This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2011, Intersections of Biology and Mathematical and Physical Sciences. The fellowship supports a research and training plan in a host laboratory for the Fellow at the intersection of biology and mathematics. The title of the research and training plan for this fellowship to Melanie Harsh is "Global assessment of the variability of plant species response to climate change." The host institution for this research is University of Washington with sponsoring scientists Drs. Hille Ris lambers Janneke and Mark Kot.
Managing, and therefore predicting, the effects of climate change is one of the greatest societal challenges. Developing and prioritizing management strategies, complicated by variability between species and regions globally, require realism in analyses and accuracy in predictions. This research seeks to understand and predict climate change impacts on species limits through models that incorporate complexity apparent in natural systems, specifically, species sensitivity (functional traits) and ability to respond to climate change (demographic and dispersal rates) along with possible interactions with the rate of climate change. The approach utilizes theoretical mathematical models, based on stage-structured integrodifference equations, and statistical models, built within a hierarchical Bayesian framework to address (1) How climate and demographic rates interact to determine response to climate change; (2) If functional traits or demographic rates can predict response to climate change. This project also identifies potential threshold limits of tolerance and relationships not readily identified through observational studies, thus rapidly advancing the field of biology and conceptual understanding by encouraging new research questions.
Training goals focus on developing the necessary skills to conduct interdisciplinary research through advanced training in modern mathematical and statistical methods, model implementation, and validation techniques, as well as communication training through oral presentations, written documents, and visual displays. Broader impacts include the dissemination of the results to conservation and natural resource organizations through written documents and presentations as well as public outreach.
This study used statistical and mathematical models to evaluate the causes and consequences of different range shift responses to climatic changes. Analysis of species occurrences over time indicate that species are responding in many ways to climate change – with species both shifting uphill and downhill. Responses cannot predicted based on temperature change alone. Water availability plays a critical role in understanding how species will respond to continued climate warming. Upward range shifts, predicted by warming temperatures, are hindered or even reversed by decreasing snowpack. Additionally, lower and upper range limits will not necessarily respond synchronously, leading to increases and decreases in range size. Decreases in range size is a new indicator of species vulnerability to climate change. This new metric of vulnerability identifies near-term vulnerability. Other commonly used vulnerability metrics address longer-term vulnerability. The moving-habitat model is a mathematical model for analyzing the effects of a moving habitat, through climate change, on species. These models can identify the maximum velocity of climate change that species can track, given species dispersal ability. But it also provides insights into our understanding of the impacts of climate change. For instance, long-distance dispersal is not always beneficial. For sedentary species (i.e. plants), climate change exerts pressure for earlier maturation. For non-sedentary organisms (i.e. mammals) climate change exerts pressure for earlier dispersal. These models provide insights into how different life-history strategies may benefit or hinder a species under increasing velocities of climate change. Broader impacts: The research resulting from this award has received broad scientific interest. All code and data have or are in the process of being published publically. The moving-habitat model is available through Dryad. In addition, four user-friendly interactive simulation models have been developed for the moving-habitat model. These simulation models are built to allow users to explore, understand, and gain an appreciation for mathematical models without having to understand the code. Simulation models are educational tools (for understanding why climate change matters), a means to test hypothesis and to generate new hypotheses. In addition, we have developed a new metric to assess species near-term vulnerability to climate, changes in range size. The methodology and code will be available in the near future.
