People, Plants, and Landscapes in Prehistoric Ecuador: A Look at the Causes and Consequences of Agriculture

在国家科学基金会的支持下，Deborah M.Pearsall和他的同事将开展一个项目的第二阶段，研究厄瓜多尔史前沿海玉米的古老，以及环境和社会因素对农业社会的出现和发展的相互影响。利用环境取芯，该项目将研究与农业出现相关的植被、土地利用方式和食物方式的变化。西南沿海瓜亚斯省已被提议作为棉花、利马豆、南瓜和菜豆的驯化中心，并且是辣椒、可可豆、绿豆、箭根、美人掌和红薯的原产地的一部分。其中许多作物出现在前震旦期(9800-6700BP)和早期形成期(5500-3500BP)。有证据表明，玉米是在前震旦纪晚期引进的，并存在于早期形成的Real Alto遗址，构成了这种作物在南美洲最早的日期之一。然而，根据现有的数据，很难评估玉米的重要性，以及它在沿海地区出现复杂社会中所发挥的作用。社会从渔民向农学家的转变对当地环境产生了重大影响，例如，当农民将森林开垦为农田时。因此，关于农业原因和后果的假设可以通过古代环境记录来检验，方法是评估生存习惯相对于自然环境(植被对气候变化的反应)和社会/政治环境(聚落模式、人口以及社会和政治复杂性的变化)变化的时间、顺序和性质。在该项目的第一阶段，通过在三个关键地点的泻湖环境中进行取芯，恢复了日期良好的环境记录。过去植被和农作物的微化石(花粉和植硅体)被保存在岩心中。在该项目的第二阶段，将对两个新地点进行取芯，并将分析所有沉积物，以寻找过去植被和作物的微化石证据，以及过去气候的元素和同位素特征。这项研究的学术价值在于它有助于理解农业的原因和后果。该项目将提供一个低地干旱热带林区农业进化的案例研究，探索环境和社会因素在农业出现中的作用。研究小组还希望记录当地人口如何适应后冰川时期的新栖息地和资源。干燥的热带森林，如曾经以西南部瓜亚岛为特征的热带森林，由于其对现代农业的优势，是新大陆最濒危的生态系统之一。越来越多的证据表明，这些栖息地也是史前农业的重点，也是许多农作物的家园。史前干旱的热带森林里的农业可持续吗？这项研究的更广泛影响将是对人类随着时间的推移对森林影响的性质的洞察，以及允许人们数千年来使用这些栖息地的做法。这些发现可能适用于热带森林可持续利用的当代问题。

With National Science Foundation support, Deborah M. Pearsall and colleagues will undertake the second phase of a 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 food-ways 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, lleren, 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, and the role it played in the emergence of complex societies on the coast, on the basis of available data, however. The transformation of societies from fisher-gatherers to agriculturalists impacts local environments significantly, for example, when farmers clear forests for fields. Hypotheses concerning the causes and consequences of agriculture can therefore be tested with ancient environmental records, by evaluating the timing, sequence, and nature of changes in subsistence practices vis a vis changes in the natural environment (vegetation responses to climate change) and the social/political environment (changes in settlement pattern, population, and social and political complexity). In the first phase of the project, well-dated environmental records were recovered by coring in lagoon environments in three key localities. Microfossils (pollen and phytoliths) of past vegetation and crops were preserved in the cores. In the second phase of the project, two new locations will be cored, and all sediments will be analyzed for microfossil evidence of past vegetation and crops, and elemental and isotopic signatures of past climate. The intellectual merit of the research lies in its contribution to understanding the causes and consequences of agriculture. The project will provide a case study of agricultural evolution in a lowland, dry tropical forest region that explores the roles of environmental and social factors in the emergence of agriculture. The research team also hopes to document how local populations adapted to the new habitats and resources of the post-glacial period.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.