With National Science Foundation support, Deborah M. Pearsall and colleagues will undertake a pilot project to study the antiquity of maize in prehistoric coastal Ecuador, and the interplay of environmental and social factors for the emergence and development of agricultural societies. Using environmental coring, the project will study changes in vegetation, land-use practices, and subsistence associated with the emergence of agriculture.
Southwestern coastal Guayas Province has been proposed as a center of domestication of cotton, lima bean, squash, and jackbean, and is part of the region in which chili pepper, cocoyam, lleran, arrowroot, Canna, and sweet potato originated. Many of these crops appear during the Preceramic (9800-6700 BP) and Early Formative (5500-3500 BP) periods.
Evidence that maize was introduced late in the Preceramic, and was present at the Early Formative Real Alto site, constitutes one of the earliest dates for this crop in South America. It is difficult to assess the importance of maize in Formative subsistence, and the role it played in the emergence of complex societies on the coast, on the basis of available data, however.
The process of transformation of societies from fisher-gatherers to agriculturalists has significant impacts on local environments. In order to test fully hypotheses concerning the causes and consequences of agriculture, and the role of maize and other crops in this process through the "window" of human impact on the environment, environmental records of 8000 years are needed. Pearsall and colleagues will attempt to retrieve such records from lagoon environments by vibracoring in three locations in southwest Guayas province with early archaeological sites. Core sediments will be sampled for pollen, phytoliths (plant opal silica), and sedimentary analysis, and organic material will be removed for carbon-14 dating. A limited number of pollen and phytolith samples will be processed after the summer 2004 field season to assess the quality of preservation. If the pilot project is successful, a new proposal will be submitted to complete the study.
Current and future paleoenvironmental research in southwestern Guayas will contribute significantly to our understanding of the causes and consequences of agriculture. It will provide a case study of agricultural evolution in a lowland, dry tropical forest region that will be useful for scholars world-wide.
Dry tropical forests, such as those that once characterized southwestern Guayas, are among the most endangered ecosystems in the New World because of the advantages they hold for modern agriculture. Evidence is accumulating that such habitats were also the focus of prehistoric agriculture, and home to many crop plants. Was agriculture sustainable in dry tropical forests prehistorically? The broader impacts of the study will be insights gained into the nature of human impact on forests through time, and practices that permitted populations to use these habitats for thousands of years. These findings may have application to the contemporary issue of sustainable uses of tropical forests.
