Although some species range widely across continents while others are found in only a handful of locations, every species on earth has a geographic distribution that is circumscribed by range boundaries. The ecological and evolutionary factors that give rise to range boundaries remain poorly understood for most species, yet they are of direct relevance for understanding potential biological responses to climate change. Range boundaries are hypothesized to be set by the combined action of spatial variation in habitat suitability, dispersal and gene flow (the movement of individuals and their genes between populations), and demography (aspects of individual performance and population growth). Depending on the relative balance of these factors, range margins may represent stable areas where species have failed to adapt to particular climatic conditions, or they may represent areas that are the forefront of range shifts under changing climatic regimes. In this study, factors that limit the geographic range of the scarlet monkeyflower (Mimulus cardinalis) in western North America will be investigated using field surveys, population modeling, and population genetic assays. The goal is to understand how spatial variation in habitat suitability, gene flow and demography give rise to stable or transient range boundaries.
An existing partnership with Yosemite National Park will be used to enhance public dissemination of results of this research. An education ranger will present information on the biological effects of climate change in national parks. A postdoctoral researcher, a female doctoral student, and a minority undergraduate will be trained as part of this project. Undergraduates will participate in a summer program at Colorado State University that enhances the undergraduate research experience through independent projects and professional development seminars.
