"Quantifying trophic relationships, habitat use and fish movements in freshwater ecosystems"

动物的运动和营养相互作用是构成食物网和生态系统的关键变量。随着对水生生态系统的压力越来越大，了解构成生态系统的基本机制变得非常重要，以便制定有效的管理和保护计划。这一点在五大湖尤其重要，在那里，入侵物种、营养物质、气候变化和生境破坏损害了一个拥有世界20%淡水并支持加拿大40%以上人口的系统的功能和健康。量化营养相互作用和栖息地利用通常非常困难，特别是在难以观察的水生系统中。我的研究将使用化学示踪剂和声学遥测相结合，以量化温度，猎物密度和顶级捕食者对鱼类运动和营养关系的影响，在半控制池塘系统和安大略的海湾。 我们试图探索的假设，并量化的关系，即食物网结构和社区动态的直接（消费）和间接（行为变化）的相互作用与捕食者和猎物密度在一个温度范围内的影响。本计画所使用的化学示踪剂，特别是稳定同位素和脂肪酸，已成为广泛应用于生态研究的工具。不幸的是，决定这些示踪剂的动力学的基本机制知之甚少。通过使用不同组织、体型和温度的受控实验室研究，我们将量化鱼类中稳定同位素和脂肪酸的周转率。这些实验室实验的结果将应用于池塘和湖泊的研究，并将提高我们的能力，将这些示踪剂应用于生态问题。我的研究直接解决了五大湖生态系统健康和化学示踪剂和声学遥测应用的紧迫问题，但也有助于我们对生态系统和食物网功能的基本理解。

The movement and trophic interaction of animals are key variables that structure food webs and ecosystems. With increasing stress being placed on aquatic ecosystems, it has become very important to understand the underlying mechanisms that structure ecosystems so that effective management and conservation plans can be developed. This is of particular relevance in the Great Lakes, where invasive species, nutrients, climate change and habitat destruction have compromised the function and health of a system that holds 20% of the world's freshwater and supports more than 40% of Canadian's population. Quantifying trophic interactions and habitat use are often very difficult, particularly in aquatic systems that are hard to observe. My research will use a combination of chemical tracers and acoustic telemetry to quantify the influence of temperature, prey density and top predators on fish movement and trophic relationships in a semi-controlled pond system and in bays of Lake Ontario. We seek to explore the hypotheses, and quantify relationships, that food web structure and community dynamics are influenced by direct (consumption) and indirect (behavior changes) interactions with predators and prey density across a range of temperatures. The chemical tracers that will be employed in this project, particularly stable isotopes and fatty acids, have become widely applied tools for ecological studies. Unfortunately, the underlying mechanisms that determine the dynamics of these tracers are poorly understood. Through controlled-laboratory studies using different tissues, body sizes and temperatures, we will quantify the turnover rates of stable isotopes and fatty acids in fish. The results of these lab experiments will be applied to pond and lake studies and will improve our ability to apply these tracers to ecological questions. My research directly addresses pressing issues for Great Lakes ecosystem health and the application of chemical tracers and acoustic telemetry, but also contributes to our fundamental understanding of how ecosystems and food webs function.