DISSERTATION RESEARCH: The Ecology of Omnivory in Peromyscus Leucopus(Rodentia: Muridae)

杂食性，被定义为以一个以上的营养水平为食(例如，包括动物和植物的饮食)，被认为有助于自然群落在自然和人为干扰或资源可获得性变化后的稳定。然而，自然界中决定杂食性的机制还没有被很好地理解。这项研究考察了食物可获得性和种群密度的组合如何调节白足小鼠(Permyscus Leucopus)的杂食性。我们预测，随着食物丰富度的增加，白脚小鼠的饮食将变得更加专业。然而，老鼠的种群密度也会增加，这可能会导致以后食物供应的减少。随着食物供应的减少，我们预测老鼠的饮食将变得更加普遍。我们使用了基于标记个体的同位素分析的观察和实验方法，来检查不同人群的饮食模式。在这里，提出了另外两个项目：1)在两个营养水平同时增加食物丰度的实验，以区分整体和相对食物丰度如何影响杂食性；2)对当地食物网中的背景同位素信号进行调查，以提供对杂食性的高质量估计。这项研究将有助于我们理解杂食性动物的驱动机制，并有可能帮助我们预测当自然栖息地经历可用资源的波动时，杂食性动物是增加还是减少。这项研究的更广泛的影响包括对研究生和本科生的培训，结果被纳入当地教育计划的潜力，以及在科学研究中促进跨学科方法。

Omnivory, defined as feeding on more than one trophic level (e.g., a diet that includes both animals and plants), is suggested to contribute to the stability of natural communities following natural and man-made disturbances or changes in resource availability. However, the mechanisms determining omnivory in nature are not well-understood. This research examines how the combination of food availability and population density may regulate omnivory in the white-footed mouse (Peromyscus leucopus). We predict that as food abundance increases, the white-footed mouse will become more specialized in its diet. However, population density of the mice will increase as well, which may result in decreased food availability at a later time. As food availability decreases, we predict that the mice will become more generalized in its diet. We have used observational and experimental approaches, based on isotopic analysis of marked individuals, to examine dietary patterns among different populations. Here, two additional projects are proposed: 1) an experiment that simultaneously increases food abundance at two trophic levels to distinguish between how overall and relative food abundance affects omnivory; 2) a survey on background isotopic signals in local food webs to provide high-quality estimates of omnivory. This research will contribute to our understanding of mechanisms driving omnivory, with the potential to help us predict whether omnivory will increase or decrease when natural habitats experience fluctuations in available resources. The broader impacts of this research include the training of graduate and undergraduate students, the potential of the results to be incorporated in local educational programs, and the stimulation of interdisciplinary approaches in scientific studies.