DISSERTATION RESEARCH: Ecological context shapes how consumers respond to predation risk

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Predators can strongly influence the structure and function of ecosystems through trophic cascades. Classically, trophic cascades emerge when predators eat intermediate consumers and thus have a positive, indirect effect on the base of the food chain. Recent work suggests, however, that the anti-predator behaviors of consumers can also drive trophic cascades. Consumers often reduce their foraging activity in order to minimize vulnerability to predators, but reduced foraging comes at the cost of reduced energy intake and growth. Hence, physiological (e.g., energy reserves, metabolic rate) and environmental conditions (e.g., resource availability, environmental stress) may influence how consumers balance these tradeoffs. For example, theory predicts that consumers may be more willing to accept increased predation risk while foraging when the risk of starvation is also high (i.e., low energy reserves or resources). The proposed laboratory and field experiments use a model food chain from the rocky shores of New England to examine consumer responses to predation risk. Despite considerable theory, more empirical research is necessary to better understand how ecological context shapes growth-predation risk tradeoffs in prey, which ultimately determine the strength of risk-driven trophic cascades and the impact of predators in ecological communities. Furthermore, because the stress of predation risk also affects how energy transfers up the food chain, insights from this work will improve scientific understanding of the importance of biodiversity, food web dynamics, and the use of predators in the management of natural ecosystems (e.g., Yellowstone National Park).Based at Northeastern University?s Marine Science Center (MSC), the PIs will engage students from diverse backgrounds in their research through summer internships and the many well-established K-12 outreach programs based at the MSC. Additionally, the proposed experiments will be integrated into their field-based Experimental Design in Marine Ecology course that is offered to undergraduate and graduate students at Northeastern.