University of Florida, Gainesville

An archaeologist looks at South America's early complex societies.

What leads to the rise and fall of civilizations? In coastal Peru, early urban societies based on maritime fishing thrived from 5,800 to 3,600 years ago. Daniel Sandweiss at the University of Maine in Orono and his colleagues report that climate and environmental changes were critical to the rise of these societies (D. H. Sandweiss et al. Proc. Natl Acad. Sci. USA 106, 1359–1363; 2009). They find that environmental shifts are well recorded in coastal geological features, which correlate to high Andes glacial cores, notably in the sixth millennium BP, when small urban centres also emerged in southwestern Asia – the 'cradle of civilization'. But as the Peruvian coastal embayments disappeared, around 3,600 years ago, so too did the societies that depended on them.

This paper particularly interested me as our work in the southern Amazon has revealed integrated towns and villages thriving several millennia later on similar resources as the early Andeans — fish, fruit and tubers. Although not as marked as coastal Peru, climatic fluctuations recorded in glacial records, notably the 'Medieval Warming' around 1100–1300 ad, coincided with the emergence of these small territorial polities.

The early complex societies of South America prompt debate over what constitutes urbanism and 'civil society' in its earliest and most minute forms,and make us reconsider the traits and typologies developed from classical civilizations and Western experience. Notably, in some South American cases, corporate labour and civic organization were not based on agricultural intensification and administration of crop surpluses.

Whether we call them urban or not, these societies show unique properties of self-organization and dynamics of the relationship of humans with natural systems.