Science Story – February 2019


Digging deep to reveal climate change.

We know that global warming is shifting species’ habitats and changing how organisms coexist. In fact, there has been substantial research done on the interactions between plants and their pollinators and herbivores under climate change. But what about the relationships between plants and soil microbes or between those microbes and each other? How are they affected by climate change? Therein lies a gap. And where there’s a gap, there’s usually a curious scientist who says, “Let’s study that.” At RMBL, that scientist is Aimée Classen, Ph.D.

Dr. Classen and her colleagues (including RMBL PI Nate Sanders) haves designed an experimental study that will simultaneously observe the responses of ecosystems to both the direct and indirect effects of warming. The experiment works by manipulating temperature and species interactions to understand, among other things, the factors that have the strongest control on carbon dynamics and the structure of communities above and below ground. It is the first global-scale experiment of its kind. And it will help us predict how climate change will alter biodiversity and how it will affect the amount of carbon taken up and released from terrestrial ecosystems. This information is critical, because the amount of carbon in the atmosphere regulates how much warming will occur.

She and her colleagues think that this area of study—how plants interact with soil microorganisms and how microbes interact with one another under warming conditions—is a missing link in much of global change ecology research. This gap is significant because soil stores most of the Earth’s terrestrial carbon. Furthermore, one of the biggest challenges ecosystem ecologists face is being able to predict how ecosystems will function in response to a warming climate. Needless to say, soil is a big player in ecosystems. Soil microbes provide plants with nutrients and can shape the patterns of plant and animal abundance. How will the composition of plant communities respond to global warming? How will soil microbial activity influence carbon feedbacks among plants, soil, and the atmosphere? These are some of the questions scientists have asked. The answers may lie beneath our feet.

The study is a coordinated project that combines experimental warming and dominant plant species removal among 10 globally distributed elevational gradients. The mountainous sites are in Sweden, Switzerland, Greenland, Canada, France, China, New Zealand, Australia, Patagonia, and of course RMBL. Mountain sites are ideal because global warming will have a greater impact on montane ecosystems due to their high levels of biodiversity and larger amounts of carbon storage.

Dr. Classen’s experimental study will be a long-term project that asks novel—and important—questions. It will increase our understanding of how ecosystems will function in the future. And it will help inform policymakers as they prepare for the changes to come. It’s the kind of research that exemplifies the unique advantages RMBL brings to science, and humanity.

Aimée Classen is a Professor at the University of Vermont in the Rubenstein School of Environmental and Natural Resources and a Gund Fellow at the Gund Institute for Environment. She has had an active research program at RMBL since 2009. She is an experimental ecosystem ecologist focusing on how global change shapes ecosystems, with an emphasis on exploring the interactions between plants, nutrients, water, and microbes in the soil.

Aimée Classen | Ph.D.