Prehistoric Maize in the Northern Andes: Pollen and Diatom Analyses of the Lake San Pablo Core, Ecuador

在1492年哥伦布时代之前，玉米是“文明新大陆的谷物”。除了最极端的环境区域外，史前的玉米种植社会遍布北美和南美洲广大的大陆地区，在许多地区出现了真正先进的社会制度。在国家科学基金会的支持下，J·斯蒂芬·阿森斯博士试图通过分析厄瓜多尔北部高地的湖泊沉积岩心，帮助理解玉米在史前时代是如何以及为什么会变得如此重要。这个南美洲北部的研究区位于温带山谷，周围环绕着现在和以前的活火山，以其高农业生产力和过去和现在的土著居民对玉米的传统依赖而闻名。预计研究岩心将包含保存在沉积物中的玉米花粉的长期全新世记录。岩芯中独特的玉米花粉颗粒的最深处显示，以及放射性碳测年，将表明它第一次被引入该地区的时间。与其他地区性研究相结合，这一信息将不仅有助于显示玉米的传播时间，还将显示玉米从哥伦比亚向南传播的路径，最终传播到墨西哥西南部，那里是7000至8000年前玉米的明显发源地。此外，对硅藻的研究将有助于记录湖泊水位的上升和下降，实际上提供了区域降雨量的长期替代记录。硅藻是某些类型的具有硅壳的单细胞藻类的微观遗迹。这将有助于确定厄瓜多尔北部高地山区引进和采用玉米农业的具体环境条件，以及史前农学家随着时间的推移可能不得不面对的气候条件的变化。这项研究试图解决的相关问题包括：1)玉米的出现是否与厄瓜多尔北部高原地区最早的农业出现相吻合，或者玉米实际上是否早于最初的农业；2)史前玉米种植集约化的轨迹；3)高原山谷的自然景观几乎完全是人工景观的变化；4)评估重大火山灰落下对安第斯河谷生态和环境的可能影响以及恢复所需的时间(例如，是否有证据表明人类在大喷发后的很长一段时间内放弃了该山谷？)。这项研究的意义在于，它将促进我们对单一最重要的新大陆农业驯化的历史的了解，有助于为中美洲玉米的传播和安第斯山脉北部的土著史前社会采用玉米提供信息基线。到目前为止，有关安第斯山脉北部玉米历史的信息充其量也只是粗略的，对其在任何一个地点的使用历史的详细研究也很少。此外，这项研究将提供一个关于气候波动、自然环境和人类生态的长期视角，该地区目前人口稠密。这些信息除了对几个学科具有科学意义外，还可能有助于制定和指导各种公共政策问题。

Before the time of Columbus in 1492, maize was "the grain that civilized the New World." Prehistoric maize farming societies were found throughout much of the vast continental areas of North and South America except in the most extreme environmental zones, and truly advanced social systems occurred in a number of areas. With National Science Foundation support, Dr. J. Stephen Athens seeks to contribute to an understanding of how and why maize rose to such importance during prehistoric times by analyzing lake sediment cores from northern highland Ecuador. This northern South American study region, situated in a temperate valley surrounded by presently and previously active volcanoes, is known for its high agricultural productivity and the traditional dependence on maize by its past and present indigenous populace. The study cores are expected to contain long Holocene records of maize pollen preserved in the sediments. The deepest appearance of distinctive maize pollen grains in the cores will indicate, along with radiocarbon dating, when it was first introduced to the region. Combined with other regional studies, this information will help signal not only the timing, but the path of the spread of maize south from Colombia and, ultimately, southwestern Mexico, its apparent place of origin 7000 to 8000 years ago. In addition, the study of diatoms, which are the microscopic remains of certain types of unicellular algae having silica shells, will serve to document the rise and fall of lake levels, in effect providing a long term proxy record of regional rainfall. This will help to determine the specific environmental conditions under which the introduction and adoption of maize agriculture occurred in the mountains of northern highland Ecuador, as well as changing climatic conditions that prehistoric agriculturalists may have had to confront through time. Related questions of interest this study will seek to address include 1) whether or not the appearance of maize coincides with the earliest appearance of agriculture in the northern highland region of Ecuador, or if maize actually post-dates initial agriculture; 2) the trajectory of the prehistoric intensification of maize cultivation over time; 3) the change of the natural landscape of the highland valley to a virtually entirely man-made landscape; and 4) an evaluation of the possible effect of major volcanic ash falls on the ecology and environment of the inter-Andean valley and the time required for recovery (e.g., is there evidence that humans abandoned the valley for a significant period following major eruptions?). The significance of the research is that it will advance our understanding of the history of the single most important New World agricultural domesticate, contributing to a baseline of information for the spread of maize from Mesoamerica and its adoption by indigenous prehistoric societies in the northern Andes. Information on the history of maize in the northern Andes heretofore has been sketchy at best, and there have been very few detailed studies of its history of use at any single location. In addition, the study will provide a long term perspective on climatic fluctuations, the natural environment, and human ecology in a region that is presently densely populated. Such information may contribute to the development and guidance of a variety of public policy issues besides being of scientific interest to several disciplines.