The Development of Sahul Agriculture with Australia as Bystander

Article excerpt

The distribution of food-plants - both potential and actually exploited - reflects the natural history of contact across the seas and through the region, often long before Pleistocene times. The later and the human contribution has to be discerned from varied lines of evidence. The inventive process of early domestication leading to cultivation in he Sahulian north (New Guinea) was not a part of plant adaptation in the south (Australia). Neither did species diffusion result in adoption of agriculture or stimulation towards domestication among the Aboriginal hunter-gatherers.

The evidence for the domestication of unique New Guinea plant species has been the spur for the hypothesis that western Melanesia is a site of agricultural origin, parental to the Oceanic subsistence systems. Suggested tentatively in 1969 (Yen 1971), the advances made in archaeology in the region together with ethnobotany and biological analyses of some plant species now reinforce this view. But the long-held theory of diffusion out of Asia has not been discarded. Southeast Asian plants did have important roles in the formation of agriculture in New Guinea on the substrate of earlier local domestications, best accounted for by the advent of Austronesian-speakers of the Lapita culture, on linguistic evidence (Tryon 1985) at the western fringe some 5500 years ago, and, from archaeology (Spriggs 1985), reaching the Bismarcks at c. 4000 years ago. The subsequent diffusion of agriculture with adaptations to the varying Pacific island environments extended to the outer reaches of Polynesia: it probably began with the exodus of Lapita pottery-bearing peoples from the northeastern New Guinea islands after cultural transformation (Allen 1991: 6), including agriculture and particularly the Melanesian tree crops indicated by association of seed remains on the Lapita sites of the Mussau Islands (Kirch 1989) and the Arawe group (Hayes 1992).

Oceanic agricultural systems were based on root and tree crops and never developed a cereal plant dominance anywhere, even though wild relatives of rice (Oryza spp.) occur widely in the extensive swampy areas of New Guinea and northern Australia. This negative characteristic distinguishes the New Guinea region, whether it is called an agricultural origin centre or, in Harlan's scheme (1992), a part of the southeast Asian `non-centre' (with its corresponding centre in north China), from any other putative centre or `non-centre' in the world (including mainland and island Southeast Asia).

No amount of ethnobotanical modelling can reveal a time clock by which we can date the beginnings of agriculture as a set of events or a processual continuum, but the archaeological research of Jack Golson on the Kuk swamp of the western Highlands of Papua New Guinea, with an earliest date for agricultural drainage at c. 9000 years b.p. (Golson 1977) is a benchmark comparable with the evidence for earliest agriculture anywhere in the world. Contrasting with the direct recovery of plant remains (generally cereals), Golson's evidence is structural, portraying man's modification of the natural edaphic environment - as much a part of the domestication process as the genetic, evidence of plants. Its strength lies in the progressive sequence of six phases of increasingly complex drainage modifications and the inferential indications of the role of dryland cultivation through the sequence (Golson 1982; 1990; Hope & Golson, this volume). Thus, confidently, most Antipodean prehistorians accept the antiquity of New Guinea agriculture at c. 10,000 years; the major events of domestication of indigenous floral elements probably occurred earlier than 9000 years, a time of ameliorating climate, but in the lesser alpine, more temperate, lower altitudes of comparative species richness.

As the late Pleistocene processes of plant selection and environmental modification towards agriculture unfolded in the New Guinea region of the Sahul continent, the Australian Aboriginal economy of hunting and gathering was maintained, seemingly without any participation in, or diffusion of, this agricultural innovation to the north. …