I am broadly interested in the ecology and evolution of plant adaptation to novel environments, whether these involve non-native species transplanted to new habitats, or locally adapted plants that occupy a range of habitats. My graduate research centered around invasive Japanese knotweed, whereas my postdoctoral work has focused on the biofuel crop switchgrass.

Switchgrass resistance to rust pathogens

Switchgrass (Panicum virgatum) is an emerging biofuel crop in North America. Rust fungi infect switchgrass, and reduces both biomass and quality. We are searching for genes that might help switchgrass resist the rust by crossing resistant and susceptible ecotypes in several different locations. Knowing this genetic information will help breeders make better switchgrass and help biologists better understand how pathogen resistance can differ over an environmental gradient.

Population genetics of Japanese knotweed in North America

Japanese knotweed has a complex population structure in part because it reproduces asexually, but hybridizes with a similar species, Giant knotweed. To complicate matters, Japanese knotweed is octoploid, but Giant is tetraploid. Using Genotyping-by-Sequencing, we were able to show that North American populations of Japanese knotweed are not clonal, as some had assumed, but still have a low enough genetic diversity that it is surprising that they have been so successful.

Local adaptation 

Knotweed occupies a large niche, so we would expect to find local adaptation in disparate populations. However, reciprocal transplantation of individuals showed that individuals in the northern part of the range were equally fit in southern habitats and vice versa. Populations retain some trace of their home habitat, however, suggesting genetic or epigenetic differentiation.

This research has been published in Evolutionary Ecology

Herbicide tolerance

In the Adirondack mountains in New York, land managers have consistently sprayed populations of knotweed with glyphosate herbicide. We showed that stands within the park were not biochemically resistant to the herbicide, but were better able to re-grow following treatment than stands that had never been sprayed.