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
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
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
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.
for the full Konza Prairie LTER IV proposal
Link to the Konza
LTER Web Site...