Hello! I am an evolutionary ecologist interested in how species-environment interactions drive patterns of biodiversity across scales, from alleles and genes to species and communities.
In addition to my research, I find great joy in teaching and mentoring junior scientists, both at Duke and at the Rocky Mountain Biological Laboratory, where I do my fieldwork. When I’m not in the field, greenhouse, or lab, I enjoy backpacking (especially long distances), playing my guitar (poorly), and building my knowledge of carpentry and construction (pun intended). I also manage a comical plant appreciation blog on Instagram: @aggressivebotany.
For more details about my research, read on below!
Ecological drivers of natural selection on plant chemistry
My main dissertation work aims to understand how ecological interactions influence selection for variation in glucosinolates, chemical compounds associated with herbivore defense in Boechera stricta. I am using large-scale manipulative experiments in the field coupled with controlled greenhouse studies to determine which biotic and abiotic conditions favor certain glucosinolate types over others. Combined with these experiments, evolutionary modeling and population genetics help me to tease apart how these variable selective pressures influence the maintenance of chemical diversity across space and time.
The genetics of plant-herbivore interactions
In collaboration with other members of the TMO lab, I am working to uncover the genes that control plant defenses against herbivores. We use genome-wide association (GWA) tests across several hundred Boechera stricta accessions to map complex, polygenic traits associated with plant defense to single-nucleotide level resolution in the genome. I’ve conducted GWA experiments with experimental herbivores in a laboratory setting as well as with thousands of plants interacting with myriad species under natural conditions in the field.
Bottom-up ecological effects of plant traits
How does individual phenotypic variation influence inter-species interactions, community assembly, and biodiversity? Using the rhizosphere as a model community, I am testing how variation in root chemistry influences the abundance and diversity of microbes in soil, and whether and how these community-level changes feed back to influence plant health.
Genetic variation for interspecies interactions
Individual- and population-level variation in whether interspecies interactions positively or negatively effect fitness has implications for the coexistence of species in communities. However, little is known about how intraspecific variation in genotypes and phenotypes might alter these outcomes. In collaboration with several student mentees, I am utilizing common garden studies involving hundreds of genotypes of Boechera stricta to assess the extent to which intraspecific variation influences interactions with heterospecific plant neighbors, as well as potential facultative arthropod mutualists.
Genetic diversity and demographic dynamics
Because Boechera species are highly self-pollinating, it is unknown whether inbreeding depression and broad-scale genetic diversity have consequences for population growth or decline. Using long-term data on the rare species Boechera fecunda, I am building demographic models to assess whether and how genetic variation influences population persistence.
Evolutionary dynamics of invasion
While working as a lab manager and technician in the Stinson lab at UMass Amherst, I collaborated on ongoing projects aiming to understand how the invasive plant garlic mustard (Alliaria petiolata) expands into novel habitat types. Specifically, my work focused on testing for environmental effects on trait expression, variation in natural selection across habitat types, and whether phenotypic plasticity and/or local adaptation may aid or hinder the invasion process in this species. We found high levels of trait plasticity as well as divergent phenotypic selection regimes across habitat types; however, interestingly, we found no evidence of either local adaptation or of adaptive plasticity. Instead, we posit that environmental heterogeneity and dispersal patterns across habitat types may influence incursion patterns in these populations.
Read more in the American Journal of Botany: https://doi.org/10.1002/ajb2.1299
Drivers of flower color variation in a selfing species
Intraspecific variation in flower color is common in nature, and is often driven by pollinator-mediated natural selection. However, even selfing species, which are rarely visited by pollinators, may consistently produce flowers of different colors. In such species, why are multiple color morphs maintained? Contributing to a multi-year study led by Jill Anderson investigating this polymorphism in Boechera stricta, an undergraduate mentee and I investigated whether flower color influences herbivore resistance. Using controlled laboratory feeding assays, we found that plants with pigmented flowers were better defended against herbivores than plants with white flowers, suggesting that herbivore pressure may influence the maintenance of multiple color morphs in this species. In addition, several other environmental factors such as elevation and soil nutrient content were found to predict flower color expression, suggesting interacting effects of biotic and abiotic stressors.
Read more in New Phytologist: https://doi.org/10.1111/nph.14998
Impacts of agriculture on ecology and evolution
Outside of my main research investigating “natural” drivers of variation in traits and species, I am very interested in understanding how these patterns of biodiversity shift in response to anthropogenic impacts, especially agriculture. Specifically, I am interested in how systematic and long-term application of agrochemicals such as pesticides and fertilizers influence the ecology and evolution of non-target species. This interest has led me to pursue two side projects in this realm:
1. Through a microbial bioinformatics training fellowship at Duke, I collaborated with Marie Simonin and others to investigate the effects of pesticide and fertilizer exposure on microbiome communities in both terrestrial (target) and wetland (non-target) ecosystems. Using high-throughput sequence data to characterize microbial communities, we found that long-term exposure to nanopesticides alters community composition of micro-eukaryotes in the sediments of wetland ecosystems. Such changes in community composition and diversity could have impacts for ecosystem processes like nutrient cycling. Further, because nanoparticle fungicides predominantly affected community composition of non-target organisms (predominantly protists) in non-target ecosystems (wetlands experiencing agricultural runoff), this study suggests that tests of new agricultural technologies ought to explicitly include non-target communities when assessing environmental risk.
Read more in Environmental Science & Technology: https://doi.org/10.1021/acs.est.0c00510
2. During a post-baccalaureate fellowship with the Organization for Tropical Studies, I initiated a study to test whether patterns of chemical, physical, and biotic defenses in an acacia species (Vachellia collinsii) vary over natural gradients of exposure to agrochemical runoff. In these long-lived species, I am interested to see whether insecticide exposure is decreasing herbivore pressure sufficiently to alter plant defense strategies, either through plastic shifts in defense phenotypes or in response to divergent selection across different chemical exposure regimes.
Genetics and physiology of abiotic stress tolerance
My undergraduate thesis in the Dalton lab at Reed College focused on investigating the role of antioxidant-associated enzymes in the ability of plants to withstand abiotic stresses such as drought and high light exposure. I utilized transgenic tools in the Populus model system to determine whether up-regulation of such enzymes enhanced stress tolerance.