Long-Term Ecological Research in Tallgrass Prairie:

The Konza Prairie LTER Program

A.K. Knapp, J.M. Briggs, J.M. Blair, D.C. Hartnett, L.C. Johnson, D.W. Kaufman and W.K. Dodds


Project Summary

A comprehensive long-term ecological research program will be continued and expanded at the Konza Prairie LTER site in NE Kansas. Konza Prairie, a pristine tallgrass prairie is, arguably, the most intensively studied grassland site on earth. The 15 year old, broadly-based research program encompasses studies from the organismic through population, community, ecosystem and landscape ecology levels. These studies are thematically linked via an overarching theme that includes the major abiotic and biotic factors influencing this ecosystem. Our central hypothesis is that fire, grazing and climatic variability are essential and interactive factors responsible for the structure and function of tallgrass prairie. In contrast to many other grasslands where ecological processes are constrained by chronic limitations of a single resource (e.g., water), organismic to ecosystem processes and dynamics in tallgrass prairie are products of spatial and temporal variability in multiple limiting resources (water, light, N). Variability in, and switching among, these primary limiting resource(s) are caused by both extant and historical fire, grazing and climatic regimes. Moreover, responses to these factors are strongly dependent on topographic and landscape position. As a result of this complexity, and because grazing and fire regimes are managed in grassland systems worldwide, data from the Konza Prairie LTER program have relevance not only for understanding this grassland, but for broader ecological issues such as stability-diversity questions and interactions between land-use, biodiversity and climate change.

The proposed research will continue to build upon a long-term database on ecological patterns and processes derived from a fully-replicated watershed-level experimental design, in place on Konza Prairie since 1980. This design includes fire (annual fire to fire exclusion) and grazing treatments (grazed bynative ungulates vs. ungrazed). In addition, short-term studies focused on key processes and mechanisms will continue to be a critical part of the Konza LTER program. Proposed new research for LTER IV includes studies of the effect of fire season (in addition to fire frequency) in tallgrass prairie, a fire-treatment reversal experiment in which watersheds that have been annually burned or unburned for 20 years will have their treatments reversed, comparative studies of bison vs. cattle as the dominant grazers, and a long-term study of how grazing, fire, climatic variability and agriculture affect annual C, H2O and energy budgets in tallgrass prairie. A key question addressed by the latter study is whether or not tallgrass prairie soils are a sink or source for C and how land-use (fire, grazing) and climate affects the C budget. Interdisciplinary synthetic efforts are proposed to integrate results from short and long-term experiments.

Click HERE for the full Konza Prairie LTER IV proposal

or

Link to the Konza LTER Web Site...