RUI: The Biogeography of Forest Change: Drought and Crown Fire in Ponderosa Pine Forests of the American Southwest

目前的理论几乎无法预测这些生态系统的命运，特别是在面临新的干扰制度和不断变化的气候的情况下。生物地理学研究在人类影响和生态系统动力学的界面上做出了重要贡献。这项研究将通过研究美国西南部黄松林在人为改变的火灾制度下极端气候条件下的演替动态来推动生物地理学和生态学理论的发展。这项研究质疑该地区的松林能否在新的火灾制度和极端气候条件相结合的史无前例的条件下坚持下去。气候变暖预计将产生大规模和快速的森林生物地理变化，但缺乏预测模型，主要是因为缺乏经验数据。这项研究将重点放在气候在严重火灾后限制松树恢复方面的作用，通过检查在20世纪40-50年代盛行的干旱中烧毁新墨西哥州森林的高强度树冠大火后树木的重新生长。由于研究期间没有充足的降水，因此可以利用树轮重建的气候和水收支模型工具，将火灾后环境的影响与气候影响分开，并加以量化。这项研究将为构建人类影响下的森林动力学理论贡献高分辨率数据，例如新的干扰机制和气候变暖情景。此外，这项工作将为在未来干旱中管理树冠火灾后的森林恢复提供重要的见解。该项目旨在通过直接实践经验、课堂项目和高级论文，培训本科院校迦太基学院的本科生进行地理实地考察、树生态学实验室技能和气候建模方面的培训。树木年代学数据将提交给国际树木年轮数据库。结果的传播将通过本科课程、专业演讲、学术期刊文章、新的数据库和新的森林动态模型，以及西南国家森林、国家公园和美洲原住民保留地的森林管理员进行。

BCS 0751715Joy Nystrom Mast, Carthage CollegeMelissa Savage, University of California-Los AngelesJohannes Feddema, University of KansasHuman activities are profoundly changing natural communities across landscapes at rapid and accelerating rates. Current theory offers little to predict the fate of these ecosystems, particularly in the face of novel disturbance regimes and a changing climate. Biogeographic research has made important contributions at the interface of human impacts and ecosystem dynamics. This study will advance biogeographical and ecological theory by examining successional dynamics in extreme climate conditions under a human-altered fire regime in ponderosa pine forests of the American Southwest. The research questions whether the regional pine forest can persist in the unprecedented conditions of a novel fire regime combined with extreme climate conditions. Climate warming changes are expected to produce large and rapid forest biogeographic shifts, yet lacking are predictive models largely due to the paucity of empirical data. The research will focus on the role of climate in limiting pine recovery after severe fire, by examining tree recruitment after high-severity crown fires that burned New Mexico forests in the drought that prevailed in the 1940-50s. The absence of abundant precipitation during the study period allows separation and quantification of the influence of the post-fire environment from climate effects, using the tools of tree-ring reconstructed climate and water budget models. The specific objectives of this project are to 1) determine whether ponderosa pine trees in the Southwest can successfully recover from anthropogenic high-severity fires during drought conditions; 2) develop a database of post-high-severity fire establishment processes influencing ponderosa pine recruitment during droughts in order to test biogeographical hypotheses; 3) predict post-disturbance forest dynamics under future climate scenarios, including the potential for recovery following high-severity fires during deeper or longer droughts in a warming climate scenario; and 4) provide guidelines for resource managers to improve strategies that can bring an important regional forest within natural ranges of variability. The research will contribute high-resolution data toward the construction of a theory of forest dynamics under human influences such as novel disturbance regimes and climate warming scenarios. In addition, this work will provide critical insights to managing forest recovery after crown fires in future droughts. The project is designed to train undergraduates from Carthage College, an undergraduate institution, in geographic fieldwork, dendroecology laboratory skills, and climate modeling through direct hands-on experience, class projects, and senior theses. Dendrochronology data will be submitted to the International Tree Ring Database. Dissemination of results will occur broadly through undergraduate courses, professional presentations, academic journal articles, new databases, and new forest dynamics models, as well as to the forest managers at the southwestern National Forests, National Parks, and Native American Reservations.