In 1988, H. Ronald Pulliam, at that time director of the University of Georgia Institute (now the Odum School) of Ecology, published “Sources, sinks, and population regulation” in the journal American Naturalist. Just ten pages long, the paper presented a simple but powerful model describing how populations can persist or sustain across heterogeneous landscapes through interactions in poor habitats (“sinks”) and good habitats (“sources”). Over twenty years later, the paper is still influencing the work of scientists. A new book edited by Pulliam’s former student Jianguo Liu looks at the paper’s profound, and still growing, impacts on the field of ecology and beyond.
Sources, Sinks and Sustainability, published by Cambridge University Press, contains essays from more than 50 leading researchers from around the world who have been influenced by Pulliam’s work. To ensure the highest quality possible, more than 70 experts worldwide reviewed the manuscripts for the 525-page book.
The book grew out of a successful symposium organized by Liu on the occasion of Pulliam’s retirement from UGA. Held at the 2008 annual meeting of the U.S. Regional Association of the International Association of Landscape Ecology, the symposium featured speakers, including a number of Pulliam’s former students and postdoctoral associates, presenting papers on research and applied science inspired by Pulliam’s 1988 paper.
“When I learned that Ron was going to retire, I wanted to do something to honor the occasion and his contributions to ecology and other areas,” said Liu, Rachel Carson Chair in Sustainability, University Distinguished Professor, and Director of the Center for Systems Integration and Sustainability at Michigan State University. Liu received his Ph.D. from UGA in 1992.
At the time of his retirement, Pulliam was Regents Professor in Ecology. Among many other accomplishments, he is a past president of the Ecological Society of America, former director of the National Biological Service, and was Science Adviser to the Secretary of the Interior from 1996 to 1997. He has more than 70 publications, including papers, articles, and books, to his credit.
Finding it impossible to highlight Pulliam’s entire distinguished career, Liu chose to focus on the classic paper “Sources, sinks, and population regulation.” “That paper was published the year I started at the Institute,” he said. “It was and still is very influential, widely cited in peer-reviewed literature across many disciplines for two decades.” Cited over 1,600 times in journals and in more than 300 books, Liu said that the paper has had an influence far beyond the field of ecology. Researchers in disciplines as diverse as microbiology, economics, public health, law, and international relations have found Pulliam’s source-sink model relevant to their work.
Liu said the paper has also had an impact on natural resource management and conservation efforts, including informing decisions about the management of protected areas, resource consumption, and invasive species. It has been applied to a wide variety of problems, including climate change, the impacts of the Chernobyl disaster on bird populations, and declining toad populations.
“The book presents progress made in understanding source-sink dynamics over the last two decades,” Liu said. “It covers all major aspects from theory to methods to applications.”
In keeping with the breadth of the 1988 paper’s influence, Liu said that the book is designed to be useful to researchers and students in many disciplines, as well as natural resource managers and policy makers. “The hope is that this book can contribute to our understanding of source–sink dynamics and to improving management and conservation to achieve sustainability of our human-dominated, and increasingly fragile, ecosystems,” he said.
Two of Liu’s graduate students, Vanessa Hull and Anita Morzillo, and distinguished conservation scientist John Wiens, chief conservation science officer at PROB Conservation Science and former chief scientist at The Nature Conservancy, were co-organizers of the symposium and co-editors of the book. Pulliam, with coauthors John Drake, associate professor at the Odum School, and Juliet Pulliam, assistant professor of biology at the University of Florida, contributed a chapter to the book’s section on progress in source–sink methodology.