Some Necessary Background

The documented settlement of the Americas, from Siberia, occurred about 11,500 BC (Lynch 1999; Fiedel 1999). Until about 3000 Be, all Americans were essentially huntergatherers, with a possible but disputed earlier investment in horticultural activity claimed for some tropical regions. Dated macroscopic plant remains for domesticated staple food plants, as opposed to snack foods, containers, and condiments, occur only after 4000 ac, and for the most part a great deal later than this (Smith 1995, 2001; Benz 2001; Piperno and Flannery 2001). In fact, with the exception of a small region of unusual precocity in southern Ecuador and northern Peru, virtually the whole tropical American sequence of development from the oldest sedentary agricultural settlements to Late Preclassic Period urbanism occurred between 2000 and 300 BC. This is indeed compaction, more so than the 5,000 years from Pre-Pottery Neolithic Jericho to Protoliterate Uruk, or from Peiligang to the Shang Dynasty. The American cultural sequence in the tropical regions of high population density has a slightly frenetic air - a little late, always in a hurry, ferociously competitive, and remarkably creative.

So far, for the Americas, no one has yet prepared an environmental case to explain the development of early agriculture as complex and detailed as that for the Southwest Asian transition, which currently revolves around environmental change from the Pleistocene into the Holocene and the impact, albeit disputed, of the brief Younger Dryas return to glacial conditions. Yet the PleistoceneHolocene boundary in the Americas was a period doubtless as well supplied with rapid climatic perturbation as it was in the Old World (Buckler et al. 1998). Because of this, Dolores Piperno and Deborah Pearsall (1998) favor a stress-based model for agricultural origins, focusing both on the Younger Dryas and on declining hunting returns in an increasingly forested early Holocene landscape. However, direct archaeological evidence for such environmental correlations with early agriculture is still elusive. Indeed, if agricultural dependence was a lifestyle that postdated 6,000 or even 5,000 years ago in the Americas, any attempt to link it directly in causal fashion with Late PleistoceneEarly Holocene environmental change will be hard to sustain. It has recently

been claimed that the establishment of sedentary settlements and agriculture in Peru can be correlated not with Early Holocene events, but with higher rainfall along the Pacific coast due to an increasing frequency of El Nino episodes after 5,800 years ago (Sandweiss et al. 1999). The debate continues.

Essentially, we still do not know why agriculture began in the various regions, presumably three, of independent agricultural origin in the New World. Kent Flannery (1986:16) poses some general possibilities which still seem to be as good as any others:

In our model, the end-Pleistocene climatic changes ... and the growth of world population ... combined between 10,000 and 5000 BC to bring about a densitydependent shift in human cultural behavior over much of the world. Emigration and high mobility declined in importance, and strategies for dealing with predictable (seasonal) and unpredictable (annual) variation on a local basis began to emerge ... In Mexico, agriculture may have begun as one of many strategies aimed at reducing the differences between wet and dry years.

In this model, increasing packing of population ("circumscription" in the terms of Robert Carneiro 1970) in the late hunter-gatherer world, plus desires to level out uncertainty and risk, would have been fundamental. The Americas in this sense fit well into the currently most popular worldwide model for the origins of agriculture, this being that it was essentially due to processes of risk minimization in the face of early or middle Holocene fluctuations in environmental circumstances. Such models have already been discussed in previous chapters for the Levant, the eastern Sahara, and the New Guinea Highlands. The major problem for the Americas is that the precise chronologies and geographical/ environmental circumstances that lay behind the various cases of agricultural inducement remain rather obscure. Agriculture certainly appears to be younger in the New World than in much of the Old, so we may presumably look for many of the stimuli in the period postdating the Younger Dryas and running down to as recently as 2000 BC. But this is a large haystack in which to look for a small number of needles.

One other general point is worthy of comment. After sedentary life began

across the American zones of early agriculture, mainly after 2000 Be, we soon witness some remarkable and unprecedented regional homogeneities in cultural style. The Early and Middle Formative periods of Mesoamerica and the Andes (including the Olmec and Chavin horizons) encompass a great deal of the American early agricultural action. Across many regions there is a degree of uniformity of style in pottery shape and surface decoration, clay figurines, art motifs and designs, even ceremonial center architecture and planning, which requires explanation. Some of these similarities also extend, at approximately the same time, into contemporary North American cultural complexes in the Eastern Woodlands of the USA. Do they reflect independent lines of common ancestry derived entirely from the Palaeoindian hunters of the Clovis horizon and its contemporaries? Or, far more likely in my view, are they due to contemporary Formative-period diffusion and/or population movement, as long ago argued in different ways by James Ford (1969), Gordon Willey (1962), Donald Lathrap (1973, 1977), and many others? Certainly, after 10,000 years of prior occupation of the Americas, we are not witnessing the actions of a single ethnolinguistic population working to invent a unique tradition of agriculture that thereafter spread to all regions. But the similarities most certainly reflect more than mere historical coincidence.

The Geography of Early Agriculture, and

General Cultural

Trajectories

The regions of early agriculture under examination are four in number. In the south lies the Andean region of southern coastal Ecuador, Peru, Bolivia, and northern Chile. This is a region of Pacific coast deserts, Andean valleys, and intermontane basins, ultimately sloping down eastward toward the rain forests of Amazonia. To the north lies Middle America - northern Colombia /Panama to central Mexico - again a region of great environmental variation from rain forests to semi-deserts and high mountains. The more specific title "Mesoamerica" is usually reserved for the cultural region extending from central Mexico to Honduras and El Salvador, this being the zone occupied by the Classic and Postclassic civilizations. To the north of Mesoamerica, through semi-arid northern Mexico, lies the US Southwest - Arizona, New Mexico, and parts of Colorado and Utah. Finally, we jump eastward, across the marginally agricultural Great Plains and southern Texas, into the fertile Eastern Woodlands of the USA. These comprise the vast drainage basins of the Mississippi and its major tributaries (Arkansas, Missouri, Tennessee, Ohio), with northward extensions to the Great Lakes and New England. With the exception of the rather nebulous possibility of early manioc agriculture in the Amazon Basin, we have no clear signs of any role for other regions, apart from those listed, in primary agricultural origins.

In terms of overall archaeological trajectory, the essential frameworks for the four regions (Figures 8.2, 8.3) are as follows:

1. In the Andes, the oldest pottery commences in the Valdivia I period in Ecuador between 3500 and 3000 Bc, with agriculture (apparently without maize at this early date) claimed in association. However, in nearby northern Peru the contemporary early archaeological record of agriculture, prior to 2000 BC, has no pottery (and again no maize), despite the presence of some impressive monumental constructions dating to the Late Preceramic Period,

from 3000 BC onward. Pottery and maize both appear, at least in quantity, in Peru's Initial Period (1800-900 BC), during which time the Kotosh religious tradition with its distinctive ceremonial constructions spread over large parts of the northern and central highlands. In the Early Horizon (900 to 200 BC), dramatic evidence for interpolity warfare made an appearance, followed by the remarkable spread of the tightly knit Chavin network of interaction (500 to 200 BC).

2.In Middle America, the first pottery is also generally quite young, being dated in Chiapas, Oaxaca, Valley of Mexico, Puebla, and Costa Rica to about 2000 BC, although claims exist for older pottery in Panama and northern Colombia. From about 4000 Bc onward, an early stage of maize domestication is attested in Guila Naquitz cave in Oaxaca, in the Tehuacan Valley in Puebla, and in the Maya lowlands, in all three cases long before the local appearance of pottery. In Mesoamerica proper, however, large ceremonial centers do not appear to be older than pottery usage, in contradistinction to the northern Peruvian situation. By 1000 BC, many regions were coming within the orbit of the Olmec network of interaction, a phenomenon similar to Chavin in Peru.

3.In the Southwestern USA, maize agriculture, pit storage, and large settlements appeared in southern Arizona by 2000 BC (with canal irrigation by 1500 BC). Pottery appeared at about the same time (Jonathan Mabry, pers. comm. 2003). Here, however, the early agriculture was not indigenous, but introduced from Mesoamerica.

4.In the Eastern Woodlands, an independent focus of native seed plant domestication was under way by 2000, perhaps 3000 BC (Bruce Smith, pers. comm. 2003), centered on the Ohio and Tennessee Valleys and adjacent portions of the Mississippi. Maize appeared in this region after 2,000 years ago, ultimately allowing agriculture to spread to its northern limits around the 120-day frost-free line, just north of the latitude of the Great Lakes.