COLLABORATIVE RESEARCH: HOW DID THE GRASSLAND BIOME EVOLVE IN SOUTH AMERICA?: INTEGRATING CENOZOIC CLIMATE, FLORAL AND FAUNAL RECORDS FROM PATAGONIA, ARGENTINA

合作研究：南美洲的草原生物群落是如何演变的？：整合阿根廷巴塔哥尼亚的新生代气候、花卉和动物记录

• 批准号: 0819910
• 负责人: Caroline Stromberg
• 金额: $ 14.96万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2013-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0819910&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; HOW; DID; GRASSLAND

COLLABORATIVE RESEARCH: HOW DID THE GRASSLAND BIOME EVOLVE IN SOUTH AMERICA?: INTEGRATING CENOZOIC CLIMATE, FLORAL AND FAUNAL RECORDS FROM PATAGONIA, ARGENTINASTROMBERG, KOHN AND MADDEN PISGrasslands, which today form ~1/4 of Earth?s vegetative cover, are thought to have developed earlier in South America than on other continents, based on floral, faunal, and sedimentological evidence at Gran Barranca, Argentina, and nearby. However, the timing and rate of change remain unclear, as well as causal mechanisms. We will determine the timing and nature of climatic, vegetational, and faunal events related to the evolution of Earth?s earliest grassland ecosystems in southern Argentina by integrating floral, stable isotopic, and faunal data through the long, well-dated, and nearly continuous sedimentological record at Gran Barranca (~42.0 to ~18.5 Ma). We will focus on evaluating whether: (1) The rise to dominance of open-habitat grasses in South America occurred in parallel with their appearance, (2) An increase in openness of habitats occurred in parallel with the rise to ecological dominance of open-habitat grasses, (3) Changes in vegetation were correlated with climate change, and (4) Hypsodonty in South American mammalian herbivores responded rapidly to the spread of open, grass-dominated habitats. Fossil phytoliths (plant silica) will be analyzed to provide detailed, continuous floral records of grasses as well as other climate- or ecology-sensitive plant groups (e.g., palms, sedges). Fossil teeth will be analyzed for stable isotope compositions, focusing on bulk d13C values and isotopic zoning of d13C and 18O values. Together with phytolith assemblage data and sedimentology, this isotopic information will be used to infer changes in habitat openness, aridity, and seasonality in terms of temperature and precipitation. Comparison with records of faunal community composition and functional morphology will elucidate the patterns of grassland expansion and faunal responses. Our data will additionally help answer the following two questions: (1) How does the timing and rate of climate change in Argentina compare with the marine record? (2) How do patterns of fauna-flora-climate evolution in South America compare with putatively similar changes that occurred later, e.g., in central North America? The proposed project incorporates several avenues for disseminating the research to the public through the Burke Museum, including an in-museum exhibit, materials for traveling study kits on the evolution of grasslands, and development of a phytolith database with images accessible on-line through the Museum's website.

合作研究：南美洲的草原生物群落是如何演化的？：整合来自巴塔哥尼亚、阿根廷斯特龙贝格、科恩和马登皮斯的新生代气候、花卉和动物记录今天的草原约占地球植被覆盖的 1/4，被认为拥有南美洲发展较早根据阿根廷大巴兰卡及附近地区的植物、动物和沉积学证据，该大陆的分布情况优于其他大陆。 然而，变化的时间和速度以及因果机制仍不清楚。我们将通过长期、准确且近乎连续的植物、稳定同位素和动物数据来确定与阿根廷南部地球最早草原生态系统演化相关的气候、植被和动物事件的时间和性质。 Gran Barranca 的沉积学记录（~42.0 至~18.5 Ma）。我们将重点评估是否：（1）南美洲开放生境草类的优势地位的上升与其出现同时发生，（2）生境开放性的增加是否与开放生境草类的生态优势地位的上升同时发生。 (3) 植被变化与气候变化相关，(4) 南美洲食草哺乳动物的多齿性对开放、以草为主的栖息地的扩张做出了快速反应。将分析化石植物硅体（植物二氧化硅），以提供草以及其他气候或生态敏感植物群（例如棕榈树、莎草）的详细、连续的花卉记录。将分析化石牙齿的稳定同位素组成，重点关注大量 d13C 值以及 d13C 和 18O 值的同位素分区。与植硅体组合数据和沉积学一起，该同位素信息将用于推断栖息地开放度、干旱度以及温度和降水季节性的变化。与动物群落组成和功能形态记录的比较将阐明草地扩张和动物反应的模式。我们的数据还将有助于回答以下两个问题：（1）阿根廷气候变化的时间和速度与海洋记录相比如何？ (2) 南美洲的动物-植物-气候演化模式与后来发生的假定类似的变化（例如北美中部）相比如何？拟议的项目包括通过伯克博物馆向公众传播研究成果的多种途径，包括博物馆内展览、草原演化旅行研究包的材料，以及开发植硅体数据库，其中的图像可通过博物馆的网站。