02512nas a2200217 4500008004100000245011800041210006900159300001600228490000600244520183800250653000902088653001402097653001702111653001402128653001102142653001702153100002102170700002102191700001902212856006302231 2016 eng d00aHigh dissimilarity within a multiyear annual record of pollen assemblages from a North American tallgrass prairie0 aHigh dissimilarity within a multiyear annual record of pollen as a5273 - 52890 v63 a
Grassland vegetation varies in composition across North America and has been historically influenced by multiple biotic and abiotic drivers, including fire, herbivory, and topography. Yet, the amount of temporal and spatial variability exhibited among grassland pollen assemblages, and the influence of these biotic and abiotic drivers on pollen assemblage composition and diversity has been relatively understudied. Here, we examine 4 years of modern pollen assemblages collected from a series of 28 traps at the Konza Prairie Long‐Term Ecological Research Area in the Flint Hills of Kansas, with the aim of evaluating the influence of these drivers, as well as quantifying the amount of spatial and temporal variability in the pollen signatures of the tallgrass prairie biome. We include all terrestrial pollen taxa in our analyses while calculating four summative metrics of pollen diversity and composition – beta‐diversity, Shannon index, nonarboreal pollen percentage, and Ambrosia:Artemisia – and find different roles of fire, herbivory, and topography variables in relation to these pollen metrics. In addition, we find significant annual differences in the means of three of these metrics, particularly the year 2013 which experienced high precipitation relative to the other 3 years of data. To quantify spatial and temporal dissimilarity among the samples over the 4‐year study, we calculate pairwise squared‐chord distances (SCD). The SCD values indicate higher compositional dissimilarity across the traps (0.38 mean) among all years than within a single trap from year to year (0.31 mean), suggesting that grassland vegetation can have different pollen signatures across finely sampled space and time, and emphasizing the need for additional long‐term annual monitoring of grassland pollen.
10afire10agrassland10aGreat Plains10aHerbivory10aPollen10aTauber traps1 aCommerford, J.L.1 aMcLauchlan, K.K.1 aMinckley, T.A. uhttps://onlinelibrary.wiley.com/doi/full/10.1002/ece3.225900471nas a2200121 4500008004100000245008000041210006900121260004300190490002100233100002100254700002100275856005300296 2016 eng d00aInvestigating North American grassland biogeography throughout the Holocene0 aInvestigating North American grassland biogeography throughout t aManhattan, KSbKansas State University0 vPhD Dissertation1 aCommerford, J.L.1 aMcLauchlan, K.K. uhttp://krex.k-state.edu/dspace/handle/2097/3279802499nas a2200181 4500008004100000245010300041210006900144260001600213300001100229490000700240520186700247100002102114700002102135700002102156700002002177700002102197856009902218 2015 eng d00aFire history reconstruction in grassland ecosystems: amount of charcoal reflects local area burned0 aFire history reconstruction in grassland ecosystems amount of ch cJan-11-2015 a1140090 v103 aFire is one of the most prevalent disturbances in the Earth system, and its past characteristics can be reconstructed using charcoal particles preserved in depositional environments. Although researchers know that fires produce charcoal particles, interpretation of the quantity or composition of charcoal particles in terms of fire source remains poorly understood. In this study, we used a unique four-year dataset of charcoal deposited in traps from a native tallgrass prairie in mid-North America to test which environmental factors were linked to charcoal measurements on three spatial scales. We investigated small and large charcoal particles commonly used as a proxy of fire activity at different spatial scales, and charcoal morphotypes representing different types of fuel. We found that small (125–250 μm) and large (250 μm–1 mm) particles of charcoal are well-correlated (Spearman correlation = 0.88) and likely reflect the same spatial scale of fire activity in a system with both herbaceous and woody fuels. There was no significant relationship between charcoal pieces and fire parameters <500 m from the traps. Moreover, local area burned (<5 km distance radius from traps) explained the total charcoal amount, and regional burning (200 km radius distance from traps) explained the ratio of non arboreal to total charcoal (NA/T ratio). Charcoal variables, including total charcoal count and NA/T ratio, did not correlate with other fire parameters, vegetation cover, landscape, or climate variables. Thus, in long-term studies that involve fire history reconstructions, total charcoal particles, even of a small size (125–250 μm), could be an indicator of local area burned. Further studies may determine relationships among amount of charcoal recorded, fire intensity, vegetation cover, and climatic parameters.
1 aLeys, érangère1 aBrewer, Simon, C1 aMcConaghy, Scott1 aMueller, Joshua1 aMcLauchlan, K.K. uhttp://stacks.iop.org/1748-9326/10/i=11/a=114009?key=crossref.eab0dcb3387227bddddc42e90e62a21d01891nas a2200157 4500008004100000245007400041210006900115300001500184490000700199520137200206100002101578700001701599700002301616700002001639856007401659 2014 eng d00aLack of eutrophication in a tallgrass prairie ecosystem over 27 years0 aLack of eutrophication in a tallgrass prairie ecosystem over 27 a1225 -12350 v953 aMany North American grasslands are receiving atmospheric nitrogen (N) deposition at rates above what are considered critical eutrophication thresholds. Yet, potential changes in grassland function due to anthropogenic N deposition are poorly resolved, especially considering that other dynamic factors such as land use and precipitation can also affect N availability. To better understand whether elevated N deposition has altered ecosystem structure or function in North American grasslands, we analyzed a 27-year record of ecophysiological, community, and ecosystem metrics for an annually burned Kansas tallgrass prairie. Over this time, despite increasing rates of N deposition that are within the range of critical loads for grasslands, there was no evidence of eutrophication. Plant N concentrations did not increase, soil moisture did not decline, forb diversity did not decline, and the relative abundance of dominant grasses did not shift toward more eutrophic species. Neither aboveground primary productivity nor N availability to plants increased. The fates of deposited N in grasslands are still uncertain, and could include management losses through burning and grazing. However, evidence from this grassland indicates that eutrophication of North American grassland ecosystems is not an inevitable consequence of current levels of N deposition.
1 aMcLauchlan, K.K.1 aCraine, J.M.1 aNippert, Jesse, B.1 aOcheltree, T.W. uhttps://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/13-1068.103210nas a2200181 4500008004100000245014900041210006900190300001500259490000800274520256100282100001502843700002102858700001702879700001502896700001702911700001902928856008102947 2013 eng d00aLinking abundances of the dung fungus Sporormiella to the density of bison: implications for assessing grazing by megaherbivores in paleorecords0 aLinking abundances of the dung fungus Sporormiella to the densit a1125 -11360 v1013 aMegaherbivores likely had important influences on past vegetation dynamics, just as they do in modern ecosystems. The exact nature of megaherbivores' role can be studied using a relatively new suite of palaeoecological techniques, including the quantification of fossil spores from Sporormiella and other coprophilous fungi as indicators of megafaunal biomass in sediment records. However, a quantitative linkage of spore abundance with megaherbivore biomass or grazing intensity has been lacking. Konza Prairie Biological Station (Kansas, USA), located in the midcontinent of North America, contains native tallgrass prairie grazed by a herd of bison (Bison bison) in a 1000-ha enclosure, providing an excellent opportunity to test the effects of megaherbivores on grassland community composition and their potential signature in the palynological record. We collected pollen and spores during 2009 and 2010 from a network of 28 modified Tauber traps. The precise locations of the bison herd were recorded using GPS collars; we calculated bison grazing intensity (kg m−2 year−1) to high spatial precision within concentric circles around each trap (radii from 25 to 500 m). Both relative (per cent) and absolute (concentration) abundances of Sporormiella were significantly higher in traps inside the enclosure and were positively correlated with bison grazing intensity. The cut-off for distinguishing between bison-grazed and ungrazed traps was determined to be 2.8% Sporormiella of the total pollen and spore sum, consistent with previous palaeoecological reconstructions. The relationship between Sporormiella abundances and available grazing area around each trap was strongest at short radii (25–100 m), suggesting that spores do not disperse far from their source. Sporormiella should thus be considered a local-scale indicator of megaherbivore presence. Traps in the grazed area had significantly higher percentages of Ambrosia and lower percentages of Poaceae pollen than traps from ungrazed areas. This suggests that the pollen record has the potential to detect the ecological effects of bison grazing on grassland community composition. Synthesis. This study refines the use of Sporormiella as a proxy for local megaherbivore presence, especially in grassland systems. Multiproxy Sporormiella and pollen analyses may help elucidate the past drivers of grassland dynamics, including the possible role of bison in mediating grass–forb interactions during the variable moisture regimes of the last 12,000 years.
1 aGill, J.L.1 aMcLauchlan, K.K.1 aSkibbe, A.M.1 aGoring, S.1 aZirbel, C.R.1 aWilliams, J.W. uhttps://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.1213002524nas 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 aFuture 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%2Fs00442-011-1938-801952nas a2200205 4500008004100000245010400041210006900145300001300214490000700227520132900234653001201563653001001575653001701585653001101602653001201613100002101625700001701646700001701663856006601680 2011 eng d00aInterannual variability of pollen productivity and transport in mid-North America from 1997 to 20090 aInterannual variability of pollen productivity and transport in a181 -1890 v273 aUnderstanding the causes of interannual variability in atmospheric pollen concentration is an important but elusive goal for public health and environmental change. We analyzed long-term daily records of pollen counts from urban Kansas City, Missouri, USA collected from 1997 to 2009 for three pollen groups: Ambrosia, Poaceae, and a third group which is mostly composed of arboreal pollen types. The annual pollen index varied from 8,368 to 80,822 over the thirteen-year period. Although Ambrosia pollen is often thought to be associated with droughts and disturbance, years with high Ambrosia pollen were associated with high summer precipitation to the south of Kansas City. Years with high Poaceae pollen were associated with high spring precipitation to the south of the city. In support of the southern influence to Kansas City pollen, Ambrosia and Poaceae pollen mostly arrived on southern winds. In contrast to the other two pollen groups, the arboreal pollen was most associated with growing season precipitation to the east of Kansas City, although it was still highest on days with southern winds. Based on the correlations with climate, the severity of an upcoming allergy season may be predicted with early-season precipitation data, while short-term severity can be forecast from local weather patterns.
10aclimate10agrass10aGreat Plains10aPollen10aRagweed1 aMcLauchlan, K.K.1 aBarnes, C.S.1 aCraine, J.M. uhttps://link.springer.com/article/10.1007%2Fs10453-010-9186-702433nas a2200181 4500008004100000245009000041210006900131260005000200490001400250520183700264653001402101653002402115653001102139653002302150100002102173700002102194856003602215 2010 eng d00aCalibrating vegetation cover and pollen assemblages in the Flint Hills of Kansas, USA0 aCalibrating vegetation cover and pollen assemblages in the Flint aManhattan, KS. 73 ppbKansas State University0 vMS Thesis3 aThe quantitative relationship between pollen assemblages in sediment and vegetation cover is largely unknown because many factors influence this relationship. This lack of quantitative relationship is particularly acute in grassland regions, where both past and future climate change have the potential to determine grassland composition and cover. The tool used to reconstruct past grassland cover is the relative abundance of distinct fossil pollen types preserved in sediment. However, the interpretation of grassland pollen assemblages as grassland vegetation types needs to be refined to improve these reconstructions. Using pollen found in the surface sediments from 24 artificially-constructed ponds in the Flint Hills ecoregion of Kansas, USA, I examined relationships between pollen and vegetation in the tallgrass prairie biome, which includes woody components. By comparing the pollen data to field-surveyed vegetation data and land cover classifications taken from Kansas Gap Analysis Program data, I correlated pollen and vegetation in this ecoregion. Pollen productivity estimates for Artemisia, Ambrosia, Asteraceae, Chenopodiaceae, Cornus, Fabaceae, Juniperus, Maclura, Poaceae, Populus, Quercus, and Salix were calculated via the Extended R-Value Model. Common pollen types identified in sediments are mostly herbaceous grassland plant species such as Poaceae, Artemisia, and Ambrosia, but woody plants such as Populus, Quercus, and Juniperus are also represented. PPEs have been calculated for four of these taxa in Europe, and values from the Flint Hills are higher. These are the first PPEs reported for eight of these taxa. This research will further advance quantitative vegetation reconstructions in the Great Plains of North America and refine interpretations of how climate change affects grasslands.
10agrassland10aKansas- Flint Hills10aPollen10aprairie vegetation1 aCommerford, J.L.1 aMcLauchlan, K.K. uhttp://hdl.handle.net/2097/417002026nas a2200169 4500008004100000245011800041210006900159300001500228490000800243520142900251100002101680700001901701700001701720700002001737700001701757856008201774 2010 eng d00aThirteen decades of foliar isotopes indicate declining nitrogen availability in central North American grasslands0 aThirteen decades of foliar isotopes indicate declining nitrogen a1135 -11450 v1873 a•Humans are increasing both the deposition of reactive nitrogen (N) and concentrations of atmospheric CO2 on Earth, but the combined effects on terrestrial ecosystems are not clear. In the absence of historical records, it is difficult to know if N availability is currently increasing or decreasing on regional scales. •To determine the nature and timing of past changes in grassland ecosystem dynamics, we measured the composition of stable carbon (C) and N isotopes in leaf tissue from 545 herbarium specimens of 24 vascular plant species collected in Kansas, USA from 1876 to 2008. We also parameterized a simple model of the terrestrial N cycle coupled with a stable isotope simulator to constrain processes consistent with observed patterns. •A prolonged decline in foliar N concentrations began in 1926, while a prolonged decline in foliar δ15N values began in 1940. Changes in the difference between foliar and atmospheric C isotopes reveal slightly increased photosynthetic water use efficiency since 1876. •The declines in foliar N concentrations and foliar δ15N suggest declining N availability in these grasslands during the 20th century despite decades of anthropogenic N deposition. Our results are consistent with progressive-nitrogen-limitation-type hypotheses where declines in N availability are driven by increased ecosystem N storage as a result of increased atmospheric CO2.
1 aMcLauchlan, K.K.1 aFerguson, C.J.1 aWilson, I.E.1 aOcheltree, T.W.1 aCraine, J.M. uhttps://nph.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-8137.2010.03322.x01962nas a2200169 4500008004100000245009300041210006900134300001300203490000600216520143000222653002001652653002201672100001701694700001501711700002101726856004501747 2010 eng d00aWidespread coupling between the rate and temperature sensitivity of organic matter decay0 aWidespread coupling between the rate and temperature sensitivity a854 -8570 v33 aMicrobial breakdown of soil organic matter influences the potential for terrestrial ecosystems to sequester carbon, and the amount of carbon dioxide released to the atmosphere1, 2, 3, 4. Predicting the sensitivity of microbial decomposition to temperature change is therefore critical to predicting future atmospheric carbon dioxide concentrations and feedbacks to anthropogenic warming5. According to enzyme kinetics, the more biogeochemically recalcitrant the organic matter, the greater the temperature sensitivity of microbial respiration6, 7, 8. Here, we measured the temperature sensitivity of microbial respiration in soils from 28 sites in North America, ranging from Alaska to Puerto Rico, to test the generality of this principle. We show that the lower the rate of respiration at a reference temperature of 20 °C—and thus the more biogeochemically recalcitrant the organic matter—the greater the temperature sensitivity of soil respiration. We compiled our findings with those from other studies, encapsulating a range of environments, and show that this relationship holds across multiple scales and soil types. Although physico-chemical protection of soil organic matter and substrate availability will also influence the temperature sensitivity of decomposition, we suggest that biogeochemically recalcitrant organic matter will respond the most sensitively to anticipated warming.
10aBiogeochemistry10aMicrobial ecology1 aCraine, J.M.1 aFierer, N.1 aMcLauchlan, K.K. uhttps://www.nature.com/articles/ngeo100901428nas a2200217 4500008004100000245009400041210006900135300001300204490000700217520072800224653001400952653002600966653002400992653002801016653001201044100001701056700001401073700002101087700001501108856008701123 2009 eng d00aLandscape-level variation in temperature sensitivity of soil organic carbon decomposition0 aLandscapelevel variation in temperature sensitivity of soil orga a373 -3750 v423 aWe examined landscape-level variation in temperature sensitivity of labile SOC across 71 sites at a central North American grassland. The observed range in activation energy of decomposition (Ea), an index of temperature sensitivity, was as great at the landscape scale as has been observed at the continental scale. Ea was lower for soils with more labile C, consistent with the ‘Carbon quality-temperature’ hypothesis. Soil pH explained 67% of the variation in Ea. Although there are strong environmental correlates with the Ea of SOC decomposition at landscape scales, the amount of variation within landscapes could confound regional- to global-scale predictions of the response of soil C to warming.
10agrassland10aMicrobial respiration10aSoil organic carbon10aTemperature sensitivity10aWarming1 aCraine, J.M.1 aSpurr, R.1 aMcLauchlan, K.K.1 aFierer, N. uhttps://www.sciencedirect.com/science/article/abs/pii/S0038071709004015?via%3Dihub00603nas a2200157 4500008004100000245009400041210006900135300001300204490000700217100001700224700002300241700002100264700002000285700002100305856011900326 2009 eng d00aThe water budget, climate variability, and climate impacts assessment in Northeast Kansas0 awater budget climate variability and climate impacts assessment a189 -1960 v321 aWilson, I.E.1 aHarrington, J., J.1 aMcLauchlan, K.K.1 aMartinson, E.J.1 aHutchinson, S.L. uhttp://lter.konza.ksu.edu/content/water-budget-climate-variability-and-climate-impacts-assessment-northeast-kansas