The Origins of Agriculture in the Lowland Neotropics
Dolores R. Piperno and Deborah M. Pearsall. San Diego, CA: Academic Press, 1998.

Reviewed by Karen E. Stothert, research associate, Center for Archaeological Research, University of Texas at San Antonio and Investigator, Museo Antropológico, Banco Central del Ecuador.

    Readers interested in the origin of agriculture and the process of plant domestication, as well as those curious about the prehistory of the New World, will find this book stimulating because it demonstrates that the peoples of the tropics, who have been ignored rotundly in most discussions of early food production, were significant players in ancient dramas. This comprehensive statement of recent research is part of a competitive dialogue among archaeoethnobotanists, and the interpretations presented reflect an alternative view of the evolution of food production in America.
 Piperno and Pearsall argue that the first productive agriculture in the New World was innovated in the tropical lowlands (neotropics) where some people at the end of the Pleistocene began to burn the forest and manipulate suitable wild plants found in seasonally dry habitats. In the Early Holocene, under continuing selective pressure, people in some tropical regions developed slash-and-burn cultivation and domesticated a series of economic plants, which today are the basis of contemporary agriculture worldwide.

    The discussion explores a complex problem that requires the integration of knowledge from many scientific fields. The scenarios suggested by the authors are provocative and informed, but like most hypotheses about the origins of cultivation, theirs is based upon controversial evidence, and involves tentative reconstructions of paleoenvironments, ecological interpretations that are under debate, and speculation about resource intensification and economic choices made by people whose archaeology is poorly known.

    The authorsâ work demonstrates how the successful study of tropical pollen, phytoliths, and starch and charcoal particles, as well as the development of better dating techniques, have revolutionized thinking. But the book is not a technical manual. The discussion focuses on human behavior in ecological systems, and each chapter contains discussions of theoretical issues, such as the role of environmental variables in the evolution of human subsistence systems and the nature of human-plant relations.

    Chapter 1 presents background material and clarifies the role of this book in correcting the ãdisproportionate reliance on macrobotanical remainsä in the archaeological study of the development of food production. The authors focus on the ecological dimensions of early hunter-gatherer systems in the tropics, on how climate and environmental shifts functioned in ãcompellingä human adjustments (p. 13), and they apply optimal foraging theory and discuss risk aversive behavior and dietary choice-making in order to model the development of food production. Their models are supported by diverse kinds of evidence.

    Chapter 2 is a fascinating description of the heterogeneous and historically changeable neotropics, with special attention to the seasonally dry forested areas which were inhabited by humans very early in history and where important New World domesticates were brought under cultivation. The authors evaluate the potential of this kind of tropical forest habitat for hunters and gatherers, and speculate that there was a period of environmental chaos between 11,000 and 10,000 years ago, which the authors view as the key factor in human economic decision-making that resulted in food production.

    Chapter 3 is a good read on the subject of the tropical crop plants brought under cultivation independently in many different areas of lowland tropical America by Native American farmers in the early Holocene. These include a profusion of economically important root crops unfamiliar to many readers, as well as sweet potatoes, yams, peanut, beans, gourds, squashes, chili peppers, cotton, avocado, pineapple and dozens of other tropical fruits, as well as maize and a few other grains.

    Chapter 4 treats the archaeological evidence for the late Pleistocene when small groups of hunters and gatherers living in various tropical environments, including deciduous forests and patchy open habitats, exploited large game animals that became extinct at the end of the period. According to the authorsâ model, these people adjusted to the loss of high-ranked prey animals and a decline in foraging return rates by innovating cultivation as an energetically efficient way to gain access to starch-rich foods (p. 236) and to increase the variety of foods in their diets.

    For the subsequent Holocene period, the authors present gripping archaeological case studies that demonstrate the independent development of food production in several regions. In the case from coastal Ecuador, phytoliths themselves were directly dated using an AMS method, and the authors conclude that squashes, bottlegourd, and a tropical root crop called leren (Calathea allouia), were under cultivation before 9000 b.p., and that maize was cultivated by around 7000 b.p.  Size trends of squash phytoliths seem to indicate that cultivators were selecting for larger fruits and seeds.

    In another study Piperno identified starch grains from edge-ground cobbles found in the San Isidro site, located in a tropical forested zone in Colombia that was occupied before 9000 b.p. That evidence suggested the importance of starchy roots in an early period before the adoption of maize, when people also cultivated leguminous plants and tropical palm seeds and nuts, including avocado.

    In central Pacific Panama, multiple lines of evidence point to the development of slash-and-burn agriculture there by 7000 b.p., and the study of phytolith assemblages from dated contexts reveal in situ changes in the form of maize plants. Evidence is strong that tropical soils supported slash-and-burn agriculture for thousands of year and that people in that region experienced various processes of socio-cultural elaboration.

    Chapter 5 is about the development and spread of effective food production. By interpreting pollen, phytolith, and charcoal residues in core samples from wetlands and by interpreting other categories of  archaeological evidence, the authors describe regional sequences from Central Panama, Ecuador, Colombia, and northern Peru where there is early evidence of environmental modification and plant manipulation.  In this region, food production systems continued to expand for thousands of years, accompanied by the development of social and political complexity.

    In contrast, in Belize people cultivating maize and using ãadvanced agricultural techniquesä entered the region only after 5000 b.p.  Similarly people living in the interior of the Amazon Basin did not modify the forest until around 5600 b.p., while people in the western Amazon were burning the forest thousands of years earlier. According to Piperno and Pearsall, the record of agriculture in the desert coast of Peru and in the semi-arid valleys of Central Mexico reflects the relatively late import of plants brought under cultivation much earlier by people in moister tropical regions.

    A concept of environmental determinism runs through the discussion. In coastal Peru, for instance, agriculture based upon imported tropical forest species was developed relatively late because the productivity of marine resources slowed the development of heavy reliance upon cultivated foods. Similarly, hunting and gathering in highland Mexico persisted until late in history because foraging for wild species continued to be the optimal energetic choice in that environmental context.
 The new evidence from the neotropics has altered significantly the story of the origin of food production. Piperno and Pearsall treat the archaeological sequences from coastal Peru, the highlands of Central Mexico, and Eastern North America as examples of secondary developments whereas these are the very same histories that figure centrally in previous syntheses of New World agriculture (see, for example, Smith 1998).

    In Chapter 6, the authors compare early neotropical agriculture with cases of incipient food production from around the world. They reject ãpopulation pressureä as a factor in the origin of agriculture, but they identify processes in the neotropics which are similar to those observed elsewhere. According to Piperno and Pearsall, small, simply organized societies living in stable settlements, modified their environments by burning, experimented with locally available food resources (in seasonally dry regions where there were good potential domesticates), tinkered with their dietary choices, and achieved better return rates for their efforts even under conditions of low population density. In the neotropics, as in other areas throughout the world, people cultivated small gardens and enjoyed the fruits for thousands of years before they developed more sophisticated agricultural systems based on a narrow range of productive crop plants.

    While on the one hand the authors emphasize the variability of human responses to conditions at the end of the Pleistocene, they also scrutinize a ãunifiedä explanation of the innovation of food production: the development of agriculture may have resulted from the worldwide human response to the environmental challenges of the end of the Pleistocene ÷ and in fact, this was the first ãmajor intellectual challengeä that confronted biologically modern Homo sapiens sapiens.

    It is intriguing that the archaeological record demonstrates the creativity of human beings in the tropics and the diversity of trajectories in the development of food production. Apparently small groups of independent householders were responsible for initiating the activities that resulted in the domestication of more than 300 species of plants along with the innovation of agricultural practices that subsequently underwrote thousands of years of cultural development. One hopes that the agricultural and economic specialists who today spearhead planning projects from offices in national capitals are as successful in imagining strategic solutions to subsistence challenges as were the earliest American farmers.

References Cited

Smith, Bruce
    1998  Origins of Agriculture. Washington, DC: The Smithsonian Institution Press.