"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日益重视，了解构成生态系统的基本机制变得非常重要，以便能够制定有效的管理和养护计划。这一点在五大湖尤其重要，入侵物种、营养物质、气候变化和栖息地破坏已经损害了这个拥有世界20%淡水和养活超过40%加拿大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往往是非常困难的，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和声学遥测相结合的方法，量化温度、猎物密度和顶级捕食者对半控制池塘系统和安大略湖海湾鱼类运动和营养关系的影响。我们试图探索假设，并量化关系，即食物网络结构和群落动态受到与捕食者和猎物密度在一定温度范围内的直接(消费)和间接(行为变化)相互作用的影响。将在该项目中使用的化学示踪剂，特别是稳定同位素和脂肪酸，已成为生态学研究的广泛应用工具。不幸的是，决定这些示踪剂动态的潜在机制还知之甚少。通过使用不同组织、体型和温度的受控实验室研究，我们将量化稳定同位素和脂肪酸在鱼类中的周转率。这些实验室实验的结果将应用于池塘和湖泊的研究，并将提高我们将这些示踪剂应用于生态问题的能力。我的研究直接解决了五大湖生态系统健康的紧迫问题，以及化学示踪剂和声波遥测的应用，但也有助于我们对生态系统和食物网如何运作的基本理解。

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.