G. David Tilman is credited with scientifically establishing the value of biodiversity in Earth’s ecosystems. He was the first to quantify how it contributes to making ecosystems more productive and more resilient to invasions of exotic species and more stable in the face of distress.

Indeed, it was the distress brought on by a Minnesota drought in 1988 that helped lead him to the revelation that ecosystem health depends on biodiversity. After analyzing data from experiments set up in the early 1980s at the University of Minnesota’s Cedar Creek Ecosystem Science Reserve, Tilman found strong support for the hypothesis that more diversity equaled more stability. He then launched the first long-term field experiment to study biodiversity. 

Tilman’s theoretical models factored in the idea that each species specializes in a particular skill at the expense of other uses of its energy, prizing success in dispersal, for example, over competing for resources. This tradeoff held the key to his findings.

Described as “paradigm challenging,” Tilman’s paper on these findings was published in Nature in 1994 and continues to be one of the most cited papers in modern ecology.

After receiving the BBVA Foundation Frontiers of Knowledge Award in 2014, Tilman noted that he was surprised by the findings. “ . . . [U]ntil then, everyone thought that ecosystem functioning was controlled by  a few dominant species, and the rest didn’t matter. Ecosystems should be conserved, certainly, but for moral rather than scientific reasons. Our discovery that less diverse systems were also less stable sparked a major discussion.”

Tilman—director of the 5,400-acre Cedar Creek research station since 1992—has focused his work on how ecosystems are impacted by human-induced environmental changes, including the loss of biodiversity, nitrogen deposition, habitat destruction and climate change. Preserving the world’s biodiversity, slowing the rate of climate change, and meeting human needs for food and energy have been the goals of his research. He is the most cited ecologist in the world.

Born in Illinois in 1949, Tilman attended the University of Michigan, where he received a B.S. (1971) and a Ph.D. (1976) in zoology. He joined the faculty at the University of Minnesota in 1976, rising to professorship in 1984. Tilman is Regents Professor and McKnight Presidential Chair in Ecology at the U of M. He also holds an appointment as professor at the Bren School of Environmental Science and Management at the University of California, Santa Barbara, and is a member of the U.S. National Academy of Sciences and the American Academy of Arts and Sciences. He was awarded the International Prize for Biology in 2008, the Heineken Prize for Environmental Sciences in 2010, the Balzan Prize in Plant Ecology and the Margalef Prize in Ecology in 2014. Other awards include the Cooper and MacArthur awards from the Ecological Society of America, the Centennial Award from the Botanical Society of America, the Princeton Environmental Prize, the Alexander von Humboldt Medal, a Guggenheim Fellowship, and was named an Honorary Member or Fellow of both the British Ecological Society and Ecological Society of America.