My research interests are focused on understanding the biogeographic history and evolution of tundra ecosystems. The overarching goal of these studies is to better understand the processes of geographic isolation, genetic divergence, and ultimately speciation that have given rise to the diversity of the arctic and alpine flora around the North Pacific Rim. Throughout the Quaternary, the north has oscillated between glacial and interglacial periods, forcing plant populations to track suitable habitat across the shifting landscape, adapt to the environmental changes, or go extinct.

To evaluate the consequences of the Quaternary on the tundra flora, my students and I are testing biogeographic hypotheses and speciation models through coalescent-based analyses of next-generation genomic sequence data from various species of plants across the region. Recently, our analyses have focused on an arctic-alpine clade of Saxifraga that is restricted to the North Pacific Rim: sect. Bronchiales. Through these investigations into the history of multiple species of plants, a general understanding of the process of speciation and extinction in the tundra is emerging. These comparative analyses are akin to investigating numerous natural experiments linked to the region's geology, hydrology, and ecology and are critical for understanding the paleoecological history of arctic and alpine ecosystems.