures. There is no evidence of specialized centers for adze production. Some of the adzes were probably produced locally, while others were obtained through exchange. This project sets the stage for future research to trace the development and the extent of southeast China Neolithic exchange networks.