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

杂食，被定义为在一个以上的营养水平上取食（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用性变化后的稳定。然而，在自然界中决定杂食的机制尚不清楚。本研究探讨了食物供应和种群密度的结合如何调节白足鼠（Peromyscus leucopus）的杂食性。我们预测，随着食物丰富程度的增加，白足鼠的饮食将变得更加专业化。然而，老鼠的种群密度也会增加，这可能导致以后食物供应减少。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。我们采用观察和实验的方法，基于对标记个体的同位素分析，来研究不同人群的饮食模式。在这里，我们提出了两个额外的项目：1)一个实验，同时增加两个营养水平的食物丰度，以区分总体和相对食物丰度如何影响杂食；2)对当地食物网的背景同位素信号进行调查，以提供高质量的杂食性估计。这项研究将有助于我们理解驱动杂食的机制，并有可能帮助我们预测当自然栖息地经历可用资源波动时杂食是增加还是减少。这项研究的广泛影响包括对研究生和本科生的培训，研究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.