G. David Tilman didn’t even read through the e-mail when he first received it.
“I only read the first sentence and thought, ‘Why do I care?’ It sat on my screen for three weeks,” said Tilman, a professor in the Department of Ecology, Evolution and Behavior.
Tilman finally read the message when he was deleting files. “I got to the last sentence, and it said, ‘You are the most-cited scientist of the last decade in your area.'”
Essential Scientific Indicators, an academic database company, had found Tilman had been cited in scientific journals more than any other environmental author from 1990 to 2000.
“I had no idea I’d be number one,” he said.
Tilman has published many articles in journals, ranging from Nature to American Naturalist, most pertaining to experimental ecology. He specializes in biodiversity, and much of his work revolves around the relationship between the diversity of species and the environments in which they live.
Tilman said he thinks the reason he has been cited so much is that his work has relevance not only to science but to policies in the real world.
“My work has two themes,” Tilman said. “One is trying to understand the basis for the incredible number of different species that exist and co-exist in the world. The other question is what effect do these species have on how the ecosystems of the world operate? This has become a very relevant question because of human threats to biological diversity.”
To explore these two themes, Tilman does something anyone sitting on their front porch can do — he watches the grass grow.
The grass in question grows 35 miles north of the University campus at the Cedar Creek Natural History Area. A team led by Tilman, consisting of biologists, chemists, entomologists and students, monitor different prairie grasses in various plots.
“If you were to come to Cedar Creek on a typical summer day, you would find about 90 people working there,” said Tilman.
Tilman and his peers have reconstructed grassland ecosystems at Cedar Creek with variations in the number and kind of species in each plot. They examine the effects that changes in biodiversity can have on the various ecosystems.
Tilman and his team have to meticulously inspect the plots in the experiment. “It takes an immense effort,” said Tilman. “We have about 500 plots total in our two biodiversity experiments. They occupy about 20 acres.”
The information gathered at Cedar Creek has been both startling and useful, Tilman said.
“There have been a lot of surprises,” Tilman said. “Just finding the highly significant effects of diversity on both how productive ecosystems were and how stable they were was not expected.”
Clarence Lehman, another professor in the Department of Ecology, Evolution and Behavior, has worked with Tilman at Cedar Creek. Lehman said part of the reason Tilman has been cited by other scientific authors so many times in the past decade is that he can combine theory and scientific evidence.
“Like very few people, he understands ecological theory and empirical ecology,” said Lehman. “Ecology progresses when we understand theory that is firmly embedded in the real world.”
Forest and Natural Resources professor Peter Riche, who has also worked with Tilman, credits Tilman for pushing the field forward with large-scale, ambitious experiments.
Riche attributes Tilman’s widespread citation to his “state-of-the-art” published works.
“He has had a number of important papers that have been provocative in the sense that he has tried to test big ideas and come to firm conclusions about those ideas,” Riche said.

Seth Woehrle welcomes comments at [email protected].