LTER: Advancing understanding of long-term feedbacks between plant biodiversity and the functioning of ecosystems in a changing environment

This project uses long-term data and experiments to predict how ecosystems will respond to environmental change. This includes changes to the chemical makeup of the atmosphere and soils, the frequency of events like fire and drought, the rate at which species go extinct, and the spread of weeds, pests, and pathogens. Many of these changes directly affect ecosystems and their ability to provide important services on which humans depend. The effects of environmental change occur over many decades and may vary through time. Predicting the effect of these changes depends on long-term experiments. Long-term feedbacks between organisms and the environment can make these changes stronger, weaker, or even reverse them. For example, soils under retired farmlands keep getting more fertile and store more atmospheric carbon for decades, but how fast this happens depends on the diversity of plant species in the area. Researchers at the Cedar Creek Long-Term Ecological Research Program (CDR) will collect long-term data in retired agricultural lands, prairies, savannas, and forests. These data will be combined with mathematical models to better understand how ecosystems respond to many environmental changes happening at the same time. CDR’s education and outreach team along with the Cedar Creek field station staff will continue to work with community partners to recruit, train, and support a STEM workforce. The project will create opportunities for K-12 students, undergraduate and graduate students, educators, policy makers, and the public. These opportunities include school field trips, a high school internship program, and onsite apprenticeships that provide training in science education. Researchers at CDR LTER will use long-term observations and experiments, theory, and models to achieve a mechanistic and predictive understanding of the role of plant biodiversity change, including lags and feedbacks, in determining ecosystem responses to a changing environment. This understanding will be achieved by leveraging CDR’s long-term research platforms that, taken together, manipulate or observe plant biodiversity under ambient and experimentally altered environmental conditions in a range of terrestrial ecosystems to document responses across scales, from leaf-scale physiology to the whole ecosystem scale. This hypothesis-based work will advance knowledge by maintaining CDR’s many research platforms and by starting four new experiments strategically positioned to resolve critical knowledge gaps about community assembly and organism-environment feedbacks. CDR scientists also will start collecting new data on carbon dynamics in directly comparable treatments spanning existing research platforms. In addition, researchers will use ecological theory, modeling, multi-site experiments, and synthesis activities to increase the generality of the insights arising from CDR site-based studies. Taken together, these projects will reveal when and why multi-decadal lags and long-term feedbacks occur as well as the role of biodiversity change on lags and feedbacks to ecosystem functioning. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.