Raised fields in the Bolivian Amazonia: a prehistoric green revolution or a flood risk mitigation strategy? Umberto Lombardo a, * , Elisa Canal-Beeby b , Seraina Fehr a , Heinz Veit a a Institute of Geography, University of Bern, Hallerstrasse 12, CH-3012 Bern, Switzerland b School of International Development, University of East Anglia, NR4 7TJ, Norwich, UK article info Article history: Received 1 July 2010 Received in revised form 7 September 2010 Accepted 16 September 2010 Keywords: Amazonia Llanos de Moxos Raised fields Pre-Columbian Archaeology Sustainable development abstract The Llanos de Moxos (LM), Beni, Bolivia, with its impressive number of pre-Columbian earthworks, is an ideal region for studying past humaneenvironment interactions in the Amazonia. Agricultural raised fields are among the most striking of those earthworks. They can offer us valuable information about the region’s agricultural carrying capacity and the nature and extent of human occupation in pre-Columbian times and, therefore, help adopt better informed conservation and development strategies for Amazonia in the future. However, before tackling these issues we need to further our understanding of why pre- Columbian raised fields were built and how they were managed in the past. Published data on raised fields in the LM is contrasted with new data gathered from field and remote sensing images. Raised fields have been analysed in relation to the hydrology, soil, topography and paleoclimate of the areas where they are found. In light of this new data we believe that there are grounds to question the current model that suggests raised field agriculture provided high yields without the need of fallow periods, repre- senting a kind of pre-Columbian green revolution. Our alternative proposal suggests that raised field agriculture allowed pre-Columbian peoples to mitigate the risk of more intense and frequent flooding than is experienced today in the LM. We show that raised fields were built only in those areas where there were no alternatives, which do not coincide with those areas where pre-Columbian societies seem to have flourished and reached high levels of social complexity. Ó 2010 Elsevier Ltd. All rights reserved. 1. Introduction Recent publications have presented a new vision of Amazonia’s past (Denevan, 1992; Erickson, 2008; Heckenberger et al., 2008; Lombardo and Prümers, 2010; Mann, 2008; McEwan et al., 2001; Pärssinen et al., 2009; Prümers, 2004; Roosevelt, 1999; Rostain, 2008; Schaan, 2008). It would now seem that Amazonia has hos- ted more complex societies than was once thought. In the past, it was suggested that poor soils and lack of proteins hindered the cultural evolution in the region (Meggers, 1954, 1971, 1995). However, with increasing evidence of the existence of well organised pre-Colum- bian societies in Amazonia, new questions arise regarding how these were sustained, the environmental constraints overcome, and how dense and numerous the pre-Columbian societies actually were. The Llanos de Moxos (LM), Beni, Bolivia, with its wealth of well preserved pre-Columbian raised fields, is a key region to begin to unravel some of these questions. Raised fields are a quite common feature in the Americas, appearing in a variety of geographical settings (for comprehensive reviews see Doolittle, 2000; Denevan, 2001; Whitmore and Turner, 2001). Phytolith analyses show that maize (Zea mays L.) was one important crop cultivated on the raised fields of French Guiana (Iriarte et al., in press). An exhaustive classification of the different kinds of pre-Columbian agricultural fields can be found in Denevan (1970). Here, we call “raised fields” those fields which were built by excavating canals/ditches and using the extracted earth to build elevated platforms. We call “ditched fields” those which resulted from the excavation of ditches but without the elevation of the agricultural surface (Fig. 1). Raised field dating from the LM are very scarce. Radiocarbon data from two settlements associated to raised fields in the Iruyañez-Omi region shows that the two sites were occupied for approximately 200 years, one 446e613 AD and the other 1311e 1446 AD (Walker, 2004: 73, 79). Erickson (2006) reports dating of raised fields that place their construction as far back as 400 BC. Raised fields have received a lot of attention in studies related to pre-Columbian demography. They have been considered key in allowing dense populations of complex societies to inhabit * Corresponding author. Tel.: þ41 (0)31 631 8578; fax: þ41 (0)31 631 8511. E-mail address: lombardo@giub.unibe.ch (U. Lombardo). Contents lists available at ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas 0305-4403/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.jas.2010.09.022 Journal of Archaeological Science 38 (2011) 502e512