The three main themes of my research are:
1. Invasion dynamics on oceanic islands
Species introductions provide a unique opportunity to address diversity dynamics in nature, particularly within insular island systems. As alien species continue to accumulate across the globe, it is increasingly important to predict their future spread and impact. Darwin was one of the first to note the potential for species introductions for understanding the distributions we observe, predicting the success of alien species would depend on their similarity to the native community they invade. Since then, invaded communities have become an important study system for understanding community assembly and eco-evolutionary feedbacks in natural systems due to the replication of invasions at different scales around the globe.
For my PhD research, I developed a bioinformatic workflow to use publically available sequence data from GenBank to estimate evolutionary relationships between all species within an ecological community, in a consistent, comparative phylogenetic framework. I used this workflow to assess Darwin's Naturalization Hypothesis at a regional scale in the San Juan Islands (Washington, USA), and across tropical islands worldwide in collaboration with Dr. Patrick Weigelt (University of Göttingen, Germany). This approach is illuminating biogeographic trends in island invasions, and I am interested in continuing to incorporate other anthropogenic, biogeographic, and climatic parameters to predict the spread of alien species given the community phylogenetic structure.
2. Community phylogeography of alpine“sky islands”
Mountains inspired Humboldt to synthesize his thoughts about how species diversity changes across space, yet we know relatively little about the diversity of multi-species assemblages within and among alpine regions. In these remote and understudied areas, evolutionary history can be particularly useful for providing insights into macro-ecological and evolutionary processes driving diversity in the absence of detailed information on functional traits.
To understand what drives diversity at the limits of plant life, I've been exploring floristic patterns across alpine summits in the remote Sawtooth Nation Forest in Central Idaho, and the Écrins National Park, France (in collaboration with Dr. Sébastien Lavergne). I'm combining field-based floristic plant collections, publically available data repositories, and advances in sequencing technologies to describe diversity. I used bioclimatic variables to evaluate environmental drivers of phylogenetic diversity patterns, and reconstructions of the glacial extent during the last maximum to assess the imprint of history on community phylogenetic diversity patterns. With novel models and statistical approaches, we are beginning to unravel dominant processes shaping alpine plant communities at regional scales.
Check out pictures from my fieldwork in Idaho and France!
3. Metatranscriptomics and community plasticity
For my postdoctoral research, I am using transcriptomes to address community diversity from a temporal angle. Predicting how species respond to environmental change is of critical importance, but quantifying ecological responses over biogeographic scales remains challenging. The ability to produce different phenotypes in heterogeneous environments—phenotypic plasticity—can be essential for responding successfully to change. Short-term (seasonal) plasticity might reflect a broad physiological niche that is adaptive in the long-term. There is recent evidence from experimental studies that plasticity at the level of gene expression can be adaptive under changing environments, but genomic plasticity has not been connected with ecological success in nature. By establishing a foundation to use genomic plasticity to track climate change, this study is a stepping stone towards understanding links between mico- and macro-ecological scales.
Follow the progress of our community plasticity reserach at the Harvard Forest NEON site here!
When I have time…
Phylogenetic diversity of medicinally useful plants
We use plant products in almost every aspect of our lives. I am particularly interested in the diversity of plants that we consume, as food or medicine. I would like to compile a database of medicinally used plants, and use comparative phylogenetic approaches to assess the diversity of these plants, and the conservation of their use across cultures.
Few localities can claim to be a Lagerstätte—a fossil site with exceptional preservation. The Miocene fossil beds in Clarkia, Idaho are one of them. In this ancient lake sediment, anoxic preservation compressed leaf tissues before they were able to decompose. Today, you can open blocks of this lakebed and watch leaves change from green to black before your eyes. While extracting ancient DNA remains challenging, I am intrigued by the idea of comparing genetic variation of 15 million year old sub-tropical plant communities with the coniferous forest that has since replaced it. Watch a video of us lifting leaves that fell from tress during the Miocene below!