Individual specialization and the trophic niche of aquatic consumers

动物从吃其他有机体中获得能量和营养，反过来，它们自己也可能成为其他消费者的食物。对这些摄食关系的研究称为营养生态学，而生态系统中的摄食关系网络称为食物网。一个物种在生态系统中的功能角色被称为它的生态位，并由它所使用的资源来定义，包括栖息地和食物。营养生态位是定义物种吃什么的生态位的一部分。生态系统中物种营养生态位的位置和大小，以及它们的丰富度，决定了生态系统的食物网络结构。这种结构影响能量和物质流动，以及我们最终可获得的食物的数量和质量。对营养生态位的研究有助于我们理解食物网络结构以及生态和进化过程。一个物种的营养生态位可以被认为是由所吃食物的类型和相对丰富度定义的一个空间。吃各种食物的物种据说占据了一个很大的营养生态位。种群由在不同方面彼此不同的个体组成，包括它们的营养生态。最近研究的一个有趣的发现是，许多物种表现出强烈的个体营养专门化。也就是说，尽管种群的营养生态位可能很大，但每个个体都倾向于将食物集中在较小的特定食物类型子集上。进化生态学家对这种现象非常感兴趣，因为它可能反映了最终导致物种形成的分化的早期阶段。我的研究项目使用个体专门化作为营养生态位大小的指数来研究水生生物的营养生态位。使用了各种技术来测量营养生态位。我的研究计划将主要使用生态示踪剂，特别是稳定同位素。这些是反映长期饮食模式的有机体化学成分的衡量标准。我将使用生态示踪数据和最近开发的数据分析方法来估计鱼类种群的营养生态位大小，并研究它们如何随着北方盾牌生态区湖泊和河流的环境条件而变化。我还将进行实验室实验，测试有关如何使用和解释生态示踪数据的关键假设。*这项研究将帮助我们了解环境如何影响动物种群的专门化和多样化过程，以及这如何影响可以共存的物种的数量和类型。它还将帮助我们了解淡水食物网是如何运作的，并可能被人类活动改变，这将改善我们对这些水生系统的管理。最后，我的实验室实验将使我们能够改进我们如何使用生态示踪剂，并将扩大它们在生态和环境研究中的应用。

Animals obtain their energy and nutrients from eating other organisms, and in turn, may themselves become food for other consumers. The study of these feeding relationships is called trophic ecology, and the network of feeding relationships in an ecosystem is called a food web. A species' functional role in an ecosystem is called its niche, and is defined by the resources it uses, both habitat and food. The trophic niche is that part of the niche defining what the species eats. Positions and dimensions of trophic niches of species in an ecosystem, as well their abundances, define the ecosystem food web structure. This structure affects energy and material flows, and the quantity and quality of foods ultimately available to us. Research on the trophic niche helps us to understand food web structure, as well as ecological and evolutionary processes.******The trophic niche of a species can be thought of as a space defined by the types and relative abundances of foods eaten. Species that eat a diversity of food types are said to occupy a large trophic niche. Populations are composed of individuals that differ from each other in various ways, including their trophic ecologies. A fascinating finding of recent research is that many species exhibit strong individual trophic specialization. That is, even though the trophic niche of the population may be large, individuals each tend to focus their feeding on a smaller, particular subset of food types. This phenomenon is very interesting to evolutionary ecologists because it may reflect the early stages of differentiation that eventually leads to speciation. My research program examines the trophic ecology of aquatic organisms using individual specialization as an index of trophic niche size.******A variety of techniques are used to measure the trophic niche. My research program will primarily use ecological tracers, in particular stable isotopes. These are measures of the chemical composition of an organism that reflect long-term dietary patterns. I will use ecological tracer data along with recently developed data analyses methods to estimate the trophic niche sizes of fish populations, and examine how they vary with respect to environmental conditions in lakes and rivers of the boreal shield ecoregion. I will also conduct laboratory experiments to test key assumptions about how ecological tracer data can be used and interpreted.******This research will help us to understand how the environment influences the specialization and diversification processes in animal populations, and how this influences the numbers and types of species that can co-exist. It will also help us understand how freshwater food webs function and may be altered by human activities, and this will improve our management of these aquatic systems. Finally, my laboratory experiments will allow us to refine how we use ecological tracers, and will broaden their application in ecological and environmental research.