02541nas a2200217 4500008004100000245011700041210006900158300000900227490000800236520184100244653001502085653002502100653002602125653001802151653000902169653003002178653002402208100001902232700001802251856005402269 2018 eng d00aPatterns and correlates of within-season breeding dispersal: a common strategy in a declining grassland songbird0 aPatterns and correlates of withinseason breeding dispersal a com a1-140 v1353 a

Dispersal is a ubiquitous behavior with important consequences for gene flow, demography, and conservation. Some birds engage in between-year breeding dispersal, but the factors shaping variation in this behavior are not well understood. In mid-continental grasslands, preliminary evidence suggested that Grasshopper Sparrows (Ammodramus savannarum) dispersed not only between seasons, but also within breeding seasons—an apparently uncommon avian behavior. We studied a population of Grasshopper Sparrows breeding in northeastern Kansas, USA, to document the spatial and temporal patterns of within-season breeding dispersal in an experimentally managed tallgrass prairie from 2013 to 2015. We combined color-band resighting, territory mapping, and radio telemetry to quantify changes in territory density, turnover of territorial males, and dispersal distances. Density of Grasshopper Sparrows varied seasonally in management-specific ways, simultaneously increasing and decreasing in watersheds that differed in management regime. Turnover was unexpectedly high, with over half of territorial males being replaced each month. We documented over a third of males dispersing up to ∼9 km between breeding attempts. Our study provides the first comprehensive description of the patterns of within-season breeding dispersal in a grassland songbird. Our results reveal the remarkable prevalence of within-season movement in this system and the relatively large distances over which birds disperse. Such mobility has important implications for survey design and habitat management, as birds select habitat at much larger spatial scales than is generally appreciated. These results also provide foundational information for tests of alternative hypotheses explaining the ecological and evolutionary basis for such movements.

10aGrasslands10ainter-patch movement10aintra-season movement10aKonza Prairie10aLTER10amid-season habitat shifts10aterritory switching1 aWilliams, E.J.1 aBoyle, W., A. uhttp://www.bioone.org/doi/pdf/10.1642/AUK-17-69.102169nas a2200205 4500008004100000245014800041210006900189300001400258490000700272520150100279653001701780653001701797653001501814653001701829653001101846100002301857700001901880700002201899856004201921 2017 eng d00aNovel observations of larval fire survival, feeding behavior, and host plant use in the regal fritillary, speyeria idalia (Drury) (Nymphalidae)0 aNovel observations of larval fire survival feeding behavior and  a146 - 1520 v713 a

Speyeria idalia is a prairie specialist that has experienced dramatic population declines throughout its range. Speyeria idalia is nearly extirpated from the eastern portion of its former range; however, populations within Kansas are relatively stable. We made several previously undescribed field observations of late-instar larvae and post-diapause female S. idalia in northeastern Kansas during 2014–2016. We report finding late-instar larvae at locations that were burned within weeks of detection. The observations of larvae shortly following a burn suggests that S. idalia larvae are capable of surviving fire and contradicts our current knowledge of this species. Additionally, we describe a feeding behavior characteristic of late-instar larvae. Larvae observed in the field and lab stripped leaves of host plants leaving only stems. This strip-style feeding behavior provided unique feeding evidence that was valuable to detecting the presence of larvae in the field. Finally, we documented larvae and post-diapause, egg depositing females using Viola sororia. The use of this relatively widespread and common plant by S. idalia populations in the Central Great Plains has only been implicitly documented but may have important conservation implications. These novel observations further our knowledge of the ecology of this imperiled species and provide timely information that may improve research and conservation management efforts directed toward S. idalia populations.

10aconservation10afeeding sign10aGrasslands10aGreat Plains10aviolet1 aMcCullough, Kelsey1 aAlbanese, Gene1 aHaukos, David, A. uhttps://doi.org/10.18473/lepi.71i3.a403192nas a2200193 4500008004100000245007400041210006900115260004300184490001400227520256300241653001902804653002602823653001802849653001502867653002202882100001802904700002302922856005302945 2017 eng d00aPhysiological and morphological responses of grass species to drought0 aPhysiological and morphological responses of grass species to dr aManhattan, KSbKansas State University0 vMS Thesis3 a

The impacts of climate change over the next 100 years on North American grasslands are unknown. Climate change is projected to increase rainfall and seasonal temperature variability, leading to increased frequency of drought and decreased rainfall amounts for many grassland locations in the central Great Plains of North America. To increase our ability to predict the effects of a changing climate, I measured multiple morphological and physiological responses from a diverse suite of C3 and C4 grasses. Due to varying characteristics associated with the different photosynthetic pathways, these grass species respond differently to altered temperature and precipitation. I monitored grass physiology and microanatomy in conjunction with varying watered availability to replicate drought. In the second chapter, I observed leaf-level physiology and root level morphology of C3 and C4 grasses when exposed to 100% water reduction. Results indicated that response to water reduction are not always dependent on the photosynthetic pathway. Root-level morphological measurements were found to vary significantly between species in the same genus; F. ovina had the highest specific root length (SRL), which is an indicator of tolerance to environmental variability. Results also indicated that grasses of interest have thresholds that when passed result in a photosynthetically inactive plant; however it was shown that they are able to recover to near pre-drought gas exchange rates when water is re-applied. The third chapter investigated both leaf-level physiology and morphology in dominant C4¬ grasses across Kansas’ rainfall gradient over the growing season. I hypothesized that variation within a species’ physiology would be greater than its’ morphology. I also hypothesized that morphology would predict variability in a species physiological response to changes in climate. This research discovered within a location and species, leaf morphology is fixed across the growing season. Strong correlations between leaf physiology and morphology were observed, however, the strength and relationship changed among the species compared. A. gerardii and P. virgatum exhibited opposing relationships when comparing their photosynthetic rates to the amount of bundle sheath cells. This result highlights strong species-specific relationship between physiology and morphology. My results illustrate the importance of utilizing plant physiology and morphology to understand how grasses may respond to future climate change scenarios.

10aClimate change10aDrought; Great Plains10aEcophysiology10aGrasslands10atallgrass prairie1 aBachle, Seton1 aNippert, Jesse, B. uhttp://krex.k-state.edu/dspace/handle/2097/3618803056nas a2200409 4500008004100000022001400041245011300055210006900168300001200237490000700249520184200256653001802098653001802116653001502134653001702149653001202166653002102178100001902199700001802218700001802236700002102254700002502275700001702300700002502317700002302342700002202365700001602387700002302403700002402426700001902450700002302469700002202492700002302514700001702537700002602554856006602580 2016 eng d a0921-297300aBaseflow physical characteristics differ at multiple spatial scales in stream networks across diverse biomes0 aBaseflow physical characteristics differ at multiple spatial sca a119-1360 v313 a

Context Spatial scaling of ecological processes is facilitated by quantifying underlying habitat attributes. Physical and ecological patterns are often measured at disparate spatial scales limiting our ability to quantify ecological processes at broader spatial scales using physical attributes. Objective We characterized variation of physical stream attributes during periods of high biological activity (i.e., baseflow) to match physical and ecological measurements and to identify the spatial scales exhibiting and predicting heterogeneity. Methods We measured canopy cover, wetted width, water depth, and sediment size along transects of 1st–5th order reaches in five stream networks located in biomes from tropical forest to arctic tundra. We used hierarchical analysis of variance with three nested scales (watersheds, stream orders, reaches) to identify scales exhibiting significant heterogeneity in attributes and regression analyses to characterize gradients within and across stream networks. Results Heterogeneity was evident at one or multiple spatial scales: canopy cover and water depth varied significantly at all three spatial scales while wetted width varied at two scales (stream order and reach) and sediment size remained largely unexplained. Similarly, prediction by drainage area depended on the attribute considered: depending on the watershed, increases in wetted width and water depth with drainage area were best fit with a linear, logarithmic, or power function. Variation in sediment size was independent of drainage area. Conclusions The scaling of ecologically relevant baseflow physical characteristics will require study beyond the traditional bankfull geomorphology since predictions of baseflow physical attributes by drainage area were not always best explained by geomorphic power laws.

10aBoreal forest10aGeomorphology10aGrasslands10aNested ANOVA10aScaling10aTemperate forest1 aRüegg, Janine1 aDodds, W., K.1 aDaniels, M.D.1 aSheehan, Ken, R.1 aBaker, Christina, L.1 aBowden, W.B.1 aFarrell, Kaitlin, J.1 aFlinn, Michael, B.1 aHarms, Tamara, K.1 aJones, J.B.1 aKoenig, Lauren, E.1 aKominoski, John, S.1 aMcDowell, W.H.1 aParker, Samuel, P.1 aRosemond, Amy, D.1 aTrentman, Matt, T.1 aWhiles, M.R.1 aWollheim, Wilfred, M. uhttps://link.springer.com/article/10.1007%2Fs10980-015-0289-y03518nas a2200193 4500008004100000245010400041210006900145260004300214490002100257520286800278653001503146653001303161653002103174653001303195653001803208100002203226700002303248856005303271 2016 eng d00aPatterns and ecological consequences of water uptake, redistribution, and loss in tallgrass prairie0 aPatterns and ecological consequences of water uptake redistribut aManhattan, KSbKansas State University0 vPhD Dissertation3 a

Water availability is a key driver of many plant and ecosystem processes in tallgrass prairies, yet we have a limited understanding of how grassland plants utilize water through space and time. Considering that tallgrass prairies experience tremendous heterogeneity in soil resources, identifying spatiotemporal variation in plant ecohydrology is critical for understanding current drivers of plant responses to water and for predicting ecosystem responses to future changes in climate. Here, I investigated the patterns, drivers, and ecological consequences of plant water use (e.g., water uptake, water redistribution, and water loss) in a native tallgrass prairie located in northeastern Kansas, USA. Using a combination of leaf gas exchange, sap flow, and isotopic techniques, I addressed four main questions: 1) How does fire and grazing by bison impact use of water from different sources and niche overlap for common grasses, forbs, and shrubs? 2) Does hydraulic lift occur in grazed and ungrazed tallgrass prairie, and does this impact facilitation for water within grassland communities? 3) What are the patterns and drivers of nocturnal transpiration in common grassland species? 4) How does diel stem sap flow and canopy transpiration vary among common grassland species?

I found that bison grazing increased the depth of water uptake by Andropogon gerardii and Rhus glabra, reducing niche overlap with co-occurring species. Conversely, grazing did not affect hydraulic lift, which was generally uncommon and likely limited by nocturnal transpiration. Further, leaf gas exchange measurements indicated that nocturnal transpiration occurred commonly in tallgrass prairie plants and was greatest among grasses and early in the growing season. Nocturnal transpiration was not driven by vapor pressure deficit or soil moisture, as commonly observed in other systems, but was regulated by nocturnal stomatal conductance in most species. Finally, I found that daytime sap flow rates were variable among species and functional types, with larger flux rates among woody species. Nocturnal sap flow rates were more consistent across species, which caused nighttime sap flow and transpiration to account for a larger proportion of daily flux rates in grasses than in forbs or shrubs. These results show that water uptake, water redistribution, and water loss are all influenced by different biotic and abiotic drivers and have varying ecological impacts across a heterogeneous landscape. Additionally, extensive differences in water flux exist among co-occurring species and plant functional groups, which likely reflect varying strategies to tolerate water limitation. These results suggest that shifts in the abundance of these species with future climate changes, or with ecosystem state changes, will likely impact ecosystem-level water balance.

10aGrasslands10aIsotopes10aPlant physiology10aSap flow10aTranspiration1 aO'Keefe, Kimberly1 aNippert, Jesse, B. uhttp://krex.k-state.edu/dspace/handle/2097/3451402827nas a2200337 4500008004100000022001300041245011600054210006900170260001600239300001400255490001200269520176800281653003502049653002002084653003002104653002302134653001502157653002902172100001902201700002002220700002302240700002102263700002002284700001702304700002602321700002002347700002002367700001702387700001902404856006602423 2015 eng d a0168192300aBiophysical controls on carbon and water vapor fluxes across a grassland climatic gradient in the United States0 aBiophysical controls on carbon and water vapor fluxes across a g cJan-12-2015 a293 - 3050 v214-2153 a

Understanding of the underlying causes of spatial variation in exchange of carbon and water vapor fluxes between grasslands and the atmosphere is crucial for accurate estimates of regional and global carbon and water budgets, and for predicting the impact of climate change on biosphere–atmosphere feedbacks of grasslands. We used ground-based eddy flux and meteorological data, and the Moderate Resolution Imaging Spectroradiometer (MODIS) enhanced vegetation index (EVI) from 12 grasslands across the United States to examine the spatial variability in carbon and water vapor fluxes and to evaluate the biophysical controls on the spatial patterns of fluxes. Precipitation was strongly associated with spatial and temporal variability in carbon and water vapor fluxes and vegetation productivity. Grasslands with annual average precipitation <600 mm generally had neutral annual carbon balance or emitted small amount of carbon to the atmosphere. Despite strong coupling between gross primary production (GPP) and evapotranspiration (ET) across study sites, GPP showed larger spatial variation than ET, and EVI had a greater effect on GPP than on ET. Consequently, large spatial variation in ecosystem water use efficiency (EWUE = annual GPP/ET; varying from 0.67 ± 0.55 to 2.52 ± 0.52 g C mm−1 ET) was observed. Greater reduction in GPP than ET at high air temperature and vapor pressure deficit caused a reduction in EWUE in dry years, indicating a response which is opposite than what has been reported for forests. Our results show that spatial and temporal variations in ecosystem carbon uptake, ET, and water use efficiency of grasslands were strongly associated with canopy greenness and coverage, as indicated by EVI.

10aEcosystem water use efficiency10aEddy covariance10aEnhanced vegetation index10aEvapotranspiration10aGrasslands10aGross primary production1 aWagle, Pradeep1 aXiao, Xiangming1 aScott, Russell, L.1 aKolb, Thomas, E.1 aCook, David, R.1 aBrunsell, N.1 aBaldocchi, Dennis, D.1 aBasara, Jeffrey1 aMatamala, Roser1 aZhou, Yuting1 aBajgain, Rajen uhttp://linkinghub.elsevier.com/retrieve/pii/S016819231500700502633nas a2200253 4500008004100000245013900041210006900180300001500249490000800264520182600272653001002098653001502108653001202123653001502135653001202150653003102162653001002193653001502203100001802218700002302236700001902259700002002278856008102298 2014 eng d00aFire dynamics distinguish grasslands, shrublands, and woodlands as alternative attractors in the Central Great Plains of North America0 aFire dynamics distinguish grasslands shrublands and woodlands as a1374 -13850 v1023 a

Grasslands are threatened globally due to the expansion of woody plants. The few remaining headwater streams within tallgrass prairies are becoming more like typical forested streams due to rapid conversion of riparian zones from grassy to wooded. Forestation can alter stream hydrology and biogeochemistry. We estimated the rate of riparian woody plant expansion within a 30 m buffer zone surrounding the stream bed across whole watersheds at Konza Prairie Biological Station over 25 years from aerial photographs. Watersheds varied with respect to experimentally-controlled fire and bison grazing. Fire frequency, presence or absence of grazing bison, and the historical presence of woody vegetation prior to the study time period (a proxy for proximity of propagule sources) were used as independent variables to predict the rate of riparian woody plant expansion between 1985 and 2010. Water yield was estimated across these years for a subset of watersheds. Riparian woody encroachment rates increased as burning became less frequent than every two years. However, a higher fire frequency (1–2 years) did not reverse riparian woody encroachment regardless of whether woody vegetation was present or not before burning regimes were initiated. Although riparian woody vegetation cover increased over time, annual total precipitation and average annual temperature were variable. So, water yield over 4 watersheds under differing burn frequencies was quite variable and with no statistically significant detected temporal trends. Overall, burning regimes with a frequency of every 1–2 years will slow the conversion of tallgrass prairie stream ecosystems to forested ones, yet over long time periods, riparian woody plant encroachment may not be prevented by fire alone, regardless of fire frequency.

10abison10aEcosystems10aForests10aGrasslands10aGrazing10aLinear regression analysis10aTrees10aWatersheds1 aRatajczak, Z.1 aNippert, Jesse, B.1 aBriggs, J., M.1 aBlair, John, M. uhttps://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.1231102394nas a2200313 4500008004100000245009600041210006900137300001300206490000700219520149500226653001601721653001401737653001201751653001501763653001201778653002001790653001201810653002201822653001901844653002101863653002701884100001701911700002101928700001801949700001801967700001701985700001902002856005902021 2013 eng d00aBlazing and grazing: influences of fire and bison on tallgrass prairie stream water quality0 aBlazing and grazing influences of fire and bison on tallgrass pr a779 -7910 v323 a

Fire and grazers (such as Bison bison) were historically among the most important agents for maintaining and managing tallgrass prairie, but we know little about their influences on water-quality dynamics in streams. We analyzed 2 y of data on total suspended solids (TSS), total N (TN), and total P (TP) (3 samples per week per stream during flow) in 3 prairie streams with fire and bison grazing treatments at Konza Prairie Biological Station, Kansas (USA), to assess whether fire and bison increase the concentrations of these water-quality variables. We quantified the spatial and temporal locations of bison (∼0.21 animal units/ha) with Global Positioning System collars and documented bison trails, paw patches, wallows, and naturally exposed sediment patches within riparian buffers. Three weeks post-fire, TN and TP decreased (t-test, p < 0.001), but TSS did not change. Bison spent <6% of their time within 10 m of the streams, increased the amount of exposed sediment in the riparian areas, and avoided wooded mainstem branches of stream (χ2 test, p < 0.001). Temporal trends suggest that low discharge or increased bison density in the stream may increase TSS and TP during the summer months. Our results indicate a weak connection between TSS and nutrients with bison access to streams over our 2-y study and indicate that low TSS and nutrients characterize tallgrass prairie streams with fire and moderate bison densities relative to surrounding land uses.

10aBison bison10aBos bison10aburning10aGrasslands10agrazers10aprescribed fire10astreams10atallgrass prairie10atotal nitrogen10atotal phosphorus10atotal suspended solids1 aLarson, D.M.1 aGrudzinski, B.P.1 aDodds, W., K.1 aDaniels, M.D.1 aSkibbe, A.M.1 aJoern, Anthony uhttps://www.journals.uchicago.edu/doi/10.1899/12-118.102826nas a2200277 4500008004100000245010400041210006900145300001200214490000600226520201300232653001502245653001502260653001202275653001102287653002102298653001202319653001102331653002002342100002302362700002002385700001702405700001802422700001302440700001702453856007802470 2013 eng d00aEvidence of physiological decoupling from grassland ecosystem drivers by an encroaching woody shrub0 aEvidence of physiological decoupling from grassland ecosystem dr a81630 -0 v83 a

Shrub encroachment of grasslands is a transformative ecological process by which native woody species increase in cover and frequency and replace the herbaceous community. Mechanisms of encroachment are typically assessed using temporal data or experimental manipulations, with few large spatial assessments of shrub physiology. In a mesic grassland in North America, we measured inter- and intra-annual variability in leaf δ13C in Cornus drummondii across a grassland landscape with varying fire frequency, presence of large grazers and topographic variability. This assessment of changes in individual shrub physiology is the largest spatial and temporal assessment recorded to date. Despite a doubling of annual rainfall (in 2008 versus 2011), leaf δ13C was statistically similar among and within years from 2008-11 (range of −28 to −27‰). A topography*grazing interaction was present, with higher leaf δ13C in locations that typically have more bare soil and higher sensible heat in the growing season (upland topographic positions and grazed grasslands). Leaf δ13C from slopes varied among grazing contrasts, with upland and slope leaf δ13C more similar in ungrazed locations, while slopes and lowlands were more similar in grazed locations. In 2011, canopy greenness (normalized difference vegetation index – NDVI) was assessed at the centroid of individual shrubs using high-resolution hyperspectral imagery. Canopy greenness was highest mid-summer, likely reflecting temporal periods when C assimilation rates were highest. Similar to patterns seen in leaf δ13C, NDVI was highest in locations that typically experience lowest sensible heat (lowlands and ungrazed). The ability of Cornus drummondii to decouple leaf physiological responses from climate variability and fire frequency is a likely contributor to the increase in cover and frequency of this shrub species in mesic grassland and may be generalizable to other grasslands undergoing woody encroachment.

10aEcosystems10aGrasslands10aGrazing10aLeaves10aPlant physiology10aSeasons10aShrubs10aWater resources1 aNippert, Jesse, B.1 aOcheltree, T.W.1 aOrozco, G.L.1 aRatajczak, Z.1 aLing, B.1 aSkibbe, A.M. uhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.008163001746nas a2200193 4500008004100000245007300041210006900114300001500183490000800198520114800206653002801354653001501382653001801397653001801415653002501433653001101458100001701469856006601486 2013 eng d00aThe importance of timing of precipitation for grassland productivity0 aimportance of timing of precipitation for grassland productivity a1085 -10890 v2133 a

Future climate change is likely to involve changes in the amount and intensity of precipitation, but also its timing during the year. To better understand how the timing of precipitation impacts plant productivity, a 27-year dataset on grass productivity for a mesic North American grassland was analyzed. Along with other climate parameters, the ability of the average date precipitation fell during different climate periods to explain grass productivity was tested. Across the 27 years, grass productivity was greater in years with more precipitation between April 15 and August 2. After accounting for differences in the total amount of precipitation during this time period, in years when precipitation between May 9 and August 27 fell later, measured grass productivity was less. Variation among years in precipitation timing was of similar importance as temperatures during critical climate periods and about 40 % of the importance of the total amount of precipitation. In all, although the mechanisms generating these responses are uncertain, precipitation timing within a growing season has substantial effects on productivity.

10acritical climate period10aGrasslands10aKonza Prairie10aPrecipitation10aPrimary productivity10aTiming1 aCraine, J.M. uhttps://link.springer.com/article/10.1007%2Fs11258-013-0236-402261nas a2200217 4500008004100000245007600041210006900117300001200186490000600198520162200204653002301826653001001849653001101859653001901870653001201889653001501901653001601916653001601932100001701948856007801965 2013 eng d00aLong-term climate sensitivity of grazer performance: a cross-site study0 aLongterm climate sensitivity of grazer performance a crosssite s a67065 -0 v83 a

Climate change will affect grasslands in a number of ways, but the consequences of a warmer, drier world for grazers is uncertain. Predicting future grazer performance is complex since climate change affects both the quantity and quality of forage through a combination of processes that occur over a range of time scales. To better predict the consequences of climate change for grazer performance, a dataset was compiled of over a quarter million bison weights distributed across 22 US herds that span a large range of climates. Patterns of bison body mass among sites, age classes, and sexes were analyzed with respect to differences in geographic patterns of climate and interannual variation in climate. While short-term effects of climate variability are likely to depend on the magnitude and timing of precipitation during the year, grazers will be negatively affected by sustained hotter, drier conditions most likely associated with reductions in forage quality. Short-term, little effect of high temperatures on bison performance is observed, which suggests that the long-term effects of higher temperatures are likely to accrue over time as nitrogen availability in grasslands is reduced and forage quality declines. If relationships observed for bison are general for cattle, the economic consequences of higher temperatures due to decreased weight gain in US cattle could be on the order of US$1B per 1°C increase in temperature. Long-term monitoring of forage quality as well as native and domesticated grazer performance is recommended to better understand climate change effects on grazers.

10aAnimal performance10abison10aCattle10aClimate change10aGrasses10aGrasslands10aMeteorology10aWeight gain1 aCraine, J.M. uhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.006706502899nas a2200265 4500008004100000245012000041210006900161300001200230490000600242520206400248653001302312653001702325653002602342653001502368653002502383653002202408653001802430653002202448100001702470700001602487700001502503700002002518700001702538856007802555 2013 eng d00aLong-term nitrogen amendment alters the diversity and assemblage of soil bacterial communities in tallgrass prairie0 aLongterm nitrogen amendment alters the diversity and assemblage  a67884 -0 v83 a

Anthropogenic changes are altering the environmental conditions and the biota of ecosystems worldwide. In many temperate grasslands, such as North American tallgrass prairie, these changes include alteration in historically important disturbance regimes (e.g., frequency of fires) and enhanced availability of potentially limiting nutrients, particularly nitrogen. Such anthropogenically-driven changes in the environment are known to elicit substantial changes in plant and consumer communities aboveground, but much less is known about their effects on soil microbial communities. Due to the high diversity of soil microbes and methodological challenges associated with assessing microbial community composition, relatively few studies have addressed specific taxonomic changes underlying microbial community-level responses to different fire regimes or nutrient amendments in tallgrass prairie. We used deep sequencing of the V3 region of the 16S rRNA gene to explore the effects of contrasting fire regimes and nutrient enrichment on soil bacterial communities in a long-term (20 yrs) experiment in native tallgrass prairie in the eastern Central Plains. We focused on responses to nutrient amendments coupled with two extreme fire regimes (annual prescribed spring burning and complete fire exclusion). The dominant bacterial phyla identified were Proteobacteria, Verrucomicrobia, Bacteriodetes, Acidobacteria, Firmicutes, and Actinobacteria and made up 80% of all taxa quantified. Chronic nitrogen enrichment significantly impacted bacterial community diversity and community structure varied according to nitrogen treatment, but not phosphorus enrichment or fire regime. We also found significant responses of individual bacterial groups including Nitrospira and Gammaproteobacteria to long-term nitrogen enrichment. Our results show that soil nitrogen enrichment can significantly alter bacterial community diversity, structure, and individual taxa abundance, which have important implications for both managed and natural grassland ecosystems.

10aBacteria10aBiodiversity10aEcosystem functioning10aGrasslands10aMicrobial ecosystems10aPlant communities10aRibosomal RNA10aSequence analysis1 aCoolon, J.D.1 aJones, K.L.1 aTodd, T.C.1 aBlair, John, M.1 aHerman, M.A. uhttps://journals.plos.org/plosone/article?id=10.1371/journal.pone.006788402086nas a2200229 4500008004100000245010700041210006900148300001300217490000800230520136700238653002301605653001601628653001501644653001301659653001801672653002401690100001701714700001601731700002001747700002301767856006601790 2012 eng d00aCommunity traitscape of foliar nitrogen isotopes reveals N availabiity patterns in a tallgrass prairie0 aCommunity traitscape of foliar nitrogen isotopes reveals N avail a395 -4030 v3563 a

Background and aims Nutrients are important determinants of community assembly, yet the roles they play in structuring plant communities are still poorly understood. One inferential approach to understanding how environmental factors structure plant communities is examining the distribution of key functional traits among species of a community—a community traitscape. Methods To better understand how nitrogen (N) and water availability structure grasslands, we measured N concentrations and isotope ratios for 366 herbaceous species in a mesic N-limited temperate grassland, Konza Prairie. We also compared foliar N concentrations and N isotopes between Konza species and a global dataset. Results Species that had either high foliar N concentrations or high δ15NL were not necessarily more or less abundant on the landscape nor more or less likely to be found in uplands, grazed areas, or burned areas. Apparently there are unique hot spots of high N availability at Konza and the typical non-Fabaceae Konza species occupies sites with greater N availability than found globally. Conclusions Although nascent, the Konza traitscapes suggest that plant diversity in nutrient-limited communities might be strongly dependent on high-nutrient availability sites that enable high-fertility species to persist in a matrix of low nutrient availability.

10aCommunity assembly10adisturbance10aGrasslands10aIsotopes10aKonza Prairie10aResource limitation1 aCraine, J.M.1 aTowne, E.G.1 aOcheltree, T.W.1 aNippert, Jesse, B. uhttps://link.springer.com/article/10.1007%2Fs11104-012-1141-702524nas a2200253 4500008004100000245009600041210006900137300001500206490000800221520175800229653001701987653001902004653002202023653001502045653001802060100001702078700002302095700001602118700001502134700001702149700001702166700002102183856006602204 2011 eng d00aFunctional consequences of climate-change induced plant species loss in a tallgrass prairie0 aFunctional consequences of climatechange induced plant species l a1109 -11170 v1653 a

Future climate change is likely to reduce the floristic diversity of grasslands. Yet the potential consequences of climate-induced plant species losses for the functioning of these ecosystems are poorly understood. We investigated how climate change might alter the functional composition of grasslands for Konza Prairie, a diverse tallgrass prairie in central North America. With species-specific climate envelopes, we show that a reduction in mean annual precipitation would preferentially remove species that are more abundant in the more productive lowland positions at Konza. As such, decreases in precipitation could reduce productivity not only by reducing water availability but by also removing species that inhabit the most productive areas and respond the most to climate variability. In support of this prediction, data on species abundance at Konza over 16 years show that species that are more abundant in lowlands than uplands are preferentially reduced in years with low precipitation. Climate change is likely to also preferentially remove species from particular functional groups and clades. For example, warming is forecast to preferentially remove perennials over annuals as well as Cyperaceae species. Despite these predictions, climate change is unlikely to unilaterally alter the functional composition of the tallgrass prairie flora, as many functional traits such as physiological drought tolerance and maximum photosynthetic rates showed little relationship with climate envelope parameters. In all, although climatic drying would indirectly alter grassland productivity through species loss patterns, the insurance afforded by biodiversity to ecosystem function is likely to be sustained in the face of climate change.

10abiogeography10aClimate change10aFunctional traits10aGrasslands10aKonza Prairie1 aCraine, J.M.1 aNippert, Jesse, B.1 aTowne, E.G.1 aTucker, S.1 aKembel, S.W.1 aSkibbe, A.M.1 aMcLauchlan, K.K. uhttps://link.springer.com/article/10.1007%2Fs00442-011-1938-802710nas a2200205 4500008004100000245010000041210006900141260005000210490001400260520205900274653001902333653001502352653002002367653001402387653001002401653001602411100002102427700002002448856003602468 2011 eng d00aLong-term effects of climate change on grassland soil systems: A reciprocal transplant approach0 aLongterm effects of climate change on grassland soil systems A r aManhattan, KS. 80 ppbKansas State University0 vMS Thesis3 a

Climate change predictions for the Great Plains region of North America include increased temperatures, changes to annual precipitation, and reduced growing season precipitation, which will likely alter grassland soil systems. To date, few studies have examined belowground community responses to predicted climate change scenarios, with fewer assessing long-term changes. My research focused on the impacts of long-term changes in precipitation and associated soil water content on belowground grassland systems (belowground plant biomass, soil carbon (C) and nitrogen (N) pools, microbial biomass C and N, and invertebrate communities) using recently collected samples from a long-term (16-yr) reciprocal core transplant between Konza Prairie Biological Station (MAP = 850 mm) and Kansas State Agricultural Research Center at Hays (MAP = 580 mm), with the Hays site having a long-term average annual precipitation amount that is ~30% less than the Konza site. Results from the experiment indicate that either increases or decreases in annual precipitation can have profound effects on belowground grassland systems. Belowground plant biomass, microbial biomass, and potential C mineralization rates were greater at the wetter Konza site regardless of soil origin. Total C stored in soils incubated at Konza was significantly greater as well, likely due to greater root inputs. The effects of precipitation were most apparent in the surface soil layers (0-20 cm), while soil origin impacted soil properties to a greater extent with increasing depth. This contrasted with results for the soil mesofauna, where total microarthropods responded negatively and nematodes responded positively to increased annual precipitation. Results of this study indicate important changes in soil C and N pools, belowground plant biomass, and soil mesofauna within grassland systems subject to changing precipitation regimes, and suggest more mesic prairie systems are more sensitive to changes in soil water availability than those in more arid grassland systems.

10aClimate change10aGrasslands10aMicroarthropods10aNematodes10aRoots10aSoil carbon1 aRostkowski, S.C.1 aBlair, John, M. uhttp://hdl.handle.net/2097/706802295nas a2200205 4500008004100000245015700041210006900198300001300267490000800280520160800288653001201896653002201908653001501930653001201945653001801957653001501975100001701990700001602007856006602023 2010 eng d00aHigh leaf tissue density grassland species consistently more abundant across topographic and disturbance contrasts in a North American tallgrass prairie0 aHigh leaf tissue density grassland species consistently more abu a193 -2030 v3373 a

Understanding the coupling between plant functional traits and abundance provides insight into the often hidden forces that structure plant communities. To better understand the coupling between leaf traits and abundance of grassland species in a mesic North American grassland, we measured specific leaf area (SLA) and its two components, tissue density and thickness for 125 grassland species. Plants with high tissue density were more abundant over a 17-year period across a range of environments: uplands, grazed and ungrazed watersheds, and frequently and infrequently burned watersheds. The consistent relationships between leaf tissue density and abundance across ecological contrasts imply that belowground resource availability constrains community composition independent of grazing and burning regimes. Leaf tissue density did not explain species abundance in lowlands, where belowground resources are the highest. Neither did it explain the differential abundance of species between grazing or fire frequency contrasts, suggesting that changes in burning or grazing select for species based on other traits. Relative to leaf tissue density, SLA was a poor predictor of abundance, reinforcing a long-observed—but often ignored—call that measurements of SLA need to be coupled with thickness measurements in order to effectively predict the performance of species. More generally, future research needs to investigate which belowground resources control community composition in the grassland and whether the importance of water or nutrients change with burning and grazing.

10aburning10aFunctional traits10aGrasslands10aGrazing10aKonza Prairie10atopography1 aCraine, J.M.1 aTowne, E.G. uhttps://link.springer.com/article/10.1007%2Fs11104-010-0515-y01691nas a2200193 4500008004100000245008200041210006900123300001100192490000800203520110700211653001701318653001501335653001301350653001501363653001801378100001701396700001801413856006601431 2010 eng d00aPlant nitrogen and phosphorus limitation in 98 North American grassland soils0 aPlant nitrogen and phosphorus limitation in 98 North American gr a73 -840 v3343 a

The availability of nutrients is a critical determinant of ecological dynamics in grasslands, but the relationships between soil resource availability and nutrient limitation across ecosystems are not clear. To better understand how soil nutrient availability determines nutrient limitation in vegetation, we grew the same species of grass (Schizachyrium scoparium) in 98 North American grassland soils and fertilized them factorially with nitrogen (N) and phosphorus (P). On average adding N, P, and the two nutrients together increased biomass relative to unfertilized plants by 81%, 22%, and 131%, respectively. Plants grown on low-P soils were not primarily limited by P. Instead, these plants were colimited by N and P, while plants grown on high-P soils were primarily limited by N and only secondarily limited by P. Limitation was not predicted by total soil N. The preponderance of colimitation between N and P on low-P soils suggests that low P availability alters the N cycle to constrain supplies to plants such that N and P are made available in proportion to their demand by plants.

10aColimitation10aGrasslands10anitrogen10aPhosphorus10astoichiometry1 aCraine, J.M.1 aJackson, R.D. uhttps://link.springer.com/article/10.1007%2Fs11104-009-0237-102388nas a2200205 4500008004100000245013700041210006900178300001300247490000800260520167900268653001501947653003201962653001901994653002802013653002002041100001902061700001602080700002002096856006602116 2009 eng d00aConservation of nitrogen increases with precipitation across a major grassland gradient in the Central Great Plains of North America0 aConservation of nitrogen increases with precipitation across a m a571 -5810 v1593 a

Regional analyses and biogeochemical models predict that ecosystem N pools and N cycling rates must increase from the semi-arid shortgrass steppe to the sub-humid tallgrass prairie of the Central Great Plains, yet few field data exist to evaluate these predictions. In this paper, we measured rates of net N mineralization, N in above- and belowground primary production, total soil organic matter N pools, soil inorganic N pools and capture in resin bags, decomposition rates, foliar 15N, and N use efficiency (NUE) across a precipitation gradient. We found that net N mineralization did not increase across the gradient, despite more N generally being found in plant production, suggesting higher N uptake, in the wetter areas. NUE of plants increased with precipitation, and δ15N foliar values and resin-captured N in soils decreased, all of which are consistent with the hypothesis that N cycling is tighter at the wet end of the gradient. Litter decomposition appeared to play a role in maintaining this regional N cycling trend: litter decomposed more slowly and released less N at the wet end of the gradient. These results suggest that immobilization of N within the plant–soil system increases from semi-arid shortgrass steppe to sub-humid tallgrass prairie. Despite the fact that N pools increase along a bio-climatic gradient from shortgrass steppe to mixed grass and tallgrass prairie, this element becomes relatively more limiting and is therefore more tightly conserved at the wettest end of the gradient. Similar to findings from forested systems, our results suggest that grassland N cycling becomes more open to N loss with increasing aridity.

10aGrasslands10aNet nitrogen mineralization10aNitrogen pools10aNitrogen use efficiency10aRegional trends1 aMcCulley, R.L.1 aBurke, I.C.1 aLauenroth, W.K. uhttps://link.springer.com/article/10.1007%2Fs00442-008-1229-102607nas a2200325 4500008004100000245011200041210006900153300001300222490000700235520168300242653000901925653000901934653001501943653001201958653001301970653001301983100001501996700002002011700002002031700001602051700002202067700001602089700002402105700001702129700001702146700001602163700001602179700002002195856006602215 2009 eng d00aControls of aboveground net primary production in mesic savanna grasslands: An inter-hemispheric comparison0 aControls of aboveground net primary production in mesic savanna  a982 -9950 v123 a

Patterns and controls of annual aboveground net primary productivity (ANPP) are fundamental metrics of ecosystem functioning. It is generally assumed, but rarely tested, that determinants of ANPP in one region within a biome will operate similarly throughout that biome, as long as physiognomy and climate are broadly consistent. We tested this assumption by quantifying ANPP responses to fire, grazing history, and nitrogen (N) addition in North American (NA) and South African (SA) savanna grasslands. We found that total ANPP responded in generally consistent ways to fire, grazing history, and N addition on both continents. Annual fire in both NA and SA consistently stimulated total ANPP (28–100%) relative to unburned treatments at sites with deep soils, and had no effect on ANPP in sites with shallow soils. Fire did not affect total ANPP in sites with a recent history of grazing, regardless of whether a single or a diverse suite of large herbivores was present. N addition interacted strongly and consistently with fire regime in both NA and SA. In annually burned sites that were not grazed, total ANPP was stimulated by N addition (29–39%), but there was no effect of N fertilization in the absence of fire. In contrast, responses in forb ANPP to fire and grazing were somewhat divergent across this biome. Annual fire in NA reduced forb ANPP, whereas grazing increased forb ANPP, but neither response was evident in SA. Thus, despite a consistent response in total ANPP, divergent responses in forb ANPP suggest that other aspects of community structure and ecosystem functioning differ in important ways between these mesic savanna grasslands.

10aANPP10afire10aGrasslands10aGrazing10anitrogen10aSavannas1 aBuis, G.M.1 aBlair, John, M.1 aBurkepile, D.E.1 aBurns, C.E.1 aChamberlain, A.J.1 aChapman, P.1 aCollins, Scott., L.1 aFynn, R.W.S.1 aGovender, N.1 aKirkman, K.1 aSmith, M.D.1 aKnapp, Alan, K. uhttps://link.springer.com/article/10.1007%2Fs10021-009-9273-102392nas a2200205 4500008004100000245011200041210006900153260004800222300001000270490001400280520168300294653000901977653000901986653001501995653001202010653001302022653001302035100001302048856012502061 2009 eng d00aControls of aboveground net primary production in mesic savanna grasslands: An inter-hemispheric comparison0 aControls of aboveground net primary production in mesic savanna  aFort Collins, CObColorado State University a1 -500 vMS Thesis3 a

Patterns and controls of annual aboveground net primary productivity (ANPP) are fundamental metrics of ecosystem functioning. It is generally assumed, but rarely tested, that determinants of ANPP in one region within a biome will operate similarly throughout that biome, as long as physiognomy and climate are broadly consistent. We tested this assumption by quantifying ANPP responses to fire, grazing history, and nitrogen (N) addition in North American (NA) and South African (SA) savanna grasslands. We found that total ANPP responded in generally consistent ways to fire, grazing history, and N addition on both continents. Annual fire in both NA and SA consistently stimulated total ANPP (28–100%) relative to unburned treatments at sites with deep soils, and had no effect on ANPP in sites with shallow soils. Fire did not affect total ANPP in sites with a recent history of grazing, regardless of whether a single or a diverse suite of large herbivores was present. N addition interacted strongly and consistently with fire regime in both NA and SA. In annually burned sites that were not grazed, total ANPP was stimulated by N addition (29–39%), but there was no effect of N fertilization in the absence of fire. In contrast, responses in forb ANPP to fire and grazing were somewhat divergent across this biome. Annual fire in NA reduced forb ANPP, whereas grazing increased forb ANPP, but neither response was evident in SA. Thus, despite a consistent response in total ANPP, divergent responses in forb ANPP suggest that other aspects of community structure and ecosystem functioning differ in important ways between these mesic savanna grasslands.

10aANPP10afire10aGrasslands10aGrazing10anitrogen10aSavannas1 aBuis, G. uhttp://lter.konza.ksu.edu/content/controls-aboveground-net-primary-production-mesic-savanna-grasslands-inter-hemispheric02732nas a2200205 4500008004100000245011100041210006900152300001300221490000800234520204700242653001902289653001502308653003002323653002702353653002002380100002402400700002002424700001602444856006602460 2008 eng d00aIncreased precipitation event size increases aboveground net primary productivity in a semi-arid grassland0 aIncreased precipitation event size increases aboveground net pri a129 -1400 v1583 a

Water availability is the primary constraint to aboveground net primary productivity (ANPP) in many terrestrial biomes, and it is an ecosystem driver that will be strongly altered by future climate change. Global circulation models predict a shift in precipitation patterns to growing season rainfall events that are larger in size but fewer in number. This “repackaging” of rainfall into large events with long intervening dry intervals could be particularly important in semi-arid grasslands because it is in marked contrast to the frequent but small events that have historically defined this ecosystem. We investigated the effect of more extreme rainfall patterns on ANPP via the use of rainout shelters and paired this experimental manipulation with an investigation of long-term data for ANPP and precipitation. Experimental plots (n = 15) received the long-term (30-year) mean growing season precipitation quantity; however, this amount was distributed as 12, six, or four events applied manually according to seasonal patterns for May–September. The long-term mean (1940–2005) number of rain events in this shortgrass steppe was 14 events, with a minimum of nine events in years of average precipitation. Thus, our experimental treatments pushed this system beyond its recent historical range of variability. Plots receiving fewer, but larger rain events had the highest rates of ANPP (184 ± 38 g m−2), compared to plots receiving more frequent rainfall (105 ± 24 g m−2). ANPP in all experimental plots was greater than long-term mean ANPP for this system (97 g m−2), which may be explained in part by the more even distribution of applied rain events. Soil moisture data indicated that larger events led to greater soil water content and likely permitted moisture penetration to deeper in the soil profile. These results indicate that semi-arid grasslands are capable of responding immediately and substantially to forecast shifts to more extreme precipitation patterns.

10aClimate change10aGrasslands10aPrecipitation variability10aPulse-reserve paradigm10aRain event size1 aHeisler-White, J.L.1 aKnapp, Alan, K.1 aKelly, E.F. uhttps://link.springer.com/article/10.1007%2Fs00442-008-1116-901496nas a2200229 4500008004100000245014700041210006900188300001300257490000700270520067200277653001100949653002100960653001500981653002500996653002701021653001801048653002101066100001501087700001801102700001801120856012801138 2006 eng d00aSpecies richness- productivity relationship for small mammals along a desert-grassland continuum: differential responses of functional groups0 aSpecies richness productivity relationship for small mammals alo a777 -7830 v873 aWe used published data to calculate small-mammal species richness at 43 sites in North America to examine the response of species richness to increasing primary productivity. We estimated species richness for the entire community and for each of 4 functional groups (insectivore, granivore, herbivore, and omnivore). Total richness exhibited a significant unimodal relationship to increasing amounts of annual precipitation and was driven by granivores; this functional group exhibited the most pronounced decline in richness with high precipitation. We suggest that the decline in granivore richness is due to increased litter associated with increased productivity.10adesert10afunctional group10aGrasslands10aPrimary productivity10aResource heterogeneity10asmall mammals10aSpecies richness1 aReed, A.W.1 aKaufman, G.A.1 aKaufman, D.W. uhttp://lter.konza.ksu.edu/content/species-richness-productivity-relationship-small-mammals-along-desert-grassland-continuum01958nas a2200253 4500008004100000245010600041210006900147300001300216490000700229520114300236653000901379653001501388653001201403653002201415653002101437100001901458700002001477700002001497700001801517700001501535700001501550700001901565856012001584 2005 eng d00aAn ecosystem in transition: causes and consequences of the conversion of mesic grassland to shrubland0 aecosystem in transition causes and consequences of the conversio a243 -2540 v553 aWoody plant expansion is one of the greatest contemporary threats to mesic grasslands of the central United States. In this article, we synthesize more than 20 years of research to elucidate the causes and consequences of the ongoing transition of C4-dominated grasslands to savanna-like ecosystems codominated by grasses and woody plants. This transition is contingent on fire-free intervals, which provide the opportunity for recruitment both of new individuals and of additional shrub and tree species into this grassland. Once shrubs establish, their cover increases regardless of fire frequency, and infrequent fires accelerate the spread of some shrub species. This process has resulted in a new dynamic state of shrub–grass coexistence in the mesic grasslands of North America. Important consequences of this shift in plant life-form abundance include alterations in plant productivity, species diversity, and carbon storage. Without drastic measures such as mechanical removal of shrubs, it is unlikely that management of fire and grazing regimes alone will be sufficient to restore historic grass dominance in these ecosystems.10afire10aGrasslands10aGrazing10atallgrass prairie10awoody vegetation1 aBriggs, J., M.1 aKnapp, Alan, K.1 aBlair, John, M.1 aHeisler, J.L.1 aHoch, G.A.1 aLett, M.S.1 aMcCarron, J.K. uhttp://lter.konza.ksu.edu/content/ecosystem-transition-causes-and-consequences-conversion-mesic-grassland-shrubland01323nas a2200193 4500008004100000245011700041210006900158300001300227490000700240520063200247653001700879653001600896653001500912653001600927653002300943100002000966700001600986856012701002 2001 eng d00aAnalytical survey of the braconid wasp fauna (Hymenoptera: Braconidae) on six Midwestern U.S. tallgrass prairies0 aAnalytical survey of the braconid wasp fauna Hymenoptera Braconi a230 -2380 v943 aA survey of the braconid wasps on midwestern United States tallgrass prairies was conducted using malaise trapping on six sites forming an east-west transect through the prairie zone in Kansas, Missouri, and Illinois. A total of 924 specimens, representing 184 species, was recovered. Statistical analyses indicated that the asymptote of actual species richness had not yet been approached using this sampling regime. Nevertheless, this is the most complete survey yet available of prairie braconid wasps. Patterns of distinctness of the prairie fauna relative to that of other nearby plant communities are beginning to emerge.10aBiodiversity10aBraconidaek10aGrasslands10aparasitoids10atallgrass prairies1 aWhitfield, J.B.1 aLewis, C.N. uhttp://lter.konza.ksu.edu/content/analytical-survey-braconid-wasp-fauna-hymenoptera-braconidae-six-midwestern-us-tallgrass04560nas a2200265 4500008004100000245009100041210006900132260005100201300001100252520369800263653001703961653001903978653000903997653001504006653002004021653001204041100001604053700001604069700001604085700002404101700002004125700001504145700001504160856011904175 2001 eng d00aInteractions between fire and invasive plants in temperate grasslands of North America0 aInteractions between fire and invasive plants in temperate grass aTallahassee, FLbTall Timbers Research Station a40 -653 aA substantial number of invasive grasses, forbs and woody plants have invaded temperate grasslands in North America. Among the invading species are winter annuals, biennials, cool-season perennials, warm-season perennials, vines, shrubs, and trees. Many of these species have been deliberately introduced and widely planted; some are still used for range improvement, pastures, lawns, and as ornamentals, though many are listed as state or federal noxious weeds. Others have been greatly facilitated by widespread land disturbance. Historically, fire has been a major selective force in the evolution of temperate grasslands. Further, prescribed fire is commonly used as a method of ecological management for native grassland communities as well as in conjunction with restoration efforts. Within this context, it is important to understand how invasive species will interact with natural and prescribed fire regimes. In this paper, we consider what is known about how exotic species that invade temperate grasslands relate to fire. The primary issues addressed for each species are (1) Does fire appear to enhance colonization? (2) To what degree does fire affect the survival of plants? (3) Are plants that are burned able to regrow following fire and, if so, how rapidly can they recover? (4) How important is competition with native species to the response to fire? and (5) What effect does an invasive species have on the characteristics of the fire regime? For many species, results are preliminary, incomplete, or inconsistent among studies. For this reason, many of the conclusions drawn for individual species must be considered preliminary. Based on analyses of individual species, a conceptual framework is presented for considering how invasive plants may interact with fire when they invade an ecosystem. The major categories of influences are the native community, the fire regime, growth conditions for both invasive and native species, and influences that disturbances, human impacts, and landscape characteristics have had in the past and will have in the future. The examples considered in this paper provide support for a few, tentative generalizations. First, among our current worst invaders of temperate grasslands, adaptation to fire is quite variable. Some species are not well adapted to burning and can be easily eliminated; other species are better adapted but can still be eliminated if fire occurs during periods of particular vulnerability and/or at high frequency. There is a set of species that is extremely well adapted to fire and will not be eliminated through burning alone. Second, competitive interactions with native species play a crucial role in the success of nonnative invaders. In cases where differential burn responses between invasive and native species can be exploited, and adequate populations of native dominant species are present, fire can sometimes tip the competitive balance away from invasives. Third, there are a few invasive species that have exceptional attributes and for which there are no easy solutions. The ability of cheatgrass (Bromus tectorum) to enhance fire, the ability of Chinese tallow (Triadica sebifera) to suppress fire, and the ability of leafy spurge (Euphorbia esula) to resprout from repeated injury make the sespecies exceptional threats to native diversity. Finally, the available information for many invasive species is very incomplete, particularly with regard to how fire affects competitive interactions with the native community. There is much more we need to know if we are to consistently predict how invasive species will respond to fire and how burning can best be used to manage for natural diversity10aalien plants10aexotic species10afire10aGrasslands10ainvasive plants10aprairie1 aGrace, J.B.1 aSmith, M.D.1 aGrace, S.L.1 aCollins, Scott., L.1 aStohlgren, T.J.1 aGalley, K.1 aWilson, T. uhttp://lter.konza.ksu.edu/content/interactions-between-fire-and-invasive-plants-temperate-grasslands-north-america02889nas a2200289 4500008004100000245013100041210006900172300001300241490000600254520190600260653001902166653002402185653001502209653001802224653001902242653002302261653002702284653002702311653002102338653001802359100001402377700001902391700002002410700002002430700002402450856012502474 2000 eng d00aAltering rainfall timing and quantity in a mesic grassland ecosystem: Design and performance of rainfall manipulation shelters0 aAltering rainfall timing and quantity in a mesic grassland ecosy a308 -3190 v33 aGlobal climate change is predicted to alter growing season rainfall patterns, potentially reducing total amounts of growing season precipitation and redistributing rainfall into fewer but larger individual events. Such changes may affect numerous soil, plant, and ecosystem properties in grasslands and ultimately impact their productivity and biological diversity. Rainout shelters are useful tools for experimental manipulations of rainfall patterns, and permanent fixed-location shelters were established in 1997 to conduct the Rainfall Manipulation Plot study in a mesic tallgrass prairie ecosystem in northeastern Kansas. Twelve 9 x 14–m fixed-location rainfall manipulation shelters were constructed to impose factorial combinations of 30% reduced rainfall quantity and 50% greater interrainfall dry periods on 6 x 6–m plots, to examine how altered rainfall regimes may affect plant species composition, nutrient cycling, and above- and belowground plant growth dynamics. The shelters provided complete control of growing season rainfall patterns, whereas effects on photosynthetic photon flux density, nighttime net radiation, and soil temperature generally were comparable to other similar shelter designs. Soil and plant responses to the first growing season of rainfall manipulations (1998) suggested that the interval between rainfall events may be a primary driver in grassland ecosystem responses to altered rainfall patterns. Aboveground net primary productivity, soil CO2 flux, and flowering duration were reduced by the increased interrainfall intervals and were mostly unaffected by reduced rainfall quantity. The timing of rainfall events and resulting temporal patterns of soil moisture relative to critical times for microbial activity, biomass accumulation, plant life histories, and other ecological properties may regulate longer-term responses to altered rainfall patterns.10aClimate change10afloristic diversity10aGrasslands10aKonza Prairie10alife histories10along-term research10aNet primary production10aprecipitation patterns10arainout shelters10asoil moisture1 aFay, P.A.1 aCarlisle, J.D.1 aKnapp, Alan, K.1 aBlair, John, M.1 aCollins, Scott., L. uhttp://lter.konza.ksu.edu/content/altering-rainfall-timing-and-quantity-mesic-grassland-ecosystem-design-and-performance02959nas a2200205 4500008004100000245009700041210006900138300001300207490000800220520223900228653003302467653002102500653001502521653002102536653002102557100001402578700001902592700001702611856012502628 2000 eng d00aHost plant species effects on arbuscular mycorrhizal fungal communities in tallgrass prairie0 aHost plant species effects on arbuscular mycorrhizal fungal comm a435 -4440 v1223 aSymbiotic associations between plants and arbuscular mycorrhizal (AM) fungi are ubiquitous in many herbaceous plant communities and can have large effects on these communities and ecosystem processes. The extent of species-specificity between these plant and fungal symbionts in nature is poorly known, yet reciprocal effects of the composition of plant and soil microbe communities is an important assumption of recent theoretical models of plant community structure. In grassland ecosystems, host plant species may have an important role in determining development and sporulation of AM fungi and patterns of fungal species composition and diversity. In this study, the effects of five different host plant species [Poa pratensis L., Sporobolus heterolepis (A. Gray) A. Gray, Panicum virgatum L., Baptisia bracteata Muhl. ex Ell., Solidago missouriensis Nutt.] on spore communities of AM fungi in tallgrass prairie were examined. Spore abundances and species composition of fungal communities of soil samples collected from patches within tallgrass prairie were significantly influenced by the host plant species that dominated the patch. The AM fungal spore community associated with B. bracteata showed the highest species diversity and the fungi associated with Pa. virgatum showed the lowest diversity. Results from sorghum trap cultures using soil collected from under different host plant species showed differential sporulations of AM fungal species. In addition, a greenhouse study was conducted in which different host plant species were grown in similar tallgrass prairie soil. After 4 months of growth, AM fungal species composition was significantly different beneath each host species. These results strongly suggest that AM fungi show some degree of host-specificity and are not randomly distributed in tallgrass prairie. The demonstration that host plant species composition influences AM fungal species composition provides support for current feedback models predicting strong regulatory effects of soil communities on plant community structure. Differential responses of AM fungi to host plant species may also play an important role in the regulation of species composition and diversity in AM fungal communities.10aArbuscular mycorrhizal fungi10afungal diversity10aGrasslands10aHost specificity10aSoil communities1 aEom, A.H.1 aHartnett, D.C.1 aWilson, G.T. uhttp://lter.konza.ksu.edu/content/host-plant-species-effects-arbuscular-mycorrhizal-fungal-communities-tallgrass-prairie02769nas a2200253 4500008004100000245011800041210006900159300001300228490000700241520200700248653001902255653001902274653001402293653001502307653001402322653001902336653002202355653002002377653001002397100001802407700002002425700002102445856004902466 2000 eng d00aPatterns and determinants of potential carbon gain in the C3 evergreen Yucca glauca (Liliaceae) in a C4 grassland0 aPatterns and determinants of potential carbon gain in the C3 eve a230 -2360 v873 aYucca glauca is a C3 evergreen rosette species locally common in the C4-dominated grasslands of the central Great Plains. Most congeners of Y. glauca are found in deserts, and Y. glauca’s morphological similarities to desert species (steeply angled leaves, evergreen habit) may be critical to its success in grasslands. We hypothesized that the evergreen habit of Y. glauca, coupled with its ability to remain physiologically active at cool temperatures, would allow this species to gain a substantial portion of its annual carbon budget when the C4 grasses are dormant. Leaf-level gas exchange was measured over an 18-mo period at Konza Prairie in northeast Kansas to assess the annual pattern of potential C gain. Two short-term experiments also were conducted in which nighttime temperatures were manipulated to assess the cold tolerance of this species. The annual pattern of C gain in Y. glauca was bimodal, with a spring productive period (maximum monthly photosynthetic rate = 21.1 ± 1.97 μmol·m−2·s−1) in March through June, a period of midseason photosynthetic depression, and a fall productive period in October (15.6 ± 1.25 μmol·m−2·s−1). The steeply angled leaves resulted in interception of photon flux density at levels above photosynthetic saturation throughout the year. Reduced photosynthetic rates in the summer may have been caused by low soil moisture, but temperature was strongly related (r2 = 0.37) to annual variations in photosynthesis, with nocturnal air temperatures below −5°C in the late fall and early spring, and high air temperatures (>32°C) in the summer, limiting gas exchange. Overall, 31% of the potential annual carbon gain in Y. glauca occurred outside the “frost-free” period (April–October) at Konza Prairie and 43% occurred when the dominant C4 grasses were dormant. Future climates that include warmer minimum temperatures in the spring and fall may enhance the success of Y. glauca relative to the C4 dominants in these grasslands.10aClimate change10acold tolerance10aevergreen10aGrasslands10aLiliaceae10aphotosynthesis10atallgrass prairie10aWater relations10aYucca1 aMaragni, L.A.1 aKnapp, Alan, K.1 aMcAllister, C.A. uhttp://www.amjbot.org/content/87/2/230.short