ABSTRACT

Grasslands cover more of the Earth's land than any other major vegetation type, and temperate grasslands are among the most endangered ecosystems on the planet. Threats to grasslands include land use changes, expansion of woody species, invasion by exotic species, and changes in climate and nutrient deposition. In the highly productive tallgrass prairies of North America, changes in fire, grazing and climate are especially critical. Conserving the biological diversity and ecosystem services provided by these grasslands, while also managing them for sustainable production, requires a comprehensive understanding of how these ecosystems will respond to current and future environmental and land-use changes. Decades of research at the Konza Prairie LTER site are producing a rich and detailed understanding of how environmental and land-use changes independently and interactively affect the structure and function of grasslands and associated groundwater and streams. New research will build on this foundation of long-term experiments and measurements to understand causes and consequences of ecological change in tallgrass prairie. This will contribute to the sustainable management, conservation and, restoration of terrestrial and aquatic resources in tallgrass prairies, and other grasslands globally. Research on restoration of grasslands is particularly timely because of the widespread loss and degradation of prairies and other grasslands. The impacts of Konza Prairie research will extend far beyond the site, through engagement with stakeholders and management and conservation agencies. Researchers will disseminate findings through the Flint Hills Discovery Center, which educates civic, professional, conservation, and governmental agencies about the tallgrass prairie and the Flint Hills region of Kansas. The Konza Environmental Education Program will engage over 1,000 school students annually in hand-on science education activities. The Konza LTER program will conduct an annual Summer Teacher's Workshop provides to train elementary and secondary teachers, and a summer field biology course at a local high school. The project will support community education through collaboration with the Kansas Association for Conservation and Environmental Education, Flint Hills Discovery Center, Manhattan Boys and Girls Club, and United School District 383.

The research is organized around four major themes (land-use change, climatic variability, altered biogeochemical cycles, and restoration ecology) and builds on a 30-yr foundation of long-term experiments and measurements in terrestrial and aquatic grassland ecosystems. Watershed- and plot-level experiments at Konza Prairie have altered fire, grazing, climate, nutrient availability in ways that have created a range of different ecological states and legacies. New research will couple ongoing long-term observations and experiments with new studies to (1) test and refine conceptual and theoretical models of community and ecosystem change, and (2) provide new insights into the mechanisms underlying ecological responses to critical environmental and land-use changes. This research will a) measure responses to long-term manipulation of fire, grazing, climate, and nutrients, b) test novel causative factors in additional experiments, c) determine the ability of bison grazing to develop and maintain alternate stable vegetation states, and d) cease or alter some long-term experimental manipulations (water or nutrient availability) to assess ecological legacy effects and feedbacks. Fire and grazing studies will address fundamental questions regarding top-down and bottom-up controls of ecological processes, and effects of heterogeneity on biodiversity and ecosystem processes. Studies of woody plant encroachment, climate change, and chronic N enrichment will address three of the most critical changes occurring in grasslands worldwide. Researchers will use intermediate fire return treatments too ask whether observed shrub encroachment under intermediate fire intervals represents a new stable state. Restoration studies will test fundamental ecology theories on controls of plant diversity and community assembly, while building a foundation for more effective strategies for restoring grasslands and conserving grassland biodiversity. This research is conceptually integrated through a common theme of sensitivity and resilience of grasslands to natural and anthropogenically-altered drivers. When these diverse and creative research projects are taken together, this long-term project is poised to address major global change phenomena and to test fundamental ecological theory related to non-linear dynamics and alternate stable states, productivity-diversity and disturbance-stability relationships, top-down vs. bottom-up regulation of ecological processes, food web dynamics, and responses to environmental heterogeneity.

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