Dissertation Research: Defining Spatial Scales of Energy Flow through River Food Webs using Stable Carbon and Nitrogen Isotopes

99-01983 Power/FinlayDDIG：使用稳定的碳和氮同位素定义通过河流食物网的能量流动的空间尺度陆地生态系统、源头溪流和下游河流之间的热带联系是热带生态系统的一个基本特征，但在特定地点调节食物网交换的过程的规模仍然不明确。理解河流食物网的努力有两种普遍的方法。第一种方法分析了从源头到大河的纵向梯度上碳源和生态系统功能的变化。一种不同的方法侧重于使用小得多的空间尺度上的实验方法来理解群落结构和功能的控制。该项目将审查碳和氮等生物活性元素的稳定同位素比率，通过在中等尺度上提供有关河流食物网过程的信息，将这些方法联系起来。这项研究对于理解空间尺度对于河流中移动的顶级捕食者(即鱼类)至关重要，并可能有助于指导河流管理。这项研究还将帮助生态学家在未来的河流食物网络研究中确定适当的调查规模。

99-01983Power/FinlayDDIG: Defining spatial scales of energy flow through river food webs using stable carbon and nitrogen isotopesTrophic linkages between terrestrial ecosystems, headwater streams, and downstream rivers are a fundamental feature of lotic ecosystems, but the scale of the processes that mediate food web exchange at a given site remain poorly defined. Two general approaches have characterized efforts to understand river food webs. The first approach analyzed changes in carbon sources and ecosystem function along longitudinal gradients from headwaters to large rivers. A contrasting approach has focused on understanding controls of community structure and function using experimental methods on a much smaller spatial scale. This project will examine stable isotope ratios of biologically active elements such as carbon and nitrogen to link these approaches by providing information about river food web processes at intermediate scales. This research is critical to understanding the spatial scales that are important to mobile top predators in rivers (i.e. fish), and could help guide management of rivers. The research will also help ecologists determine the appropriate scale of investigation in future river food web studies.