My research is hypothesis driven and often utilizes comparative research among marine (e.g., seagrass systems, salt marshes, algal communities), freshwater (e.g., wetlands, rivers, lakes), and terrestrial (e.g., old fields, forests) systems to generate robust conclusions about the ecological and evolutionary processes that govern community dynamics. This broad, multi-environment and taxon approach necessitates an interdisciplinary program combining field experimentation, behavioral analyses, natural products chemistry, phylogenetics, quantitative genetics, and synthetic statistical analyses. Below I summarize a few of the major themes of my research. Publications describing individual studies can be found here.
Herbivore control of plant community structure and exotic plant invasions
Large vertebrate herbivores often have strong impacts on plants, but in many parts of the world human activities have profoundly altered herbivore communities through habitat modification, hunting, removal of top predators, and introductions of non-native species. My research examines the impacts of these altered plant-herbivore dynamics on plant communities and particularly exotic plant invasions, with the long-term goal of understanding how anthropogenic modifications of biotic interactions ultimately influence the ecological goods and services provided by natural communities.
One particularly exciting finding has been that the replacement of native with exotic herbivores can facilitate exotic plant invasions and ecosystem re-organization, focusing attention on the long-term implications of altered plant-herbivore dynamics.
The ecology and evolution of chemically-mediated consumer-prey interactions
To bridge the gap between plants and herbivores, I use behavioral analyses and natural products chemistry to understand how plant traits, particularly defense-related traits, influence herbivore feeding preferences and ultimately plant evolution. Recently initiated work employs phylogenetics to examine macroevolutionary trends in plant defenses, and quantitative genetics to examine the potential for diffuse selection by different guilds of herbivores on anti-herbivore defenses.
The ecological and evolutionary consequences of altered diversity
The consequences of altered species and genetic diversity can have dramatic impacts on population, community, and ecosystem-level attributes, but the mechanisms are often unclear. My research addresses this gap by asking to what extent do species and genotypes perform complementary functions in ecosystems, such that diversity buffers ecosystems against disturbance, and how often do positive interactions among species lead to ecosystem transformation.