Species range limits can be areas of high or low adaptive diversity depending on genetic variation, the strength of natural selection, and the amount and nature of gene flow from nearby populations. In this study, field experiments are used to understand the role of gene flow and selection in the adaptive diversity of Mimulus laciniatus, a Sierra Nevada annual plant with a restricted, well-defined geographic range. Preliminary data reveal climate adaptations at low- and high-elevation range limits. Experiments to determine the nature of selection along these range limits are ongoing while experimental matings will provide an understanding of the role of gene flow, from both far and nearby populations, on adaptive potential at range edges. Finally, genetic markers (microsatellites) are being used to estimate gene flow and population sizes across the species range.
In addition to providing basic insights about evolution at range limits, this research will inform species management and conservation efforts at a time when climate change is resulting in increasingly warmer habitats. Mountain systems host an impressive diversity of plant species. Developing an understanding of how genetic diversity, gene flow, and climate adaptation interact may contribute to strategies aimed more broadly at conserving these unique floras. Additionally, this project continues to support undergraduates, including many members of underrepresented groups in science; students participate as research assistants and often develop their own independent research projects.
