My research focuses on interactions between behaviour and consumer-resource dynamics. A mix of theoretical and empirical approaches is used to consider the dynamics of specific systems. Theoretical questions of interest include herbivore and carnivore movement in relation to resource availability and predation risk, optimal diet, patch selection, and dispersal patterns in heterogeneous environments, the effect of social interference and territoriality on consumer-resource interactions and impacts of harvesting by humans on fish and mammal populations.
Empirical work has been concentrated on 3 different terrestrial ecosystems over the past decade: large herbivores and their carnivores in Serengeti National Park (Tanzania), woodland caribou, wolves, and moose in boreal forests of northern Ontario (Canada), and both wild and semi-domesticated reindeer in Norway. In each case, my graduate students and I conduct detailed field and experimental studies of both behavioural and demographic responses to landscape heterogeneity. Theoretical models are used to understand the potential impact of behavioural strategies on population and community dynamics and these theoretical predictions are then tested against observational data.
As part of the Food from Thought research program, Kevin McCann, Andrew MacDougall and I lead a collaborative research team to evaluate the impact of agricultural practices on terrestrial and aquatic ecosystem services. One theme involves testing the sublethal impact of a suite of anthropogenic stressors (nutrient additions due to fertilizer run-off, pesticide application, and temperature increase due to global climate change) on phytoplankton and zooplankton populations in massive aquatic mesocosms in the Biodiversity Institute of Ontario. A second theme is focused on evaluating the effect of marginal land restoration (prairies, wetlands, and secondary forest) on arthropod and aquatic invertebrate biodiversity across 25 farms and 5 conservation areas on the north shore of Lake Erie, using DNA barcoding to discriminate among species.
An ongoing applied research interest relates to sustainable harvesting of fish and mammal populations. Key questions relate to long-term stability of harvested populations due to dynamic variation in harvester effort, effects of bioeconomic dynamics on long-term stability of fish stocks and prices, and spatial processes in harvested populations with and without no-harvest reserves