GRBQ084-2272G-C12[265-288]. qxd 11/28/2005 19:48 Page 265 pinnacle SUBHAKANT:GRBQ084:Chapters:Chapter-12: 12 The Ideal Free Distribution, Food Production, and the Colonization of Oceania Douglas Kennett, Atholl Anderson, and Bruce Winterhalder Islands in Oceania were some of the last habitable habitats, stimulating dispersal, and ultimately mi- land masses on earth to be colonized by humans. grations to more distant islands in Oceania. Current archaeological evidence suggests that these islands were colonized episodically rather than The processes involved in the development continuously, and that bursts of migration were of food production worldwide during the last followed by longer periods of sedentism and popu- 10,000 years were complex and spatially vari- lation growth. The decision to colonize isolated, able. At a minimum, they involved some combi- unoccupied islands and archipelagos was complex nation of the following set of factors: (1) the and dependent on a variety of social, technological expansion of diet-breadth during the late Pleis- and environmental variables. In this chapter we tocene and early Holocene, leading to the develop an integrative, multivariate approach to development of co-evolutionary relationships island colonization in Oceania based on a model between humans and potential domesticates from behavioral ecology known as the Ideal Free (Richards et al. 2001; Rindos 1984; Stiner et al. Distribution. This ecological model provides a 1999, 2000; Winterhalder and Goland 1997); framework that considers the dynamic character of (2) intensified exploitation of wild plants and an- island suitability along with density-dependent imals by some prehistoric foragers (Henry and density-independent variables influencing mi- 1989); (3) translocation of wild plants and ani- gratory behavior. Unique among existing models, mals by foraging groups and the management it can account for the episodic nature of certain as- or cultivation of these wild species in some in- pects of the colonization process. Within this con- stances (Piperno and Pearsall 1998); (4) the ini- text we critically evaluate the role of foraging, low- tial domestication of plants and animals in sev- level food production, and ultimately intensive eral independent centers (Cowan and Watson food production, as important contextual variables 1992; Price and Gebauer 1995a; Smith 1998); that influenced decisions to disperse. We argue (5) the adoption of these plants and animals by that intensive food production was one variable foragers living in adjacent regions, often in dif- that contributed to decreasing suitability of island ferent habitats; (6) subsequent experimentation 265 GRBQ084-2272G-C12[265-288]. qxd 11/28/2005 19:48 Page 266 pinnacle SUBHAKANT:GRBQ084:Chapters:Chapter-12: FIGURE 12.1. Map of Oceania showing the relevant islands and archipelagos. leading to a reliance on food production or the sion of anatomically modern humans into pre- stability of mixed subsistence strategies (low- viously unoccupied territory, most notably the level food production; Smith 2001a; Tucker, this colonization of ever smaller and more remote volume); ( 7) continued transmission of new islands in the Pacific, Mediterranean, and and improved domesticates through exchange Caribbean (Diamond and Bellwood 2003; Kee- networks (Hastorf 1999), and (8) the ultimate gan and Diamond 1987; Kirch 2000; Kirch and emergence of more intensive food production Green 2001; Patton 1996; but see Anderson in certain locations (Smith 1998). Some of the 2003a). consequences of food production included lo- In this chapter we explore the dispersal of calized population growth, the spread of do- people into Oceania and the role that food pro- mesticated plants and animals along with agrar- duction may have played in this complex social ian knowledge and technology through and ecological process. In particular, we are in- exchange networks, the actual migration of food terested in the migration of people onto islands producers into regions occupied by foraging in Near and Remote Oceania (Figure 12.1).1 populations (Cavalli-Sforza 1996; Diamond and Near Oceania consists of several large islands Bellwood 2003), and a general increase in hu- in the Bismarck Archipelago, positioned man impacts on natural ecosystems (Bellwood 100–200 km to the northwest coast of New 2001; Diamond and Bellwood 2003; Redman Guinea, and the Solomon Islands, a series of 1999). The demographic expansion of farming smaller islands that stretch to the southeast. populations is linked to significant cultural, lin- Prior to sea-level rise during the late Pleis- guistic, and biological changes (Bellwood tocene and early Holocene, the Solomons 2001). It has also been argued that the emer- formed a single larger island known as Greater gence of food production fostered the expan- Bougainville. Vanuatu and New Caledonia 266 ideal free distribution and oceania GRBQ084-2272G-C12[265-288]. qxd 11/28/2005 19:48 Page 267 pinnacle SUBHAKANT:GRBQ084:Chapters:Chapter-12: form the western boundary of Remote Oceania, particular islands—factors like position, size, which also includes 38 major archipelagos of and the distance between pairs along likely 344 colonized islands in West and East Polyne- routes of colonization. In this view, the likeli- sia (Kirch 1984). West Polynesia encompasses hood that an island will be colonized decreases the larger, aggregated archipelagos of Tonga with distance, as does the possibility of follow-up and Samoa, plus some smaller archipelagos. assistance once an island is occupied. However, In its early prehistory, Fiji is also regarded as colonization of distant islands may be promoted West Polynesian. Except for New Zealand, is- by configurational effects. For instance, archi- lands in East Polynesia tend to be smaller and pelagos consisting of larger aggregations of more dispersed. islands potentially provide greater resource di- All of the islands in Near Oceania lie within versity for colonists compared with individual the tropics, but several islands in Remote Ocea- islands. Island size also influences the probabil- nia are subtropical or are positioned farther to ity of successful colonization because larger is- the south, and have temperate climates; for in- lands offer a greater quantity and diversity of stance New Zealand lies between 35 to 45Њ habitats and resources. south. Little seasonality in rainfall or tempera- Although physical and geometric properties ture occurs close to the equator, but cooler tem- are important for understanding island colo- peratures and distinctive wet and dry seasons nization, purely biogeographical models have become more common to the south (Spriggs shortcomings. Based on the geometry of posi- 1997; Anderson 2001a). The initial colonization tion, distance, and size, they highlight the prob- of Remote Oceania involved a sixfold increase abilistic elements of “blindly” reaching a partic- in minimum voyaging distances over those at- ular island and surviving there. They do not tained in Near Oceania (200 km) and distances help to analyze the reasons for initiating migra- of up to 3700 km were crossed to reach New tion, nor the intentional or unintentional conse- Zealand and Hawaii. quences of settlement for an island’s resource The study of island colonization has a long potential, and thus for the long-term persist- history with a large body of literature developed ence of settlement. Although likely to be impor- during the last 30 years (Fitzpatrick 2004; tant, such factors are extraneous to biogeo- Keegan and Diamond 1987). Much of this re- graphic models. search was stimulated by MacArthur and Wil- In Oceania, explanations for island coloniza- son’s 1967 book entitled The Theory of Island Bio- tion can be grouped into push or pull models. geography, and by the recognition that islands Most push models invoke demographic pres- provide a well-bounded context for studying cul- sure as the primary causal force initiating dis- tural evolutionary processes. In the late 1980s, persal (Clark and Terrell 1978; Anderson 1996). Keegan and Diamond (1987) synthesized the It has been argued that population levels on literature on island colonization in various parts islands generally increase with agricultural in- of the world and concluded that biogeographi- tensification, and eventually the population ex- cal principles, particularly their physical and ceeds carrying capacity, stimulating segments geometrical properties, provided a useful of the population to move to adjacent islands. framework for understanding the colonization Pull models often propose a rapid dispersal of process. They argued that climatic, geological, people through Oceanic island chains, as op- and oceanographic differences among islands portunistic foragers skim off the highest-quality shaped their terrestrial and marine productivity resources (Clark and Terrell 1978; Anderson and influenced the ability of humans to colo- 1996; Davidson and Leach 2001) and quickly nize them. Superimposed on these ecological move on to the next propitious location. Al- qualities are geometric properties influencing though an improvement, the combination of bio- the likelihood that seafaring migrants will reach geographic patterning and push-pull variables ideal free distribution and oceania 267 GRBQ084-2272G-C12[265-288]. qxd 11/28/2005 19:48 Page 268 pinnacle SUBHAKANT:GRBQ084:Chapters:Chapter-12: + East Polynesia 35,000 BP S.E Asia Lapita Marginal South Polynesia W. Polynesia h g i HighH w o Low L _ Colonizing Mobility