RESEARCH
My research focuses on communities of biological organisms and food webs, which determine the flows of energy through ecosystems. These energy flows determine the abundances and dynamics of organisms in communities. In turn these abundances and dynamics determine several of the services we receive from ecosystems such as food, nutrient cycling, and the control of climate and diseases. I hope that my research on food webs and species interactions can help us to understand how these systems function and how we can conserve and protect them.
Individual Foraging Behavior and Intraspecific Variation.
All species interactions happen at the level of the individual. Thus, for ecologists to understand the influence of species interactions at the community level, we must have knowledge of what determines the interactions among species at the individual level and how we can scale that knowledge to the level of interactions among populations. The bulk of my dissertation research centers on the exploration of individual foraging behavior, how individual behavior can lead to intraspecific variation in diet preferences, and the consequences of this individual variation for community dynamics. To investigate these relationships I use statistical models, mathematical models, and lab and field experiments. My empirical research is based in the rocky intertidal of Oregon examining the dog whelk, Nucella ostrina, as a model generalist predator feeding on its invertebrate prey: primarily the mussel, Mytilus trossulus, and the acorn barnacle, Balanus glandula.
Foraging Behavior and Food Web Stability.
Since the beginning of the field of ecology, researchers have searched for the mechanisms that underlie the stability of communities and food webs. Despite this rich history of study and a vast theoretical literature on stability in ecological systems, empirical investigations of the mechanisms that lead to stability are rare and manipulative experiments testing these mechanisms are even more scarce.
A promising mechanism for stability in food webs is adaptive (or flexible) foraging by predators. Adaptive foraging occurs when predators shift their prey preferences to respond to changes in prey densities. This allows the strength of the links between species to respond to fluctuations in predator-prey dynamics which can stabilize food webs.
To test adaptive foraging's role in the stability of communities, I use field experiments that manipulate the preferences of predators and then follow the consequent prey dynamics.
A promising mechanism for stability in food webs is adaptive (or flexible) foraging by predators. Adaptive foraging occurs when predators shift their prey preferences to respond to changes in prey densities. This allows the strength of the links between species to respond to fluctuations in predator-prey dynamics which can stabilize food webs.
To test adaptive foraging's role in the stability of communities, I use field experiments that manipulate the preferences of predators and then follow the consequent prey dynamics.
Predator Numerical Responses.
Predators respond to the density of their prey in two fundamental ways: 1) behaviorally through what is called the functional response and 2) through reproduction known as the numerical response. The functional response determines the number of prey that are eaten by each predator given the density of prey available. The numerical response then determines the number of new predators produced given the number of prey eaten by each predator. The functional response and its influence on predator-prey interactions has received extensive study, however the numerical response has been largely neglected and little is known about its influence on predator-prey dynamics and communities.
In a collaborative effort with my lab mate Leah Segui, we are investigating how assumptions about the nature of numerical responses (shape, causal mechanisms, etc.) influences predator-prey dynamics and the stability of predator-prey interactions. We are doing this using a comprehensive literature review on numerical responses and applying differential equations to explore the consequences of numerical response assumptions.
In a collaborative effort with my lab mate Leah Segui, we are investigating how assumptions about the nature of numerical responses (shape, causal mechanisms, etc.) influences predator-prey dynamics and the stability of predator-prey interactions. We are doing this using a comprehensive literature review on numerical responses and applying differential equations to explore the consequences of numerical response assumptions.
