Collaborative Research: Adding animals to the equation: assessing herbivore impacts on carbon cycling in northern Alaska

小型哺乳动物以北极苔原上的植被为食。虽然这种放牧可能影响冻土带生态系统的许多方面，但目前的模型不包括小型哺乳动物的放牧。在这个项目中，田鼠和旅鼠的丰度将在实验中使用围栏来改变。研究人员将观察这些地块的响应，特别是关注碳和氮循环的变化。为了了解当前的气候如何控制小型哺乳动物放牧的重要性，研究人员将在阿拉斯加的三个地点进行研究，分别位于苏厄德半岛、布鲁克斯山脉的山麓和北极沿海平原。将在这些地点研究田鼠和旅鼠的自然丰度，为在整个北极地区应用实验结果提供背景。研究结果将用于扩展苔原生态系统的数学模型，将小型哺乳动物的放牧纳入其中，这将改善对北极未来可能发生变化的预测。这项研究将涉及许多本科生，研究者将把他们的研究融入课堂和其他教育项目中。此外，他们还将在AK州巴罗市主持一个广播节目。研究人员将调查小型哺乳动物食草在控制快速变化的北极苔原中碳和养分循环中的重要性。通过沿纬度梯度的三个地点的研究，研究人员将采用观察和实验相结合的方法来量化啮齿动物（田鼠和旅鼠）放牧在冻土带生态系统功能中的作用。对啮齿动物种群动态和生态系统功能的观察将为理解北极冻土带对全球气候的反馈提供关键的新信息。通过封闭和围护来控制啮齿动物密度将显示啮齿动物种群的潜在变化如何影响苔原生态系统的反应。将观测和实验结果结合到定量生态系统模式中，将加强对未来变化和气候反馈的预测。

Small mammals graze on the vegetation of the Arctic tundra. Although this grazing may influence many aspects of tundra ecosystems, current models do not include grazing by small mammals. In this project, the abundance of voles and lemmings will be varied experimentally using fenced plots. The investigators will observe the responses in the plots, especially focusing on changes in the cycling of carbon and nitrogen. To understand how the current climate controls the importance of grazing by small mammals, the investigators will conduct their studies at three sites in Alaska located in the Seward Peninsula, the foothills of the Brooks Range, and on the Arctic coastal plain. The natural abundance of voles and lemmings will be studied at these sites to provide background for applying the experimental results throughout the Arctic. The results will be used to expand a mathematical model of tundra ecosystems to include grazing by small mammals, which will improve the predictions that can be made about how the Arctic may change in the future. The research will involve a number of undergraduate students and investigators will integrate their research into classes and other educational programs. In addition, they will present a radio program in Barrow, AK. The investigators will investigate the importance of herbivory by small mammals in controlling the cycling of carbon and nutrients in the rapidly changing Arctic tundra. Through studies at three sites along a latitudinal gradient, the investigators will employ both observations and experiments to quantify the role of grazing by rodents (voles and lemmings) in the functioning of tundra ecosystems. The observations of rodent population dynamics along with ecosystem function will provide key new information relevant to understanding the feedbacks of the Arctic tundra to the global climate. The manipulation of rodent density through exclosures and enclosures will show how potential changes in rodent populations may influence the tundra ecosystem response. In corporation of the observational and experimental results into a quantitative ecosystem model will enhance predictions of future changes and feedbacks with climate.