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

巴西东南部的大西洋森林是世界上最受威胁的热带森林之一。 关于这片多样化热带森林的历史和生态的许多方面仍然是未知的，即使它正在以快速的速度被清除。 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地区主要由大西洋季节性热带森林占据，但它也包含塞拉多（巴西稀树草原）的最南端分布，这是季节性森林中散布的天然斑块。 该地区已经被美洲原住民占领了数千年，但在过去的150年里，密集的森林砍伐已经将大西洋森林减少到各种大小的孤立片段。 在这片广阔的森林/塞拉多交错带和一些森林碎片中的三个湖泊将被取芯用于孢粉学研究。 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，特别是自欧洲接触以来的过去几百年。 这项研究将产生有关全新世气候变化、自然和人为火灾以及人类干扰的森林/塞拉多交错带发展的古生态记录。 它将讨论由于大西洋热带森林的森林分割而造成的生物多样性丧失和生态退化问题，并将深入了解热带地区养护生物学和环境规划方面的关键问题。 这项研究也将促进热带地区的孢粉学科学，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，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

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.