Joy Nystrom Mast, Carthage College Melissa Savage, University of California-Los Angeles Johannes Feddema, University of Kansas
Human 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.
