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Nutrients and networks

Ecology, Evolution and Behavior graduate students’ research goes to press

Charlotte Riggs and Peter Wragg

With a focus on the effects of nutrient availability on grassland biodiversity and carbon dioxide release, Ecology, Evolution and Behavior Ph.D. candidates Charlotte Riggs and Peter Wragg published their Nutrient Network-based research in three separate journals this summer.

Riggs, whose research focuses on the effects of elevated nitrogen inputs on the decay of soil carbon by soil microorganisms, published in June in Biogeochemistry. She and her co-authors reported results from a study of five Nutrient Network experimental grassland sites in the Central Great Plains of the United States, where they found a decreased amount of carbon dioxide released from soil and decreased decomposition of soil carbon following nitrogen addition. Together, these results suggest that nitrogen increase could increase soil carbon sequestration in grasslands in the future.

Wragg’s research examines human impacts on how grassland plants interact through resources, fire and microclimate. Wragg has established two Nutrient Network experiments in South Africa. Published in both Nature Plants and Nature Communications this July, Wragg was part of a Nutrient Network team that found that plant production was limited by more than one nutrient at most of the 42 grassland sites that they examined. Cedar Creek, for example, a high-latitude site, was most limited by nitrogen. The team also found that as nutrient availability increases, grasslands could become more heavily populated by exotic species.

Both Riggs and Wragg have performed experiments with the global Nutrient Network as well as working with the Long-Term Ecological Research (LTER) program at Cedar Creek.