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

捕食者可以通过营养级联强烈影响生态系统的结构和功能。传统上，当捕食者吃掉中间消费者时，营养级联就会出现，从而对食物链的基础产生积极的、间接的影响。然而，最近的研究表明，消费者的反捕食者行为也可以推动营养级联。消费者经常减少觅食活动，以最大限度地减少对捕食者的脆弱性，但减少觅食是以减少能量摄入和生长为代价的。因此，生理(如能量储备、代谢率)和环境条件(如资源可获得性、环境压力)可能会影响消费者如何平衡这些权衡。例如，理论预测，当饥饿风险也很高(即能源储备或资源较低)时，消费者可能更愿意在觅食时接受更高的捕食风险。拟议的实验室和野外实验使用了来自新英格兰岩石海岸的一个食物链模型，以检查消费者对捕食风险的反应。尽管有相当多的理论，但有必要进行更多的实证研究，以更好地了解生态环境如何影响猎物的生长-捕食风险权衡，最终决定风险驱动的营养级联的强度以及捕食者对生态群落的影响。此外，由于捕食风险的压力也影响了能量在食物链上的转移，这项工作的见解将提高对生物多样性、食物网络动态以及捕食者在自然生态系统管理(例如黄石国家公园)中使用的重要性的科学理解。基于东北大学S海洋科学中心(MSC)，PI将通过暑期实习和MSC许多成熟的K-12推广项目吸引来自不同背景的学生参与他们的研究。此外，建议的实验将被整合到他们在东北大学为本科生和研究生提供的基于现场的海洋生态实验设计课程中。

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.