Origins of Agriculture at Kuk Swamp in the Highlands of New Guinea
P. Denham,1* S. G. Haberle,2 C. Lentfer,3 R. Fullagar,4 J. Field,4
Therin,4 N. Porch,5 B. Winsborough6
Multidisciplinary investigations at Kuk Swamp in the Highlands of Papua New Guinea show that agriculture arose independently in New Guinea by at least 6950 to 6440 calibrated years before the present (cal yr B.P.). Plant exploitation and some cultivation occurred on the wetland margin at 10,220 to 9910 cal yr
P. (phase 1), mounding cultivation began by 6950 to 6440 cal yr B.P. (phase
, and ditched cultivation began by 4350 to 3980 cal yr B.P. (phase 3).
Clearance of lower montane rainforests began in the early Holocene, with modification to grassland at 6950 to 6440 cal yr B.P. Taro (Colocasia esculenta) was utilized in the early Holocene, and bananas (Musa spp.) were intensively cultivated by at least 6950 to 6440 cal yr B.P.
Investigations into the antiquity of agriculture began in the Highlands of Papua New Guinea in 1966, with subsequent excavations in the 1970s at Kuk Swamp in the Wahgi Valley. The finds from Kuk were the oldest and most com- prehensive of any wetland archaeological site in the interior (1, 2) and were claimed to represent the independent origins of agriculture in New Guinea during the early Holocene (3). These claims were, however, largely unsubstantiated. Archaeological remains of former cultivation dating back to the early Holocene at Kuk were reported but never fully published (1, 2). Pre- vious researchers noted an association between Musa spp. phytoliths and archaeological phases (4) and documented the presence of numerous edible plants throughout the Holocene (5). The mechanisms of dispersal and anthropogenic as- sociations of these plant remains were uncer- tain. Erosion rates in the catchment (6) and palynology at several sites in the Highlands (7, 8) were suggestive of accelerated forest clear- ance beginning in the early Holocene, but the timing and nature of initial clearance were un-
1School of Archaeology and Anthropology, Australian National University, Canberra ACT 0200, Australia. 2Resource Management in Asia-Pacific Program, Re- search School of Pacific and Asian Studies, Australian National University, Canberra, ACT 0200, Australia. 3School of Environmental Science and Management, Southern Cross University, P.O. Box 157, Lismore, New South Wales 2480, Australia. 4Department of Archaeology, University of Sydney, Sydney, New South Wales 2006, Australia. 5School of Geography and Environmental Science, Monash University, PO Box 11A, Clayton, Victoria 3800, Australia. 6Winsbor- ough Consulting, 23606 Round Mountain Circle, Le- ander, TX 78641, USA.
*To whom correspondence should be addressed at Department of Archaeology, Flinders University, GPO Box 2100, Adelaide, South Australia 5100, Australia.
known. Given these problems, the notion of early independent agricultural development in New Guinea has been questioned (9, 10).
Here we present multidisciplinary data from renewed investigations at Kuk that show that agriculture arose independently in New Guinea by at least 6950 to 6440 calibrated years before the present (cal yr B.P.). We conducted new archaeological investigations and used radio- carbon dating, stratigraphic analyses, and a suite of archaeobotanical and paleoecological analyses (including diatom, insect, phytolith, pollen, and starch grain analyses). These find- ings contribute to our knowledge of agricultural origins across the globe and have broader im- plications for understanding the development of human societies.
Site and stratigraphy. Kuk Swamp is located in a large intermontane valley in the interior of New Guinea at 1560 m above mean sea level (AMSL) (Fig. 1). The Wahgi Valley has a slightly seasonal lower montane humid climate with a mean annual temperature of
19°C and mean annual rainfall of 2700
The Kuk site is situated on a wetland
margin comprising a low-gradient alluvial fan deposited after the Last Glacial Maximum (LGM) at 21,500 cal yr B.P. (6). These alluvial deposits overlay lacustrine and paludal peats that accumulated during the last glacial period.
The early to mid-Holocene stratigraphy represents immature paleosol profiles, which are characteristic of periodically waterlogged environments (Fig. 2A). Despite this pedo- genesis, biostratigraphic signatures, as indi- cated by distinctive phytolith and pollen assemblages, are retained between and with- in individual units. These biostratigraphic signatures are corroborated by synchro- nous samples collected from deeper, well-
preserved, and largely unaltered fills of ditch- es and paleochannels.
Paleoecological evidence. Paleoecologi- cal records from several sites in New Guinea show that from 17,500 cal yr B.P. to the end of the last glacial period, open grasslands between 1200 and 2000 m AMSL were com- pletely replaced by forests dominated by Nothofagus (11). The altitudinal expansion of forests was caused by warming climates, in- creased precipitation, and less frequent fires (12). In the absence of anthropogenic distur- bance, the upland valleys during the Holo- cene would be expected to support montane rainforest on dry slopes and vegetation rang- ing from seral swamp forest to open grass and/or sedge in wetlands (11). The first signs of human impact are recognized as a reduc- tion or change in the forest composition, fol- lowed by the expansion of open herbaceous vegetation and, in many cases, increased con- centrations of charcoal in sediments (13, 14). Today, upland valleys are dominated by an- thropogenic grasslands frequently burned by people. The timing of the earliest anthropo- genic impacts on upland landscapes is vari- able and occurs as early as 7800 cal yr B.P. in the Baliem Valley of the Indonesian province of Papua (8) and as late as 1700 cal yr B.P. in the Tari Basin of Papua New Guinea (11).
To investigate the nature and timing of the transition from forest to grassland in the Wahgi Valley, we took 24 sediment sam- ples from overlapping monoliths containing 1.3 m of continuous Holocene strata and Pleistocene peat (Fig. 2A). Samples from this section were augmented with 14 sam- ples selected from the fills of prehistoric agricultural features excavated at proximal locations at the site. A minimum of 300 pollen grains and 200 phytoliths were counted for each sample. We obtained ra- diocarbon dates on paired and other organic material collected during excavation.
Fig. 1. Site location map.
www.sciencemag.org SCIENCE VOL 301
11 JULY 2003