ABSTRACT

Twenty-five years of intensive study has revealed a Shortgrass Steppe (SGS) ecosystem for which, despite chronic water stress, periods of severe drought, and intensive grazing by large herbivores, the essential ecological structure and functioning remain intact. With global change, however, a range of conditions is anticipated to develop far outside those experienced during the last several thousand years. Forecasting how the SGS will respond depends on understanding of key ecosystem drivers, including climate, physiography, biotic structure, natural disturbance, and human land use. The resilient ecosystem, bounded within natural variation but interrupted by human influence, may be supplanted by an unfamiliar one, with humans playing a much more direct role. The goal of the proposed research is to test the limits of resilience, function and structure of the SGS, by both continuing past work and by experimentally manipulating factors in new experiments that are known from previous work to be important. Multiple temporal scales of change and a combination of long-term monitoring, short- and long-term experiments will enable forecasts of the impacts of global change on the SGS. Experiments will involve manipulating factors that will most likely change in the future, and selecting ecological attributes and interactions previously identified either as vulnerable to change or likely to influence multiple other interactions. The project is organized into research groups that focus on biotic interactions and ecosystem processes, with multiple interdisciplinary studies united by cross-LTER studies, data synthesis and modeling.

Besides publishing hundreds of peer-reviewed journal articles and scholarly books in outlets with global reach, including a recent SGS synthesis volume, SGS-LTER impacts Colorado State University, communities and land users within Colorado, and beyond. Activities include outreach to ranchers, non-governmental organizations and land managers (especially from the U.S. Department of Agriculture); a large educational program integrated across K-12; involvement by hundreds of undergraduates as field crew, independent study students, and REU students; and an active graduate program. Much SGS education work reaches out to groups underrepresented in STEM disciplines. The ability to provide outreach is vastly improved upon recent completion of new classroom building at the field site. SGS maintains a proactive Information Management system that works to improve access to long-term data sets and the project web page is being redesigned to facilitate data access.

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