The PIs propose to use paleobotanical and paleogeochemical data with a model developed for understanding modern controls on vegetation distribution to explore the fundamental mechanisms behind complex advance, retreat, and further advance of a boreal-tundra ecotone along the Brooks Range in Alaska. The paleobotanical evidence will be used to examine several different approaches to discern movements of the ecotone with a species-level resolution with the changes in climate variables (temperature, precipitation amount, and seasonality of precipitation). The analysis will provide independent climate and vegetation datasets. The climate dataset will be used to drive an ecosystem model to simulate changing vegetation under changing climate. The results of the study will provide a useful predictive capability for separating climate-induced changes from those caused by feedbacks in the climate-vegetation system when attempting predictions of boreal forest ecosystem responses to future climate change.
