Collaborative Research: Adding animals to the equation: linking observational, experimental and modeling approaches to assess herbivore impacts on carbon cycling in northern Alaska

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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.