Doctoral Dissertation Research: Holocene History of Atlantic Tropical Forest and Cerrado in Southeastern Brazil: The Role of Climate, Fire, and Human Disturbance

博士论文研究：巴西东南部大西洋热带森林和塞拉多的全新世历史：气候、火灾和人类干扰的作用

• 批准号: 0002346
• 负责人: Kam-biu Liu
• 金额: $ 0.99万
• 依托单位: Louisiana State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-15 至 2002-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0002346&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Holocene; History

The Atlantic forest in southeastern Brazil is one of the most threatened tropical forests in the world. Many aspects concerning the history and ecology of this diverse tropical forest are still unknown, even as it is being cleared at a rapid rate. This project will study the history of vegetation changes in southeastern Brazil since the middle Holocene in the context of climatic changes, fire occurrence, and human disturbance. The ecologically sensitive region in the state of Sao Paulo is occupied mainly by Atlantic seasonal tropical forest, but it also contains the southernmost distribution of cerrado (Brazilian savanna), which occurs as natural patches interspersed within the seasonal forest. The region has been occupied by native Americans for thousands of years, but intensive deforestation over the last 150 years has reduced the Atlantic forest into isolated fragments of various sizes. Three lakes within this broad forest/cerrado ecotone and in some of the forest fragments will be cored for palynological study. The sediments will be analyzed for pollen and microscopic charcoal to produce detailed records of vegetational changes and fire history for the last several millennia, especially focusing on the last several hundred years since the European contact. This study will produce paleoecological records on the development of the forest/cerrado ecotone in relation to Holocene climatic changes, natural and anthropogenic fires, and human disturbance. It will address questions concerning the loss of biodiversity and ecological degradation due to forest fragmentation in the Atlantic tropical forest, and it will provide insight into key issues in conservation biology and environmental planning in the tropics. This study will also advance the science of palynology in the tropics, especially its application in the study of human impacts on tropical vegetation. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.

巴西东南部的大西洋森林是世界上受威胁最严重的热带森林之一。 尽管森林正在迅速被砍伐，但有关这片多样化热带森林的历史和生态的许多方面仍然未知。 该项目将研究巴西东南部自全新世中期以来在气候变化、火灾发生和人类干扰的背景下植被变化的历史。 圣保罗州的生态敏感区主要由大西洋季节性热带森林占据，但也包含最南端的塞拉多（巴西稀树草原）分布，这些区域以天然斑块散布在季节性森林中。 该地区数千年来一直被美洲原住民占据，但过去 150 年的密集森林砍伐已使大西洋森林变成了大小不一的孤立碎片。 这片广阔的森林/塞拉多生态交错带和一些森林碎片中的三个湖泊将成为孢粉学研究的核心。 将对沉积物进行花粉和微观木炭分析，以详细记录过去几千年的植被变化和火灾历史，特别是欧洲接触以来的最后数百年。 这项研究将产生与全新世气候变化、自然和人为火灾以及人类干扰有关的森林/塞拉多交错带发展的古生态记录。 它将解决由于大西洋热带森林的森林破碎化而导致的生物多样性丧失和生态退化的问题，并将深入了解热带地区保护生物学和环境规划的关键问题。 这项研究还将推动热带孢粉学科学的发展，特别是其在人类对热带植被影响研究中的应用。 作为博士论文研究改进奖，该奖项还将为有前途的学生建立强大的独立研究生涯提供支持。