02222nas a2200145   4500008004100000245011800041210006900159300001500228490000700243520167900250100001501929700001701944700001901961856009601980       1998                        eng d00aBiotic interactions between grazers and plants: Relationships contributing to atmospheric boundary layer dynamics0 aBiotic interactions between grazers and plants Relationships con  a1247 -12590 v553 aDuring 1987 and 1988 First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE) studies conducted in the tallgrass prairie of central Kansas, variations in ungulate grazing intensity produced a patchy spatial and temporal distribution of remaining vegetation. Equally variable plant regrowth patterns contributed further to a broad array of total primary production that resulted in a pronounced mosaic of grazing impacts. This regrowth potential, derived from a relative growth rate (RGR) equation comparing ungrazed and grazed plants, determines much of the ecosystem dynamics within and among the grazed pastures and between years. Rates of change in new plant growth (DRGRg) ranged from 2100% to 140%; however, 78% of the time in 1987 and 71% in 1988, productivity increased as a function of grazing intensity. Since plant growth potential in ungrazed (RGRug) and grazed systems (RGRg) have inherently different attributes, interactions with the abiotic environment may develop many uncertainties. Thus, changes in growth rates in grazed areas compared to ungrazed areas (DRGRg) may impose major controls over system productivity and associated biological processes currently not accounted for in ecosystem models.
 Because FIFE microsite atmospheric boundary layer (ABL) studies did not directly incorporate grazing intensity into their design, Type I and Type II statistical errors may introduce significant uncertainties for understanding cause and effect in surface flux dynamics. As a consequence these uncertainties compromise the ability to extrapolate microsite ABL biophysical findings to other spatial and temporal scales.1 aDyer, M.I.1 aTurner, C.L.1 aSeastedt, T.R.  uhttp://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1998)055%3C1247%3ABIBGAP%3E2.0.CO%3B200738nas a2200217   4500008004100000245007500041210006900116260003800185300001300223653002200236100001900258700001700277700001700294700001800311700001100329700002000340700001900360700001900379700002400398856009800422       1998                        eng d00aA landscape perspective of patterns and processes in tallgrass prairie0 alandscape perspective of patterns and processes in tallgrass pra  aNew YorkbOxford University Press  a265 -27910atallgrass prairie1 aBriggs, J., M.1 aNellis, M.D.1 aTurner, C.L.1 aHenebry, G.M.1 aSu, H.1 aKnapp, Alan, K.1 aBriggs, J., M.1 aHartnett, D.C.1 aCollins, Scott., L.  uhttp://knz.lternet.edu/content/landscape-perspective-patterns-and-processes-tallgrass-prairie00742nas a2200205   4500008004100000245008500041210006900126260003800195300001300233653002200246100002000268700001900288700002000307700001700327700002000344700001900364700001900383700002400402856011000426       1998                        eng d00aPatterns and controls of aboveground net primary production in tallgrass prairie0 aPatterns and controls of aboveground net primary production in t  aNew YorkbOxford University Press  a193 -22110atallgrass prairie1 aKnapp, Alan, K.1 aBriggs, J., M.1 aBlair, John, M.1 aTurner, C.L.1 aKnapp, Alan, K.1 aBriggs, J., M.1 aHartnett, D.C.1 aCollins, Scott., L.  uhttp://knz.lternet.edu/content/patterns-and-controls-aboveground-net-primary-production-tallgrass-prairie02955nas a2200169   4500008004100000245009100041210006900132300001500201490000700216520235500223653002202578100001702600700002002617700001802637700001502655856011502670       1997                        eng d00aSoil N and plant responses to fire, topography and supplemental N in tallgrass prairie0 aSoil N and plant responses to fire topography and supplemental N  a1832 -18430 v783 aTallgrass prairie in the Flint Hills region of Kansas is characterized by considerable topographic relief coupled with variation in soil properties. These topoedaphic gradients, together with variation in fire regimes, result in temporal and landscape-level variability in soil resource availability and plant responses. Nitrogen usually is considered to be the nutrient most limiting to primary productivity in tallgrass prairie, but few studies have addressed how N availability varies seasonally, or across the landscape and with fire frequency. We measured soil inorganic N, in situ net N mineralization, aboveground net primary productivity (ANPP), and N mass on plots either fertilized with N in 1993 or in 1994, or unfertilized, in uplands and lowlands of two annually burned and two long-term unburned sites during the 1994 growing season. In addition, our study was conducted in the year following record rainfall, allowing us to assess the potential for high precipitation amounts to affect subsequent N cycling and plant production. Both fire treatment and topography affected soil N availability. In general, N mineralization was greater on unburned than on burned sites and was up to five times greater on uplands than lowlands. Total extractable soil N was highest early in the season and least at midseason, and it also tended to be higher in unburned sites than burned sites on unfertilized plots. Added N increased ANPP, but there were no differences between plots fertilized in 1994 and those fertilized in 1993. In general, patterns of ANPP on control plots were consistent with known production responses to topography and burning (higher in annually burned sites and in lowland sites) but were inversely related or unrelated to patterns of N availability (higher in unburned sites and at upland topographic positions). Potential loss of N by volatilization during spring burning was greater than in years with normal rainfall amounts and represented a significant portion of aboveground plant N mass. Potential N losses did not appear to limit ANPP or N availability in the current growing season. Our results suggest that different factors control soil N mineralization and plant productivity, which explains, in part, why patterns of ANPP are not well correlated with patterns of N availability in tallgrass prairie ecosystems.10atallgrass prairie1 aTurner, C.L.1 aBlair, John, M.1 aSchartz, R.J.1 aNeel, J.C.  uhttp://knz.lternet.edu/content/soil-n-and-plant-responses-fire-topography-and-supplemental-n-tallgrass-prairie01694nas a2200181   4500008004100000245006700041210006700108300001100175490000800186520112600194100001901320700001601339700001701355700001801372700001701390700001701407856008801424       1997                        eng d00aSpatial and temporal patterns of vegetation in the Flint Hills0 aSpatial and temporal patterns of vegetation in the Flint Hills  a10 -200 v1003 aIn tallgrass prairie, complex interactions among multiple limiting resources in combination with a variety of land use practices can lead to a heterogeneous landscape. Remote-sensing data (AVHRR) were coupled with abiotic factors to explore spatial and temporal vegetation patterns of the Flint Hills in Kansas and Oklahoma. This information should enable the detection of both natural (e.g., interannual variation in precipitation and temperature) and anthropogenic (e.g., climate change, over-grazing, land-use practices) stresses on this grassland ecosystem. Shifts in the spatial and temporal patterns of vegetation (as measured from NDVI by AVHRR) have been correlated with meteorological data (from 117 weather stations) to identify key abiotic variables that determined vegetation patterns across this region. In 4 years, the combination of annual precipitation and growing degree days was useful to detect spatial and temporal vegetation patterns of the Flint Hills. However, it is imperative that land-use patterns are known in order to assess adequately spatial and temporal patterns of vegetation in this area.1 aBriggs, J., M.1 aRieck, D.R.1 aTurner, C.L.1 aHenebry, G.M.1 aGoodin, D.G.1 aNellis, M.D.  uhttp://knz.lternet.edu/content/spatial-and-temporal-patterns-vegetation-flint-hills02502nas a2200181   4500008004100000245006800041210006800109300001300177490000700190520192500197653002002122653000902142653001802151653001902169100001902188700001702207856009602224       1995                        eng d00aPlant productivity and nitrogen gas fluxes in tallgrass prairie0 aPlant productivity and nitrogen gas fluxes in tallgrass prairie  a255 -2660 v103 aWe explored relationships between plant productivity and annual fluxes of nitrogen (N2) and nitrous oxide (N2O) in a tallgrass prairie landscape in central Kansas. Our objective was to develop predictive relationships between these variables that could be used in conjunction with remote sensing information on plant productivity to produce large-area estimates of N gas fluxes. Our hypothesis was that there are inherent relationships between plant productivity and N gas fluxes in tallgrass prairie because both are controlled by water and N availability. The research was carried out as part of a multi-investigator project, the First ISLSCP Field Experiment (FIFE, ISLSCP = International Satellite Land Surface Climatology Program), directed toward the use of remote sensing to characterize land-atmosphere interactions. Fluxes of N2 (denitrification) and N2O were measured using soil core techniques. Estimates of annual flux were produced by temporal extrapolation of measured rates. Annual aboveground net primary productivity (ANPP) was estimated from measurements of the maximum standing crop of plant biomass. There were strong relationships between ANPP and N gas fluxes, and between a satellite remote sensing-based index of plant productivity (normalized difference vegetation index, NDVI) and gas fluxes. We used these relationships to convert images of NDVI into images of N gas fluxes for one 83 ha watershed and for the entire 15 by 15 km FIFE site. These images were used to compute mean landscape gas fluxes (0.62 g N m-2 y-1 for N2, 0.66 g N m-2 y-1 for N2O) and total N gas production for the two areas. Our flux and production values are useful for comparison with values produced by simulation models and site-specific studies, and for assessing the significance of N gas production to ecosystem and landscape scale processes related to nutrient cycling, water quality and atmospheric chemistry.
10adenitrification10aNDVI10anitrous oxide10aremote sensing1 aGroffman, P.M.1 aTurner, C.L.  uhttp://knz.lternet.edu/content/plant-productivity-and-nitrogen-gas-fluxes-tallgrass-prairie01110nas a2200145   4500008004100000245003500041210003500076300001100111490000600122520071900128100001500847700001700862700001900879856006600898       1993                        eng d00aHerbivory and its consequences0 aHerbivory and its consequences  a10 -160 v33 aWe argue that herbivores often induce nonlinear or biphasic growth and development in plants. Collectively these individual responses translate into a system—level optimization curve wherein at low levels of herbivory overall community responses show increases in production potential, whereas extreme herbivory causes extreme reduction in productivity. The transition between these two states defines a point of optimal herbivory in respect to C and N processes.We present four case examples from the literature demonstrating such nonlinear responses, suggesting a widespread existence for this herbivore—plant phenomenon. The nonlinear responses appear to demonstrate temporal and spatial scale dependencies.1 aDyer, M.I.1 aTurner, C.L.1 aSeastedt, T.R.  uhttp://knz.lternet.edu/content/herbivory-and-its-consequences02255nas a2200145   4500008004100000245011100041210006900152300001300221490000600234520169600240100001701936700001901953700001501972856012201987       1993                        eng d00aMaximization of aboveground grassland production: the role of defoliation frequency, intensity and history0 aMaximization of aboveground grassland production the role of def  a175 -1860 v33 aProduction of tallgrass prairie vegetation was measured on experimental plots in which defoliation intensity and frequency were manipulated by mowing and using movable exclosures on areas chronically grazed by cattle. Defoliation history largely controlled whether or not defoliated plants overcompensated (exhibited enhanced production compared to undefoliated controls) for tissue removal. Plants on chronically grazed sites only compensated for foliage removed by grazers. Production on plots mowed prior to the year of measurement was similar to that on chronically grazed sites, while previously unmowed plots exhibited substantial aboveground overcompensation. Aboveground production was maximized by the most frequent mowing treatment and by intermediate mowing heights. Nitrogen and phosphorus concentrations and amounts in aboveground tissues were increased by mowing and grazing. Current mowing regime was more important than mowing history in determining nitrogen concentrations except very early in the growing season. Effects of grazing and mowing on belowground biomass were inconsistent, but frequent mowing appeared to limit accumulation of belowground N reserves and biomass. In North American grasslands, overcompensation is a nonequilibrium plant response to grazing. Photosynthate that would be stored as reserves and used for root growth and flower and seed production instead is used to replace lost leaf area, thereby resulting in higher foliage productivity. However, under chronic grazing or mowing, vegetation is prevented from maintaining high nutrient and water uptake capacity (large root biomass) and accumulating reserves that allow overcompensation responses.1 aTurner, C.L.1 aSeastedt, T.R.1 aDyer, M.I.  uhttp://knz.lternet.edu/content/maximization-aboveground-grassland-production-role-defoliation-frequency-intensity-and00614nas a2200169   4500008004100000245009200041210006900133300001700202490000700219653002200226100001700248700001900265700001500284700001900299700001800318856010800336       1992                        eng d00aEffects of management and topography on the radiometric response of a tallgrass prairie0 aEffects of management and topography on the radiometric response  a18855 -186660 v9710atallgrass prairie1 aTurner, C.L.1 aSeastedt, T.R.1 aDyer, M.I.1 aKittel, T.G.F.1 aSchimel, D.S.  uhttp://knz.lternet.edu/content/effects-management-and-topography-radiometric-response-tallgrass-prairie00553nas a2200133   4500008004100000245011600041210006900157300001300226490000600239100001500245700001700260700001900277856012300296       1991                        eng d00aInfluence of mowing and fertilization on biomass, productivity and spectral reflectance in Bromus inermis plots0 aInfluence of mowing and fertilization on biomass productivity an  a443 -4520 v11 aDyer, M.I.1 aTurner, C.L.1 aSeastedt, T.R.  uhttp://knz.lternet.edu/content/influence-mowing-and-fertilization-biomass-productivity-and-spectral-reflectance-bromus01265nas a2200145   4500008004100000245010500041210006900146300001300215490000700228520071200235100001500947700001700962700001900979856012100998       1991                        eng d00aRemote sensing measurements of production processes in grazing lands: the need for new methodologies0 aRemote sensing measurements of production processes in grazing l  a495 -5050 v343 a<p>Remote sensing of grazinglands to obtain estimates of productivity relies entirely upon absorption and reflectance properties of the vegetation and its background to provide accurate qualitative and quantitative values. Interpretations of these signals are highly dependent on vegetation responses to perturbations, such as grazing or alterations in nutrient cycles. If remote sensing models of grassland growth ignore feedbacks derived from grazing animals, or only negative feedbacks are assumed, there is a likelihood of errors developing during model validation. We review fundamental assumptions made when using remote sensing data from grazing systems and give examples of the problems involved</p>1 aDyer, M.I.1 aTurner, C.L.1 aSeastedt, T.R.  uhttp://knz.lternet.edu/content/remote-sensing-measurements-production-processes-grazing-lands-need-new-methodologies00586nas a2200133   4500008004100000245010300041210006900144260004300213300001100256490002100267653002200288100001700310856012500327       1990                        eng d00aEffects of grazing on primary production and surface climatological variables in tallgrass prairie0 aEffects of grazing on primary production and surface climatologi  aManhattan, KSbKansas State University  a1 -1050 vPhD Dissertation10atallgrass prairie1 aTurner, C.L.  uhttp://knz.lternet.edu/content/effects-grazing-primary-production-and-surface-climatological-variables-tallgrass-prairie02267nas a2200205   4500008004100000245008400041210006900125260004600194300001300240520156600253653001201819100001801831700001801849700001701867700001501884700001901899700001601918700002101934856010601955       1989                        eng d00aEffects of manipulation on foliage characteristics of Andropgon gerardii Vitman0 aEffects of manipulation on foliage characteristics of Andropgon   aLincoln, NEbUniversity of Nebraska Press  a143 -1463 a<p>The effects of burning, mowing, and nitrogen fertilizer on the chlorophyll, nitrogen, and phosphorus content of big bluestem were measured using a factorial experimental design at Konza Prairie Research Natural Area. While spring burning usually increased foliage production, burning had no effect on mid-season chlorophyll or nitrogen concentrations. Chlorophyll concentrations were significantly increased by fertilizer and mowing treatments. Nitrogen concentrations of foliage were higher on fertilized and mowed plots. Mowing also increased phosphorous concentrations of foliage, but nitrogen fertilizer significantly reduced phosphorus concentrations. These results support other research indicating that 1) nitrogen use efficiency (grams biomass produced per gram of foliage nitrogen) is higher on burned prairie, 2) removal of foliage by mowing results in more nutrient-rich regrowth, and 3) the amount of phosphorus available to big bluestem foliage is limited. The dilution of phosphorus caused by added nitrogen was a consequence of increased productivity on these plots and suggessts phosphorus uptake in excess of requirements for maximum growth. The relationships between burning, mowing, and nitrogen on the spectral reflectance patterns of vegetation indicated that chlorophyll (or nitrogen) concentrations of foliage appeared to more strongly affect indices of greenness and plant vigor than did the amount of plant biomass. Key words: biomass, burning, mowing, big bluestem, Andropogon gerardii, chlorophyll, nitrogen, phosphorus, Kansas</p>10aburning1 aRamundo, R.A.1 aShapley, T.D.1 aTurner, C.L.1 aDyer, M.I.1 aSeastedt, T.R.1 aBragg, T.B.1 aStubbendieck, J.  uhttp://knz.lternet.edu/content/effects-manipulation-foliage-characteristics-andropgon-gerardii-vitman