Two decades ago, over the summer before he started working as a grad student investigating the effect of limiting nutrients on plant species under Regents Professor David Tilman, Stan Harpole spent a summer at the Cedar Creek Ecosystem Science Reserve learning the ins and outs of quantifying changes in experimental grassland plots over time.
“Dave said, why not work at Cedar Creek the summer before you start grad school — even though he knew I was going to do my Ph.D. work in California,” Harpole recalls. “I was put in charge of E-111, the monoculture gardens, collecting data on production of seeds. … What was really exciting about that was that it helped inform my later experiments in California and also led to my first publication.”
Eventually Harpole took the experience gained and the connections made at Cedar Creek to Germany, where they continue to influence work in his current position as a professor at the Helmholtz Centre for Environmental Research in Leipzig. As part of the Cedar Creek–based Nutrient Network, which coordinates environmental change experiments at close to 100 sites around the world, he collaborates with CBS scientists to further improve understanding of how nitrogen and other plant nutrients altered by humans in turn alter fundamental workings of grassland ecosystems. In fact, the Minnesota ecosystem reserve served as model when he set up his own experimental plots half a world away.
“It’s a classic system,” Harpole says. “It will always be a part of what I do.”
The Nutrient Network is just one example of how research at Cedar Creek is producing predictions about how ecosystems work that apply — and guide strategies for minimizing adverse impacts of human influence — around the world. And Harpole himself is one of numerous former graduate students and postdoctoral fellows who are using their experiences at Cedar Creek as a launch pad for work that is expanding understanding of ecological theory and environmental practice from Canada to New Zealand and beyond.
“The long-term work at Cedar Creek has produced many globally relevant predictions,” says Eric Seabloom, CBS associate professor and a co-founder of the Nutrient Network. For example, in one long-running study, Cedar Creek researchers have shown how reducing plant species numbers can make ecosystems more susceptible to disease while decreasing productivity, stability and resistance to invasion. And another experiment that has been underway for two decades is yielding valuable information on how multiple human-caused changes interact to influence ecosystem function.
Even as those research projects inform our understanding of how human disruptions affect natural systems around the world, the grad students and postdocs who worked on them have gone on to have their own global impact as well. Cedar Creek “alumni” are helping carry out Nutrient Network research at sites around the United States as well as in the Netherlands, South Africa and beyond. Others trained in ecosystem science research at Cedar Creek have gone on to apply the knowledge and skills learned here to work in Australia, the United Kingdom, New Zealand, the Netherlands, Sweden, Canada, France and more.
“Cedar Creek is sort of like this point of gravity,” Harpole says. “We keep moving around it.”
— Mary Hoff