A Wiggle-Match Date for Polynesian Settlement of New Zealand. (Method)

Article excerpt

Introduction

New Zealand was the last substantial landmass to be colonised by humans before the industrial age. Although it is now well established that the Polynesian settlers of New Zealand originated in central East Polynesia (e.g. Penny et al. 2002), the date of such settlement has proved controversial. An early transient contact c. 50-150 AD, based on Pacific rat-bone (Rattus exulans) dates obtained from natural sites, was proposed by Holdaway (1996, 1999) and Holdaway & Beavan (1999) on the premise that the rats, an introduced predator to New Zealand, accompanied the early Polynesians as a food source or stowaways (Roberts 1991; Matisoo-Smith et al. 1998). However, the reliability of the early rat-bone dates was disputed, especially as aberrant rat-bone dates were reported from several archaeological sites (Anderson 1996, 2000; Beavan & Sparks 1998; Smith & Anderson 1998; Hedges 2000; Higham & Petchey 2000). Brook (2000) suggested, from dating predation damage of the landsnail Placostylus ambagiosus, that the Pacific rat probably became established in northernmost North Island at around the same time as permanent Polynesian settlement. Most recently, Holdaway et al. (2002) provided support for the early rat-bone dates, and suggested that the Pacific rat was present in New Zealand well before permanent Polynesian settlement.

Various authors have shown that there are no human archaeological contexts in New Zealand which pre-date the 12th century AD (Anderson 1991; McFadgen 1994; McFadgen et al. 1994; Higham & Hogg 1997; Higham et al. 1999). Recent archaeological and radiocarbon evidence now suggests strongly that the earliest settlers in the New Zealand archipelago arrived around c. 1250-1300 AD (McFadgen et al. 1994; Higham & Hogg 1997; Higham et al. 1999). In addition, evidence from New Zealand's outlier islands (Norfolk, Kermadecs) supports the notion that southern Polynesia was all settled at virtually the same time in prehistory (Higham & Johnson 1996; Anderson et al. 2001). This evidence supports the socalled `late' settlement model first proposed by Anderson (1991).

Dating environmental events

Other dates for human settlement have been inferred from changes in environmental sequences. Short-lived, minor disturbances in the pollen record, including small increases in bracken (Pteridium esculentum) and other seral taxa, were attributed by Sutton (1987, 1994) to activities by a small but `archaeologically invisible' population of early Polynesian colonists prior to c. 1300 AD. His interpretation forms the basis for the `early' settlement model (Sutton 1987). However, critics have pointed out that such disturbances are indistinguishable from those resulting from natural background events, such as lightning-induced fires, impacts from volcanic eruptions, storms or droughts, and that these occurred throughout the Holocene with increasing frequency, and also in pre-Holocene pollen records (McGlone 1989; Wilmshurst et al. 1997; Ogden et al. 1998; Newnham et al. 1998a; McGlone & Wilmshurst 1999).

McGlone & Wilmshurst (1999) concluded that the first evidence for Polynesian environmental impact dates broadly to c. 1200-1400 AD based on palynological data from many sites throughout New Zealand. A similar finding was reported by Ogden et al. (1998). Opal phytolith data from tephra-palaeosol sequences in the Bay of Plenty in eastern North Island are also consistent with these results (Kondo et al. 1994; Sase & Hosono 1996), as are dunefield and sedimentological studies from northern and eastern North Island (McFadgen 1994; Wilmshurst 1997; Page & Trustrum 1997; Brook 1999; Horrocks et al. 2001a) and also isotope analyses on speleothems in northern South Island (Hellstrom et al. 1998). Taken together, the palaeoenvironmental research suggests that deforestation, beginning in the period c. 1200-1400 AD, occurred virtually simultaneously across much of New Zealand. …