The evolution plant mating/breeding systems. Angiosperms exhibit a spectacular diversity of mating strategies among individuals, populations and species. Much of my research aims to elucidate the role of selective factors in the evolution and ecology of different plant reproductive systems. Most recently, I have begun investigating how strong selection generated by factors such as climate change and pollinator declines influence plant mating systems.
My current and future research will use the mixed-mating species Triodanis perfoliata to further elucidate the evolutionary consequences of self- and cross-fertilization both within and among populations. Individuals of this species exhibit flowers open to cross-pollination, as well as cleistogamous flowers (those that do not open, but self-fertilize and set fruit). Cleistogamy is thought to provide advantages under certain scenarios (e.g., low pollinator abundance, intense herbivory), yet offspring of cleistogamous flowers may be relatively less vigorous due to inbreeding depression. One of our ongoing projects is now examining how the mating system varies spatially and temporally in this relatively widespread native of North America.
Collaborator: Carol Goodwillie, East Carolina U
Evolutionary responses to climate change. The pressures of climate change are widely recognized, however we are only beginning to understand impacts on natural populations. Specifically, we have limited empirical information regarding the frequency of adaptive versus plastic responses to climate change. I have employed multiple approaches to understand how populations are responding to climate change. Recently, I have used the space for time approach to estimate genetic and demographic consequences of climate change with a combination of published empirical genetic data and spatially explicit demographic modeling (Brown et al. 2016).
Current projects in my lab are using a combination of methods to address crucial questions about how climate change has and will influence plant populations. As well, we are interested in testing hypotheses about the relative resilience of populations based on breeding system and standing genetic diversity. For example, my current MNS student, Colette Berg, is synthesizing data from thousands of digitized herbarium records of Triodanis to quantify how phenology, species distribution and breeding system have changed in the genus over the last two hundred years. Congruently we are employing the space for time method in a project that is investigating genetic diversity and evolutionary history of T. perfoliata collected from over twenty populations spanning the continental United States. Using population genomics and spatial statistics we will test hypotheses about the role of breeding systems and evolutionary history in driving genetic diversity among populations. We will then use these data to model the consequences of climate changes on genetic diversity of populations in the future.
Collaborator: Jason Brown, Southern IL U