bluuebunny/crossref_metadata_2025 huggingface dataset:
Estilo(s) de Liderança de Diretores Escolares
Authors: Inocêncio Serafim António Martins , Grave-Resendes Lídia da Conceição
Published: June 2016

O objetivo principal desta investigação foi identificar e caraterizar o estilo(s) de liderança dos diretores em oito escolas secundárias da região do Alentejo-Portugal. Esta investigação pretendeu compreender, por um lado, a forma como os docentes e o pessoal não docente das escolas em estudo avaliam o comportamento apresentado pelo Diretor(a) na sua organização escolar através das suas perceções e por outro, o modo como essa liderança era percecionada pelos seus diretores. Optámos por um estudo de caso múltiplo, envolvendo não só uma abordagem qualitativa de cariz essencialmente descritivo / interpretativo, mas também outra quantitativa...Palavras-Chave: Gestão Escolar; Liderança Escolar; Estilos de Liderança; Diretores.
Exploring Inter-Departmental Variation in Departmental Stress Using Medical Claims Data
Authors: Britt David W. , Moore Lydia , Shuck Brad , Benson Patricia , Osam E. Kobena
Published: June 2016

Background:

Over the last several years there has been an increasing emphasis on making organizations healthy and functional places to work.

Objective:

To develop a scale of departmental stress from residualized, aggregated medical-claims data.

Methods:

Following the strategy of using aggregated individual data to infer the characteristics of larger units, we use medical-claims data from a metropolitan research university. Logged residuals of average individual medical claims are aggregated over a two-year period, controlling for compositional (% Female and % 50 and older) and other factors (Department size and Presence of a lab using toxic chemicals). We then examine the internal consistency and factor structure of a scale constructed from a reduced-set of 14 ICD-9 medical claim categories.

Results:

Our results indicate a dominant primary factor that explains 44% of the common variance. The scale is also internally consistent, with a Cronbach’s Alpha of. 87.

Conclusion:

We conclude that there is meaningful, coherent variation in medical claims across departments that is tentatively interpreted in terms of departmental stress.
Polyamines in relation to metal concentration, distribution, relative water content and abscisic acid in wheat plants irrigated with waste water heavily polluted with heavy metals
Authors: Aldesuquy Heshmat Soliman
Published: June 2016

Present study was carried out in order to investigate the effect of grain presoaking in spermine (0.15 mM), spermidine (0.3 mM) and their interaction on growth vigor, metal distribution as well as leaf turgidity and abscisic acid in wheat plants. Waste water at concentrations 25%, 50% and 100% caused noticeable decreases in growth vigor of root and shoot, leaf area, relative water content and water use efficiency. On the other hand, waste water stress caused remarkable increases in heavy metals and saturation water deficit as well as abscisic acid content of flag leaf. Exogenous application of Spm, Spd or their interaction could counteract the adverse effects of heavy metals in waste water by improving growth vigor of root and shoot, water use efficiency, retention of leaf turgidity and decreasing abscisic acid in leaves and grains. Furthermore, these polyamines reduced heavy metals translocation from root to leaves till reach to grains.
Medicinal plants and sustainable livelihood in Pauri district of Garhwal Himalaya, Uttarakhand, India.
Authors: Rawat Vardan Singh
Published: June 2016

The present study was conducted in the Thalisain block of Pauri Garhwal to document the medicinal plants used by the local communities. 53 plant species distributed in 38 families were documented. Of the total plant species 49% were herbs, 26% trees, 23% shrubs and 2% climbers. 16 different plant parts were used by local communities for different ailments. Medicinal plants were widely used by major sections of the community against common colds, cough, skin diseases, snake bite, fever, joint pains, bronchitis etc. Women and local healers called vaids have a vital role in environmental management due to traditional knowledge and use of plants as medicine with undocumented knowledge. It has been observed as one of the best option of sustainable livelihoods for the residents of the area.
Hepato-renal protective effects of gallic acid and p-coumaric acid in nicotinamide/streptozotocin-induced diabetic rats
Authors: Moneim* Adel Abdel , Abd El-Twab Sanaa M. , Ashour Mohamed B. , Yousef Ahmed I.
Published: June 2016

The goal of diabetes treatment is primarily to save life and alleviate symptoms and secondary to prevent long-term diabetic complications resulting from hyperglycemia. Thus, our present investigation was designed to evaluate the hepato-renal protective effects of gallic acid and p-coumaric acid in nicotinamide/streptozotocin (NA/STZ)-induced diabetic rats. Experimental type 2 diabetes was induced by a single intraperitoneal (i.p.) injection of STZ (65 mg/kg b.wt.), after 15 min of i.p. injection of NA (120 mg/kg b.wt.). Gallic acid and p-coumaric acid were orally administered to diabetic rats at a dose of 20, 40 mg/kg b.wt./day, respectively, for 6 weeks. Body weight, serum glucose, protein profile, liver function enzymes and kidney function indicators was assayed. Treatment with either gallic acid or p-coumaric acid significantly ameliorated the elevated levels of glucose, alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea and uric acid. Both compounds were also found to restore total protein, albumin, and globulin as well as body weight of diabetic rats to near normal values. It can conclude that both gallic acid and p-coumaric acid have potent hypoglycemic and hepato-renal protective effects in diabetic rats. Therefore, our results suggest promising hypoglycemic agents that can attenuate the progression of diabetic hepatopathy and nephropathy.
Composite fish culture for gainful employment
Authors: Panda Sasmita
Published: June 2016

Composite fish culture is a most popular technique to obtain maximum yield of fish from a pond/reservoir. The technology involves employment of compatible and non-competing fish culture through utilisation of different feeding zones of the pond or reservoir, resulting maximum production of fish per unit area of water. It is accomplished in four steps i.e. Pre stocking, Stocking, Post stocking and harvesting.
The Relation between serum uric acid & HbA1c in geriatric patients of Type 2 Diabetes in Amravati, Maharashtra, India.
Authors: W. Jagtap M. , H. Rohankar P. , Kale* Shital Ashokrao
Published: June 2016

Type 2 Diabetes mellitus (DM) is a heterogeneous disease which is characterized by variable degrees of insulin resistance or/and impaired insulin secretion as well as its deficiency (absolute/relative). The study was carried out to determine the relationship between serum concentration of uric acid and HbA1c among the geriatric group with type 2 diabetes mellitus in diabetic camps carried out at Amravati. We performed a cross sectional study on 30 patients of both genders of geriatric group, and a control group of 30 age and sex matched normal healthy individuals. Serum uric acid was tested by Uricase/PAP method [7, 15] and HbA1c by NycoCard READER II (color reflectometry) [6]. We observed the positive correlation between uric acid and HbA1c, as 0.080 which was found to be significant as 2.50 between the uric acid and HbA1c in geriatric patients of type 2 Diabetes. In healthy controls, we observed the positive correlation between uric acid and HbA1c as 0.074 which was not significant.
Diffussion-thermo and chemical reaction effects on an unsteady MHD free convection flow in a micropolar fluid
Authors: Sheri Siva , Shamshuddin M.D.
Published: June 2016

This paper considers a boundary layer analysis on the effects of
diffusion-thermo, heat absorption and homogeneous chemical reaction on mag-
netohydrodynamic flow of an incompressible, laminar chemically reacting mi-
cropolar fluid past a semi-infinite vertical porous plate is made
numerically. The governing partial differential equations are solved
numerically using the finite element method. The numerical results are
compared and found to be in good agreement with previous results as special
case of the present inves- tigation. The effects of the various important
parameters entering into the problem on the velocity, microrotation,
temperature and concentration fields within the boundary layer are discussed
and explained graphically. Also the effects of the pertinent parameters on
the local Skin friction coefficient, wall Couple stress and rates of heat
and mass transfer in terms of the local Nusselt and Sherwood numbers are
presented numerically in tabular form.
Hydrogen Sulfide Induces Keap1 S-sulfhydration and Suppresses Diabetes-Accelerated Atherosclerosis via Nrf2 Activation
Authors: Xie Liping , Gu Yue , Wen Mingliang , Zhao Shuang , Wang Wan , Ma Yan , Meng Guoliang , Han Yi , Wang Yuhui , Liu George , Moore Philip K. , Wang Xin , Wang Hong , Zhang Zhiren , Yu Ying , Ferro Albert , Huang Zhengrong , Ji Yong
Published: June 2016

Hydrogen sulfide (H2S) has been shown to have powerful antioxidative and anti-inflammatory properties that can regulate multiple cardiovascular functions. However, its precise role in diabetes-accelerated atherosclerosis remains unclear. We report here that H2S reduced aortic atherosclerotic plaque formation with reduction in superoxide (O2−) generation and the adhesion molecules in streptozotocin (STZ)-induced LDLr−/− mice but not in LDLr−/−Nrf2−/− mice. In vitro, H2S inhibited foam cell formation, decreased O2− generation, and increased nuclear factor erythroid 2–related factor 2 (Nrf2) nuclear translocation and consequently heme oxygenase 1 (HO-1) expression upregulation in high glucose (HG) plus oxidized LDL (ox-LDL)–treated primary peritoneal macrophages from wild-type but not Nrf2−/− mice. H2S also decreased O2− and adhesion molecule levels and increased Nrf2 nuclear translocation and HO-1 expression, which were suppressed by Nrf2 knockdown in HG/ox-LDL–treated endothelial cells. H2S increased S-sulfhydration of Keap1, induced Nrf2 dissociation from Keap1, enhanced Nrf2 nuclear translocation, and inhibited O2− generation, which were abrogated after Keap1 mutated at Cys151, but not Cys273, in endothelial cells. Collectively, H2S attenuates diabetes-accelerated atherosclerosis, which may be related to inhibition of oxidative stress via Keap1 sulfhydrylation at Cys151 to activate Nrf2 signaling. This may provide a novel therapeutic target to prevent atherosclerosis in the context of diabetes.
‘‘Silver Sagebrush Community Associations in Southeastern Alberta, Canada.’’ Rangeland Ecology & Management 58:400-405
Authors: Aldridge Cameron L. , Boyce Mark S. ,   Society for Range Management
Published: June 2016

Understanding the distribution and abundance of habitat and resources is an important issue in wildlife conservation and will advance understanding of wildlife habitat relationships (Morrison 2001). Jones et al. (2005) developed a vital habitat layer, describing the distribution of silver sagebrush (Artemisia cana Pursh) in southeastern Alberta, Canada, and identifying relationships between sagebrush characteristics and physiographic parameters. This paper adds greatly to our understanding of poorly-studied silver sagebrush communities and as Jones et al. (2005) point out, this is an important first step in developing management plans for sage-grouse (Centrocercus spp.) recovery. This product has recently been used to understand sage-grouse habitat relationships, linking habitat to the viability of the endangered Alberta greater sage-grouse (Centrocercus urophasianus) population (Aldridge 2005).
A Protocol for Retrospective Remote Sensing-Based Ecological Monitoring of Rangelands
Authors: Washington-Allen Robert A. , West Neil E. , Douglas Ramsey R. ,   Society for Range Management
Published: June 2016

The degree of rangeland degradation in the United States is unknown due to the failure of traditional field-based monitoring to capture the range of variability of ecological indicators and disturbances, including climatic effects and land use practices, at regional to national spatial scales, and temporal scales of decades. Here, a protocol is presented for retrospective monitoring and assessment of rangeland degradation using historical time series of remote sensing data and catastrophe theory as an ecological framework to account for both gradual and rapid changes of state. This protocol 1) justifies the use of time-series satellite imagery in terms of the spatial and temporal scale of data collection; 2) briefly explains how to acquire, process, and transform the data into ecological indicators; 3) discusses the use of time-series analysis as the appropriate procedure for detecting significant change; and 4) explains what reference conditions are appropriate. Landsat data have been collected and archived since 1972, and include complete coverage of US rangelands. Characteristics of land degradation can be retrospectively measured for a nearly 33-year trend using surrogate remote sensing-based indicators that correlate with changes in life-form composition (time series of thematic maps), declines in vegetation productivity (vegetation indices), accelerated soil erosion (soil indices), declines in soil quality (piospheric analysis), and changes in landscape configuration (time series of thematic maps). Aspects of 2 retrospective studies are presented as examples of application of the protocol to considerations of the land use impacts from military training and testing and ranching activities on rangelands.
Response of Two Semiarid Grasslands to a Second Fire Application
Authors: Carleton White S. , Rosemary Pendleton L. , Burton Pendleton K. ,   Society for Range Management
Published: June 2016

Prescribed fire was used in two semiarid grasslands to reduce shrub cover, promote grass production, and reduce erosional loss that represents a potential non-point-source of sediment to degrade water quality. This study measured transported soil sediment, dynamics in soil surface microtopography, cover of the woody shrub, grass, and bare ground cover classes, and soil fertility measured by nitrogen-mineralization potentials for the respective cover classes over a 9-year period during which 2 fires occurred. In general, the effects of two drought periods were equal to or greater than the effects of fire on the measured parameters. Following the second fire at the grama grass-dominated site, the number of live junipers was significantly lowered (P < 0.001). Fire consumed grass and shrub cover, which created the potential for greater transport of sediment and loss in soil surface elevation. Soil fertility under shrubs was significantly higher than soil fertility under grasses in both grassland sites before and after the first fire; however, that highly significant pattern was not present after the second fire for about 2 years at both sites. This suggests that the reestablishment of a natural fire frequency would likely dampen the well-documented pattern of greater soil fertility under shrub islands relative to grass islands. Repeat use of prescribed fire may keep shrub cover in check and promote fundamental changes in soil processes within semiarid grasslands, but its value must be weighed against the increased potential for erosion following fire.
Seed Production and Dispersal of Sulfur Cinquefoil in Northeast Oregon
Authors: Dwire Kathleen A. , Parks Catherine G. , Mclnnis Michael L. ,   Society for Range Management
Published: June 2016

Sulfur cinquefoil (family Rosaceae) is an invasive, herbaceous perennial, native to Eurasia. It has wide ecological amplitude and has become established throughout North America in numerous habitat types. Sulfur cinquefoil reproduces only by seed (achenes); however, little is known about its regenerative strategy or reproductive biology. To improve understanding of the mechanisms of expansion for sulfur cinquefoil, we quantified seed production and measured seed dispersal at sites infested with sulfur cinquefoil in different habitats in northeast Oregon. Seed dispersal was measured by using sticky traps (30 3 100 cm, replaced every 2 weeks) radiating in 4 cardinal directions from individual source plants. Estimated seed production for 2 years (2001 and 2002) was nearly 4 times higher than previously reported (»6 000 seeds per plant; range » 2 620- 15 150 seeds per plant). For most sites, seed production was similar in both years. However, site, year, and their interaction (site 3 year) had significant influence on flower and stem production. Seeds were dispersed from July through mid- October 2001, although almost 40% of the seeds were captured between mid-July and mid-August. Dispersal followed a classic decay function; approximately 83% of the seeds were captured within 60 cm of the source plants. Once sulfur cinquefoil reaches a site, it appears to spread and persist by releasing numerous seeds near the parent plants, thereby forming increasingly dense stands.
Evaluation of High-Resolution Satellite Imagery for Assessing Rangeland Resources in South Texas
Authors: Everitt J. H. , Yang C. , Fletcher R. S. ,   Society for Range Management
Published: June 2016

QuickBird satellite imagery was evaluated for differentiating among rangeland cover types on the Welder Wildlife Refuge in south Texas. The satellite imagery had a spatial resolution of 2.8 m and contained 11-bit data. Four subsets of the satellite image were extracted and used as study sites. Field spectral measurements made among the dominant vegetation types showed significant differences in visible and near-infrared reflectance. Unsupervised classification techniques were used to classify false color composite (green, red, and near-infrared bands) images of each study site. Accuracy assessments performed on the classification maps of the 4 sites had overall accuracies ranging from 79% to 89%. These results indicate that QuickBird imagery can be a useful tool for identifying rangeland cover types at a regional level.
Vegetation on Gunnison’s Prairie Dog Colonies in Southwestern Colorado
Authors: Grant-Hoffman Madeline N. , Detling James K. ,   Society for Range Management
Published: June 2016

Prairie dogs (Cynomys spp.) have been labeled keystone species because of the role they play as disturbance creators and ecosystem engineers in the western grasslands of North America. Most studies have concentrated on the black-tailed species (C. ludovicianus); however, other species of prairie dogs may have different effects on their ecosystems. We measured plant cover and biomass, canopy height, and plant nitrogen concentration on and off 6 Gunnison’s prairie dog (C. gunnisoni) towns and 6 paired areas off prairie dog towns in southern Colorado. Multivariate analysis of variance and analysis of variance showed no significant differences (P > 0.05) in vegetation cover or biomass on and off of Gunnison’s prairie dog towns, contrary to what has been found for black-tailed prairie dog towns. No significant differences were found in canopy height (P > 0.05); however, this may be due to already short vegetation (5-7 cm). Only 1 of 4 focal plants showed a significant difference in nitrogen concentration. No significant differences were found in species diversity on and off prairie dog towns; however, because of drought, these results are inconclusive. This study found few vegetation differences on and off Gunnison’s prairie dog towns. Furthermore, those differences were more subtle than those reported on black-tailed prairie dog towns. While the mechanisms for differences in vegetation on and off Gunnison’s prairie dog towns may be similar to those on black-tailed prairie dog towns, the magnitude of these differences may be different.
Comparison of Stocking Rates From Remote Sensing and Geospatial Data
Authors: Hunt E. Raymond , Miyake Brian A. ,   Society for Range Management
Published: June 2016

Remote sensing data from the Advanced Very High Resolution Radiometer (AVHRR) have coarse spatial resolution (1 km2 pixel size) and high temporal resolution, which can be used to estimate net primary production regionally. The normalized difference vegetation index (NDVI) is used to determine the fraction of absorbed photosynthetically active radiation, which is sensitive to differences in growth caused by a large year-to-year variation in precipitation. The 12-year average of net primary production was used to calculate stocking rates in animal-unit months per acre for the state of Wyoming. Stocking rates were also calculated for Wyoming from 1:500 000 scale soil and climate geospatial data layers based on stocking rates from the US Department of Agriculture Natural Resources Conservation Service Technician Guide to Range Sites and Range Condition. In a pixel-by-pixel comparison, there was a weak but significant correlation between the 2 methods based on the spatial distribution of precipitation. There were classes of vegetation type for which the AVHRR data predicted either much lower or much higher stocking rates. More work needs to be done to reduce geospatial data uncertainties for the determination of stocking rates from both NDVI and stocking rate tables. Remote sensing indicates the actual condition of vegetation, so this is an important step in the development of regional forecasting of range condition, trend, and projected stocking rates for decision support tools.
Estimating Biophysical Characteristics of Musk Thistle (Carduus nutans) With Three Remote Sensing Instruments
Authors: Mirik Mustafa , Steddom Karl , Michels Gerald L. ,   Society for Range Management
Published: June 2016

Identifying the dynamics and extent of noxious weeds in a spatial and temporal context improves monitoring, planning, and management practices. Musk thistle (Carduus nutans L.), a noxious weed, is a good candidate for detection by remote sensing platforms because it may produce a unique spectral signature due to a large, purple-red flower head. Therefore, 3 remote sensing instruments—a ground hyperspectral spectrometer, a multispectral ground radiometer, and an airborne hyperspectral imaging spectrometer—were used to establish regression models between reflected data and the biophysical parameters (density, height, flower head density, and percent ground cover) of musk thistle. The coefficients of determination (R2) obtained from simple regression models for vegetation indices and musk thistle biophysical variables ranged from 0.46 to 0.77. Multiple regression models with up to 3 variables increased R2 by an average of 0.07. This study indicated that normalized difference and simple ratio indices can be used for specific applications such as detection of musk thistle biophysical variables in rangelands. Once applied to the image, these results will produce a map of parameters that can be used to determine the size of infestation and the reduction in rangeland productivity.
Applying Improved Estimates of MODIS Productivity to Characterize Grassland Vegetation Dynamics
Authors: Reeves Mathew C. , Zhao Maosheng , Running Steven W. ,   Society for Range Management
Published: June 2016

Prescribed fire was used in two semiarid grasslands to reduce shrub cover, promote grass production, and reduce erosional loss that represents a potential non-point-source of sediment to degrade water quality. This study measured transported soil sediment, dynamics in soil surface microtopography, cover of the woody shrub, grass, and bare ground cover classes, and soil fertility measured by nitrogen-mineralization potentials for the respective cover classes over a 9-year period during which 2 fires occurred. In general, the effects of two drought periods were equal to or greater than the effects of fire on the measured parameters. Following the second fire at the grama grass-dominated site, the number of live junipers was significantly lowered (P < 0.001). Fire consumed grass and shrub cover, which created the potential for greater transport of sediment and loss in soil surface elevation. Soil fertility under shrubs was significantly higher than soil fertility under grasses in both grassland sites before and after the first fire; however, that highly significant pattern was not present after the second fire for about 2 years at both sites. This suggests that the reestablishment of a natural fire frequency would likely dampen the well-documented pattern of greater soil fertility under shrub islands relative to grass islands. Repeat use of prescribed fire may keep shrub cover in check and promote fundamental changes in soil processes within semiarid grasslands, but its value must be weighed against the increased potential for erosion following fire.
Herbaceous Restoration of Juniper Dominated Grasslands With Chaining and Fire
Authors: Ansley R. J. , Wiedemanm H. T. , Castellano M. J. ,   Society for Range Management
Published: June 2016

Juniper (Juniperus spp.) encroachment in grasslands usually progresses toward a stable woody state of mature trees that requires a significant disturbance to shift succession in another direction. Fire alone is often inadequate to shift succession in dense stands of mature juniper and must be preceded by a mechanical treatment such as chaining to reduce juniper competition and increase herbaceous growth that fuels a subsequent fire. However, little long-term data are available that measure combined effects of mechanical and fire treatments on restoration of juniper-dominated grasslands. Here, on a degraded (40% bare ground) north Texas site dominated by redberry juniper (Juniperus pinchotii Sudw), we quantify long-term herbaceous responses to mechanical chaining followed by fire. Two types of chaining, ground-level and elevated, were evaluated and all chained plots were burned 4 years after chaining. Herbaceous and woody responses were measured for several years after both chaining and fire treatments and compared to untreated controls. At study termination, both of the chaining + fire treatments reduced juniper cover from 32% to < 6%, but mortality was < 10%, because most plants basal-sprouted. Total grass production did not increase in chained treatments over the untreated until 3 growing seasons after chaining. Grass production declined the first growing season following the fire treatment, but increased in treated plots to 3 times the untreated the second and third year postfire. Total grass cover in treated plots did not increase over the untreated until the second year after the fire treatment. There was no difference in juniper or herbaceous responses between the 2 chain types. Results suggest increases in herbaceous production from chaining alone were due to increased growth of existing vegetation patches whereas the fire treatment appeared to stimulate herbaceous recruitment into bare soil areas.
The Accuracy of Ground-Cover Measurements
Authors: Booth D. T. , Cox S. E. , Meikle T. W. ,   Society for Range Management
Published: June 2016

Ground cover is a key indicator of rangeland condition and influences rangeland management decisions, yet there have been few advances in ground-cover measurement methods. The advent of digital photography and automated image processing promise a revolution in the way ground cover is measured. To assess the potential for automation we compared conventional and automated methods for measuring ground cover against known artificial populations. The known populations were created from 20 nadir images of a Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle Young) vegetation type acquired with a 5-megapixel Olympus E20 digital single lens reflex camera mounted on an aluminum camera frame at 2 m above ground level. The images were converted to color, 2-dimensional images that no longer represented real-world conditions but had known cover values and conserved a simplified form of the pattern and spatial context of the plant community. These images were then printed at 1:1 scale to a 1 X 1-m poster. Posters were evaluated for color cover under laboratory conditions using the conventional techniques of steel-point frame, laser-point frame, line-point intercept, ocular estimation, and line intercept. Photographs of the posters were measured for color cover using standard and custom-created algorithms within the VegMeasure image analysis framework, and using the Digital Grid Overlay method. Results indicate that conventional techniques had significantly greater correlation (92% agreement of measured to known) than measurements from the algorithms used in the VegMeasure analysis (70%). The critical factor influencing accuracy of point-sampling methods was the area of the contact point for the given method. These findings provide an important measure of relative accuracy among methods for land managers and for researchers seeking to improve rangeland monitoring methods.
Do Pasture-Scale Nutritional Patterns Affect Cattle Distribution on Rangelands?
Authors: Ganskopp Dave , Bohnert Dave ,   Society for Range Management
Published: June 2016

Heterogeneous distribution of ungulates about the landscape can be a particularly vexing problem for resource managers. Although livestock preferences for leaves over stems among plants and patches of herbage are well documented, effects of senescent for- age (herbage supporting both green and cured materials) on cattle distribution and nutrition at pasture scales have not been investigated. Our primary objective was to determine the proportions of time cattle spent foraging within senescent and con- ditioned sectors (areas supporting only current season’s herbage) of pastures. Other endeavors included the following: comparing velocities of foraging cattle in conditioned and senescent sectors, determining diet quality of cattle confined to conditioned and senescent treatments, and quantifying levels of forage utilization by cattle in conditioned and senescent treatments. Global positioning system collars were used to track cattle movement and activity in treated crested wheatgrass (Agropyron desertorum [Fisher ex Link] Schultes) pastures. Over a 7-day trial, cattle were found in senescent and conditioned areas 41% and 59% of the time, respectively. When cattle were grazing, 32% of observations were in senescent sectors and 68% were in conditioned areas. With a decline in standing crop in the conditioned treatment, cattle switched to senescent herbage (73% of observations) on day 7. Standing crop was reduced by 13% to 40% in conditioned sectors and increased by 10% in senescent areas. Despite dispa- rities in the crude protein of standing crops in senescent (x= 6.5%) and conditioned (x= 11.3%) treatments, cattle confined to treatment harvested diets of similar quality (x= 13.6% CP) at turn-out. Cattle walked farther when making transitions between treatments, and walked farther each day as the trial progressed. A preference of foraging cattle for portions of pastures grazed (con- ditioned areas) during the previous growing season suggests that utilization patterns established by livestock are self-sustaining.
Fluxes of CO2 From Grazed and Ungrazed Tallgrass Prairie
Authors: Owensby Clenton E. , Ham Jay M. , Auen Lisa M. ,   Society for Range Management
Published: June 2016

To determine the impact of seasonal steer grazing on annual CO2 fluxes of annually burned native tallgrass prairie, we used relaxed eddy accumulation on adjacent pastures of grazed and ungrazed tallgrass prairie from 1998 to 2001. Fluxes of CO2 were measured almost continuously from immediately following burning through the burn date the following year. Aboveground biomass and leaf area were determined by clipping biweekly during the growing season. Carbon lost because of burning was estimated by clipping immediately prior to burning. Soil CO2 flux was measured biweekly each year using portable chambers. Steers were stocked at twice the normal season-long stocking rate (0.81 ha steer-1) for the first half of the grazing season (– May 1 to July 15) and the area was left ungrazed the remainder of the year. That system of grazing is termed ‘‘intensive-early stocking.’’ During the early growing season, grazing reduced net carbon exchange relative to the reduction in green leaf area, but as the growing season progressed on the grazed area, regrowth produced younger leaves that had an apparent higher photosynthetic efficiency. Despite a substantially greater green leaf area on the ungrazed area, greater positive net carbon flux occurred on the grazed area during the late season. Net CO2 exchange efficiency was greatest when grazing utilization was highest. We conclude that with grazing the reduced ecosystem respiration, the open canopy architecture, and the presence of young, highly photosynthetic leaves are responsible for the increased net carbon exchange efficiency. Both GR and UG tallgrass prairie appeared to be carbon-storage neutral for the 3 years of data collection (1998 ungrazed: – 31 g C m-2, 1998 grazed: –5 g C m-2; 1999 ungrazed: –40 g C m-2, 1999 grazed: –11 g C m-2; 2000 ungrazed: +66 g C m-2, 2000 grazed: 0 g C m-2).
Elevated Atmospheric CO2 Magnifies Intra-specific Variation in Seedling Growth of Honey Mesquite: An Assessment of Relative Growth Rates
Authors: Polley Wayne H. , Tischler Charles R. , Johnson Hyrum B. ,   Society for Range Management
Published: June 2016

The shrub honey mesquite (Prosopis glandulosa var. glandulosa Torr.) readily encroaches into rangelands in the southwestern United States that vary in annual rainfall by almost a factor of 5 (200 to 1 000 mm). This occurs partly because mesquite seedlings grow rapidly and become uncoupled from competition with established herbaceous vegetation. Species that occupy such a wide precipitation gradient frequently include plants that differ genetically in seedling growth rate. Whether atmospheric carbon dioxide (CO2) enrichment affects seedling biomass uniformly across mesquite genotypes or magnifies the expression of genetic variation in seedling growth remains unresolved. We measured the effects of CO2 enrichment on growth of seedlings derived from 14 adult plants (open-pollinated families), 7 plants each from rangelands located near extremes of the rainfall gradient occupied by the shrub (arid southeastern New Mexico vs. mesic central Texas). Growth was measured over days 10 to 30 following emergence on well-watered seedlings in glasshouses at ambient and elevated CO2 concentrations (391 and 706 lmol mol-1, respectively). Proportional responses of biomass (day 30) to CO2 enrichment varied from 1.03 to 1.74 among families. CO2 enrichment did not consistently favor the largest or fastest-growing families at ambient CO2. Rather, proportional responses of biomass to elevated CO2 were highly correlated across families with the stimulation of relative growth rate (RGR) at elevated CO2. Biomass at ambient CO2 was 19% greater, on average, in families from mesic rangeland than from arid rangeland, but families from extremes of the precipitation gradient did not diverge by seedling size or response to CO2. Selection for greater RGR could augment the mean growth response of mesquite seedlings to CO2. Even in the absence of selection, CO2 enrichment could increase mesquite establishment by enhancing seedling growth and thereby exacerbate the management challenge of minimizing woody encroachment.
Cattle Consumption of Velvet Lupine (Lupinus leucophyllus) in the Channel Scablands of Eastern Washington
Authors: Ralphs Michael H. , Panter Kip E. , Gay Clive ,   Society for Range Management
Published: June 2016

Certain lupines (Lupinus spp.) contain alkaloids that cause contracture-type skeletal birth defects and cleft palate (‘‘crooked calf syndrome’’) when consumed by cows during the 40th to 70th day of gestation. The objective of this study was to determine when cattle graze velvet lupine (Lupinus leucophyllus Dougl.) during its phenological development, and whether this period overlaps the critical period of gestation. Grazing studies were conducted in 2001, 2002, and 2003 in the same 100 ha pasture in eastern Washington. A second objective was addressed in 2001 to determine if cows with crooked calves consumed more lupine than cows with normal calves. Five mature Hereford cows with crooked calves at their side and 6 mature Hereford cows with normal calves grazed together for the summer. There was no difference (P = 0.17) in the amount of lupine consumed between groups, and all cows consumed some lupine. In 2002, 10 3-year-old Hereford cows with normal calves were used, and in 2003, 8 of the same cows from the 2002 study with normal calves were used. In all 3 years, cows started consuming lupine in July and August after annual grasses dried and annual forbs matured. Lupine is a deep-rooted perennial that remained green and succulent longer into the summer than the associated forages. Concentration of the teratogenic alkaloid anagyrine declined as lupine seeds shattered in late June and early July. Lupine consumption occurred during the critical period of gestation in 2 of the 3 years, but no crooked calves were produced. Apparently, the cows did not ingest sufficient amounts of anagyrine over the susceptible period of time to produce crooked calves. The management recommendation for this site is to restrict access to lupine during July when cattle begin to graze lupine and anagyrine levels may still be relatively high. Once the seeds shatter, toxicity greatly declines.
Effects of Livestock Grazing on Duck Nesting Habitat in Utah
Authors: West Ben C. , Messmer Terry A. ,   Society for Range Management
Published: June 2016

Periodic vegetation disturbance is an important yet controversial tool for waterfowl managers. Some have reported livestock grazing removes residual vegetation and thus is detrimental to nesting ducks, and others argue that such disturbance is necessary to maintain grassland health. We evaluated the impact of winter livestock grazing on duck nesting at Bear River Migratory Bird Refuge, Utah. During winter 1999, 6 experimental plots were grazed by cattle and 6 were ungrazed; in winter 2000, 8 plots were grazed and 8 were ungrazed. All grazing treatments were conducted during 15 November-15 March and averaged a stocking rate of 9.5 animal unit months/ha. During the following spring nesting season, we measured visual obstruction readings (VOR) on grazed and ungrazed sites. Although VOR on ungrazed sites were greater than those on grazed sites, this difference became less important as the nesting season progressed. Winter grazing impacted the nesting habitat of early-nesting ducks such as mallards (Anas platyrhynchos), but not that of late-nesting species such as cinnamon teal (Anas cyanoptera) and gadwall (Anas strepera). When using livestock grazing to manage grasslands, waterfowl managers should consider their management goals, the species composition of breeding duck populations, and environmental conditions.
Sideoats Grama Growth Responses to Seasonal Fires and Clipping
Authors: Ansley James R. , Castellano Michael J. , Pinchak William E. ,   Society for Range Management
Published: June 2016

There is increased interest in the use of summer-season fires to limit woody plant encroachment on southern prairie grasslands, but collateral effects of these fires on grasses are poorly understood. We quantified effects of repeated winter fires, repeated summer fires, simulated grazing (clipping), and their interaction on yields of the C4 midgrass, sideoats grama (Bouteloua curtipendula) in northern Texas. Monoculture patches of sideoats grama were exposed to 1 of 3 fire treatments: 1) no burn, 2) 2 winter fires in 3 years, or 3) 2 summer fires in 3 years; and to 1 of 2 clip treatments (no clip or clip once each spring). Total yield (live + standing dead), live yield, percent live tissue, and foliar cover were measured in spring and late-growing season (late-season) over a 7-year period. In unclipped plots, late-season total yield did not fully recover until 2 growing seasons after winter fires and 3 growing seasons after summer fires. By 5 years postfire, total yield was greater in both fire treatments than in the no burn. Live yields recovered more quickly than total yields following summer fires but never exceeded the no burn. Percent live tissue was greater in both fire treatments than in the no burn for up to 2 years postfire. Clipping reduced total and live yields in the no burn and winter-fire treatments but not in the summer-fire treatment. By 5 years postfire, total and live yields were greater in the summer fire + clip than the no burn + clip or winter fire + clip treatments. Results suggest that 1) sideoats grama is tolerant of summer fires but full recovery may require at least 3 years, and 2) in the long-term, summer fire + clipping may stimulate sideoats grama production more than winter fire + clipping or clipping alone.
Changes in Soil Properties and Enzymatic Activities Following Manure Applications to a Rangeland
Authors: Bell Jourdan M. , Robinson Clay A. , Schwartz Robert C. ,   Society for Range Management
Published: June 2016

Manure amendments to rangelands may alter soil functions related to nutrient recycling. We investigated the influence of grazing and cattle manure on soil carbon, nitrogen, Mehlich 3 phosphorus, and activities of alkaline phosphatase and dehydrogenase. Fertilizer treatments (unamended, manure, or urea + potassium dihydrogen phosphate [KH2PO4] fertilizer) were imposed under grazed and nongrazed conditions in a short-grass native rangeland. Manure was applied at rates of – 125 kg N ha-1 and – 42 kg P ha-1, and urea + KH2PO4 was applied at 75 kg N ha-1 and 20 kg P ha-1, respectively. Total aboveground biomass and soil samples at 4 depths (0-200 mm) were collected throughout 2 growing seasons. A controlled environment study also evaluated fertilizer source effects on enzymatic activities at 5 P rates (0-120 mg kg-1 P as manure or urea + KH2PO4). Amendments significantly (P < 0.05) increased extractable P following the second application for the 3 uppermost depth increments. Extractable P was greatest on manure-amended plots, increasing 44% from February 1999 to July 2000 at the surface. However, increases in P extractability as a proportion of total P applied were similar for manure and KH2PO4. Enzymatic activities were significantly (P < 0.001) influenced by sampling date and soil depth. There were no consistent grazing effects on enzyme activities. Amendments did not influence dehydrogenase activities in the field; however, in the controlled environment, activities averaged 16% greater across all rates for manure-amended soil as compared with urea + KH2PO4-amended soil (P = 0.025). Phosphatase activities increased significantly following manure applications under both field (P = 0.007) and controlled environment (P = 0.003) conditions. Elevated phosphatase activities following manure applications probably led to enhanced P mineralization and similar P extractabilities as a proportion of total P applied for manure- and KH2PO4-amended soils. Therefore, when determining applications rates, total manure P should be considered bioavailable.
An Advanced, Low-Cost, GPS-Based Animal Tracking System
Authors: Clark Patrick E. , Johnson Douglas E. , Kniep Mark A. ,   Society for Range Management
Published: June 2016

An improved global positioning system (GPS)-based animal tracking system is needed to meet quickly evolving demands of ecological research, range livestock production, and natural resource management. Commercially available tracking systems lack the data storage capacity needed to frequently collect animal location data (e.g., 15-minute intervals or less) over long-term deployment periods (e.g., 1 year or more). Some commercial systems have remote data-download capabilities, reducing the need to recapture tagged animals for data retrieval, but these systems download data via satellite (Argos), global system for mobile communications (GSM) cellular telephone, or telemetry radio frequencies. Satellite systems are excessively expensive, and GSM cellular coverage is extremely limited within the United States. Radio-based systems use narrow-band very-high- or ultra-high frequencies requiring the user to obtain frequency allocations. None of these existing systems were designed to provide continual, real-time data access. The Clark GPS Animal Tracking System (Clark ATS) was developed to meet the evolving demands of animal ethologists, ecologists, natural resource managers, and livestock producers. The Clark ATS uses memory-card technology for expandable data storage from 16 megabytes to 8 gigabytes. Remote data downloading and program uploading is accomplished using spread-spectrum radio transceivers, which do not require narrow-band radio frequency allocations. These radios also transmit, at a user-defined time interval, a real-time, GPS-location beacon to any Clark ATS base station within range (about 24 km or 15 miles line of sight). Advances incorporated into the Clark ATS make it possible to evaluate animal behavior at very fine spatial- and temporal-resolution over long periods of time. The real-time monitoring provided by this system enables researchers to accurately examine animal distribution and activity responses to acute, short-term disturbances relative to longer- term behavioral patterns. The Clark ATS also provides a huge time- and cost-savings to researchers and natural resource managers attempting to relocate a tagged animal in the field for direct observation or other operations.
Nutritive Quality of Big Bluestem (Andropogon gerardii) and Eastern Gamagrass (Tripsacum dactyloides) Exposed to Tropospheric Ozone
Authors: Lewis John S. , Ditchkoff Stephen S. , Lin Jihn C. ,   Society for Range Management
Published: June 2016

Tropospheric ozone (O3) is a phytotoxic air pollutant widespread in industrialized nations of the world. Ozone is produced by the photo-oxidation of hydrocarbons released into the atmosphere by combustion of fossil fuels. Studies demonstrate O3 can be transported from metropolitan areas to rural areas important to agricultural and forestry practices. Reports regarding O3 effects have focused on vegetation important to food production or agronomic crops of economic importance. However, relatively little is known about O3 effects on native plant species. The effects of tropospheric O3 on two warm-season grasses, eastern gamagrass (Tripsacum dactyloides L.) and big bluestem (Andropogon gerardii Vitman), were examined during June-September of 2003. Plants were fumigated with three levels of O3 in a randomized-block experiment with three replicates of each treatment. Grasses were grown in open-top chambers with introduced carbon-filtered (CF) air, characteristic of clean air quality; non-filtered (NF) air, representative of quality in Auburn, AL; and air with double (2X) the ambient concentration of O3. Because forage quality can be as important as quantity, we determined various effects on nutritive quality characteristics in addition to biomass yield. Big bluestem exhibited little response to O3 exposure. For eastern gamagrass, we generally found decreased nutritive quality with increasing O3 exposure as evidenced by increased concentrations of cell wall constituents and decreased concentrations of N. Regrowth of both species exhibited little treatment effect which emphasizes the importance of timing and duration of O3 exposures in relation to physiological stage of plant development. Decreased nutritive quality parameters observed for eastern gamagrass may have implications to diet selection and nutrient intake by ruminant herbivores. In addition, range managers can use species-specific information regarding O3 sensitivity to make decisions about mechanical harvesting and grazing regimes of these forages growing in areas exposed to elevated O3 concentrations.