Phytoliths in the Flora of Ecuador: Methodology for Paleoenvironmental Reconstruction

在国家科学基金会的支持下，Deborah Pearsall博士和她的学生将为今天的各种赤道植物群落构建诊断植硅体剖面。“植物硅体”是由植物产生的微小二氧化硅形式，最终被结合到土壤中。虽然单个物种产生不止一种植硅体形式，而且很少有形式是任何单一物种所特有的，但通过对保存在地下的植硅体组合的分析，通常有可能识别出存在的植物。因此，植硅体分析是环境重建的重要工具。多年来，考古学家一直在埃尔多尔工作，试图了解这一地区如何出现复杂的社会。从灌溉条件较好的北部海岸到较为干燥的南部海岸，这个国家的生态环境各不相同。从西到东，植被带从横跨安第斯山脉的干旱海岸线变化到热带雨林。古生态学家知道，这些区域随着过去的气候变化而发生了重大变化，考古学家希望了解与这些自然现象有关的文化变化。皮尔索尔博士的研究将为这一过程提供数据。她和她的学生将在赤道上建立两个横断面，一个横贯南北，另一个横贯东西。通过对已经收集的标本的分析以及额外的实地考察，他们将确定与特定环境相关的植硅体组合，并注意到最重要的指示类型。在此基础上，就有可能从古老的土壤中提取植硅体组合并重建古环境。这项工作之所以重要，有几个原因。这将有助于建立一个环境背景来理解文化变化。它还将为人类对环境的长期影响提供新的线索。生态学家不确定史前在技术简单水平上活动的人类如何影响他们的环境。小规模砍伐和焚烧农业对雨林边界和植物群落的影响有多大？在这项研究中收集的数据将为这个问题提供新的线索。它还将建立一个数据库，供考古学家和自然科学家广泛使用。

With National Science Foundation support, Dr. Deborah Pearsall and her students will construct diagnostic phytolith profiles for a variety of present day Equadorian vegetation communities. `Phytoliths` are microscopic silica forms which are produced by plants and which are eventually incorporated into the soil. Although a single species produces more than one phytolith form and few forms are unique to any single species, through analysis of phytolith assemblages preserved in the ground, it is often possible to identify the plants which were present. Phytolith analysis therefore constitutes an important tool for environmental reconstruction. For many years archaeologists have worked in Equador and attempted to understand how complex societies arose in this region. The country varies ecologically from the better watered Northern to drier Southern coast. From West to East vegetation zones change from arid coastline across the Andes to tropical Amazonian rainforest. Paleoecologists know that these zones shifted significantly in response to past climate changes and archaeologists wish to understand cultural change in relation to these natural phenomena. Dr. Pearsall's research will provide data to assist in this process. She and her students will establish two transects across Equador, one running North-South, the other East-West. Through analysis of already collected specimens as well as additional fieldwork they will define phytolith assemblages which correlate with specific environments and note the most important indicator types. On this basis it will then be possible to extract phytolith assemblages from old soils and reconstruct paleoenvironments. This work is important for several reasons. It will help to establish an environmental context to understand cultural change. It will also shed new light on long term human impact on the environment. Ecologists are uncertain about how humans who functioned prehistorically at technologically simple levels affected their surroundings. To what extent were rainforest boundaries and plant communities influenced by small scale slash and burn agriculture? The data collected during this research will shed new light on this question. It will also establish a data base which will be widely used by archaeologists and natural scientists.