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A Biodiversity Bellweather

Research at Cedar Creek Ecosystem Science Reserve offers a picture of the planet’s future and a unique opportunity to shape it.

Cedar Bog Lake

In late December 1936, someone taking a walk in the countryside near the Township of Bethel, now East Bethel, who happened past Cedar Bog Lake might have come across a studious young man gathering samples and taking notes. Raymond Lindeman, then just beginning graduate studies at the University of Minnesota, conducted fieldwork at the site in the waning days of that year. His observations would provide the underpinnings for his thesis on how energy moves through aquatic ecosystems. Those insights would ultimately drive a profound conceptual shift in thinking that marks the beginning of the modern field of ecosystem science. 

Lindeman was among the first scientists to do research at Cedar Lake Bog in what would become part of Cedar Creek Forest and, eventually, Cedar Creek Ecosystem Science Reserve. In the years since, his successors have continued to take inspiration from his work and build on his legacy. Scientists from all over the world make their way to the field station or draw on the wealth of data available online. Some sink permanent research roots in the research station’s intellectually fertile soil. 

Cedar Creek occupies a singular place in the field of ecology due to its storied past and the many scientific breakthroughs associated with the station, starting with Lindeman’s seminal discovery. But its greatest contribution may be in illuminating our future. 

Ecological time machines 

“We’re trying to give society an early warning about where we are going and what our actions imply,” says Regents Professor and Cedar Creek Director David Tilman. “Cedar Creek has done some of the leading-edge research in ecology,” he says, noting major discoveries relating to how ecosystems function, the effects of nitrogen deposition, and the importance of biodiversity and fire frequency. 

These novel insights were made possible because of the long-running experiments at Cedar Creek, which Tilman describes as “time machines” that allow scientists to explore the future impacts of our actions. By adjusting variables such as CO₂, rainfall and temperature in experimental plots and observing the effects over long periods of time, Cedar Creek scientists can anticipate the environmental impact of human activity decades from now. 

“Long-term experiments sometimes reveal surprises over time — results that were unanticipated when the experiment was established, and that take years to reveal themselves,” notes Sarah Hobbie, co-director of Long-Term Ecological Research at Cedar Creek and a professor in the Department of Ecology, Evolution and Behavior. 

“We’re creating novel conditions for which there is no historical analogue through these unique multifactor experiments,” says Eric Seabloom, a professor in the Department of Ecology, Evolution and Behavior and co-director of Long-Term Ecological Research with Hobbie. “It’s like creating a bunch of different future earth scenarios.” 

Since the National Science Foundation began funding long-term research at Cedar Creek in 1982, the station has established more than 1,100 permanent, long-term experimental plots. The 

experiments continue to evolve. Case in point, the Big Biodiversity experiment, or BigBio for short. The experiment, which turned 25 last year, played a key role in advancing understanding of the role of plant diversity in ecosystem functioning. Tilman published those findings in a series of papers from 1997 to 2006, and since then he and other researchers have continued to ask new questions that shed light on human impact on the environment. For instance, researchers superimposed warming treatments and drought treatments on many of the plots in BigBio. 

Taking the long view

As new experiments are added, a more complete understanding of how people alter and depend on nature emerges. A new study will consider what happens upstream of the lessons learned in BigBio by considering the most important driver of biodiversity loss: habitat loss and fragmentation. 

The experiment — Rescuing Ecosystems and Species Currently Undergoing Extinction, or RESCUE — is designed to uncover how human-caused habitat destruction leads to extinctions in the island-like fragments of habitat that remain. It will test whether frequent, diverse seed inputs can help rescue the species that would otherwise go extinct thereby maintaining the benefits that these species provide for ecosystems and people. 

“We expect in these small islands of habitat that, without these inputs, we will lose species and some of the benefits that those species provide for people,” says principal investigator Forest Isbell, an associate professor in the Department of Ecology, Evolution and Behavior and associate director of Cedar Creek.

Isbell notes that the baseline knowledge established from BigBio is integral to anticipating what will happen in this new experiment. Scientists expect experimental habitat loss to drive biodiversity loss, and they will use the information from BigBio to anticipate how this biodiversity loss will alter ecosystem function and stability. 

Ultimately, Isbell and colleagues want to understand how to reduce the undesirable impacts of habitat fragmentation on biodiversity, ecosystems and nature’s benefits to people. 

“Because we have the biodiversity experiments, we are able to integrate these cascading effects from habitat loss to biodiversity to ecosystems to people better than we would have before we conducted the biodiversity experiments,” he says.

Here, there and everywhere

The station’s long-running experiments represent valuable research infrastructure akin to a radio telescope or a particle accelerator, says Seabloom. “The fact that this platform exists makes it possible to ask entirely new questions that the researchers who set up the experiments never anticipated.”

In an effort to apply lessons learned at Cedar Creek more broadly, Seabloom and others are working to test whether the results observed in the experiments can be generalized to other locations around the world. He notes the robust feedback between prediction, experimentation and observation that sets the station apart and has positioned it as an ecological research powerhouse.

Seabloom and Elizabeth Borer, a professor in the Department of Ecology, Evolution and Behavior, are co-founders of the Nutrient Network, which tests some of the predictions and results from Cedar Creek at 140 sites in 25 countries.

“One of the first long-term research experiments at Cedar Creek showed when you add nutrients plants grow larger, but interestingly some species start going extinct,” says Seabloom. “Now we can say that at many sites around the world you get the same effect.” He notes that testing findings 

from Cedar Creek experiments in other systems is a critical step toward understanding when and where results are relevant.

A question of scale

“In order to actually manage biodiversity globally and achieve sustainable development goals you have to be able to monitor and evaluate how biodiversity is changing in real time,” says Jeannine Cavender-Bares, a professor in the Department of Ecology Evolution and Behavior and director of the new National Science Foundation–funded Biology Integration Institute. 

Cavender-Bares and colleagues are developing a new remote-sensing technique called spectral biology to detect changes in plant biodiversity across biological scales with an eye to better understand how changes at one scale give rise to emergent properties at higher scales. 

“We’re trying to figure out how to interpret spectral signatures to know how biodiversity is changing,” says Cavender-Bares, who piloted the idea at Cedar Creek in recent years. 

Isbell notes that this new approach supports the broader goal of measuring how generalizable the findings from Cedar Creek experiments are by linking up small-scale, on-the-ground measurement to global satellite data.

“We do really feel this is a way to revolutionize biology,” says Cavender-Bares. “We can now get so much information about biodiversity rapidly at any scale. This has never been possible before.”

Cross-pollination and collaboration

Access to decades of data providing a baseline difficult to establish from scratch is a major draw for scientists and students alike. But that only partly explains the prolific output associated with the station. Researchers are also drawn to Cedar Creek for the opportunities for collaboration and camaraderie it provides.

“You can see the value of intellectual diversity and diversity of minds at work here at Cedar Creek,” says Tilman, who prioritized collaboration from the very start of his tenure as director more than two 

decades ago. “Most people, if you ask them what they are doing at Cedar Creek, won’t be able to resist also saying, ‘I’m having fun.’” 

For investigators with ties to the station, the cross-pollination can lead in unexpected directions. “You end up doing projects and experiments you wouldn’t have otherwise,” says Seabloom. “Projects are more complex because of that collaboration across subdisciplines. Everybody gets a deeper view of the world.” 

A community of the curious 

Researchers aren’t the only visitors to the station. In recent years, community members have made their way to the station in increasing numbers to participate in nature hikes and other programs. At the same time, busloads of school-age children pull up in front of the Lindeman Research and Discovery Center throughout fall, summer, spring and even winter. They venture to Cedar Bog Lake and other spots around the station to learn about the natural world. Tilman describes the school-age visitors to the station as “natural born scientists,” brimming with curiosity and inquisitiveness about the natural world. 

“Cedar Creek is a phenomenal place for education and community engagement because you can get up close and personal with science,” says Caitlin Barale Potter, the station’s engagement coordinator. “There are not many other places where you can walk around world-famous long-term research experiments and learn directly from the scientists who run them.” 

There were more than 10 times as many K–12 students and other visitors last year than a decade earlier. “We’ve seen an incredible growth in engagement,” says Potter. “Thanks to investment in staff, infrastructure and partnerships, our reach has increased by an order of magnitude!” 

Cedar Creek is making moves to build on that momentum. The station recently hosted the first meeting of the Cedar Creek Community Engagement Advisory Committee, a group of supporters with deep affinity for Cedar Creek and an interest in expanding access to it to develop forward-looking strategies for building on the success of the station’s engagement efforts to date. 

“Our growth over the last decade has shown that if we listen to what our community wants and find ways to build it, our community will come — and will bring their friends and family, share their love for the reserve widely, and continue to support us,” says Potter.

—STEPHANIE XENOS 

Posted 
November, 2020