Phytoliths in the Flora of Ecuador: Establishing Vegetation Signatures and a Key to Diagnostics

在国家科学基金会的支持下，密苏里大学的黛博拉·M·皮尔索尔博士和他的同事们将继续对厄瓜多尔植物区系中植硅体生产的性质进行基础研究。在过去的30年里，植硅体--植物组织中产生的微小硅体--有助于我们理解新大陆热带地区的人与景观之间的相互作用。从自然积累的沉积物中提取的植硅体，例如在湖泊中堆积的沉积物，提供了过去植被的详细记录，以及人类活动(如砍伐森林用于农业)对植被的影响。从史前村庄和古代农田中发现的植硅石，为人类将植物用于食物、仪式和医药提供了同样有价值的信息。成功利用这些耐用的植物微化石提供的丰富信息依赖于发现可用于识别关键野生物种和经济植物的植硅体。该项目的第一阶段(1997年8月至2000年12月)在这方面取得了进展。对解释热带低地植被变化和稳定性至关重要的森林物种被发现能够产生独特的植物硅体，并开发了识别玉米等作物的新方法。新项目建立在这些进展的基础上。首先，皮尔索尔和学生助理将研究原始项目剩余植物中的植硅体生产，并将所有新的诊断植硅体添加到密苏里大学的数据库中。然后，将开始为厄瓜多尔从太平洋海岸到亚马逊，以及从南部干燥森林到北部潮湿低地的沿海植物群落建立植硅体植被“签名”。皮尔索尔的两位同事将参与这项工作，他们是多元统计分析专家罗伯特·本弗博士和植物学家兼生态学家罗宾·肯尼迪博士。研究小组将分析从厄瓜多尔各地的比较土壤样本中恢复的诊断植硅体的模式，并开发识别植被类型(干燥热带森林、常绿森林等)的描述性和统计方法。从土壤中的植硅体组合而来。该项目的最后阶段侧重于使初步成果、新的植硅体类型和植被特征可供其他研究人员访问和使用。将测试一种交互式的、基于网络的、由新大陆热带植物物种产生的植硅体鉴定工具。植硅体分析在考古学中是一门年轻的学科(现代研究可以追溯到20世纪70年代)，因此许多基础研究仍有待完成。这项研究将促进我们对不同植物科和植被类型中植硅体产生的了解。该项目的学术价值还体现在研究结果的未来应用上，例如，研究新大陆农业的起源和演变，以及热带森林农业的性质和可持续性等问题。这项研究的更广泛影响是，在整个新大陆热带地区工作的研究人员将发现植硅体植被特征、诊断植硅体数据库和原型密钥有用。通过网络传播成果将使厄瓜多尔和其他拉丁美洲国家的研究人员和学生更多地了解植硅体研究方法和方法方面的进展。

With National Science Foundation support, Dr. Deborah M. Pearsall and colleagues at the University of Missouri will continue basic research into the nature of phytolith production in the flora of Ecuador. Over the past 30 years, phytoliths-microscopic silica bodies produced in plant tissues-have contributed to our understanding of human-landscape interactions in the New World tropics. Phytoliths extracted from naturally accumulating sediments, such as those that build up in lakes, provide a detailed record of past vegetation, and the impact on vegetation of human activities such as cutting of forests for agriculture. Phytoliths recovered from prehistoric villages and ancient agricultural fields provide equally valuable information on human uses of plants for foods, and in ritual and medicine. Successful tapping of the wealth of information provided by these durable plant microfossils is dependent on discovering phytoliths that can be used to identify key wild species and economic plants. Advances in this area were made in the first phase of the project (August 1997 to December 2000). Forest species critical for interpreting vegetation change and stability in tropical lowland settings were found to produce distinctive phytoliths, and new approaches for identifying crops such as corn were developed.The new project builds on these advances. First, Pearsall and student assistants will study phytolith production in plants remaining from the original project, and add all new diagnostic phytoliths to the University of Missouri database. Work will then begin on establishing phytolith vegetation "signatures" for plant communities in Ecuador, from Pacific coast to the Amazon, and along the coast from the dry forests of the south to the humid northern lowlands. Two colleagues will join Pearsall for this effort, Dr. Robert Benfer, an expert in multivariate statistical analysis, and Dr. Robin Kennedy, botanist and ecologist. The research team will analyze patterns of diagnostic phytoliths recovered from comparative soil samples from across Ecuador, and develop descriptive and statistical ways of identifying vegetation types (dry tropical forest, evergreen forest, etc.) from the combinations of phytoliths in the soil. The final stage of the project focuses on making the primary results, new phytolith types and vegetation signatures, accessible and useable by other researchers. An interactive, web-based identification aid to phytoliths produced by New World tropical plant species will be tested.Phytolith analysis is a young discipline in archaeology (modern studies date to the 1970s), and as such much basic research remains to be accomplished. This study will advance our knowledge of phytolith production in diverse plant families and vegetation types. The intellectual merit of the project also lays in future applications of the results of the research, for example, to questions of the origins and evolution of agriculture in the New World, and the nature and sustainability of tropical forest agriculture. The broader impacts of the study are that researchers working in regions throughout the New World tropics will find the phytolith vegetation signatures, database of diagnostic phytoliths, and prototype key useful. Web-based dissemination of results will broaden the access of researchers and students based in Ecuador and other Latin American nations to advances in phytolith research methods and approaches.