His research and teaching interests center on environmental history, animal history, and the history of the environmental sciences. His articles have appeared in such publications as Environmental History, Environmental Humanities, Social Studies of Science, Osiris, the Journal of the History of Biology, and the Journal of American History. He is the author of Wired Wilderness: Technologies of Tracking and the Making of Modern Wildlife (Johns Hopkins, 2010) as well as the forthcoming book Surroundings: A History of Environmentalisms and Environmentalizations, which explores the diverse ways in which people have conceived of their surroundings in explicitly environmental terms since the late eighteenth century. He is currently researching the role of quantitative data and mathematical models in transforming the scientific study of the Earth’s surface in the twentieth century.