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

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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.