Lance T. Vermeire

Agricultural Research Service, Kerrville, Texas, United States

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Publications (51)81.22 Total impact

  • David H. Branson · Lance T. Vermeire
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    ABSTRACT: Rangeland management practices such as burning and grazing may affect the development, survival, and reproduction of grasshopper populations. Experiments in the northern Great Plains that examine effects of fire and grazing utilization on grasshoppers are lacking. As part of a larger study examining vegetation responses to late summer fire and postfire grazing utilization in semiarid mixed prairie in eastern Montana to aid in postfire management decisions, we examined grasshopper responses to late summer fire and postfire grazing intensity. The experiment was repeated using adjacent blocks, with blocks receiving fire treatment in either 2003 or 2004 and grazing in the following year. Treatments were no fire and no grazing, and summer fire followed by grazing at 0%, 17%, or 50% forage utilization on a biomass basis. Grasshopper sampling was conducted before fire and for 2 years post fire. Fire reduced grasshopper density 36–53% across experiments, sampling periods, and postfire grazing treatments, but the effects of grazing and fire were species dependent. The two most abundant grasshopper species, Ageneotettix deorum (Scudder) and Opeia obscura (Thomas), were reduced 80% and 84% the first year after the 2003 fire, but only O. obscura was affected following the 2004 fire. Late summer fire appears to be a useful management tool to reduce populations of some grasshopper species in the northern Great Plains, while other species appear more responsive to food limitation from increased postfire grazing utilization. Fire effects were largely driven by two species, indicating that late-season fire impacts could be species dependent.
    No preview · Article · Nov 2015 · Rangeland Ecology & Management
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    ABSTRACT: We estimate rangeland managers assessing ecosystem health have measured soil stability .800,000 times. Our aim was to use quantitative data from a site in the Northern Great Plains, USA and asemi-quantitative literature search to demonstrate the robustness of soil stability as an indicator of ecosystem functioning. Empirical data included measurements of plant and soil properties along a locallivestock grazing gradient to determine whether soil stability (e.g., % water-stable aggregates) explained primary productivity and soil water transport for a mixed-grass prairie site in the Northern Great Plains. We measured: annual net primary productivity (ANPP), elevation, % soil moisture, measures of soil stability, and soil water transport (field-saturated infiltrability and sorptivity) across points spanning a localgradient in livestock grazing intensity (none vs. light to moderate stocking rates; mean distance separating points=39.9 m [range=5.2-71.3 m]). Across the sampled gradient, variation in ANPP was best explainedby a model with field-saturated infiltrability and % soil moisture. Infiltrability explained slightly more of the variation. We then determined that moderate amounts of variation in infiltrability were explained byANPP, % soil moisture, and % water-stable aggregates. We determined that most of this variation was explained by ANPP and then soil moisture. Our empirical findings indicate that plant production wascorrelated with infiltration though we could not determine whether variation in plant production was caused by variation in infiltration or vice versa.We generally failed to show that soil stability (e.g., % waterstableaggregates) was a useful predictor of primary productivity and soil water transport. Our semiquantitative literature review also indicated that soil stability was not a consistent predictor of either plantproduction or infiltration. The varying evidence reported here on whether soil stability is a predictor of ecosystem function illustrates the difficulty in identifying an indicator of ecosystem health that (1) is apredictor of ecosystem function across grassland types, (2) is sensitive to rangeland management, and (3) can be easily implemented by non-experts.
    Full-text · Article · Nov 2015 · Ecosphere
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    ABSTRACT: In perennial grassland dominated systems, belowground bud banks regulate plant community dynamics. Plant community responses to disturbance are largely driven by the ability to generate future aboveground growth originating from belowground axillary buds. This study examined bud bank dynamics for Bouteloua gracilis, Hesperostipa comata, and Pascopyrum smithii following fire in northwestern mixed-grass prairie in eastern Montana, USA. Belowground axillary buds were counted and classified for three growing seasons to determine immediate and short-term effects of summer, fall, and spring prescribed burns on patterns of bud bank activity, dormancy, and mortality. Prescribed burns did not result in immediate mortality of B. gracilis, H. comata, or P. smithii buds. Surprisingly, spring prescribed burns immediately increased the number of active B. gracilis buds. Summer fire, however, reduced B. gracilis active bud numbers. Fall burns immediately activated P. smithii buds, whereas fire did not influence any immediate bud dynamics for H. comata. Reduced bud numbers of H. comata may limit the ability to respond to fire. Season of fire directly manipulated bud activity, dormancy, and mortality for these species throughout the growing and dormant seasons following fire. Using season of fire to manipulate bud bank dynamics illustrates potential to improve post-fire management strategies based on known bud development trajectories and bud dynamics following fire.
    Full-text · Article · Jun 2015 · Plant Ecology
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    ABSTRACT: The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410, or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.
    Full-text · Article · Apr 2015 · Rangelands
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    ABSTRACT: Although climate models forecast warmer temperatures with a high degree of certainty, precipitation is the primary driver of aboveground net primary production (ANPP) in most grasslands. Conversely, variations in temperature seldom are related to patterns of ANPP. Thus forecasting responses to warming is a challenge, and raises the question: how sensitive will grassland ANPP be to warming? We evaluated climate and multi-year ANPP data (67 years) from eight western US grasslands arrayed along mean annual temperature (MAT; ~7-14 °C) and mean annual precipitation (MAP; ~250-500 mm) gradients. We used regression and analysis of covariance to assess relationships between ANPP and temperature, as well as precipitation (annual and growing season) to evaluate temperature sensitivity of ANPP. We also related ANPP to the standardized precipitation evaporation index (SPEI), which combines precipitation and evapotranspiration to better represent moisture available for plant growth. Regression models indicated that variation in growing season temperature was negatively related to total and graminoid ANPP, but precipitation was a stronger predictor than temperature. Growing season temperature was also a significant parameter in more complex models, but again precipitation was consistently a stronger predictor of ANPP. Surprisingly, neither annual nor growing season SPEI were as strongly related to ANPP as precipitation. We conclude that forecasted warming likely will affect ANPP in these grasslands, but that predicting temperature effects from natural climatic gradients is difficult. This is because, unlike precipitation, warming effects can be positive or negative and moderated by shifts in the C3/C4 ratios of plant communities.
    Full-text · Article · Feb 2015 · Oecologia
  • Morgan L. Russell · Lance T. Vermeire
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    ABSTRACT: Belowground accumulation of vegetative buds provides a reservoir of meristems that can be utilized following disturbance. Perennial grass bud banks are the primary source of nearly all tiller growth, yet understanding of fire and nitrogen effects on bud banks is limited. We tested effects of fire and nitrogen addition on bud banks of purple threeawn (Aristida purpurea Nutt.), a perennial C4 bunchgrass. Fire (no fire, summer fire, fall fire) and nitrogen addition (0, 46, 80 kg·ha- 1) treatments were assigned in a completely randomized, fully factorial design and axillary buds were evaluated on two similar sites in southeastern Montana 1 and 2 years after fire. Permanently marked plants were assessed for live tiller production, and randomly selected tillers were sampled to determine active and dormant buds per tiller. Fire and nitrogen had opposite effects on axillary buds. Summer and fall fire reduced active buds by 42% relative to nonburned plots. Adding nitrogen at 46 or 80 kg·ha- 1 increased active buds per tiller 60% compared with plots with no nitrogen addition. The number of dormant buds per tiller was similar across fire treatments and levels of nitrogen. Fire and nitrogen had interacting effects on total buds at the tiller level. Without nitrogen addition, fall and summer fire reduced total buds per tiller about 70%. Nitrogen had no effect on total buds per tiller for nonburned plants. However, total number of buds per tiller was greater with nitrogen addition following fall fire and increased with each increase in nitrogen following summer fire. Results indicate fire effectively controls purple threeawn through bud bank reduction and that nitrogen can stimulate bud production. Interacting effects of fire and nitrogen on buds reveal a potential source of inconsistency in nitrogen effects and a possible method of facilitating recovery of fire-sensitive bunchgrasses after fire.
    No preview · Article · Dec 2014 · Rangeland Ecology & Management
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    ABSTRACT: Native plant biodiversity loss and exotic species invasions are threatening the ability of many ecosystems to maintain key functions and processes. We currently lack detailed plant biodiversity data at a national scale with which to make management decisions and recommendations based on current conservation challenges. We collected plant biodiversity and exotic species richness data from 4 sites in the Northern Great Plains using the modified Whittaker (MW) and Natural Resources Inventory (NRI) methods to evaluate any major differences between indicators generated from these methods and offer recommendations based on findings. Our data indicated that the NRI protocols underestimated both total plant species richness and exotic species richness compared with the MW approach. More importantly, however, results show that biodiversity indicators from the two methods showed similar trends. Increasing time spent on making species richness measurements and implementing a more systematic approach to detecting species within a plot could improve biodiversity inventory and monitoring efforts in NRI while also providing a link between existing long-term data and any new information collected. These adjustments would ultimately help those interested in adopting NRI methods and using plant biodiversity data to increase the amount and quality of information collected.
    Full-text · Article · Nov 2014 · Ecological Indicators
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    N. A. Dufek · L. T. Vermeire · R. C. Waterman · A. C. Ganguli
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    ABSTRACT: Purple threeawn (Aristida purpurea Nutt.) is a native perennial bunchgrass with limited forage value that dominates sites with disturbed soils and persists with repeated severe grazing. Fire and nitrogen addition have been used to reduce threeawn and can increase grazing utilization of threeawn by livestock. We evaluated effects of fire, spring urea addition, and phenological stage on purple threeawn forage quality 1 yr postfire on two similar sites in southeastern Montana during the 2011 (site 1) and 2012 (site 2) growing seasons. Fire (no fire, summer fire, fall fire) and rate of nitrogen addition (0, 46, 80 kg N·ha−1) were arranged in a completely randomized, fully factorial design. Samples were collected at five phenological stages throughout each growing season. Forage quality was assessed using nutrient analyses of crude protein (CP), net energy (NEm), and total digestible nutrients; antiquality analyses of neutral detergent fiber (NDF), acid detergent fiber, and silica; in vitro fermentation for organic matter disappearance (IVOMD) and NDF disappearance; and gas production (asymptotic [maximum] gas production, fractional rate of gas production, lag time, and average fermentation rate). In vegetative stages, summer and fall fire increased CP from 6.2% to 12.1% and 13.0%, respectively, and NDF decreased from 72.1% to 69.4% and 68.2%, respectively. Summer and fall fire reduce silica content from 7.0% to 4.1% and 4.3%, respectively. Purple threeawn IVOMD increased by 14.0% and 13.0% following summer and fall fire, respectively, compared to nonburned plots. Nitrogen addition increased CP from 7.5% to 8.0% and 8.4%, respectively, with 46% and 80 kg N·ha−1, respectively. In vitro fermentation and gas production variables did not change due to nitrogen addition. Fire generally improved purple threeawn forage quality to a greater extent than did nitrogen addition. Results indicate fire can potentially improve the suitability of purple threeawn as a forage species.
    Full-text · Article · May 2014 · Rangeland Ecology & Management
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    Marnie E. Rout · Lance T. Vermeire · Kurt O. Reinhart
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    ABSTRACT: Since nitrogen is the primary limiting nutrient in terrestrial ecosystems, understanding the regulators of nitrogen (N2) fixation is critical. Our aim was to identify predictors of free-living N2-fixer activity across a fire history gradient in a temperate semiarid grassland. We predicted that recent fire would increase soil nitrogen and phosphorus, and the activity of a functional gene (nifH) for N2 fixation would be positively correlated with phosphorus and negatively correlated with nitrogen. We sampled 18 plots from a mixed-grass prairie site in the Northern Great Plains. Plots had variable prescribed fire histories (e.g. time since fire) and were sampled five times from September 2011 - August 2012. For each, we quantified 21 soil properties and the activity of the nifH gene (DNA and mRNA) using quantitative PCR. Multiple linear regressions were performed to determine the best predictor(s) of variation in nifH mRNA copy number. Predictor variables included 21 soil properties, two weather variables, and two fire history variables. The seasonal sampling tracked the progression of a regional drought. Greater levels of nifH DNA and mRNA were observed in early (moist) than late (drought stage) sampling. For the moist period, we determined the greatest amount of variation in nifH mRNA was explained by a model with 4 variables (R2= 0.35). The nifH mRNA was positively correlated with manganese and negatively correlated with iron, sulfur, and temperature. Based on comparisons of squared semi-partial coefficients of determination, we determined three variables were equally influential (temperature, iron, and sulfur) followed by manganese. Soil moisture was a main factor limiting nifH activity. Some soil properties were also useful predictors of nifH mRNA. However, we failed to detect correlations between nifH activity and either fire history variables, nitrogen, or phosphorus. A small number of other soil properties, exhibiting patterns of collinearity [e.g. manganese correlated with sulfur (r= 0.42) and iron (r=0.80)], were useful predictors of variation in nifH activity.
    Full-text · Conference Paper · Mar 2014
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    ABSTRACT: In the face of an increasingly variable climate, long-term cattle weight gain datasets are rare, yet invaluable, for determining site-specific influences of seasonal weather patterns on cattle production. Here, we present a long-term (1936–2005) yearling Hereford steer dataset collected at the Northern Great Plains Research Laboratory (NPGRL) near Mandan, ND, USA. Data were analyzed using weighted AICc model averaging to examine the effects of spring (April–June) and summer (July–September) temperature and precipitation, as well as prior growing season (prior April–September) and prior fall/winter (prior October–March) precipitation on cattle production (kg/ha) under light (37.4 ± 5.3 SD Animal Unit Days [AUD]/ha across all study years) and heavy (91.6 ± 22.2 SD AUD/ha) stocking rates. Because Kentucky bluegrass (Poa pratensis L.) invaded the grassland at NPGRL in the early 1980s, we modeled cattle production separately for pre- (1936–1983) and post-invasion (1986–2005) years to determine if the plant community shift influenced sensitivity to seasonal weather patterns. Cattle production under heavy stocking was more sensitive to seasonal weather variability than under light stocking during both pre- and post-invasion years. Interestingly, the magnitude and robustness of coefficients changed between the pre- and post-invasion years, with seasonal weather patterns explaining more cattle production variation during the post-invasion years. Though cattle sensitivity to seasonal weather patterns differed between light and heavy stocking for both pre- and post-invasion years, invasion status did change cattle response to weather. For example, cattle production in P. pratensis invaded pastures was more heavily influenced by cool, wet springs and wet prior grazing seasons than was production in un-invaded pastures. For cattle stocked heavily in native pastures, wet winters more strongly increased cattle production than in invaded pastures.
    Full-text · Article · Jan 2014 · Agriculture Ecosystems & Environment
  • Lance T. Vermeire · Jessica L. Crowder · David B. Wester
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    ABSTRACT: Most wildfires occur during summer in the northern hemisphere, the area burned annually is increasing, and fire effects during this season are least understood. Understanding plant response to grazing following summer fire is required to reduce ecological and financial risks associated with wildfire. Forty 0.75-ha plots were assigned to summer fire then 0, 17, 34 or 50% biomass removal by grazing the following growing season, or no fire and no grazing. Root, litter, and aboveground biomass were measured before fire, immediately after grazing, and 1 yr after grazing with the experiment repeated during 2 yr to evaluate weather effects. Fire years were followed by the second driest and fifth wettest springs in 70 yr. Biomass was more responsive to weather than fire and grazing, with a 452% increase from a dry to wet year and 31% reduction from a wet to average spring. Fire reduced litter 53% and had no first-year effect on productivity for any biomass component. Grazing after fire reduced postgrazing grass biomass along the prescribed utilization gradient. Fire and grazing had no effect on total aboveground productivity the year after grazing compared to nonburned, nongrazed sites (1 327 vs. 1 249 ± 65 kg · ha−1). Fire and grazing increased grass productivity 16%, particularly for Pascopyrum smithii. The combined disturbances reduced forbs (51%), annual grasses (49%), and litter (46%). Results indicate grazing with up to 50% biomass removal the first growing season after summer fire was not detrimental to productivity of semiarid rangeland plant communities. Livestock exclusion the year after summer fire did not increase productivity or shift species composition compared to grazed sites. Reduction of previous years' standing dead material was the only indication that fire may temporarily reduce forage availability. The consistent responses among dry, wet, and near-average years suggest plant response is species-specific rather than climatically controlled.
    No preview · Article · Jan 2014 · Rangeland Ecology & Management
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    ABSTRACT: Native plant biodiversity loss and exotic species invasions are threatening the ability of many ecosystems to maintain key functions and processes. We currently lack detailed plant biodiversity data at a national scale with which to make management decisions and recommendations based on current conservation challenges. We collected plant biodiversity and exotic species richness data from 4 sites in the Northern Great Plains using the modified Whittaker (MW) and Natural Resources Inventory (NRI) methods to evaluate any major differences between indicators generated from these methods and offer recommendations based on findings. Our data indicated that the NRI protocols underestimated both total plant species richness and exotic species richness compared with the MW approach. More importantly, however, results show that biodiversity indicators from the two methods showed similar trends. Increasing time spent on making species richness measurements and implementing a more systematic approach to detecting species within a plot could improve biodiversity inventory and monitoring efforts in NRI while also providing a link between existing long-term data and any new information collected. These adjustments would ultimately help those interested in adopting NRI methods and using plant biodiversity data to increase the amount and quality of information collected.
    Full-text · Article · Jan 2014 · Ecological Indicators
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    Dustin J Strong · Amy C Ganguli · Lance T Vermeire
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    ABSTRACT: Fire behavior associated with wild and prescribed fires is variable, but plays a vital role in how a plant responds to fire. Understanding the relationship between fire behavior and rangeland plant community response will help to improve the use of prescribed fire to achieve management objectives. Fire is an important ecological process in many rangeland ecosystems and can be used as a tool to maintain grassland plant communities and shift community composition. Purple threeawn (Aristida pur-purea Nutt.) is a grass native to North America that has poor forage quality and the ability to form near monocultures. Therefore, the identification of tools to reduce purple threeawn abundance is desirable. We assessed the effects of summer and fall prescribed fire on purple threeawn plant basal area, tiller production , and plant mortality one growing season post fire in the northern Great Plains. Thermocouples and portable data loggers were used to measure the resumen
    Full-text · Article · Dec 2013 · Fire Ecology
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    Dustin J. Strong · Lance T. Vermeire · Amy C. Ganguli
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    ABSTRACT: Purple threeawn (Aristida purpurea Nutt. varieties) is a native grass capable of increasing on rangelands, forming near monocultures, and creating a stable state. Productive rangelands throughout the Great Plains and Intermountain West have experienced increases in purple threeawn abundance, reducing overall forage quality. Our objectives were to 1) reveal the effects of prescribed fire and nitrogen amendments on purple threeawn abundance and 2) assess nontarget plant response posttreatment. Season of fire (no fire, summer fire, fall fire) and nitrogen addition (0 kg N · ha−1, 46 kg N · ha−1, and 80 kg N · ha−1) were factorially arranged in a completely randomized design and applied to two similar sites in southeastern Montana. We evaluated fire and nitrogen effects on purple threeawn basal cover, relative composition, and current-year biomass one growing season postfire at two sites treated during different years. Spring weather following fire treatments was very different between years and subsequently impacted community response. Initial purple threeawn biomass at both sites was 1 214 ± 46 kg · ha−1 SEc. When postfire growing conditions were wet, current-year biomass of purple threeawn was reduced 90% and 73% with summer and fall fire, respectively. Under dry postfire growing conditions, purple threeawn current-year biomass was reduced 73% and 58% with summer and fall fire, respectively. Nitrogen additions had no effect on purple threeawn current-year biomass at either site. Current-year biomass of C3 perennial grass doubled with nitrogen additions and was not impacted by fire during a wet spring. Nitrogen additions and fire had no effect on C3 perennial grass current-year biomass following a dry spring. Prescribed fire appears to be a highly effective tool for reducing purple threeawn abundance on semiarid rangelands, with limited detrimental impacts to nontarget species.
    Full-text · Article · Sep 2013 · Rangeland Ecology & Management
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    ABSTRACT: a b s t r a c t Quantifying the effects of seasonal temperature and precipitation on cow–calf production on rangelands is challenging, as few long-term (420 yrs) studies have been reported. However, an understanding of how seasonal weather inconsistency affects beef production is needed for beef producers to better manage their herds on native rangelands to minimize enterprise risk with respect to climatic variability. Cow–calf beef production data collected at the USDA-ARS High Plains Grasslands Research Station near Cheyenne, WY, USA from 1975 to 2012 were tested using model averaging for effects of spring (April–June) and summer (July–September) temperature and precipitation, as well as prior winter (October–March) and prior growing season (April–September) precipitation on beef production. Two breeds were used at different times during the study period (Herefords from 1975 to 2001 and a Red Angus  Charolais  Sa-lers cross from 2003 to 2012; there was no grazing in 2002) and examined separately to test for differential effects of seasonal weather by breed. Herefords were more sensitive to seasonal weather patterns than the crossbreds, with Hereford pair total beef production showing the largest effect sizes and Hereford cows showing the highest R 2 value (0.66) among models. Wet springs and wet winters particularly increased Hereford beef production in this northern mixed-grass prairie, whereas beef production from the crossbreds did not show any weather effect patterns. The model structure used maximizes utility of these data to be built into decision support tools to help ranchers optimize stocking rates and minimize enterprise risk in advance of the grazing season. Published by Elsevier B.V.
    Full-text · Article · Aug 2013 · Livestock Science
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    ABSTRACT: Questions: What factors explain the variation in plant survival parameters across species and ecosystems? Location: Western North America. Methods: We compiled six long-term datasets from western North America to test for ecosystem-dependent demographic responses for forbs and grasses. Based on these data, we characterized 123 survivorship curves for 109 species. Three demographic parameters were extracted from these survivorship curves: survival rate at age 1, life expectancy at age 1, and a parameter describing the shape of the survivorship curve. We used a mixed-effects model to compare the differences in demographic parameters between life forms (forbs or grasses) and among ecosystems, incorporating “ecosystem” as a random factor, with life form treated as a categorical factor, and mean annual precipitation and mean annual temperature treated as continuous variables. Results: Grasses had higher survival and longer life expectancy than forbs at one year of age. Both forbs and grasses followed Type III survivorship curves, though forbs were closer to Type II compared to the grasses. Averaging across species, hazard ratios for whole survivorship curves differed among most ecosystems. While mean annual precipitation had no effect on any demographic parameter, mean annual temperature had a significantly negative effect on both first year survival rates and life expectancy for forbs. Conclusions: Our results demonstrate that life form exerts a strong influence on demographic parameters and their response to temperature variation among ecosystems. This unprecedented information on the age-specific demography of herbaceous plants has implications for population modeling and research on life history evolution and senescence. Linkage: http://onlinelibrary.wiley.com/doi/10.1111/jvs.12106/abstract
    Full-text · Article · Jul 2013 · Journal of Vegetation Science
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    ABSTRACT: Cattle weight gain responses to seasonal weather variability are difficult to predict for rangelands because few long-term (>20 yr) studies have been conducted. However, an increased understanding of temperature and precipitation influences on cattle weight gains is needed to optimize stocking rates and reduce enterprise risk associated with climatic variability. Yearling steer weight gain data collected at the USDA-ARS High Plains Grasslands Research Station at light, moderate, and heavy stocking rates for 30 years (1982-2011) were used to examine the effects of spring (April-June) and summer (July-September) temperature and precipitation, as well as prior-growing-season (prior April-September) and fall/winter (October-March) precipitation, on beef production (kg . ha(-1)). At heavier stocking rates, steer production was more sensitive to seasonal weather variations. A novel finding was that temperature (relatively cool springs and warm summers) played a large predictive role on beef production. At heavier stocking rates, beef production was highest during years with cool, wet springs and warm, wet summers, corresponding to optimum growth conditions for this mixed C-3-C-4 plant community. The novelty and utility of these findings may increase the efficacy of stocking rate decision support tools. The parsimonious model structure presented here includes three-month seasonal clusters that are forecasted and freely available from the US National Oceanic and Atmospheric Administration up to a year in advance. These seasonal weather forecasts can provide ranchers with an increased predictive capacity to adjust stocking rates (in advance of the grazing season) according to predicted seasonal weather conditions, thereby reducing enterprise risk.
    Full-text · Article · Jul 2013 · Rangeland Ecology & Management
  • M. L. Russell · L. T. Vermeire · N. A. Dufek · D. J. Strong
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    ABSTRACT: Aristida purpurea (purple threeawn) is a competitive native perennial grass with monoculturistic tendencies and poor palatability. We examined effects of fire, defoliation, and interspecific/intraspecific planting for 1) threeawn responses in the presence of threeawn, Bouteloua gracilis, or Pascopyrum smithii, and 2) B. gracilis and P. smithii response with threeawn. Biomass, aboveground production, tillers, and axillary buds were analyzed following two fire and four clipping treatments applied to three species-pair combinations in a completely randomized factorial design with nine replications. Fire killed 36% of threeawn. Fire reduced surviving threeawn biomass 61% and reduced production 27%. Threeawn production was greatest when neither plant was clipped and least when competing species were moderately clipped, or when both plants were severely clipped. Tiller counts of burned threeawn were similar among clipping treatments, and less than non-clipped or moderately clipped plants not burned. Fire decreased threeawn axillary buds on average by 25%. Moderately clipped plants had greater production than those from other clipping treatments across species. Average threeawn percentage of pot biomass was greater with B. gracilis (46 ± 3% SE) than P. smithii (38 ± 3% SE). Fire reduced threeawn from 60 ± 3% to 23 ± 3% of pot biomass, indicating good potential for rapid reductions in threeawn dominance and restoration of plant diversity with fire.
    No preview · Article · May 2013 · Rangeland Ecology & Management
  • David H. Branson · Lance T. Vermeire
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    ABSTRACT: Rangeland fire is a common naturally occurring event and management tool, with the amount and structure of biomass controlling transfer of heat belowground. Temperatures that grasshopper eggs are exposed to during rangeland fires are mediated by species-specific oviposition traits. This experiment examined egg mortality in two slant-faced grasshopper species with differing oviposition traits, namely Aulocara elliotti (Thomas) and Opeia obscura (Thomas). We hypothesized that A. elliotti egg mortality would increase with fire intensity because the shallow egg location below the soil surface would result in exposure to higher temperatures, and that the deeper O. obscura eggs would not be affected by fire intensity. Fire intensity did not significantly affect the mortality of O. obscura eggs, with very low mortality in all treatments. Fire intensity significantly affected mortality of A. elliotti eggs, which are laid in shallow egg pods with the midpoint of the egg clutch at a depth of ∼ 0.825 cm. Aulocara elliotti egg mortality increased with higher levels of heat application, with 79% egg mortality in the 4 500 kg · ha -1 heat treatment. Heat effects on A. elliotti egg mortality were similar to those previously observed for another shallow-egg-laying species. Limited research has examined if rangeland fires reduce population densities of specific economically important grasshopper species. The results from this experiment indicate that grasshopper species with the midpoint of the egg pod less than 1 cm below the surface are likely in general to be vulnerable to fire-induced egg mortality during rangeland fires.
    No preview · Article · Jan 2013 · Rangeland Ecology & Management
  • David H. Branson · Lance T. Vermeire
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    ABSTRACT: Background/Question/Methods Rangeland management practices such as burning or livestock grazing have the potential to manipulate the habitat of grasshoppers and/or their predators and thus impact population densities and community composition. Few studies have examined the effects of fire and grazing on grasshopper population dynamics in the northern Great Plains, especially during population increases. Interest in fire stems from its use as a management tool and unplanned events; however, there is increased interest in using fire to shift grazing animal distribution and to increase the structural heterogeneity of rangelands. As part of a study examining patch burning effects on plant community dynamics and grazing distribution in northern mixed prairie in Montana, we examined how patch burning and livestock grazing affects grasshopper population dynamics. Homogenous and heterogeneous management treatments were assigned to six pastures, with heterogeneity created by burning 25% of each treatment pasture in a given year. Patch burns occured during spring and fall of 2009. Total grasshopper density was estimated by counting the number of grasshoppers within a series of 60, 0.1m2 aluminum wire rings in each plot, with sweep net samples used to establish grasshopper community composition. Results/Conclusions Patch burning effects on grasshopper populations differed significantly between the spring and fall patch burn, likely due to differences in the timing of fire. There was no indication of strong effects from a spring patch burn on grasshoppers, when the most abundant grasshopper species would have been in the egg stage. Although a few grasshopper species overwinter as nymphs, these species were not dominant in these pastures. By contrast, fall patch burning negatively affected grasshopper population densities but there was little evident impact of patch grazing. The examination of species diversity metrics was constrained by the low replication in the study, but the effects of cattle grazing on grasshopper populations appeared smaller than patch burning.
    No preview · Conference Paper · Aug 2011

Publication Stats

501 Citations
81.22 Total Impact Points

Institutions

  • 2011
    • Agricultural Research Service
      Kerrville, Texas, United States
  • 2005
    • Oklahoma State University - Stillwater
      • Department of Plant and Soil Sciences
      SWO, Oklahoma, United States
  • 2004
    • University of Nebraska at Lincoln
      Lincoln, Nebraska, United States
  • 2000-2001
    • Texas Tech University
      Lubbock, Texas, United States