Collaborative Research: Does the legacy of long-term chronic climate change alter ecosystem responses to short-term climatic extremes?

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Climate change may be manifested in the Midwestern United States as a combination of gradual warming and changes in rainfall along with increases in extreme weather events such as heat waves and droughts. Such gradual and extreme changes have typically been studied independently, however they are most likely to occur simultaneously, raising important questions about how they may interact. For example, will the nature of ecosystem responses to drought be affected by a gradual increase in temperature? This project will address this question by building on a long-term climate change study in a Kansas grassland, the Rainfall Manipulation Plots (RaMPs) experiment. The RaMPs experiment has imposed 15 years of altered rainfall patterns, larger rainfall events and longer periods between events, and 10 years of continuous (1-2 degree C) warming. Those treatments have resulted in consistently dry soils, increased plant water stress, reduced plant growth, genetic changes in populations of the most abundant grass species, and changes in soil carbon dioxide emissions, nutrients, and microbes. These varied responses are predicted to increase the ecosystem's resistance to extreme drought and its ability to recover after drought. To test those predictions, two years of extreme drought (similar to the 1930's dust bowl) followed by a year of normal rainfall will be imposed on experimental plots and multiple ecosystem responses will be measured.A field-based course for undergraduates entitled 'Climate Change and Grasslands' will be offered. This course will enhance students' basic understanding of the scientific process and introduce them to the complexities of climate-ecosystem interactions through lectures, class projects and field trips that showcase results from climate change experiments in Wyoming, Colorado and New Mexico.