Doctoral Dissertation Research: Fire-Vegetation Dynamics in Highland Pine Forests of the Dominican Republic: An Investigation at Multiple Time Scales

许多自然过程和许多不同形式的人类活动改变了世界不同地区的植被格局。大大改变植被状况的因素之一是火灾，包括人为火灾和自然原因，特别是闪电引起的火灾。一些重点研究考察了人类不在研究地点的史前时期的自然火灾，而另一些研究考察了历史时期或现代土地管理实践中的火灾。很少有人注意检查从史前到现代时期同一地区的火灾和植被之间的关系。本博士论文研究项目将整合古生物学、树木年代学和生态学研究，在多时间尺度上调查多米尼加共和国中部高地的火-植被动态。学生将在不同的时间尺度上使用不同的方法。通过分析沉积物中的花粉和木炭，我们将了解几千年来火作为植被变化的媒介的长期历史。研究人员将通过对两处被大火烧毁的松树林的年轮核进行分析，研究近几个世纪的火灾历史，并分析这两处和其他8处最近被烧毁的松树林在过去十年中的植被再生情况。这三种研究方法的整合将扩大对多米尼加高地火灾和植被之间的进化和生态联系的理解。这项研究将提供关于火-植被动态的资料，并将补充该区域目前和计划进行的旨在解释该区域更广泛的植被格局的研究。该项目的研究结果将有助于加深对热带山地森林群落演替途径的理论认识，并将为指导土地管理者在高原环境中对火的利用和控制做出决策提供实用信息。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研究生涯。

Numerous natural processes and many different forms of human activity have altered vegetation patterns in different parts of the world. Among the factors that have dramatically altered vegetation regimes are fires, both human-generated as well as those arising from natural causes, especially lightning. Some focused studies have examined natural fires during prehistoric periods when humans were absent from the study locales, while others have examined fires during historic time periods or as modern land-management practices. Little attention has been given to examining the relationships between fires and vegetation in the same area from prehistoric to contemporary time periods. This doctoral dissertation research project will integrate paleontological, dendrochronological, and ecological research to investigate fire-vegetation dynamics at multiple time scales in the central highlands of the Dominican Republic. The student will use different approaches for each time scale. The long-term history of fire as an agent of vegetation change over millennia will be undertaken by analyzing pollen and charcoal in sediments. Fire histories over recent centuries will be examined through analysis of tree-ring cores from two stands of fire-scarred pines, and present vegetation regeneration over the last decade will be analyzed in these two and in eight other stands that recently burned. The integration of these three research approaches will expand understandings of the evolutionary and ecological links between fire and vegetation in the Dominican highlands. The study will provide information about fire-vegetation dynamics and will complement current and planned studies in the region aimed at explaining broader-scale vegetation patterns in the region. The results of this research project should contribute to deeper theoretical understandings of successional pathways in tropical mountain forest communities, and it will provide practical information the can guide land managers in making decisions regarding the use and control of fire in highland environments. 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.