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Sample records for grazing whiteclover red

  1. Potential Activity, Size, and Structure of Sulfate-Reducing Microbial Communities in an Exposed, Grazed and a Sheltered, Non-Grazed Mangrove Stand at the Red Sea Coast

    PubMed Central

    Balk, Melike; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    After oxygen, sulfate is the most important oxidant for the oxidation of organic matter in mangrove forest soils. As sulfate reducers are poor competitors for common electron donors, their relative success depends mostly on the surplus of carbon that is left by aerobic organisms due to oxygen depletion. We therefore hypothesized that sulfate-cycling in mangrove soils is influenced by the size of net primary production, and hence negatively affected by mangrove degradation and exploitation, as well as by carbon-exporting waves. To test this, we compared quantitative and qualitative traits of sulfate-reducing communities in two Saudi-Arabian mangrove stands near Jeddah, where co-occurring differences in camel-grazing pressure and tidal exposure led to a markedly different stand height and hence primary production. Potential sulfate reduction rates measured in anoxic flow-through reactors in the absence and presence of additional carbon sources were significantly higher in the samples from the non-grazed site. Near the surface (0–2 cm depth), numbers of dsrB gene copies and culturable cells also tended to be higher in the non-grazed sites, while these differences were not detected in the sub-surface (4–6 cm depth). It was concluded that sulfate-reducing microbes at the surface were indeed repressed at the low-productive site as could be expected from our hypothesis. At both sites, sulfate reduction rates as well as numbers of the dsrB gene copies and viable cells increased with depth suggesting repression of sulfate reduction near the surface in both irrespective of production level. Additionally, sequence analysis of DNA bands obtained from DGGE gels based on the dsrB gene, showed a clear difference in dominance of sulfate-reducing genera belonging to the Deltaproteobacteria and the Firmicutes between sampling sites and depths. PMID:26733999

  2. Grazing Occultations.

    ERIC Educational Resources Information Center

    Cunningham, Doug; Hlynialuk, John

    1983-01-01

    A "grazing occultation" occurs when a star or other astronomical body is covered up by the extreme northern or southern limb of the moon in its easterly motion about the earth. Graze phenomena, organizing a graze expedition, and the scientific/educational value of observing grazes are among the topics discussed. (JN)

  3. Direct and indirect effects of high pCO2 on algal grazing by coral reef herbivores from the Gulf of Aqaba (Red Sea)

    NASA Astrophysics Data System (ADS)

    Borell, E. M.; Steinke, M.; Fine, M.

    2013-12-01

    Grazing on marine macroalgae is a key structuring process for coral reef communities. However, ocean acidification from rising atmospheric CO2 concentrations is predicted to adversely affect many marine animals, while seaweed communities may benefit and prosper. We tested how exposure to different pCO2 (400, 1,800 and 4,000 μatm) may affect grazing on the green alga Ulva lactuca by herbivorous fish and sea urchins from the coral reefs in the northern Gulf of Aqaba (Red Sea), either directly, by changing herbivore behaviour, or indirectly via changes in algal palatability. We also determined the effects of pCO2 on algal tissue concentrations of protein and the grazing-deterrent secondary metabolite dimethylsulfoniopropionate (DMSP). Grazing preferences and overall consumption were tested in a series of multiple-choice feeding experiments in the laboratory and in situ following exposure for 14 d (algae) and 28 d (herbivores). 4,000 μatm had a significant effect on the biochemical composition and palatability of U. lactuca. No effects were observed at 1,800 relative to 400 μatm (control). Exposure of U. lactuca to 4,000 μatm resulted in a significant decrease in protein and increase in DMSP concentration. This coincided with a reduced preference for these algae by the sea urchin Tripneustes gratilla and different herbivorous fish species in situ (Acanthuridae, Siganidae and Pomacanthidae). No feeding preferences were observed for the rabbitfish Siganus rivulatus under laboratory conditions. Exposure to elevated pCO2 had no direct effect on the overall algal consumption by T. gratilla and S. rivulatus. Our results show that CO2 has the potential to alter algal palatability to different herbivores which could have important implications for algal abundance and coral community structure. The fact that pCO2 effects were observed only at a pCO2 of 4,000 μatm, however, indicates that algal-grazer interactions may be resistant to predicted pCO2 concentrations in the

  4. Ecology of the red-tide dinoflagellate Ceratium furca: distribution, mixotrophy, and grazing impact on ciliate populations of Chesapeake Bay.

    PubMed

    Smalley, Gabriela W; Coats, D Wayne

    2002-01-01

    Ceratium furca is a primarily photosynthetic dinoflagellate also capable of ingesting other protists. During 1995 and 1996, we documented the abundance of C. furca in Chesapeake Bay and determined grazing rates on prey labeled with fluorescent microspheres. Abundance usually remained below 20 cells ml(-1), although the species was capable of localized late-summer blooms (< or = 478 cells ml(-1)) in the more saline lower to mid-Bay region. Feeding rates ranged from 0 to 0.11 prey dinoflagellate(-1) h(-1) or from 0 to 37 pg C dinoflagellate(-1) h(-1) and were highest at lower salinities. Clearance rates averaged 2.5 +/- 0.35 microl dinoflagellate(-1) h(-1). Impact of C. furca feeding on prey populations was higher in the lower Bay, averaging 67% of Strobilidium spp. removed d(-1). Ingestion rates were positively correlated with prey abundance and dissolved inorganic nitrogen, but negatively with salinity, depth, dissolved inorganic phosphorus, and inorganic P:N ratio. Daily consumption of prey biomass by C. furca averaged 4.6% of body carbon, 6.5% of body nitrogen, and 4.0% of body phosphorus. with maximal values of 36, 51, and 32%, respectively. Thus, the ability to exploit an organic nutrient source when inorganic nutrients are limiting may give C. furca a competitive advantage over purely photosynthetic species.

  5. Amazing Grazing.

    ERIC Educational Resources Information Center

    Peterson, Cris

    Countless acres of grasslands stretch across the American West. Centuries ago, bison roamed the range freely and lived off the grass. By the 19th century, herds of cattle grazed the same land. Over time, much of the original grassland was either plowed and planted or trampled to dust, causing the topsoil to dry up and blow away. Today many…

  6. [The supply of wild ruminants with major and trace elements. 1. The cadmium content of winter grazing and the cadmium status of red deer, fallow deer, roes and moulons].

    PubMed

    Anke, M; Grün, M; Briedermann, L; Missbach, K; Hennig, A; Kronemann, H

    1979-12-01

    The Cd-determination of 10 different winter grazings for wild ruminants in seven different biotopes showed significant differences of the habitats resulting from the previous Cd-emission of metallurgy smelting non-ferrous metals. The winter grazing of the Tharandt Forest and the Harz mountains contained significantly more Cd than that of the Lower Flaming hills, the western Erzgebirge and the northern agrarian areas. The bark and the tips of conifer twigs, twigs of oak and mountain ash, bilberry and heather plants, i. e. perennial plants resp. parts of plants proved to be particularly rich in Cd. On an average, wild ruminants consume more Cd than domesticated ruminants, which do not consume parts of perennial plants. The rumen contents of all wild ruminants contained, with 0.20 to 0.25 mg/kg dry matter more Cd than could be expected from the content of the grazing. In the Cd-contaminated areas the amount of Cd in the rumen contents too showed the Cd-load. The kidneys, livers and the covering hair of a total of 172 head red deer, roes and mouflons reflected the Cd-load and the dependence of the Cd-level on the age. The Cd-concentration ascertained in the organs of the wild ruminants was compared with that of sheep and cattle. The, on an average, higher Cd-load of the wild ruminants was confirmed. The kidneys of wild ruminants older than five years should, as a general principle, not be eaten and neither should the livers of animals from Cd-contaminated biotopes. The limb defects of mouflons from Cd-contaminated areas are discussed in connection with Cd-induced secondary Cu-deficiency resp. Mn- and Zn-deficiency. A reference is made to further works.

  7. Biochanin A, an isoflavone produced by red clover, promotes weight gain of steers grazed in mixed grass pastures and fed dried-distillers' grains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochanin A (BCA) is an isoflavone produced by red clover (Trifloium pratense L.) that can inhibit hyper-ammonia producing bacteria (HAB) to reduce deamination in the rumen and increase the feed amino acids available for gastric digestion. An in vitro experiment was conducted to evaluate the effect...

  8. MONITORING GRAZING LANDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An important step in developing a ranch or allotment management plan for grazing lands is defining a rangeland monitoring program to evaluate progress toward achieving management objectives. A monitoring program can: 1) help determine the benefits gained from changes in grazing management or invest...

  9. Prescribed grazing on pasturelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Principles of grazing management center round the temporal and spatial distribution of various kinds and number of livestock. Within the context of this chapter, management of grazing or browsing will be characterized in terms of intensity, method, and season (timing), and as a function of the type ...

  10. An international terminology for grazing lands and grazing animals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 1991, Terminology for Grazing Lands and Grazing Animals was published with the objective of ‘developing a consensus of clear definitions of terms used in the grazing of animals.’ During the XVIII International Grassland Congress, held in Canada in 1997, a new Terminology working group was formed ...

  11. Advances in grazing distribution practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing distribution management practices are intended to improve livestock production efficiency while conserving or enhancing environmental conditions, and sustaining or promoting other ecosystem services on grazed lands. Ancient practices such as herding, fencing, vegetation treatment (e.g., fi...

  12. 25 CFR 700.711 - Grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Grazing permits. 700.711 Section 700.711 Indians THE... Grazing § 700.711 Grazing permits. (a) All livestock grazed on the New Lands must be covered by a grazing... residency on the New Lands Range Unit of permit issue, and (4) Own livestock which graze on the range...

  13. 25 CFR 700.711 - Grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Grazing permits. 700.711 Section 700.711 Indians THE... Grazing § 700.711 Grazing permits. (a) All livestock grazed on the New Lands must be covered by a grazing... residency on the New Lands Range Unit of permit issue, and (4) Own livestock which graze on the range...

  14. 25 CFR 700.709 - Grazing privileges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Grazing privileges. 700.709 Section 700.709 Indians THE... Grazing § 700.709 Grazing privileges. (a) A list of permittees eligible to receive grazing permits is kept... individuals eligible for New Lands grazing permits who: (1) Have a current HPL grazing permit, or have had...

  15. 25 CFR 700.709 - Grazing privileges.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Grazing privileges. 700.709 Section 700.709 Indians THE... Grazing § 700.709 Grazing privileges. (a) A list of permittees eligible to receive grazing permits is kept... individuals eligible for New Lands grazing permits who: (1) Have a current HPL grazing permit, or have had...

  16. Grazing: the whole picture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Environmental concerns for our farms include nutrient leaching to ground water, runoff in surface water, gaseous emissions, and the carbon footprint of our production systems. Recent reports have labeled grazing-based dairies as less environmentally sustainable compared to year around confinement sy...

  17. 25 CFR 167.12 - Grazing fees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing fees. 167.12 Section 167.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.12 Grazing fees. Grazing fees shall not be charged at this time. 1 1 Grazing Committees were organized in May...

  18. 25 CFR 167.12 - Grazing fees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Grazing fees. 167.12 Section 167.12 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.12 Grazing fees. Grazing fees shall not be charged at this time. 1 1 Grazing Committees were organized in May...

  19. Adaptive grazing management experiment: The new frontier of grazing management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Adaptive Grazing Management experiment at the USDA-ARS Central Plains Experimental Range addresses important gaps in our current understanding of grazing management including: 1) lack of management-science partnerships to more fully understand the effect of management decisions, 2) need for mana...

  20. Simulating rotational grazing management.

    PubMed

    Cros, M J; Duru, M; Garcia, F; Martin-Clouaire, R

    2001-09-01

    Dairy systems predominantly based on rotational grazing are notoriously hard to manage. In order to ensure profitability, this type of production requires quite good organisation, planning, and operating capability on the part of the farmer. A simulation-based decision support system, called SEPATOU, has been developed for this purpose. At the core of the decision support approach lies an explicit and rigorous modelling of the management strategy that underlies a dairy farmer's decision-making behaviour (real or hypothetical). The SEPATOU system is a discrete-event simulator that reproduces the day-to-day dynamics of the farmer's decision process and the response of the controlled biophysical system for which models of grass growth, animal consumption, and milk production are used. SEPATOU provides the means to evaluate and compare tentative strategies by simulating their application throughout the production season under different hypothetical weather conditions. The relative worth of a strategy can be assessed by analysing the effects on the biophysical system and their variability across the representative range of possible conditions that is considered. The activities to be managed concern the type and amount of conserved feed, where to fertilise and how much, the choice of fields to harvest, and most importantly, which field to graze next. Typically, SEPATOU is designed to be used by extension services and farming system scientists. It is implemented in C++ and is currently undergoing a validation process with the intended users.

  1. Experimental evidence that livestock grazing intensity affects the activity of a generalist predator

    NASA Astrophysics Data System (ADS)

    Villar, Nacho; Lambin, Xavier; Evans, Darren; Pakeman, Robin; Redpath, Steve

    2013-05-01

    Grazing by domestic ungulates has substantial impacts on ecosystem structure and composition. In grasslands of the northern hemisphere, livestock grazing limits populations of small mammals, which are a main food source for a variety of vertebrate predators. However, no experimental studies have described the impact of livestock grazing on vertebrate predators. We experimentally manipulated sheep and cattle grazing intensity in the Scottish uplands to test its impact on a relatively abundant small mammal, the field vole (Microtus agrestis), and its archetypal generalist predator, the red fox (Vulpes vulpes). We demonstrate that ungulate grazing had a strong consistent negative impact on both vole densities and indices of fox activity. Ungulate grazing did not substantially affect the relationship between fox activity and vole densities. However, the data suggested that, as grazing intensity increased i) fox activity indices tended to be higher when vole densities were low, and ii) the relationship between fox activity and vole density was weaker. All these patterns are surprising given the relative small scale of our experiment compared to large red fox territories in upland habitats of Britain, and suggest that domestic grazing intensity causes a strong response in the activity of generalist predators important for their conservation in grassland ecosystems.

  2. How Supplementation Affects Grazing Behavior

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers are still in the early stages of understanding how supplementation affects grazing behavior. Conventional nutrition wisdom, including early research with grazing cattle, has been based almost entirely upon stored feeds fed in confinement. In these situations, most dietary “choices” were ...

  3. Grazing incidence beam expander

    NASA Astrophysics Data System (ADS)

    Akkapeddi, P. R.; Glenn, P.; Fuschetto, A.; Appert, Q.; Viswanathan, V. K.

    1985-01-01

    A Grazing Incidence Beam Expander (GIBE) telescope is being designed and fabricated to be used as an equivalent end mirror in a long laser resonator cavity. The design requirements for this GIBE flow down from a generic Free Electron Laser (FEL) resonator. The nature of the FEL gain volume (a thin, pencil-like, on-axis region) dictates that the output beam be very small. Such a thin beam with the high power levels characteristic of FELs would have to travel perhaps hundreds of meters or more before expanding enough to allow reflection from cooled mirrors. A GIBE, on the other hand, would allow placing these optics closer to the gain region and thus reduces the cavity lengths substantially. Results are presented relating to optical and mechanical design, alignment sensitivity analysis, radius of curvature analysis, laser cavity stability analysis of a linear stable concentric laser cavity with a GIBE. Fabrication details of the GIBE are also given.

  4. 25 CFR 167.8 - Grazing rights.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing rights. 167.8 Section 167.8 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.8 Grazing rights. (a) The Superintendent shall determine grazing rights of bona fide live-stock owners based...

  5. 25 CFR 167.9 - Grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Grazing permits. 167.9 Section 167.9 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.9 Grazing permits. (a) All livestock grazed on the Navajo Reservation must be covered by an authorized...

  6. 25 CFR 167.8 - Grazing rights.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Grazing rights. 167.8 Section 167.8 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.8 Grazing rights. (a) The Superintendent shall determine grazing rights of bona fide live-stock owners based...

  7. 25 CFR 167.9 - Grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing permits. 167.9 Section 167.9 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.9 Grazing permits. (a) All livestock grazed on the Navajo Reservation must be covered by an authorized...

  8. Monitoring grazing intensity: an experiment with canopy spectra applied to satellite remote sensing

    NASA Astrophysics Data System (ADS)

    Li, Fei; Zhao, Ying; Zheng, Jiajia; Luo, Juhua; Zhang, Xiaoqiang

    2016-04-01

    The quantification of grassland grazing intensity (GI) and its detailed spatial distribution are important for grassland management and ecological protection. Remote sensing has great potential in these areas, but its use is still limited. This study analyzed the impacts of grazing on biophysical properties of vegetation and suggested using biomass to quantify GI because of its stability and interpretability. In comparison to a single spectral index, such as the red edge index (REI), combining REI and a cellulose absorption ratio index calculated from hyperspectral data performs better for biomass estimation. Further, an auxiliary spectral index, called the grazing monitoring index (GMI), was developed based on differences in spectral reflectance in the infrared range. Experiments in a grazing area of the Inner Mongolia grassland indicated that GMI can identify GI, with three range intervals (GMI <0, 0-1, and ≥1) used to describe the biomass distribution. The results showed that combining GMI and biomass was more successful than existing approaches for identifying the grassland variability resulting from the spatial heterogeneity of grazing behavior. The thresholds of biomass for four GI levels (ungrazed, lightly grazed, moderately grazed, and heavily grazed) could be determined by the intersections of biomass distributions. In addition, the approach developed at the on-ground canopy scale was extended to remotely sensed Hyperion data. The results showed that the approach could successfully identify the grazing treatments of blocks in the experimental grazing area. Overall, our study provides inspiration and ideas for using satellite remote sensing for evaluating plant production, standing biomass, and livestock impacts.

  9. Effects of grazing intensity and chemical seedhead suppression on steers grazing tall fescue pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The first year of a 2 yr grazing study was conducted to evaluate use of Chaparral™ to suppress reproductive growth in tall fescue grazed with low and moderate grazing intensities. Chaparral applications (0 and 2.0 oz/acre) and grazing intensities were arranged as RCBD with three replications. Variab...

  10. 25 CFR 168.8 - Grazing fees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Grazing fees. 168.8 Section 168.8 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.8 Grazing fees. (a) The rental value of all uses of Hopi Partitioned lands by...

  11. 43 CFR 4110.2 - Grazing preference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing preference. 4110.2 Section 4110.2..., DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Qualifications and Preference § 4110.2 Grazing preference....

  12. 43 CFR 9239.3 - Grazing, Alaska.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing, Alaska. 9239.3 Section 9239.3..., DEPARTMENT OF THE INTERIOR TECHNICAL SERVICES (9000) TRESPASS Kinds of Trespass § 9239.3 Grazing, Alaska. (a) Reindeer. (1) Any use of the Federal lands for reindeer grazing purposes, unless authorized by a...

  13. 25 CFR 168.8 - Grazing fees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing fees. 168.8 Section 168.8 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.8 Grazing fees. (a) The rental value of all uses of Hopi Partitioned lands by...

  14. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  15. 50 CFR 35.9 - Livestock grazing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Livestock grazing. 35.9 Section 35.9 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) THE... grazing. (a) The grazing of livestock, where established prior to the date of legislation which...

  16. 50 CFR 35.9 - Livestock grazing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 8 2011-10-01 2011-10-01 false Livestock grazing. 35.9 Section 35.9 Wildlife and Fisheries UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR (CONTINUED) THE... grazing. (a) The grazing of livestock, where established prior to the date of legislation which...

  17. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  18. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of...

  19. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of...

  20. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  1. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  2. 25 CFR 173.6 - Stock grazing.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Stock grazing. 173.6 Section 173.6 Indians BUREAU OF... WITHDRAWN OR ACQUIRED IN CONNECTION WITH INDIAN IRRIGATION PROJECTS § 173.6 Stock grazing. Permittees may graze upon lands covered by such permits, such stock as may be required in connection with the...

  3. 25 CFR 167.8 - Grazing rights.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ownership records as established in accordance with § 167.7 or who have acquired grazing rights by marriage... provided in § 167.9. (b) All enrolled members of the Navajo Tribe over 18 years of age are eligible to acquire and hold grazing permits. Minors under 18 years of age can get possession of grazing permits...

  4. 25 CFR 167.8 - Grazing rights.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ownership records as established in accordance with § 167.7 or who have acquired grazing rights by marriage... provided in § 167.9. (b) All enrolled members of the Navajo Tribe over 18 years of age are eligible to acquire and hold grazing permits. Minors under 18 years of age can get possession of grazing permits...

  5. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of...

  6. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of...

  7. 25 CFR 168.5 - Grazing capacity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Grazing capacity. 168.5 Section 168.5 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING REGULATIONS FOR THE HOPI PARTITIONED LANDS AREA § 168.5 Grazing capacity. (a) The Area Director shall prescribe the maximum number of...

  8. Theory of grazing electromagnetic induction

    NASA Astrophysics Data System (ADS)

    Binder, P.-M.; Guerrero, Juan F.

    2016-11-01

    We calculate the emf produced when a square loop grazes a point dipole, moving parallel to it. To do this we combine analytical and numerical work. An emf signal with a three-peak structure which was previously observed is thus explained, while other signal forms are predicted.

  9. Aberrations for Grazing Incidence Optics

    NASA Technical Reports Server (NTRS)

    Saha, Timo T.

    2008-01-01

    Large number of grazing incidence telescope configurations have been designed and studied. Wolte1 telescopes are commonly used in astronomical applications. Wolter telescopes consist of a paraboloidal primary mirror and a hyperboloidal or an ellipsoidal secondary mirror. There are 8 possible combinations of Wolter telescopes. Out of these possible designs only type 1 and type 2 telescopes are widely used. Type 1 telescope is typically used for x-ray applications and type 2 telescopes are used for EUV applications. Wolter-Schwarzshild (WS) telescopes offer improved image quality over a small field of view. The WS designs are stigmatic and free of third order coma and, therefore, the PSF is significantly better over a small field of view. Typically the image is more symmetric about its centroid. As for the Wolter telescopes there are 8 possible combinations of WS telescopes. These designs have not been widely used because the surface equations are complex parametric equations complicating the analysis and typically the resolution requirements are too low to take full advantage of the WS designs. There are several other design options. Most notable are wide field x-ray telescope designs. Polynomial designs were originally suggested by Burrows4 and hyperboloid-hyperboloid designs for solar physics applications were designed by Harvey5. No general aberration theory exists for grazing incidence telescopes that would cover all the design options. Several authors have studied the aberrations of grazing incidence telescopes. A comprehensive theory of Wolter type 1 and 2 telescopes has been developed. Later this theory was expanded to include all possible combinations of grazing incidence and also normal incidence paraboloid-hyperboloid and paraboloid-ellipsoid telescopes. In this article the aberration theory of Wolter type telescopes is briefly reviewed.

  10. Near anastigmatic grazing incidence telescope

    NASA Technical Reports Server (NTRS)

    Korsch, D.

    1984-01-01

    A performance capability assessment is presently conducted for short versus long grazing incidence telescope designs, in view of the observation that the field curvature and astigmatism that are the primary residual aberrations of a Wolter-type incidence telescope can be substantially reduced through mirror length reduction. A major advantage of the short element telescope is that, if sufficiently short, both the paraboloid and hyperboloid surfaces may be fabricated as a single piece; this significantly facilitates the task of alignment.

  11. Replication of grazing incidence optics

    NASA Technical Reports Server (NTRS)

    Ulmer, Melville P.

    1986-01-01

    The replication of grazing incidence optics is reviewed. Electroform and epoxy replication are described and compared. It is concluded that for light weight and deep nesting, replication has a distinct advantage over direct production. The resolution of optics produced in this manner is however, limited to about 10 arc seconds; a typical value is 40 arc seconds. Epoxy replicated pieces tend to have better optical figures than electroformed optics, but the latter can be made thinner to make more deeply nested systems.

  12. Ecology of grazing lawns in Africa.

    PubMed

    Hempson, Gareth P; Archibald, Sally; Bond, William J; Ellis, Roger P; Grant, Cornelia C; Kruger, Fred J; Kruger, Laurence M; Moxley, Courtney; Owen-Smith, Norman; Peel, Mike J S; Smit, Izak P J; Vickers, Karen J

    2015-08-01

    Grazing lawns are a distinct grassland community type, characterised by short-stature and with their persistence and spread promoted by grazing. In Africa, they reveal a long co-evolutionary history of grasses and large mammal grazers. The attractiveness to grazers of a low-biomass sward lies in the relatively high quality of forage, largely due to the low proportion of stem material in the sward; this encourages repeat grazing that concomitantly suppresses tall-grass growth forms that would otherwise outcompete lawn species for light. Regular grazing that prevents shading and maintains sward quality is thus the cornerstone of grazing lawn dynamics. The strong interplay between abiotic conditions and disturbance factors, which are central to grazing lawn existence, can also cause these systems to be highly dynamic. Here we identify differences in growth form among grazing lawn grass species, and assess how compositional differences among lawn types, as well as environmental variables, influence their maintenance requirements (i.e. grazing frequency) and vulnerability to degradation. We also make a clear distinction between the processes of lawn establishment and lawn maintenance. Rainfall, soil nutrient status, grazer community composition and fire regime have strong and interactive influences on both processes. However, factors that concentrate grazing pressure (e.g. nutrient hotspots and sodic sites) have more bearing on where lawns establish. Similarly, we discuss the relevance of enhanced rates of nitrogen cycling and of sodium levels to lawn maintenance. Grazer community composition and density has considerable significance to grazing lawn dynamics; not all grazers are adapted to foraging on short-grass swards, and differences in body size and relative mouth dimensions determine which species are able to convert tall-grass swards into grazing lawns under different conditions. Hence, we evaluate the roles of different grazers in lawn dynamics, as well as the

  13. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... that is physically located in a county that is, during the normal grazing period for the specific type... grazing period for the specific type of grazing land or pastureland for the county, as determined by the... any time during the normal grazing period for the specific type of grazing land or pastureland for...

  14. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... that is physically located in a county that is, during the normal grazing period for the specific type... grazing period for the specific type of grazing land or pastureland for the county, as determined by the... any time during the normal grazing period for the specific type of grazing land or pastureland for...

  15. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... that is physically located in a county that is, during the normal grazing period for the specific type... grazing period for the specific type of grazing land or pastureland for the county, as determined by the... any time during the normal grazing period for the specific type of grazing land or pastureland for...

  16. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... that is physically located in a county that is, during the normal grazing period for the specific type... grazing period for the specific type of grazing land or pastureland for the county, as determined by the... any time during the normal grazing period for the specific type of grazing land or pastureland for...

  17. 7 CFR 760.305 - Eligible grazing losses.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... that is physically located in a county that is, during the normal grazing period for the specific type... grazing period for the specific type of grazing land or pastureland for the county, as determined by the... any time during the normal grazing period for the specific type of grazing land or pastureland for...

  18. 43 CFR 4130.6 - Other grazing authorizations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Other grazing authorizations. 4130.6... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6 Other grazing authorizations. Exchange-of-use grazing...

  19. 25 CFR 700.713 - Tenure of grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Tenure of grazing permits. 700.713 Section 700.713... New Lands Grazing § 700.713 Tenure of grazing permits. (a) All active regular grazing permits shall be... grazing permits are applicable and become a condition of all previously granted permits....

  20. 43 CFR 4130.5 - Free-use grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Free-use grazing permits. 4130.5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued...

  1. 25 CFR 700.713 - Tenure of grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Tenure of grazing permits. 700.713 Section 700.713... New Lands Grazing § 700.713 Tenure of grazing permits. (a) All active regular grazing permits shall be... initial issuance. (b) Amendments to these regulations extending or limiting the tenure of grazing...

  2. 43 CFR 4130.2 - Grazing permits or leases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing permits or leases. 4130.2 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.2 Grazing permits or leases. (a) Grazing permits and leases authorize use...

  3. 43 CFR 4130.5 - Free-use grazing permits.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Free-use grazing permits. 4130.5 Section... Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to... directly and exclusively by the applicant and his family. The issuance of free-use grazing permits...

  4. 43 CFR 4130.5 - Free-use grazing permits.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Free-use grazing permits. 4130.5 Section... Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to... directly and exclusively by the applicant and his family. The issuance of free-use grazing permits...

  5. 43 CFR 4130.5 - Free-use grazing permits.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Free-use grazing permits. 4130.5 Section... Authorizing Grazing Use § 4130.5 Free-use grazing permits. (a) A free-use grazing permit shall be issued to... directly and exclusively by the applicant and his family. The issuance of free-use grazing permits...

  6. Guild structure of a riparian avifauna relative to seasonal cattle grazing

    USGS Publications Warehouse

    Knopf, F.L.; Sedgwick, J.A.; Cannon, R. W.

    1988-01-01

    Knopf et al. found that summer cattle grazing has an adverse effect on the presence of certain willow-dependent songbirds. Pastures that have historical summer grazing no longer have the Willow flycatcher, Lincoln's sparrow and the White-crowned sparrow present. Yet in these same areas, birds like the American Robin, Brown-headed cowbird and the Red-winged blackbird have increased in density. One possible answer for the decrease in some songbirds is the fact that the main focus of the Arapaho National Wildlife Refuge is on waterfowl habitat, which requires large amounts of open space (opposite of desirable songbird habitat).

  7. CLOSE STELLAR BINARY SYSTEMS BY GRAZING ENVELOPE EVOLUTION

    SciTech Connect

    Soker, Noam

    2015-02-20

    I suggest a spiral-in process in which a stellar companion grazes the envelope of a giant star while both the orbital separation and the giant radius shrink simultaneously, forming a close binary system. The binary system might be viewed as evolving in a constant state of 'just entering a common envelope (CE) phase.' In cases where this process takes place, it can be an alternative to CE evolution where the secondary star is immersed in the giant's envelope. Grazing envelope evolution (GEE) is made possible only if the companion manages to accrete mass at a high rate and launches jets that remove the outskirts of the giant envelope, hence preventing the formation of a CE. The high accretion rate is made possible by the accretion disk launching jets which efficiently carry the excess angular momentum and energy from the accreted mass. The orbital decay itself is caused by the gravitational interaction of the secondary star with the envelope inward of its orbit, i.e., dynamical friction (gravitational tide). Mass loss through the second Lagrangian point can carry additional angular momentum and envelope mass. The GEE lasts for tens to hundreds of years. The high accretion rate, with peaks lasting from months to years, might lead to a bright object referred to as the intermediate luminosity optical transient (Red Novae; Red Transients). A bipolar nebula and/or equatorial ring are formed around the binary remnant.

  8. Grazing function g and collimation angular acceptance

    SciTech Connect

    Peggs, S.G.; Previtali, V.

    2009-11-02

    The grazing function g is introduced - a synchrobetatron optical quantity that is analogous (and closely connected) to the Twiss and dispersion functions {beta}, {alpha}, {eta}, and {eta}'. It parametrizes the rate of change of total angle with respect to synchrotron amplitude for grazing particles, which just touch the surface of an aperture when their synchrotron and betatron oscillations are simultaneously (in time) at their extreme displacements. The grazing function can be important at collimators with limited acceptance angles. For example, it is important in both modes of crystal collimation operation - in channeling and in volume reflection. The grazing function is independent of the collimator type - crystal or amorphous - but can depend strongly on its azimuthal location. The rigorous synchrobetatron condition g = 0 is solved, by invoking the close connection between the grazing function and the slope of the normalized dispersion. Propagation of the grazing function is described, through drifts, dipoles, and quadrupoles. Analytic expressions are developed for g in perfectly matched periodic FODO cells, and in the presence of {beta} or {eta} error waves. These analytic approximations are shown to be, in general, in good agreement with realistic numerical examples. The grazing function is shown to scale linearly with FODO cell bend angle, but to be independent of FODO cell length. The ideal value is g = 0 at the collimator, but finite nonzero values are acceptable. Practically achievable grazing functions are described and evaluated, for both amorphous and crystal primary collimators, at RHIC, the SPS (UA9), the Tevatron (T-980), and the LHC.

  9. Predicting forage intake by grazing beef cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Voluntary intake by cattle is controlled by a complex mix of physical and physiological factors that interact with a variety of environmental, geo-spatial, and experiential influences external to the animal. These factors are intensified in grazing ruminants, where selective grazing and variability...

  10. MEASURING INVERTEBRATE GRAZING ON SEAGRASSES AND EPIPHYTES

    EPA Science Inventory

    The chapter describes methods to assess grazing rates, grazer preferences, and grazer impacts, by mobile organisms living in the canopy or in the rhizome layer in any seagrass system. One set of methods quantifies grazing activity in small to medium sized, mobile organisms livin...

  11. Waterfowl production in relation to grazing

    USGS Publications Warehouse

    Kirsch, L.M.

    1969-01-01

    A 4-year production study of upland nesting waterfowl on the Missouri Coteau area of North Dakota showed that pair numbers, nesting densities and nest success were generally reduced by grazing. It is suggested that cover removal such as regular grazing and mowing be discontinued on areas managed primarily for waterfowl production and that management practices which create dense rank cover be substituted.

  12. Productivity and hay requirements of beef cattle in a Midwestern year-round grazing system.

    PubMed

    Janovick, N A; Russell, J R; Strohbehn, D R; Morrical, D G

    2004-08-01

    Our objective was to evaluate a replicated (n = 2) Midwestern year-round grazing system's hay needs and animal production compared with a replicated (n = 2) conventional (minimal land) system over 3 yr. Because extended grazing systems have decreased hay needs for the beef herd, it was hypothesized that this year-round system would decrease hay needs without penalizing animal production. In the minimal land (ML) system, two replicated 8.1-ha smooth bromegrass-orchardgrass-birdsfoot trefoil (SB-OG-BFT) pastures were rotationally stocked with six mature April-calving cows and calves and harvested as hay for winter feeding in a drylot. After weaning, calves were finished on a high-concentrate diet. Six mature April-calving cows, six mature August-calving cows, and their calves were used in the year-round (YR) grazing system. During the early and late summer, cattle grazed two replicated 8.1-ha SB-OG-BFT pastures by rotational stocking. In mid-summer and winter, April- and August-calving cows grazed two replicated 6.1-ha, endophyte-free tall fescue-red clover (TF-RC) and smooth bromegrass-red clover (SB-RC) pastures, respectively, by strip-stocking. In late autumn, spring-calving cows grazed 6.1-ha corn crop residue fields by strip-stocking. Calves were fed hay with corn gluten feed or corn grain over winter and used as stocker cattle to graze SB-OG-BFT pastures with cows until early August the following summer. First-harvest forage from the TF-RC and SB-RC pastures was harvested as hay. Body condition scores of April-calving cows did not differ between grazing systems, but were lower (P < or = 0.03) than those of August-calving cows from mid-gestation through breeding. Preweaning calf BW gains were 47 kg/ha of perennial pasture (P < 0.01) and 32 kg/cow (P = 0.01) lower in the YR grazing system than in the ML system. Total BW gains ofpreweaning calf and grazing stocker cattle were 12 kg/ha of perennial pasture less (P = 0.07), but 27 kg/cow greater (P = 0.02) in

  13. 25 CFR 167.10 - Special grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Special grazing permits. 167.10 Section 167.10 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.10 Special grazing permits. The problem of special grazing permits shall be settled by the Bureau of...

  14. 25 CFR 700.719 - Establishment of grazing fees.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Establishment of grazing fees. 700.719 Section 700.719... New Lands Grazing § 700.719 Establishment of grazing fees. The Commissioner may establish a minimum acceptable grazing fee per SUYL. The Commissioner may consult with the Tribe prior to establishing fees....

  15. 25 CFR 700.719 - Establishment of grazing fees.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Establishment of grazing fees. 700.719 Section 700.719... New Lands Grazing § 700.719 Establishment of grazing fees. The Commissioner may establish a minimum acceptable grazing fee per SUYL. The Commissioner may consult with the Tribe prior to establishing fees....

  16. 25 CFR 167.11 - Tenure of grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Tenure of grazing permits. 167.11 Section 167.11 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.11 Tenure of grazing permits. (a) All active regular grazing permits shall be for one year and shall...

  17. 36 CFR 293.7 - Grazing of livestock.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Grazing of livestock. 293.7...-PRIMITIVE AREAS § 293.7 Grazing of livestock. (a) The grazing of livestock, where such use was established..., shall be permitted to continue under the general regulations covering grazing of livestock on...

  18. 25 CFR 167.11 - Tenure of grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Tenure of grazing permits. 167.11 Section 167.11 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.11 Tenure of grazing permits. (a) All active regular grazing permits shall be for one year and shall...

  19. 36 CFR 222.11 - Grazing advisory boards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Grazing advisory boards. 222... MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.11 Grazing advisory boards. (a) Establishment. Persons holding term permits to graze livestock on National Forest System lands with...

  20. 36 CFR 222.11 - Grazing advisory boards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Grazing advisory boards. 222... MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.11 Grazing advisory boards. (a) Establishment. Persons holding term permits to graze livestock on National Forest System lands with...

  1. 25 CFR 167.10 - Special grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Special grazing permits. 167.10 Section 167.10 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO GRAZING REGULATIONS § 167.10 Special grazing permits. The problem of special grazing permits shall be settled by the Bureau of...

  2. 36 CFR 293.7 - Grazing of livestock.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Grazing of livestock. 293.7...-PRIMITIVE AREAS § 293.7 Grazing of livestock. (a) The grazing of livestock, where such use was established..., shall be permitted to continue under the general regulations covering grazing of livestock on...

  3. 43 CFR 4200.1 - Authority for grazing privileges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Authority for grazing privileges. 4200.1... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; LIVESTOCK § 4200.1 Authority for grazing privileges. The BLM is authorized under the Alaska Livestock Grazing...

  4. 43 CFR 4110.2-3 - Transfer of grazing preference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Transfer of grazing preference. 4110.2-3... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Qualifications and Preference § 4110.2-3 Transfer of grazing preference. (a) Transfers of grazing preference...

  5. 36 CFR 222.4 - Changes in grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Changes in grazing permits... RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.4 Changes in grazing permits. (a) The Chief, Forest Service, is authorized to cancel, modify, or suspend grazing and...

  6. 43 CFR 2711.4-1 - Grazing improvements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing improvements. 2711.4-1 Section... MANAGEMENT ACT Sales: Procedures § 2711.4-1 Grazing improvements. No public lands in a grazing lease or... authorized grazing improvements have been met....

  7. 43 CFR 4110.2-2 - Specifying grazing preference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Specifying grazing preference. 4110.2-2... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Qualifications and Preference § 4110.2-2 Specifying grazing preference. (a) All grazing permits and...

  8. 25 CFR 700.722 - Grazing associations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... association may hold a grazing permit to benefit its members according to the rules of the association constitution and bylaws. All of the association's livestock will be run under an association brand...

  9. 25 CFR 700.722 - Grazing associations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... association may hold a grazing permit to benefit its members according to the rules of the association constitution and bylaws. All of the association's livestock will be run under an association brand...

  10. Metabolic profile in Chilota lambs grazing Calafatal.

    PubMed

    Gallardo, María Asunción; Noro, Mirela; De la Barra, Rodrigo; Pulido, Rubén

    2014-04-01

    The aim of this study was to determine the productive and metabolic response in Chilota lambs grazing Calafatal or naturalized pasture. The experiment was conducted at the Experimental Station Butalcura (INIA, Chiloé) during October, November, and December 2011. Eight Chilota and six Suffolk Down 2-month-old lambs, uncastrated males, no twin, were located to graze a typical secondary succession of the Chiloé Archipelago, as a Calafatal (a secondary succession which derivates from human intervention on native forest in Chiloé Archipelago). Simultaneously, eight male 2-month-old Chilota lambs were located to graze a naturalized pasture, another secondary succession derived from human intervention on native forest in Chiloé Archipelago. Animals had free access to water sources. Measurements were performed one time a month, for three consecutive months for productive indicators: live weight, average daily gain and body condition score, and blood indicators of protein and energetic metabolism. Productive and metabolic response was similar between both types of pastures (P > 0.05). However, Chilota and Suffolk Down lambs grazing Calafatal showed higher plasma concentrations of βOH-butyrate, but lower non-esterified fatty acids (NEFA) than Chilota lambs grazing naturalized pasture (P < 0.05). Chilota lambs grazing naturalized pasture showed the highest plasma concentrations of NEFA and urea (P < 0.05). It was concluded that, under the conditions of the study, Chilota lambs grazing naturalized pasture, which had higher contents of crude protein and metabolizable energy, showed better metabolic balance, but not performance, than Chilota and Suffolk Down lambs grazing Calafatal.

  11. Properties And Performance Of Grazing Incidence Reflectors

    NASA Astrophysics Data System (ADS)

    Aspnes, D. E.; Kelso, S. M.

    We numerically analyze at near-grazing incidence various configurations containing elliptical, toroidal, and the recently proposed common-axis rotationally symmetric anamorphic (CARSA) elements to determine the type and importance of aberrations inherent in each. CARS pairs of elliptical mirrors are shown to have negligible focusing errors for typical synchrotron source dimensions, and therefore comprise useful building blocks from which to construct grazing-incidence optical systems. To minimize aberrations, cylindrical, spherical, or toroidal elements should be avoided.

  12. Properties and performance of grazing incidence reflectors

    NASA Astrophysics Data System (ADS)

    Aspnes, D. E.; Kelso, S. M.

    1982-05-01

    Various configurations containing elliptical, toroidal, and the recently proposed common-axis rotationally symmetric anamorphic (CARSA) elements are numerically analyzed at near-grazing incidence, to determine the type and importance of aberrations inherent in each. CARS pairs of elliptical mirrors are shown to have negligible focusing errors for typical synchrotron source dimensions, and therefore comprise useful building blocks from which to construct grazing-incidence optical systems. To minimize aberrations, cylindrical, spherical, or toroidal elements should be avoided.

  13. Magnetic alignment in grazing and resting cattle and deer

    PubMed Central

    Begall, Sabine; Červený, Jaroslav; Neef, Julia; Vojtěch, Oldřich; Burda, Hynek

    2008-01-01

    We demonstrate by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring “deer beds” in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north–south direction. Direct observations of roe deer revealed that animals orient their heads northward when grazing or resting. Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsmen, ranchers, or hunters. Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation. To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. This study reveals the magnetic alignment in large mammals based on statistically sufficient sample sizes. Our findings open horizons for the study of magnetoreception in general and are of potential significance for applied ethology (husbandry, animal welfare). They challenge neuroscientists and biophysics to explain the proximate mechanisms. PMID:18725629

  14. Magnetic alignment in grazing and resting cattle and deer.

    PubMed

    Begall, Sabine; Cerveny, Jaroslav; Neef, Julia; Vojtech, Oldrich; Burda, Hynek

    2008-09-09

    We demonstrate by means of simple, noninvasive methods (analysis of satellite images, field observations, and measuring "deer beds" in snow) that domestic cattle (n = 8,510 in 308 pastures) across the globe, and grazing and resting red and roe deer (n = 2,974 at 241 localities), align their body axes in roughly a north-south direction. Direct observations of roe deer revealed that animals orient their heads northward when grazing or resting. Amazingly, this ubiquitous phenomenon does not seem to have been noticed by herdsmen, ranchers, or hunters. Because wind and light conditions could be excluded as a common denominator determining the body axis orientation, magnetic alignment is the most parsimonious explanation. To test the hypothesis that cattle orient their body axes along the field lines of the Earth's magnetic field, we analyzed the body orientation of cattle from localities with high magnetic declination. Here, magnetic north was a better predictor than geographic north. This study reveals the magnetic alignment in large mammals based on statistically sufficient sample sizes. Our findings open horizons for the study of magnetoreception in general and are of potential significance for applied ethology (husbandry, animal welfare). They challenge neuroscientists and biophysics to explain the proximate mechanisms.

  15. Resistance of nitrifiers inhabiting activated sludge to ciliate grazing.

    PubMed

    Pajdak-Stós, Agnieszka; Fiałkowska, Edyta; Fyda, Janusz; Babko, Roman

    2010-01-01

    We monitored the succession of nitrifiers in a newly opened wastewater treatment plant for five weeks. After the first distinct decrease in total nitrogen, we began monitoring the appearance, size and number of nitrifying bacteria colonies using the fluorescence in situ hybridization (FISH) method. Ammonia oxidizing bacteria (AOB) colonies were visualized under green excitation as red, and nitrite oxidizing bacteria (NOB) colonies were visualized under blue excitation as green. The changes in protozoan community were monitored simultaneously. Ciliates were divided into four functional groups: predatory, bacterivorous free-swimming, bacterivorous crawling, and sessile. The results showed that at the time of the first distinct total nitrogen decrease, the mean length of both AOB and NOB were relatively low, but the colonies, especially those of nitrite oxidizers, were abundant. In time, the distribution of ammonia oxidizer colonies shifted towards larger sizes, but their quantity decreased. In the case of nitrite oxidizers, a similar trend was noticeable but less pronounced. These changes corresponded with an increasing number of crawling bacterivorous ciliates dominated by the "scavenger" genus Aspidisca. The increasing size of nitrifier colonies may have been due to the growing grazing pressure from crawling bacterivorous ciliates. The strong grazing pressure did not negatively affect N-NH(4)(+) removal effectiveness.

  16. Effects of anthropogenic fragmentation and livestock grazing on western riparian bird communities

    USGS Publications Warehouse

    Tewksbury, J.J.; Black, A.E.; Nur, N.; Saab, V.A.; Logan, B.D.; Dobkin, D.S.

    2002-01-01

    Deciduous vegetation along streams and rivers provides breeding habitat to more bird species than any other plant community in the West, yet many riparian areas are heavily grazed by cattle and surrounded by increasingly developed landscapes. The combination of cattle grazing and landscape alteration (habitat loss and fragmentation) are thought to be critical factors affecting the richness and composition of breeding bird communities. Here, we examine the influence of land use and cattle grazing on deciduous riparian bird communities across seven riparian systems in five western states: Montana, Idaho, Nevada, Oregon and California. These riparian systems are embedded in landscapes ranging from nearly pristine to almost completely agricultural. We conducted landscape analysis at two spatial scales: local landscapes (all land within 500 m of each survey location) and regional landscapes (all land within 5 km of each survey location). Despite the large differences among riparian systems, we found a number of consistent effects of landscape change and grazing. Of the 87 species with at least 15 detections on two or more rivers, 44 species were less common in grazed sites, in heavily settled or agricultural landscapes, or in areas with little deciduous riparian habitat. The Veery (Catharus fuscescens), Song Sparrow (Melospiza melodia), Red-naped Sapsucker (Sphyrapicus nuchalis), Fox Sparrow (Passerella iliaca), and American Redstart (Setophaga ruticilla) were all less common under at least three of these conditions. In contrast, 33 species were significantly more common in one or more of these conditions. Sites surrounded by greater deciduous habitat had higher overall avian abundance and 22 species had significantly higher individual abundances in areas with more deciduous habitat. Yet, areas with more agriculture at the regional scale also had higher total avian abundance, due in large part to greater abundance of European Starling (Sturnus vulgaris), American Robin

  17. Effect of prior grazing experiences on grazing behavior and performance of lactating cows

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of grazing experiences early in life on grazing behavior and performance of lactating dairy heifers was evaluated in a 3-year study. Sixty-four Holstein and Holstein x Jersey calves were randomly assigned to one of 4 treatments (n = 16) in 2008. Treatments were combinations of managing he...

  18. Grazing activity and ruminal bacterial population associated with frothy bloat in steers grazing winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two grazing experiments were designed to elucidate the shifts in rumen bacterial populations (Exp. 1) and grazing activities (Exp. 2) in wheat forage diets between bloated and non-bloated steers. In Exp. 1, the bacterial DNA density was greatest for Ruminococcus flavefaciens, Streptococcus bovis, a...

  19. Water quality and the grazing animal.

    PubMed

    Hubbard, R K; Newton, G L; Hill, G M

    2004-01-01

    Grazing animals and pasture production can affect water quality both positively and negatively. Good management practices for forage production protect the soil surface from erosion compared with conventionally produced crops. Grazing animals and pasture production can negatively affect water quality through erosion and sediment transport into surface waters, through nutrients from urine and feces dropped by the animals and fertility practices associated with production of high-quality pasture, and through pathogens from the wastes. Erosion and sediment transport is primarily associated with high-density stocking and/or poor forage stands. The two nutrients of primary concern relating to animal production are N and P. Nitrogen is of concern because high concentrations in drinking water in the NO(3) form cause methemoglobinemia (blue baby disease), whereas other forms of N (primarily nitrite, NO(2)) are considered to be potentially carcinogenic. Phosphorus in the PO(4) form is of concern because it causes eutrophication of surface water bodies. The effect of grazing animals on soil and water quality must be evaluated at both the field and watershed scales. Such evaluation must account for both direct input of animal wastes from the grazing animal and also applications of inorganic fertilizers to produce quality pastures. Watershed-scale studies have primarily used the approach of nutrient loadings per land area and nutrient removals as livestock harvests. A number of studies have measured nutrient loads in surface runoff from grazed land and compared loads with other land uses, including row crop agriculture and forestry. Concentrations in discharge have been regressed against standard grazing animal units per land area. Watersheds with concentrated livestock populations have been shown to discharge as much as 5 to 10 times more nutrients than watersheds in cropland or forestry. The other major water quality concern with grazing animals is pathogens, which may move

  20. Influence of grazing management on claw disorders in Swedish freestall dairies with mandatory grazing.

    PubMed

    Bergsten, C; Carlsson, J; Jansson Mörk, M

    2015-09-01

    Our hypothesis was that grazing time, the number of days (duration) and number of hours per day, affected claw health. From Swedish freestall herds that fulfilled our criteria of claw-trimming routines, 201 herds were randomly selected for a telephone interview regarding grazing management. Herd data were retrieved from the Swedish Official Milk Recording Scheme. Claw disorders to be analyzed were recorded at maintenance claw trimming before and after the grazing period and included mild and severe dermatitis, severe heel-horn erosion, and sole ulcer (including severe sole hemorrhage). Any remark included one or more of these recorded disorders. The odds for having a recorded claw disorder at the autumn trimming in relation to grazing management, as well as to herd- and cow-related parameters, was tested using multilevel logistic regression models. The final statistical analysis included 17,600 cows in 174 herds, which were distributed from the south to the north of Sweden with decreasing length of mandatory grazing period because of climate. Grazing duration was statistically associated with the risk of sole ulcer, but it was not linear. However, grazing duration was not statistically associated with the odds for any remark, dermatitis, or heel-horn erosion. The odds for dermatitis were lower with access to pasture for 24 h compared with either day or night access. Otherwise, the number of hours that the animals had access to grazing per day was not significantly associated with any of the other analyzed claw disorders. Higher pasture stocking density (number of cow hours per day per hectare) was associated with a higher odds for dermatitis and sole ulcer. For all recorded claw disorders, the highest odds for having a disorder after the grazing period were consistently when the cow had the same claw disorder before the release to pasture. The positive effects of grazing on claw health were less than expected, and the previous known effects of breed, days in milk

  1. Eye redness

    MedlinePlus

    Bloodshot eyes; Red eyes; Scleral injection; Conjunctival injection ... There are many causes of a red eye or eyes. Some are medical emergencies. Others are a cause for concern, but not an emergency. Many are nothing to worry about. Eye ...

  2. Biogenic production of dimethyl sulfide: Krill grazing

    SciTech Connect

    Daly, K.L.; DiTullio, G.R. )

    1993-01-01

    Dimethyl sulfide (DMS), a dominant sulfur compound in sea water, is a possible precursor for cloud condensation nuclei in the atmosphere and may influence global climate. The primary source of DMS is phytoplankton, but the mechanisms remain uncertain, and concentrations of DMS in the ocean vary spatially and temporally. Laboratory studies suggest zooplankton grazing may be an important process leading to the formation of DMS in the ocean. This paper describes ocean studies which examine the suggestion that grazing by krill may be a significant source for DMS production in the antarctic coastal region. 11 refs., 2 figs.

  3. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... 2000. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of ... 2000 - The Red Sea between the East Africa coast and Saudi Arabian peninsula. project:  MISR category:  ...

  4. Modeling the grazing effect on dry grassland carbon cycling with modified Biome-BGC grazing model

    NASA Astrophysics Data System (ADS)

    Luo, Geping; Han, Qifei; Li, Chaofan; Yang, Liao

    2014-05-01

    Identifying the factors that determine the carbon source/sink strength of ecosystems is important for reducing uncertainty in the global carbon cycle. Arid grassland ecosystems are a widely distributed biome type in Xinjiang, Northwest China, covering approximately one-fourth the country's land surface. These grasslands are the habitat for many endemic and rare plant and animal species and are also used as pastoral land for livestock. Using the modified Biome-BGC grazing model, we modeled carbon dynamics in Xinjiang for grasslands that varied in grazing intensity. In general, this regional simulation estimated that the grassland ecosystems in Xinjiang acted as a net carbon source, with a value of 0.38 Pg C over the period 1979-2007. There were significant effects of grazing on carbon dynamics. An over-compensatory effect in net primary productivity (NPP) and vegetation carbon (C) stock was observed when grazing intensity was lower than 0.40 head/ha. Grazing resulted in a net carbon source of 23.45 g C m-2 yr-1, which equaled 0.37 Pg in Xinjiang in the last 29 years. In general, grazing decreased vegetation C stock, while an increasing trend was observed with low grazing intensity. The soil C increased significantly (17%) with long-term grazing, while the soil C stock exhibited a steady trend without grazing. These findings have implications for grassland ecosystem management as it relates to carbon sequestration and climate change mitigation, e.g., removal of grazing should be considered in strategies that aim to increase terrestrial carbon sequestrations at local and regional scales. One of the greatest limitations in quantifying the effects of herbivores on carbon cycling is identifying the grazing systems and intensities within a given region. We hope our study emphasizes the need for large-scale assessments of how grazing impacts carbon cycling. Most terrestrial ecosystems in Xinjiang have been affected by disturbances to a greater or lesser extent in the past

  5. INFLUENCE OF PROTOZOAN GRAZING ON CONTAMINANT BIODEGRADATION. (R825418)

    EPA Science Inventory

    The influence of protozoan grazing on biodegradation rates in samples from contaminated aquifer sediment was evaluated under aerobic and anaerobic conditions. Predator¯prey biomass ratios suggested that protozoan grazing might be influencing bacterial populations....

  6. Dietary selection by domestic grazing ruminants: Current state of knowledge

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ruminants grazing biodiverse pasture face many choices, including when and where to graze and how much herbage to consume. Scientific research has led to considerable knowledge about some of these choices (e.g. herbage DMI), but other aspects of the complex decision-making process of a grazing rumin...

  7. 76 FR 80329 - Information Collection; Grazing Permit Administration Forms

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... following information: Name and address of applicant Type, amount, and location of requested grazing Period..., Application for Term Grazing Permit, collects the following information: Name and address of applicant Type..., Application for Term Private Land Grazing Permit, collects the following: Name and address of applicant...

  8. 43 CFR 4710.5 - Closure to livestock grazing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Closure to livestock grazing. 4710.5... FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If... grazing use by all or a particular kind of livestock. (b) All public lands inhabited by wild horses...

  9. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Who establishes grazing rental rates? 166.400 Section 166.400 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and...

  10. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Who establishes grazing rental rates? 166.400 Section 166.400 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and...

  11. 43 CFR 4110.3 - Changes in grazing preference.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Changes in grazing preference. 4110.3... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Qualifications and Preference § 4110.3 Changes in grazing preference. (a) The authorized officer...

  12. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When is grazing capacity determined? 166.305 Section 166.305 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify,...

  13. Tillage requirements for vegetables following winter annual grazing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Alabama, over 400,000 ac of winter annuals are grazed prior to planting summer row crops. Previous research indicates that cattle grazed on ryegrass (Lolium multiflorum L.) pastures over the winter months in Alabama can be profitable, but winter grazing creates excessive compaction, which advers...

  14. 25 CFR 166.400 - Who establishes grazing rental rates?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... rental rate that is less or more than the grazing rental rate established by us. We will assist a tribe... under paragraph (a) of this section. (c) Indian landowners may give us written authority to grant... grazing rental rate set by us; or (2) Below the grazing rental rate set by us, subject to our...

  15. How Does “Hunger” Level Impact Grazing Behavior?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing behavior can be influenced through feeding and grazing management decisions. Research at our USDA-ARS lab showed that ruminal fill, or how ‘hungry’ the cow is, can affect grazing behavior. Cows that had less ruminal fill took a bigger bite that was shallow and wide, compared to a ‘full’ cow ...

  16. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true When is grazing capacity determined? 166.305 Section 166... and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify, or approve a permit, in consultation with the Indian landowners, we will establish the total grazing...

  17. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false When is grazing capacity determined? 166.305 Section 166... and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify, or approve a permit, in consultation with the Indian landowners, we will establish the total grazing...

  18. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false When is grazing capacity determined? 166.305 Section 166... and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify, or approve a permit, in consultation with the Indian landowners, we will establish the total grazing...

  19. 25 CFR 166.305 - When is grazing capacity determined?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When is grazing capacity determined? 166.305 Section 166.305 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.305 When is grazing capacity determined? Before we grant, modify,...

  20. 76 FR 31977 - Notice of Intent To Prepare an Environmental Impact Statement for Domestic Sheep Grazing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ... Sheep Grazing Allotments for Term Grazing Permit Renewals in the Southern San Luis Valley, CO AGENCY... sheep grazing permits on 12 allotments and 1 cattle grazing allotment in the southern San Luis Valley.... SUPPLEMENTARY INFORMATION: Term permits on 12 sheep grazing and 1 cattle grazing allotments located in...

  1. Predicting forage intake in extensive grazing systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Voluntary intake by cattle and other ruminants is controlled by a complex mix of physical and physiological factors that interact with a variety of environmental, geo-spatial, and experiential influences external to the animal. These factors are intensified in grazing ruminants, where selective gra...

  2. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL...; rare combinations of outstanding ecosystems, or the protection and enhancement of the values for...

  3. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL...; rare combinations of outstanding ecosystems, or the protection and enhancement of the values for...

  4. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL...; rare combinations of outstanding ecosystems, or the protection and enhancement of the values for...

  5. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL...; rare combinations of outstanding ecosystems, or the protection and enhancement of the values for...

  6. 36 CFR 292.48 - Grazing activities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Grazing activities. 292.48 Section 292.48 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE NATIONAL...; rare combinations of outstanding ecosystems, or the protection and enhancement of the values for...

  7. Chapter 2: Livestock and Grazed Lands Emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 342 MMT CO2 eq. of greenhouse gasses (GHGs) were emitted from livestock, managed livestock waste, and grazed land in 2013. This represents about 66% of total emissions from the agricultural sector, which totaled 516 MMT CO2 eq. Compared to the base line year (1990), emissions from livesto...

  8. Delineating Grazing: Observations of Remote Control Use.

    ERIC Educational Resources Information Center

    Eastman, Susan Tyler; Newton, Gregory D.

    1995-01-01

    States that contrary to previous reports of "grazing," most viewers only used their remote control devices (RCDs) once or twice every half hour. Claims that the dominant RCD operation was direct channel punching, as opposed to dial turning. Concludes that most RCD activity did not take place during a program, thus voiding industry…

  9. The Gratifications of Grazing: Why Flippers Flip.

    ERIC Educational Resources Information Center

    Walker, James R.; Bellamy, Robert V., Jr.

    An exploratory study focused on usage patterns of television remote control devices (RCDs), examining how and why individuals use television RCDs to "graze." The study identified the gratifications obtained from RCD use and evaluated their relative importance in accounting for variations in RCD use. Subjects were 455 undergraduates in…

  10. 75 FR 29572 - Information Collection; Grazing Management

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ...] [FR Doc No: 2010-12707] DEPARTMENT OF THE INTERIOR Bureau of Land Management [LLWO220000-L10200000.PH0000.00000000; OMB Control Number 1004-0019] Information Collection; Grazing Management AGENCY: Bureau of Land Management, Interior. ACTION: 30-day Notice and Request for Comments. SUMMARY: The Bureau...

  11. 25 CFR 167.9 - Grazing permits.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... permittee who has five or more horses on his current permit will be required to apply any acquired sheep... shall be authorized to graze more than ten head of horses or to accumulate a total of over 350 sheep... permitted holdings of any individual permittee shall not exceed 350 sheep units or the equivalent...

  12. Woodlands Grazing Issues in Mediterranean Basin

    NASA Astrophysics Data System (ADS)

    Campos, P.

    2009-04-01

    In Mediterranean basin, woodlands grazing still continue to be important commercial owners' benefits. These owners manage woodlands vegetations as if they were not at risk of degradation and declining. Frequently, no temporally grazing set-aside is taken into account to avoid overgrazing of annual and perennial vegetations. Although less common, in the northern shore of Mediterranean basin undergrazing might increase the frequency and the number of catastrophic forest fires. This under/over grazing regime occurs in the Mediterranean basin woodlands with contrasted differences on land property rights, local economies and government livestock policy incentives. Spain and Tunisia are examples of these Mediterranean livestock contrasts. Most of Spanish Mediterranean woodlands and livestock herds are large private ownerships and owners could maintain their lands and livestock herds properties on the basis of moderate cash-income compensation against land revaluation and exclusive amenity self-consumption. The later is less tangible benefit and it could include family land legacy, nature enjoyment, country stile of life development, social status and so on. In public woodlands, social and environmental goals -as they are cultural heritage, biodiversity loss mitigation, soil conservation and employment- could maintain market unprofitable woodlands operations. Last three decades Spanish Mediterranean woodlands owners have increased the livestock herds incentivized by government subsidies. As result, grazing rent is pending on the level of European Union and Spanish government livestock subsidies. In this context, Spanish Mediterranean woodlands maintain a high extensive livestock stoking population, which economy could be called fragile and environmentally unsustainable because forest degradation and over/under grazing practices. Tunisian Mediterranean woodlands are state properties and livestock grazing is practice as a free private regimen. Livestock herds are small herd

  13. Grazing livestock are exposed to terrestrial cyanobacteria.

    PubMed

    McGorum, Bruce C; Pirie, R Scott; Glendinning, Laura; McLachlan, Gerry; Metcalf, James S; Banack, Sandra A; Cox, Paul A; Codd, Geoffrey A

    2015-02-25

    While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.

  14. Bivalve grazing can shape phytoplankton communities

    USGS Publications Warehouse

    Lucas, Lisa; Cloern, James E.; Thompson, Janet K.; Stacey, Mark T.; Koseff, Jeffrey K.

    2016-01-01

    The ability of bivalve filter feeders to limit phytoplankton biomass in shallow waters is well-documented, but the role of bivalves in shaping phytoplankton communities is not. The coupled effect of bivalve grazing at the sediment-water interface and sinking of phytoplankton cells to that bottom filtration zone could influence the relative biomass of sinking (diatoms) and non-sinking phytoplankton. Simulations with a pseudo-2D numerical model showed that benthic filter feeding can interact with sinking to alter diatom:non-diatom ratios. Cases with the smallest proportion of diatom biomass were those with the fastest sinking speeds and strongest bivalve grazing rates. Hydrodynamics modulated the coupled sinking-grazing influence on phytoplankton communities. For example, in simulations with persistent stratification, the non-sinking forms accumulated in the surface layer away from bottom grazers while the sinking forms dropped out of the surface layer toward bottom grazers. Tidal-scale stratification also influenced vertical gradients of the two groups in opposite ways. The model was applied to Suisun Bay, a low-salinity habitat of the San Francisco Bay system that was transformed by the introduction of the exotic clam Potamocorbula amurensis. Simulation results for this Bay were similar to (but more muted than) those for generic habitats, indicating that P. amurensis grazing could have caused a disproportionate loss of diatoms after its introduction. Our model simulations suggest bivalve grazing affects both phytoplankton biomass and community composition in shallow waters. We view these results as hypotheses to be tested with experiments and more complex modeling approaches.

  15. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Will the grazing capacity be increased if I graze... INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.307 Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands...

  16. Response of mountain meadows to grazing by recreational pack stock

    USGS Publications Warehouse

    Cole, David N.; Van Wagtendonk, Jan W.; McClaran, Mitchel P.; Moore, Peggy E.; McDougald, Neil K.

    2004-01-01

    Effects of recreational pack stock grazing on mountain meadows in Yosemite National Park were assessed in a 5-year study. Yosemite is a designated wilderness, to be managed such that its natural conditions are preserved. Studies were conducted in 3 characteristic meadow types: shorthair sedge (Carex filifolia Nutt.), Brewer's reed grass (Calamagrostis breweri Thurber), and tufted hairgrass [Deschampsia cespitosa (L.) Beauv.]. Horses and mules grazed experimental plots at intensities of 15 to 69% utilization for 4 seasons. In all 3 meadows, grazing caused decreases in productivity. The mean reduction after 4 years of grazing was 18% in the shorthair sedge meadow, 17% in the Brewer's reed grass meadow, and 22% in the tufted hairgrass meadow. Grazing also caused shifts in basal groundcover (usually a reduction in vegetation cover and increase in bare soil cover), and changes in species composition. Productivity and vegetation cover decreased as percent utilization increased, while bare soil cover increased as utilization increased. Changes in species composition were less predictably related to differences in grazing intensity. Passive management of grazing is insufficient in wilderness areas that are regularly used by groups with recreational stock. Wilderness managers need to monitor meadow conditions and the grazing intensities that occur. Our study suggests that biomass and ground cover are more sensitive indicators of grazing impact than species composition. Managers must make decisions about maximum acceptable levels of grazing impact and then develop guidelines for maximum use levels, based on data such as ours that relates grazing intensity to meadow response.

  17. Kinetics of lossy grazing impact oscillators

    NASA Astrophysics Data System (ADS)

    Hunt, Jeffery P.; Sarid, Dror

    1998-06-01

    The equation of motion of a grazing impact oscillator is generalized to include compliant boundaries and impact energy dissipation, yielding the phase diagram, indentation and force. Good agreement with experimental results using tapping-mode atomic force microscopy is demonstrated. The relationship between phase and set-point amplitude is discussed in terms of the dissipation, showing that for a parameter space for which the system is highly nonlinear a chaotic response is possible.

  18. Seasonality constraints to livestock grazing intensity.

    PubMed

    Fetzel, Tamara; Havlik, Petr; Herrero, Mario; Erb, Karl-Heinz

    2017-04-01

    Increasing food production is essential to meet the future food demand of a growing world population. In light of pressing sustainability challenges such as climate change and the importance of the global livestock system for food security as well as GHG emissions, finding ways to increasing food production sustainably and without increasing competition for food crops is essential. Yet, many unknowns relate to livestock grazing, in particular grazing intensity, an essential variable to assess the sustainability of livestock systems. Here, we explore ecological limits to grazing intensity (GI; i.e. the fraction of net primary production consumed by grazing animals) by analysing the role of seasonality in natural grasslands. We estimate seasonal limitations to GI by combining monthly net primary production data and a map of global livestock distribution with assumptions on the length of nonfavourable periods that can be bridged by livestock (e.g. by browsing dead standing biomass, storage systems or biomass conservation). This allows us to derive a seasonality-limited potential GI, which we compare with the GI prevailing in 2000. We find that GI in 2000 lies below its potential on 39% of the total global natural grasslands, which has a potential for increasing biomass extraction of up to 181 MtC/yr. In contrast, on 61% of the area GI exceeds the potential, made possible by management. Mobilizing this potential could increase milk production by 5%, meat production by 4% or contribute to free up to 2.8 Mio km² of grassland area at the global scale if the numerous socio-ecological constraints can be overcome. We discuss socio-ecological trade-offs, which may reduce the estimated potential considerably and require the establishment of sound monitoring systems and an improved understanding of livestock system's role in the Earth system.

  19. Neutron Reflectivity and Grazing Angle Diffraction

    PubMed Central

    Ankner, J. F.; Majkrzak, C. F.; Satija, S. K.

    1993-01-01

    Over the last 10 years, neutron reflectivity has emerged as a powerful technique for the investigation of surface and interfacial phenomena in many different fields. In this paper, a short review of some of the work on neutron reflectivity and grazing-angle diffraction as well as a description of the current and planned neutron rcflectometers at NIST is presented. Specific examples of the characterization of magnetic, superconducting, and polymeric surfaces and interfaces are included. PMID:28053457

  20. Grazing of heterotrophic dinoflagellate Noctiluca scintillans (Mcartney) Kofoid on Gymnodinium catenatum Graham.

    PubMed

    Alonso Rodríguez, Rosalba; Ochoa, José Luis; Uribe Alcocer, Manuel

    2005-01-01

    A dinoflagellate bloom ("red tide" event) dominated by the toxic Gymnodinium catenatum Graham (Gymnodiniales, Dinophyceae; 99.7%) and the noxious Noctiluca scintillans (Mcartney) Kofoid (Noctilucaceae, Dinophyceae; 0.3%) was observed in Bahia de Mazatlán Bay, México, on 24-26 January 2000. Photographic and microscopic analysis of samples during such an event, allowed us to collect evidence of a marked The particularity of grazing of G. catrenatum by by N. scintillans cells, suggesting a mechanism of "biocontrol" between these species that may contribute to attenuate a potentially toxic phenomenon under natural conditions.

  1. Red Sky with Red Mesa

    ScienceCinema

    None

    2016-07-12

    The Red Sky/Red Mesa supercomputing platform dramatically reduces the time required to simulate complex fuel models, from 4-6 months to just 4 weeks, allowing researchers to accelerate the pace at which they can address these complex problems. Its speed also reduces the need for laboratory and field testing, allowing for energy reduction far beyond data center walls.

  2. Effect of grazing fresh legumes or feeding silage on fatty acids and enzymes involved in the synthesis of milk fat in dairy cows.

    PubMed

    Wiking, Lars; Theil, Peter K; Nielsen, Jacob H; Sørensen, Martin T

    2010-08-01

    The impact of fresh legume types or silage on the composition of milk fatty acids and transcription of enzymes involved in the synthesis of milk fat in cows was studied. Three groups of cows grazed high proportions of white clover, red clover and lucerne, respectively. A fourth group of cows was fed maize/grass silage. The cows grazing high proportions of legumes produced significantly more 18:1 trans-11, 18:2 cis9-trans11, 18:2 trans10-cis12 and 18:3 fatty acids than cows fed silage. White clover and lucerne grazing resulted in significantly lower output of 18:1 trans9 in milk than red clover grazing and maize/grass silages. Transcription of stearoyl-CoA desaturase (SCD) in mammary tissue was significantly increased by grazing high proportions of legume whereas fatty acid synthase and acetyl-CoA carboxylase were not affected by type of feeding. Furthermore, average milk fat globule diameter was correlated to daily milk fat yield but was not affected by feeding. Although the fresh forage affected the transcription of SCD in mammary tissue, the largest effects were on the trans11-based fatty acids. It is concluded that type of forage, i.e. fresh or silage, had a greater impact on rumen fermentation pattern than on transcription of enzymes involved in the synthesis of milk fat.

  3. Growth phase and elemental stoichiometry of bacterial prey influences ciliate grazing selectivity.

    PubMed

    Gruber, David F; Tuorto, Steven; Taghon, Gary L

    2009-01-01

    Protozoa are known to selectively graze bacteria and can differentiate prey based on size and viability, but less is known about the effects of prey cellular composition on predator selectivity. We measured the effect of growth phase and elemental stoichiometry of Escherichia coli on grazing by two ciliates, Euplotes vannus and Cyclidium glaucoma. Bacterial cells of a single strain were transformed with green and red fluorescent protein and harvested from culture at differing growth stages. Cells in exponential growth phase had low carbon:phosphorus (39) and nitrogen:phosphorus (9) ratios, while cells from stationary phase had high carbon:phosphorus of 104 and nitrogen:phosphorus of 26. When offered an equal mixture of both types of bacteria, Cyclidium grazed stationary phase, high carbon:phosphorus, high nitrogen:phosphorus cells to 22% of initial abundance within 135 min, while Euplotes reduced these cells to 33%. Neither ciliate species decreased the abundance of the exponential phase cells, lower carbon:phosphorus and nitrogen:phosphorus, relative to control treatments. Because protozoa have higher nitrogen:phosphorus and carbon:phosphorus ratios than their prokaryotic prey, this study raises the possibility that it may be advantageous for protozoa to preferentially consume more slowly growing bacteria.

  4. Carbon budgets for an irrigated intensively grazed dairy pasture and an unirrigated winter-grazed pasture

    NASA Astrophysics Data System (ADS)

    Hunt, John E.; Laubach, Johannes; Barthel, Matti; Fraser, Anitra; Phillips, Rebecca L.

    2016-05-01

    Intensification of pastoral agriculture is occurring rapidly across New Zealand, including increasing use of irrigation and fertiliser application in some regions. While this enables greater gross primary production (GPP) and livestock grazing intensity, the consequences for the net ecosystem carbon budget (NECB) of the pastures are poorly known. Here, we determined the NECB over one year for an irrigated, fertilised and rotationally grazed dairy pasture and a neighbouring unirrigated, unfertilised, winter-grazed pasture. Primary terms in the NECB calculation were: net ecosystem production (NEP), biomass carbon removed by grazing cows and carbon (C) input from their excreta. Annual NEP was measured using the eddy-covariance method. Carbon removal was estimated with plate-meter measurements calibrated against biomass collections, pre- and post-grazing. Excreta deposition was calculated from animal feed intake. The intensively managed pasture gained C (NECB = 103 ± 42 g C m-2 yr-1) but would have been subject to a non-significant C loss if cattle excreta had not been returned to the pasture. The unirrigated pasture was C-neutral (NECB = -13 ± 23 g C m-2 yr-1). While annual GPP of the former was almost twice that of the latter (2679 vs. 1372 g C m-2 yr-1), ecosystem respiration differed by only 68 % between the two pastures (2271 vs. 1352 g C m-2 yr-1). The ratio of GPP to the total annual water input of the irrigated pasture was 37 % greater than that of the unirrigated pasture, i.e. the former used the water input more efficiently than the latter to produce biomass. The NECB results agree qualitatively with those from many other eddy-covariance studies of grazed grasslands, but they seem to be at odds with long-term carbon-stock studies of other New Zealand pastures.

  5. Peracute vanadium toxicity in cattle grazing near a vanadium mine.

    PubMed

    McCrindle, C M; Mokantla, E; Duncan, N

    2001-12-01

    Animals may act as bioindicators for potential human health problems associated with mining and refining. Eight cattle died after a vanadium mine dam collapsed close to the area in which they were grazing. Necropsies were conducted on five cattle. Affected animals had shown a watery bloody diarrhea, red urine and listlessness before collapsing. On necropsy (n = 5) there was a moderate bilateral multifocal granulomatous-like conjunctivitis. The most prominent lesions were eosinophillic granulomatous-like inflammation of the thymus, mediastinal and mesenteric lymph nodes, oesophagus, abomasum and colon. There was also marked hyperaemia of the abomasal mucosa with petechiation. Pulmonary and tracheal haemorrhage was also present. Histopathology showed severe inflammatory cell infiltration (mainly eosinophils with lesser numbers of neutrophils and macrophages) of lymphoid tissue associated with the thymus, lymph nodes, esophagus, abomasum, colon and conjunctiva. There were also areas of tissue necrosis, congested blood vessels and haemorrhage. Conjunctival lesions point to a systemic rather than a local effect as the cattle in this case died following ingestion rather than inhalation of vanadium. The causal relationship between intoxication and death is conventionally based on the level of that toxin present in tissues at necropsy. The variability in demonstrating vanadium in biological samples may have been due to the rapid excretion of vanadium by the living animal, or the solubility of the salts, which results in the substance leaching into the fluid portion of the samples. Cross-reactions with colorimetric tests for arsenic should also be noted.

  6. Comparison of bloat potential between a variety of soft-red versus a variety of hard-red winter wheat forage.

    PubMed

    Akins, M S; Kegley, E B; Coffey, K P; Caldwell, J D; Lusby, K S; Moore, J C; Coblentz, W K

    2009-10-01

    Some aspects of wheat pasture bloat have been researched extensively, but few studies have evaluated the effect of wheat type or variety on bloat. Eight Gelbvieh x Angus ruminally cannulated heifers (515 +/- 49 kg of BW) and 48 Angus heifers (238 +/- 12 kg of BW) grazed 1-ha pastures of hard-red or soft-red winter wheat (Triticum aestivum L.) to evaluate the effect of wheat variety on bloat potential. In Exp. 1, cattle grazed from November 11 to 22 and from November 26 to December 7, 2006, in a crossover design. In Exp. 2, cattle were shrunk for 20 h and then grazed from December 19 to 20, 2006, and from January 19 to 20, 2007. In both experiments, bloat was scored at 1000 and 1600 h daily. Rumen samples were collected at 0600, 1200, and 1800 h during each of the last 2 d of each period in Exp. 1 and during both days of each period of Exp. 2. Rumen samples were evaluated for pH, foam production and strength, and viscosity. In Exp. 1, cannulated heifers grazing soft-red had a greater (P < 0.01) percentage of observed bloat (21.9 vs. 5.6%) than those grazing hard-red winter wheat, but bloat incidence was low (2.1%) for the stocker cattle, with no difference between hard-red and soft-red winter wheat (P = 0.52). Viscosity of the rumen fluid was affected (P = 0.03) by the wheat variety x time interaction, with soft-red at 1200 and 1800 h being more viscous than soft-red at 0600 h and hard-red at all times. Foam strength, as determined by bubbling CO(2) gas through rumen fluid, had a wheat variety x time interaction (P = 0.02) with both wheat varieties similar at 0600 h but soft-red having greater foam strength at 1200 and 1800 h. In Exp. 2, no bloat was observed, and no differences between wheat varieties were observed for any of the rumen foam measures. Therefore, for these 2 varieties, the soft-red winter wheat had a greater bloat potential than the hard-red winter wheat based on results from the cannulated heifers, but no differences were observed in the frequency

  7. 25 CFR 161.302 - What restrictions are placed on grazing permits?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What restrictions are placed on grazing permits? 161.302... PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.302 What restrictions are placed on grazing permits? Only a grazing permit issued under this part authorizes the grazing of livestock within...

  8. 25 CFR 166.414 - What forms of grazing rental payments are acceptable?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What forms of grazing rental payments are acceptable? 166... GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.414 What forms of grazing rental payments are acceptable? (a) When grazing rental payments are...

  9. 25 CFR 161.301 - What will a grazing permit contain?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What will a grazing permit contain? 161.301 Section 161... LANDS GRAZING PERMITS Permit Requirements § 161.301 What will a grazing permit contain? (a) All grazing... stating that the permit authorizes no other privilege than grazing use; (9) A provision stating that...

  10. 25 CFR 161.400 - What are the criteria for reissuing grazing permits?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What are the criteria for reissuing grazing permits? 161... PARTITIONED LANDS GRAZING PERMITS Reissuance of Grazing Permits § 161.400 What are the criteria for reissuing grazing permits? (a) The Navajo Nation may prescribe eligibility requirements for grazing...

  11. 25 CFR 166.414 - What forms of grazing rental payments are acceptable?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What forms of grazing rental payments are acceptable? 166... GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.414 What forms of grazing rental payments are acceptable? (a) When grazing rental payments are...

  12. 25 CFR 161.301 - What will a grazing permit contain?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What will a grazing permit contain? 161.301 Section 161... LANDS GRAZING PERMITS Permit Requirements § 161.301 What will a grazing permit contain? (a) All grazing... stating that the permit authorizes no other privilege than grazing use; (9) A provision stating that...

  13. 25 CFR 161.302 - What restrictions are placed on grazing permits?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What restrictions are placed on grazing permits? 161.302... PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.302 What restrictions are placed on grazing permits? Only a grazing permit issued under this part authorizes the grazing of livestock within...

  14. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How are grazing permits allocated within each range unit... NAVAJO PARTITIONED LANDS GRAZING PERMITS Reissuance of Grazing Permits § 161.403 How are grazing permits... grazing permit will be determined by considering the number of animal units previously authorized in...

  15. 25 CFR 161.400 - What are the criteria for reissuing grazing permits?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What are the criteria for reissuing grazing permits? 161... PARTITIONED LANDS GRAZING PERMITS Reissuance of Grazing Permits § 161.400 What are the criteria for reissuing grazing permits? (a) The Navajo Nation may prescribe eligibility requirements for grazing...

  16. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How are grazing permits allocated within each range unit... NAVAJO PARTITIONED LANDS GRAZING PERMITS Reissuance of Grazing Permits § 161.403 How are grazing permits... grazing permit will be determined by considering the number of animal units previously authorized in...

  17. 43 CFR 4130.6-4 - Special grazing permits or leases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Special grazing permits or leases. 4130.6... LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6-4 Special grazing permits or leases. Special grazing permits...

  18. Red Hill

    EPA Pesticide Factsheets

    Information about the Red Hill Bulk Fuel Storage Facility in Hawaii Administrative Order on Consent (AOC), an enforceable agreement of the Hawaii Department of Health, the Environmental Protection Agency, and the U.S. Navy -- Defense Logistics Agency.

  19. Developmental instability and fitness in Periploca laevigata experiencing grazing disturbance

    USGS Publications Warehouse

    Alados, C.L.; Giner, M.L.; Dehesa, L.; Escos, J.; Barroso, F.; Emlen, J.M.; Freeman, D.C.

    2002-01-01

    We investigated the sensitivity of developmental instability measurements (leaf fluctuating asymmetry, floral radial asymmetry, and shoot translational asymmetry) to a long‐standing natural stress (grazing) in a palatable tannin‐producing shrub (Periploca laevigata Aiton). We also assessed the relationship between these measures of developmental instability and fitness components (growth and floral production). Developmental instability, measured by translational asymmetry, was the most accurate estimator of a plant’s condition and, consequently, environmental stress. Plants with less translational asymmetry grew more and produced more flowers. Plants from the medium‐grazed population were developmentally more stable, as estimated by translational and floral asymmetry, than either more heavily or more lightly grazed populations. Leaf fluctuating asymmetry was positively correlated with tannin concentration. The pattern of internode growth also responded to grazing impact. Plants under medium to heavy grazing pressure accelerated early growth and consequently escaped herbivory later in the season, i.e., at the beginning of the spring, when grazing activity was concentrated in herbaceous plants. Periploca laevigata accelerated growth and finished growing sooner than in the other grazing treatment. Thus, its annual growth was more mature and less palatable later in the season when grazers typically concentrate on shrubs. The reduction of developmental instability under medium grazing is interpreted as a direct effect of grazing and not as the release from competition.

  20. Polar stellar-spots and grazing planetary transits. Possible explanation for the low number of discovered grazing planets

    NASA Astrophysics Data System (ADS)

    Oshagh, M.; Santos, N. C.; Figueira, P.; Adibekyan, V. Zh.; Santerne, A.; Barros, S. C. C.; Lima, J. J. G.

    2015-11-01

    We assess whether there is a physically feasible explanation for the few discovered (nearly) grazing planetary transits through all ground- and space-based transit surveys. We performed simulations to generate a synthetic distribution of detectable planets based on their impact parameter, and found that more (nearly) grazing planets should have been detected than have been detected. Our explanation for the insufficient number of (nearly) grazing planets is based on the simple assumption that many (nearly) grazing planets transit host stars that harbor a dark giant polar spot, and thus the transit light-curve vanishes due to the occultation of the grazing planet and the polar spot. We conclude by evaluating the properties required of polar spots to cause the grazing transit light-curve to disappear and find that the spot properties are compatible with the expected properties from observations.

  1. Wild Herbivore Grazing Enhances Insect Diversity over Livestock Grazing in an African Grassland System

    PubMed Central

    Roets, Francois; Samways, Michael J.

    2016-01-01

    Southern Africa’s grassland biodiversity is threatened by habitat transformation such as commercial forestry. Ecological networks (ENs) have been instigated to alleviate the pressure of habitat transformation on local biodiversity. ENs are large scale webs of corridors and patches of natural vegetation criss-crossing production landscapes that can simulate conditions in protected areas (PAs). Many ENs have lost many native large mammal species, which have been replaced by domestic livestock to retain natural grazing dynamics, which could have an impact on the long-term value of ENs for insects. Here we compared dung beetle, butterfly and grasshopper diversity in ENs across a landscape mosaic of timber plantations, where 1) wild megaherbivores were maintained, 2) in ENs where these herbivores were replaced by livestock and, 3) in a nearby World Heritage PA which retained its natural complement of megaherbivores. Sites in the PA far from any plantation were similar in composition to those in the wild grazed EN. Presence of the wild grazers improved the alpha- and beta-diversity of all focal insect taxa when compared to domestic grazing. Furthermore, species composition shows significant differences between the two grazing systems indicating that an assemblage of native large mammals facilitates insect diversity conservation. We support the maintenance or introduction of large native mammals in ENs or similar conservation areas in production landscapes to simulate the ecological conditions and natural heterogeneity in nearby PAs. PMID:27783685

  2. SLOPE PROFILOMETRY OF GRAZING INCIDENCE OPTICS.

    SciTech Connect

    TAKACS,P.Z.

    2003-01-14

    Profiling instruments are well-suited to the measurement of grazing incidence optics, such as those found in synchrotron radiation beam lines. Slope measuring profilers, based upon the principle of the pencil beam interferometer, have proven to be especially useful in measuring the figure and slope errors on cylindrical aspheres. The Long Trace Profiler, in various configurations, is the most widely used of this class of profiler. Current performance provides slope measurement accuracy at the microradian level and height measurements accurate to 25 nm over 1 meter trace lengths.

  3. Dietary selection of sheep grazing the semi-arid grasslands of Inner Mongolia, China at different grazing intensities.

    PubMed

    Schiborra, A; Gierus, M; Wan, H W; Glindemann, T; Wang, C J; Susenbeth, A; Taube, F

    2010-08-01

    The objective of this study was to investigate dietary selection of sheep grazing semi-arid grassland in Inner Mongolia, China, using the difference in organic matter digestibility (OMD) of herbage ingested and herbage on offer as indicator for selection. Faecal N was used as digestibility index for herbage ingested (FOMD), while OMD of herbage on offer (GOMD) was estimated from gas production obtained by the Hohenheim gas test. It was hypothesized that the difference between FOMD and GOMD is high, when grazing animals select against low quality herbage provided that herbage is abundant. In a grazing experiment, six grazing intensities (1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/ha), representing light to very heavy grazing intensity for the semi-arid grassland, were compared. The amount of herbage on offer decreased with increasing grazing intensity. Independent statistical analysis of FOMD and GOMD showed that the differences between grazing intensities for both OMD determinations (FOMD: 54.0-57.3%, GOMD: 55.2-57.5%) were not significant (p > 0.05). The difference between FOMD and GOMD was not significant for grazing intensities, but varied between sampling periods from -4 to 1 percentage units. In conclusion, the lack of significance for the difference between FOMD and GOMD suggests that for the semi-arid grassland of Inner Mongolia, China, sheep did not select their feed due to a homogeneous nutritional composition of herbage on offer in 2005, regardless of grazing intensity.

  4. Grazing Affects Exosomal Circulating MicroRNAs in Cattle

    PubMed Central

    Muroya, Susumu; Ogasawara, Hideki; Hojito, Masayuki

    2015-01-01

    Circulating microRNAs (c-miRNAs) are associated with physiological adaptation to acute and chronic aerobic exercise in humans. To investigate the potential effect of grazing movement on miRNA circulation in cattle, here we profiled miRNA expression in centrifugally prepared exosomes from the plasma of both grazing and housed Japanese Shorthorn cattle. Microarray analysis of the c-miRNAs resulted in detection of a total of 231 bovine exosomal miRNAs in the plasma, with a constant expression level of let-7g across the duration and cattle groups. Expression of muscle-specific miRNAs such as miR-1, miR-133a, miR-206, miR-208a/b, and miR-499 were undetectable, suggesting the mildness of grazing movement as exercise. According to validation by quantitative RT-PCR, the circulating miR-150 level in the grazing cattle normalized by the endogenous let-7g level was down-regulated after 2 and 4 months of grazing (P < 0.05), and then its levels in housed and grazing cattle equalized when the grazing cattle were returned to a housed situation. Likewise, the levels of miR-19b, miR-148a, miR-221, miR-223, miR-320a, miR-361, and miR-486 were temporarily lowered in the cattle at 1 and/or 2 month of grazing compared to those of the housed cattle (P < 0.05). In contrast, the miR-451 level was up-regulated in the grazing cattle at 2 months of grazing (P = 0.044). The elevation of miR-451 level in the plasma was coincident with that in the biceps femoris muscle of the grazing cattle (P = 0.008), which suggests the secretion or intake of miR-451 between skeletal muscle cells and circulation during grazing. These results revealed that exosomal c-miRNAs in cattle were affected by grazing, suggesting their usefulness as molecular grazing markers and functions in physiological adaptation of grazing cattle associated with endocytosis, focal adhesion, axon guidance, and a variety of intracellular signaling, as predicted by bioinformatic analysis. PMID:26308447

  5. Dugong grazing and turtle cropping: grazing optimization in tropical seagrass systems?

    PubMed

    Aragones, Lemnuel V; Lawler, Ivan R; Foley, William J; Marsh, Helene

    2006-10-01

    Grazing by dugongs and cropping by green turtles have the capacity to alter the subsequent nutritional quality of seagrass regrowth. We examined the effects of simulated light and intensive grazing by dugongs and cropping by turtles on eight nutritionally relevant measures of seagrass chemical composition over two regrowth periods (short-term, 1-4 months; long-term, 11-13 months) at two seagrass communities (a mixed species community with Zostera capricorni, Halophila ovalis, Halodule uninervis, Cymodocea rotundata and C. serrulate; and a monospecific bed of Halodule uninervis) in tropical Queensland, Australia. The concentrations of organic matter, total nitrogen, total water-soluble carbohydrates, total starch, neutral detergent fiber, acid detergent fiber, acid lignin, as well as the in vitro dry matter digestibility (IVDMD) were measured in the leaves and below-ground parts of each species using near-infrared reflectance spectroscopy (NIRS). Regrowth of preferred species such as H. ovalis and H. uninervis from simulated intensive dugong grazing after a year exhibited increased (by 35 and 25%, respectively, relative to controls) whole-plant N concentrations. Similarly, regrowth of H. ovalis from simulated turtle cropping showed an increase in the leaf N concentration of 30% after a year. However, these gains are tempered by reductions in starch concentrations and increases in fiber. In the short-term, the N concentrations increased while the fiber concentrations decreased. These data provide experimental support for a grazing optimization view of herbivory in the tropical seagrass system, but with feedback in a different manner. Furthermore, we suggest that in areas where grazing is the only major source of natural disturbance, it is likely that there are potential ecosystem level effects if and when numbers of dugongs and turtles are reduced.

  6. Nitrous oxide and greenhouse gas emissions from grazed pastures as affected by use of nitrification inhibitor and restricted grazing regime.

    PubMed

    Luo, Jiafa; Ledgard, Stewart F; Lindsey, Stuart B

    2013-11-01

    Integration of a restricted grazing regime in winter with the use of a nitrification inhibitor can potentially reduce N2O emissions from grazed pasture systems. A three year field study was conducted to compare annual N2O emission rates from a "tight nitrogen" grazed farmlet with those from a control farmlet. The control farmlet was managed under a conventional rotational all-year grazing regime, while the "tight nitrogen" farmlet was under a similar grazing regime, except during winter and early spring seasons when cows grazed for about 6h per day. A nitrification inhibitor (dicyandiamide, DCD) was applied onto the "tight nitrogen" farmlet immediately after grazing through winter and early spring. A chamber technique was used to measure N2O emissions in several paddocks from each farmlet during three contrasting seasons each year. The IPCC (Intergovernmental Panel on Climate Change) inventory methodology was used to estimate CH4 and indirect N2O emissions and the life cycle assessment (LCA) methodology was used to calculate CO2 emissions from the farm systems. The individual and combined effects of restricted grazing and DCD use on N2O emissions were also determined. During the late spring/summer and autumn periods, N2O emission rates were generally similar between the two farmlets. The use of a restricted grazing regime and DCD reduced N2O emissions from the grazed farmlet during the winter/early spring seasons by 43-55%, 64-79% and 45-60% over each of the three years, respectively. The use of restricted grazing and DCD both resulted in a similar reduction in N2O emissions, but there was no significant further reduction from the combination of these technologies. For the three study years, the annual N2O emission rate from the "tight nitrogen" farmlet was 20% lower, on average, than from the control. Total annual greenhouse gas (GHG) emissions, however, were only 5% less in the "tight nitrogen" system.

  7. From the lab bench: A systematic approach to grazing cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A column was written to discuss the use of grazing systems to overcome challenges of managing grazed pastures. Kentucky cattlemen must manage around summer slumps in growth of cool-season perennial grasses, periodic drought, and cattle markets that do not always cooperate with pasture growth patter...

  8. Economic viability of beef cattle grazing systems under prolonged drought

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prolonged drought in the Southern Great Plains of the USA in recent years has raised concerns about vulnerability of beef cattle grazing systems under adverse climate change. To help address the economic viability of beef grazing operations in the Southern Great Plains, this paper provides an econom...

  9. Using dual-purpose crops in sheep-grazing systems.

    PubMed

    Dove, Hugh; Kirkegaard, John

    2014-05-01

    The utilisation of dual-purpose crops, especially wheat and canola grown for forage and grain production in sheep-grazing systems, is reviewed. When sown early and grazed in winter before stem elongation, later-maturing wheat and canola crops can be grazed with little impact on grain yield. Recent research has sought to develop crop- and grazing-management strategies for dual-purpose crops. Aspects examined have been grazing effects on crop growth, recovery and yield development along with an understanding of the grazing value of the crop fodder, its implications for animal nutrition and grazing management to maximise live-weight gain. By alleviating the winter 'feed gap', the increase in winter stocking rate afforded by grazing crops allows crop and livestock production to be increased simultaneously on the same farm. Integration of dual-purpose wheat with canola on mixed farms provides further systems advantages related to widened operational windows, weed and disease control and risk management. Dual-purpose crops are an innovation that has potential to assist in addressing the global food-security challenge.

  10. Using packrat middens to assess grazing effects on vegetation change

    USGS Publications Warehouse

    Fisher, J.; Cole, K.L.; Anderson, R. Scott

    2009-01-01

    Research on grazing effects usually compares the same sites through time or grazed and ungrazed sites over the same time period. Both approaches are complicated in arid environments where grazing can have a long undocumented history and landscapes can be spatially heterogenous. This work employs both approaches simultaneously by comparing grazed and ungrazed samples through both time and space using fossil plant macrofossils and pollen from packrat middens. A series of 27 middens, spanning from 995 yr BP to the present, were collected from Glen Canyon in southeastern Utah, USA. These middens detail vegetation change just prior to, and following, the historical introduction of domesticated grazers and also compares assemblages from nearby ungrazable mesas. Pre-grazing middens, and modern middens from ungrazed areas, record more native grasses, native herbs, and native shrubs such as Rhus trilobata, Amelanchier utahensis, and Shepherdia rotundifolia than modern middens from grazed areas. Ordinations demonstrate that site-to-site variability is more important than any temporal changes, making selection of comparable grazed versus ungrazed study treatments difficult. But within similar sites, the changes through time show that grazing lowered the number of taxa recorded, and lessened the pre-existing site differences, homogenizing the resultant plant associations in this desert grassland.

  11. Grazing effects on carbon fluxes in a northern China grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing is a widespread use of grasslands in northern China, but if stocking rate exceeds grassland carrying capacity, degradation and desertification can occur. As a result, grazing management is critical and can play a significant role in driving C sink and source activity in grassland ecosystems...

  12. Targeted grazing: Applying the research to the land

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The discipline of range science is in part based on the observation that vegetation on rangelands changes in response to livestock grazing. For much of the history of range science, livestock grazing was considered to affect range plants and ecological condition negatively. Thus range plants were cl...

  13. 36 CFR 293.7 - Grazing of livestock.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Grazing of livestock. 293.7 Section 293.7 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE WILDERNESS... National Forests and in accordance with special provisions covering grazing use in units of National...

  14. 36 CFR 293.7 - Grazing of livestock.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Grazing of livestock. 293.7 Section 293.7 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE WILDERNESS... National Forests and in accordance with special provisions covering grazing use in units of National...

  15. Grazing Intensity Does Not Affect Plant Diversity in Shortgrass Steppe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Responses of livestock gain and forage production to grazing intensity in shortgrass steppe are well-established, but effects on basal cover and plant diversity are less so. A long-term grazing intensity study was initiated on shortgrass steppe at the Central Plains Experimental Range (USDA-Agricult...

  16. Cattle grazing and vegetation succession on burned sagebrush steppe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is limited information on the effects of cattle grazing to longer-term plant community composition and productivity following fire in big sagebrush steppe. This study evaluated vegetation response to cattle grazing over seven years (2007-2013) on burned Wyoming big sagebrush (Artemisia triden...

  17. Simulated grazing responses on the proposed prairies National Park

    NASA Astrophysics Data System (ADS)

    Parton, William J.; Wright, R. Gerald; Risser, Paul G.

    1980-03-01

    The tallgrass prairie version of the ELM Grassland Model was used to evaluate the potential impact of establishing a tallgrass prairie National Park in the Flint Hills region of Kansas. This total ecosystem model simulates ( a) the flow of water, heat, nitrogen, and phosphorus through the ecosystem and( b) the biomass dynamics of plants and consumers. It was specifically developed to study the effects of levels and types of herbivory, climatic variation, and fertilization upon grassland ecosystems. The model was used to simulate the impact of building up herds of bison, elk, antelope, and wolves on a tallgrass prairie. The results show that the grazing levels in the park should not be decreased below the prepark grazing levels (moderate grazing with cattle) and that the final grazing levels in the park could be maintained at a slightly higher level than the prepark grazing levels.

  18. Mixed Grazing Systems Benefit both Upland Biodiversity and Livestock Production

    PubMed Central

    Fraser, Mariecia D.; Moorby, Jon M.; Vale, James E.; Evans, Darren M.

    2014-01-01

    Background With world food demand expected to double by 2050, identifying farming systems that benefit both agricultural production and biodiversity is a fundamentally important challenge for the 21st century, but this has to be achieved in a sustainable way. Livestock grazing management directly influences both economic outputs and biodiversity on upland farms while contributing to potentially damaging greenhouse gas emissions, yet no study has attempted to address these impacts simultaneously. Methods Using a replicated, landscape-scale field experiment consisting of five management ‘systems’ we tested the effects of progressively altering elements within an upland farming system, viz i) incorporating cattle grazing into an upland sheep system, ii) integrating grazing of semi-natural rough grazing into a mixed grazing system based on improved pasture, iii) altering the stocking ratio within a mixed grazing system, and iv) replacing modern crossbred cattle with a traditional breed. We quantified the impacts on livestock productivity and numbers of birds and butterflies over four years. Results, Conclusion and Significance We found that management systems incorporating mixed grazing with cattle improve livestock productivity and reduce methane emissions relative to sheep only systems. Systems that also included semi-natural rough grazing consistently supported more species of birds and butterflies, and it was possible to incorporate bouts of summer grazing of these pastures by cattle to meet habitat management prescriptions without compromising cattle performance overall. We found no evidence that the system incorporating a cattle breed popular as a conservation grazer was any better for bird and butterfly species richness than those based on a mainstream breed, yet methane emissions from such a system were predicted to be higher. We have demonstrated that mixed upland grazing systems not only improve livestock production, but also benefit biodiversity

  19. Carbon flux assessment in cow-calf grazing systems.

    PubMed

    Chiavegato, M B; Rowntree, J E; Powers, W J

    2015-08-01

    Greenhouse gas (GHG) fluxes and soil organic carbon (SOC) accumulation in grassland ecosystems are intimately linked to grazing management. This study assessed the carbon equivalent flux (Ceq) from 1) an irrigated, heavily stocked, low-density grazing system, 2) a nonirrigated, lightly stocked, high-density grazing system, and 3) a grazing-exclusion pasture site on the basis of the GHG emissions from pasture soils and enteric methane emissions from cows grazing different pasture treatments. Soil organic carbon and total soil nitrogen stocks were measured but not included in Ceq determination because of study duration and time needed to observe a change in soil composition. Light- and heavy-stocking systems had 36% and 43% greater Ceq than nongrazed pasture sites, respectively ( < 0.01). The largest contributor to increased Ceq from grazing systems was enteric CH emissions, which represented 15% and 32% of the overall emissions for lightly and heavily stocked grazing systems, respectively. Across years, grazing systems also had increased nitrous oxide (N2O; < 0.01) and CH emissions from pasture soils ( < 0.01) compared with nongrazed pasture sites but, overall, minimally contributed to total emissions. Results indicate no clear difference in Ceqflux between the grazing systems studied when SOC change is not incorporated ( = 0.11). A greater stocking rate potentially increased total SOC stock ( = 0.02), the addition of SOC deeper into the soil horizon ( = 0.01), and soil OM content to 30 cm ( < 0.01). The incorporation of long-term annual carbon sequestration into the determination of Ceq could change results and possibly differentiate the grazing systems studied.

  20. Grazing behavior and production characteristics among cows differing in residual feed intake while grazing late season Idaho rangeland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives were to determine if cows classified as either low- or high-residual feed intake (LRFI or HRFI) differed in BW, BCS, and winter grazing activity over time. Thirty Hereford x Angus (LRFI = 16; HRFI = 14) 2-year-old cows grazed sagebrush-steppe for 78 d beginning 29 September 2016. Body...

  1. Integrating remote sensing and conventional grazing/browsing models for modelling carrying capacity in southern African rangelands

    NASA Astrophysics Data System (ADS)

    Adjorlolo, C.; Botha, J. O.; Mhangara, P.; Mutanga, O.; Odindi, J.

    2014-10-01

    Woody vegetation encroachment into grasslands or bush thickening, a global phenomenon, is transforming the Southern African grassland systems into savanna-like landscapes. Estimation of woody vegetation is important to rangeland scientists and land managers for assessing its impact on grass production and calculating its grazing and browsing capacity. Assessment of grazing and browsing components is often challenging because agro-ecological landscapes of this region are largely characterized by small scale and heterogeneous land-use-land-cover patterns. In this study, we investigated the utility of high spatial resolution remotely sensing data for modelling grazing and browsing capacity at landscape level. Woody tree density or Tree Equivalents (TE) and Total Leaf Mass (LMASS) data were derived using the Biomass Estimation for Canopy Volume (BECVOL) program. The Random Forest (RF) regression algorithm was assessed to establish relationships between these variables and vegetation indices (Simple Ratio and Normalized Difference Vegetation Index), calculated using the red and near infrared bands of SPOT5. The RF analysis predicted LMASS with R2 = 0.63 and a Root Mean Square Error (RMSE) of 1256 kg/ha compared to a mean of 2291kg/ha. TE was predicted with R2 = 0.55 and a RMSE = 1614 TE/ha compared to a mean of 3746 TE/ha. Next, spatial distribution maps of LMASS/ha and TE/ha were derived using separate RF regression models. The resultant maps were then used as input data into conventional grazing and browsing capacity models to calculate grazing and browsing capacity maps for the study area. This study provides a sound platform for integrating currently available and future remote sensing satellite data into rangeland carrying capacity modelling and monitoring.

  2. Figure and finish of grazing incidence mirrors

    SciTech Connect

    Takacs, P.Z. ); Church, E.L. . Army Armament Research, Development and Engineering Center)

    1989-08-01

    Great improvement has been made in the past several years in the quality of optical components used in synchrotron radiation (SR) beamlines. Most of this progress has been the result of vastly improved metrology techniques and instrumentation permitting rapid and accurate measurement of the surface finish and figure on grazing incidence optics. A significant theoretical effort has linked the actual performance of components used as x-ray wavelengths to their topological properties as measured by surface profiling instruments. Next-generation advanced light sources will require optical components and systems to have sub-arc second surface figure tolerances. This paper will explore the consequences of these requirements in terms of manufacturing tolerances to see if the present manufacturing state-of-the-art is capable of producing the required surfaces. 15 refs., 14 figs., 2 tabs.

  3. Examining ecological consequences of feral horse grazing using exclosures.

    USGS Publications Warehouse

    Beever, E.A.; Brussard, P.F.

    2000-01-01

    Although feral horses have inhabited western North America since the end of the 16th century, relatively little synecological research has been conducted to quantitatively characterize how they interact with ecosystem components. Because feral horses exhibit watering behavior markedly different from that of domestic cattle, it is particularly important to evaluate response of ecosystem elements near water sources to horse use. To assess this response, we performed live-trapping of small mammals and 2-tiered vegetative sampling in 2 mountain ranges in central Nevada in the interior Great Basin, USA. At low elevations, plots around horse-excluded springs exhibited notably greater plant species richness, percent cover, and abundance of grasses and shrubs, as well as more small mammal burrow entrances than plots at horse-grazed springs. At high elevations, meadows protected from grazing exhibited maximum vegetation heights 2.8 times greater than vegetation grazed by horses only and 4.5 times greater than vegetation grazed by horses and cattle. Species richness in quadrats was most different between the horse-and-cattle-grazed meadow and its ungrazed counterpart, suggesting the possibility of synergistic effects of horse and cattle grazing in the same location. This study, the first in the Great Basin to investigate quantitatively ecosystem consequences of feral horse use with exclosures, represents a preliminary step in identifying factors that determine the magnitude of horse grazing impacts. 

  4. Interactions between global and grazing bifurcations in an impacting system.

    PubMed

    Mason, Joanna F; Piiroinen, Petri T

    2011-03-01

    It is well known that the locus of boundary crises in smooth systems contains gaps that give rise to periodic windows. We show that this phenomenon can also be observed in an impacting system, and that the mechanism by which these gaps are created is different. Namely, here gaps are created and disappear at points along the branches of boundary crises where they are intersected by branches of grazing bifurcations. We locate a novel type of double-crisis vertex which we call a grazing-crisis vertex. Additionally, we illustrate several types of basin-boundary metamorphosis that are intricately related with grazing bifurcations.

  5. American Red Cross

    MedlinePlus

    ... Espanol Local Red Cross ( ) Change Chapter Edit Zip Code Edit Zip Code Shop the Red Cross Store Toggle Navigation Menu ... Espanol Local Red Cross ( ) Change Chapter Edit Zip Code Edit Zip Code Shop the Red Cross Store ...

  6. The interaction of diurnal grazing pattern, ruminal metabolism, nutrient supply and management in cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Daily herbage intake depends on several factors that govern the initiation and cessation of successive grazing bouts. Ruminal fill, which regulates grazing bout-eating behavior, is one such factor. Under grazing conditions, nutrient supply varies among grazing bouts, not only in amount, but also in ...

  7. 25 CFR 161.300 - When is a permit needed to authorize grazing use?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When is a permit needed to authorize grazing use? 161.300... PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.300 When is a permit needed to authorize grazing... Navajo Partitioned Land for grazing purposes....

  8. 25 CFR 166.408 - Is the grazing rental rate established by the BIA adjusted periodically?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Is the grazing rental rate established by the BIA... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.408 Is the grazing rental rate established by the BIA adjusted...

  9. 25 CFR 161.207 - What livestock are authorized to graze?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What livestock are authorized to graze? 161.207 Section... LANDS GRAZING PERMITS General Provisions § 161.207 What livestock are authorized to graze? The following livestock are authorized to graze on the Navajo Partitioned Lands: horses, cattle, sheep, goats,...

  10. 25 CFR 166.301 - How is Indian land for grazing purposes described?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How is Indian land for grazing purposes described? 166... GRAZING PERMITS Land and Operations Management § 166.301 How is Indian land for grazing purposes described? Indian land for grazing purposes should be described by legal description (e.g., aliquot parts, metes...

  11. 25 CFR 161.300 - When is a permit needed to authorize grazing use?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When is a permit needed to authorize grazing use? 161.300... PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.300 When is a permit needed to authorize grazing... Navajo Partitioned Land for grazing purposes....

  12. 43 CFR 4130.6-2 - Nonrenewable grazing permits and leases.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Nonrenewable grazing permits and leases...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6-2 Nonrenewable grazing permits and leases....

  13. 43 CFR 6304.25 - What special provisions apply to livestock grazing?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... grazing? 6304.25 Section 6304.25 Public Lands: Interior Regulations Relating to Public Lands (Continued... Specifically Addressed by the Wilderness Act § 6304.25 What special provisions apply to livestock grazing? (a) If you hold a BLM grazing permit or grazing lease for land within a wilderness area, you may...

  14. 25 CFR 161.307 - When may a permittee commence grazing on Navajo Partitioned Land?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When may a permittee commence grazing on Navajo... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land? The permittee may graze on Navajo Partitioned Land on the...

  15. 25 CFR 700.715 - Assignment, modification, and cancellation of grazing permits.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Assignment, modification, and cancellation of grazing... OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.715 Assignment, modification, and cancellation of grazing permits. (a) Grazing permits may be assigned or transferred with the written consent...

  16. 25 CFR 166.408 - Is the grazing rental rate established by the BIA adjusted periodically?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Is the grazing rental rate established by the BIA... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.408 Is the grazing rental rate established by the BIA adjusted...

  17. 25 CFR 161.207 - What livestock are authorized to graze?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What livestock are authorized to graze? 161.207 Section... LANDS GRAZING PERMITS General Provisions § 161.207 What livestock are authorized to graze? The following livestock are authorized to graze on the Navajo Partitioned Lands: horses, cattle, sheep, goats,...

  18. 25 CFR 161.307 - When may a permittee commence grazing on Navajo Partitioned Land?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When may a permittee commence grazing on Navajo... AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.307 When may a permittee commence grazing on Navajo Partitioned Land? The permittee may graze on Navajo Partitioned Land on the...

  19. 25 CFR 700.715 - Assignment, modification, and cancellation of grazing permits.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Assignment, modification, and cancellation of grazing... OPERATIONS AND RELOCATION PROCEDURES New Lands Grazing § 700.715 Assignment, modification, and cancellation of grazing permits. (a) Grazing permits may be assigned or transferred with the written consent...

  20. 43 CFR 4130.6-1 - Exchange-of-use grazing agreements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Exchange-of-use grazing agreements. 4130.6... LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.6-1 Exchange-of-use grazing agreements. (a) An...

  1. Experimental Evidence for Grazing System Research: What Does it Tell Us?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research on grazing systems has been conducted for the past 60 years and the experimental evidence consistently indicates that rotational grazing is comparable to continuous grazing on rangelands. For example, over 80% of the peer-reviewed studies reported that rotational grazing did not result in h...

  2. Plant Diversity: Effects of Grazing System and Stocking Rate in Northern Mixed-Grass Prairie

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of grazing system, stocking rate, and grazing system X stocking rate interactions, on plant diversity are poorly understood in rangelands. A grazing system (season-long and short-duration rotational grazing) X stocking rate (light: 16 steers•80 ha-1, moderate: 4 steers•12 ha-1 and heavy: 4 s...

  3. Impact of processing on in vitro digestion of milk from grazing organic and confined conventional herds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Debate on differences between milk from grazing and non-grazing cows has not addressed the effects that standard processing may have on milk digestibility. In this study, raw milk from grazing organic (ORG) and non-grazing conventional (CONV) herds was adjusted to 0 and 3.25% fat and processed as fo...

  4. Herds of methane chambers grazing bubbles

    NASA Astrophysics Data System (ADS)

    Grinham, Alistair; Dunbabin, Matthew

    2014-05-01

    Water to air methane emissions from freshwater reservoirs can be dominated by sediment bubbling (ebullitive) events. Previous work to quantify methane bubbling from a number of Australian sub-tropical reservoirs has shown that this can contribute as much as 95% of total emissions. These bubbling events are controlled by a variety of different factors including water depth, surface and internal waves, wind seiching, atmospheric pressure changes and water levels changes. Key to quantifying the magnitude of this emission pathway is estimating both the bubbling rate as well as the areal extent of bubbling. Both bubbling rate and areal extent are seldom constant and require persistent monitoring over extended time periods before true estimates can be generated. In this paper we present a novel system for persistent monitoring of both bubbling rate and areal extent using multiple robotic surface chambers and adaptive sampling (grazing) algorithms to automate the quantification process. Individual chambers are self-propelled and guided and communicate between each other without the need for supervised control. They can maintain station at a sampling site for a desired incubation period and continuously monitor, record and report fluxes during the incubation. To exploit the methane sensor detection capabilities, the chamber can be automatically lowered to decrease the head-space and increase concentration. The grazing algorithms assign a hierarchical order to chambers within a preselected zone. Chambers then converge on the individual recording the highest 15 minute bubbling rate. Individuals maintain a specified distance apart from each other during each sampling period before all individuals are then required to move to different locations based on a sampling algorithm (systematic or adaptive) exploiting prior measurements. This system has been field tested on a large-scale subtropical reservoir, Little Nerang Dam, and over monthly timescales. Using this technique

  5. 43 CFR 4110.2-3 - Transfer of grazing preference.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... property and the grazing preference, in animal unit months, attached to that base property. (c) If a... the transfer. (e) If an unqualified transferee acquires rights in base property through operation...

  6. Nitrogen Mineralization by Acanthamoeba polyphaga in Grazed Pseudomonas paucimobilis Populations

    PubMed Central

    Sinclair, James L.; McClellan, J. Forbes; Coleman, David C.

    1981-01-01

    Nitrogen mineralization was studied in a simple grazing system in which the protozoan Acanthamoeba polyphaga was grown with the bacterium Pseudomonas paucimobilis (two soil organisms isolated from the shortgrass prairie in northern Colorado). In different experiments, either carbon or nitrogen was adjusted to be in limiting amounts. When carbon was limiting, grazers were almost entirely responsible for nitrogen mineralization, with bacteria themselves contributing little. When nitrogen was limiting, nitrogen mineralization by grazers permitted continued growth by the grazed bacteria and a greater bacterial biomass production. The increased growth of the grazed bacteria did not result in an increased total amount of carbon used, but the grazed bacteria used carbon more efficiently than the ungrazed bacteria. PMID:16345864

  7. Fire and grazing regulate belowground processes in tallgrass prairie

    USGS Publications Warehouse

    Johnson, Loretta C.; Matchett, John R.

    2001-01-01

    In tallgrass prairie, belowground processes are even more important than in forested systems because aboveground biomass and standing dead litter are periodically removed by frequent fires or grazers. Thus, studies that address factors regulating belowground processes are especially relevant for tallgrass prairie. We predicted that effects of grazing and burning differ belowground and that changes in root productivity caused by burning or grazing provide feedback that affects ecosystem fluxes of C and N. These differences in belowground response should be driven largely by changes in N dynamics and the degree to which burning and grazing affect the pathway and magnitude of N loss and the degree of N limitation in these systems. Fire, the major pathway of N loss in ungrazed tallgrass prairie, should result in reduced net N mineralization and N availability. We expected plants to compensate for increased N limitation by increasing their allocation to roots, as manifested in increased soil respiration and C cycling belowground. In contrast, grazing conserves N in the ecosystem by redistributing the N once contained in grass to labile forms in urine and dung. Thus, we predicted that grazing should increase N cycling rates and N availability to plants. Consequently, grazed plants should be less N limited and should allocate less C to roots and more to shoots. This, in turn, should decrease belowground C cycling, manifested as reduced soil CO2 flux.We explored the roles of grazing and burning on root growth in experimental watersheds at Konza Prairie, Kansas, USA. To assess effects of fire on root productivity, we installed root ingrowth cores in two watersheds without grazers that differ in fire frequency: annually vs. infrequently burned (four years since the last fire). To assess effects of grazing, we installed root ingrowth cores in an annually burned watershed grazed by bison and in fenced controls (exclosures). Within bison “grazing lawns,” root ingrowth cores

  8. Pasture-scale measurement of methane emissions of grazing cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying methane emission of cattle grazing on southern Great Plains pastures using micrometeorology presents several challenges. Cattle are elevated, mobile point sources of methane, so that knowing their location in relation to atmospheric methane concentration measurements becomes critical. St...

  9. Technical note: Monitoring grazing bites and walking activity with pedometers.

    PubMed

    Umemura, K

    2013-02-01

    Three types of pedometers installed on loosely fitted neck collars were investigated to determine the accuracy with which the devices measured the number of grazing bites performed by cows. The pedometer memory stored the summed number of bites over 1-h intervals for up to 10d, and the battery had a life of more than 3 mo. The values recorded by the pedometers were linearly related to the number of bites measured by visual observation and were unaffected by rumination. The correlation coefficients between the pedometer values and the number of bites were all >0.9. Circadian and day-to-day variations in the number of grazing bites were obtained by all 3 pedometers. The regression coefficients differed among the pedometers. The pedometers also responded to the occurrence of walking steps. The values recorded by the pedometers were linearly related to the observed number of walking steps. The correlation coefficients between the pedometer values and the number of steps were all >0.9. Although the number of walking steps affected the number of grazing bites, the number of bites greatly exceeded the number of walking steps. One type of pedometer, equipped with a 2-dimensional accelerometer, was used to analyze both grazing and walking behaviors. The back-forth and right-left movements of the pedometer had similar values during walking, whereas the values of the back-forth movements were greater during grazing. I conclude that pedometers can be used to measure the number of grazing bites but that this technique requires calibration to relate the pedometer values to the number of grazing bites. Observations of the back-forth and right-left movements of pedometers on neck collars will aid in distinguishing the grazing and walking behaviors of cows.

  10. Fire management in fens and wet grasslands grazed by cattle

    USGS Publications Warehouse

    Middleton, Beth A.

    2006-01-01

    Managers grapple with the problem of shrub invasion in fens and wet grasslands, and the invasion of shrubs is a particular problem in newly acquired natural areas that were once grazed by cattle. The specific management for any particular fen or wet grassland depends greatly on its previous land-use history. Managers should have a clear understanding of the grazing and drainage history of newly acquired fens and wet grasslands so that well-informed management decisions can be made.

  11. Indicators of grazing impact in Inner Mongolian steppe ecosystems

    NASA Astrophysics Data System (ADS)

    Blank, B.; Breuer, L.; Butterbach-Bahl, K.; Frede, H.-G.

    2009-04-01

    The DFG research group 536 MAGIM (Matter fluxes in grasslands of Inner Mongolia as influenced by stocking rate) investigates the influence of grazing intensity on matter and water cycles in grazed steppe ecosystems of Inner Mongolia. This Sino-German co-operation applies an interdisciplinary approach to investigate major ecosystem functions and how they are affected by grazing and overgrazing. Within the research group an indicator system is developed to systemize the feedback of ecosystem parameters to the influence of grazing and to analyse, which parameter or parameter group reacts most sensitively. Parameters were measured at up to five different grazing intensities (from ungrazed to heavy grazed) and are related to four thematic indicator groups (plant productivity, atmosphere, pedosphere, hydrosphere). The parameters were scaled to allow assessing the influence of grazing intensity between different sets of parameters. For this the average value of a parameter at the lowest grazing intensity (ungrazed) was set 100%, so that the values at the other intensities could be scaled scaled adequately. Then the difference between highest and lowest grazing intensity was determined. According to this difference the influence of grazing was characterized as weak (< 20% difference), medium (20-40%), strong (40-60%) and very strong (> 60%). Impact of grazing on the parameters will be marked as weak (w), medium (m), strong (s) and very strong (vs) in the text. The group plant productivity includes the vegetation parameters aboveground biomass and belowground biomass. Belowground biomass (s) was significantly different between grazing treatments with the highest value at the ungrazed site (399.00 g m-2 a-1) and the lowest at the heavy grazed site (208.00 g m-2 a-1). Aboveground biomass (m) ranged between 91.33-131.67 g m-2 a-1 and differed significantly between the ungrazed and the heavy grazed site, again with higher values at the ungrazed site (Gao et al. 2008). The group

  12. Influence of grazing and available moisture on breeding densities of grassland birds in the central platte river valley, Nebraska

    USGS Publications Warehouse

    Kim, D.H.; Newton, W.E.; Lingle, G.R.; Chavez-Ramirez, F.

    2008-01-01

    We investigated the relationship between grassland breeding bird densities and both grazing and available moisture in the central Platte River Valley. Nebraska between 1980 and 1996. We also compared species richness and community similarity of breeding birds in sedge (Carex spp.) meadows and mesic grasslands. Densities of two species had a significant relationship with grazing and six of seven focal species had a significant relationship with available moisture. Bobolink (Dolichonyx oryzivorus) and Brown-headed Cowbird (Molothrus ater) densities were lower in grazed plots compared to ungrazed plots, whereas Red-winged Blackbird (Agelaius phoeniceus) densities were greater in sedge-meadow plots compared to mesic grassland plots. Bobolink, Dickcissel (Spiza americana). and Brown-headed Cowbird were negatively associated with available moisture with breeding densities peaking during the driest conditions. Our results suggest that wet conditions increase species richness for the community through addition of wetland-dependant and wetland-associated birds, but decrease densities of ground-nesting grassland birds in wet-meadow habitats, whereas dry conditions reduce species richness but increase the density of the avian assemblage. We propose that wet-meadow habitats serve as local refugia for grassland-nesting birds during local or regional droughts.

  13. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not covered by the permit? 166.307 Section 166.307 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations...

  14. Development of Adjustable Grazing Incidence Optics

    NASA Astrophysics Data System (ADS)

    Reid, Paul B.; Davis, W.; Schwartz, D. A.; Trolier-McKinstry, S.; Wilke, R. H. T.

    2010-03-01

    We report on the development of adjustable grazing incidence optics. We are developing bimorph mirrors for high resolution (sub-arc second) imaging. Bimorph mirrors consist of a thin layer of piezo-electric material deposited on the back surface of a thin (< 0.4 mm) thermally formed glass or electroplated metal segmented mirror. Voltage applied across the thickness of the piezo produces a strain in the plane of the mirror surface. The strain produces bending of the mirror similar to the bi-metallic effect. No reaction structure is necessary, which allows one to densely nest mirror shells for large effective area. A pixilated array of outer electrodes on the piezo material localizes the strain to the particular piezo "pixel.” Mirror figure errors are corrected (on-orbit) via induced localized deformations. We have successfully deposited a 1-micrometer thick layer of the piezo-electric material lead-zirconate-titanate (PZT) on thin glass mirrors. We report on the electrical and mechanical properties of the bimorph mirrors, and mirror requirements. We discuss finite element modeling of bimorph mirrors. In particular, we focus on how a difference in mirror mounting affects the influence functions ( the induced deformations). We are also developing the use of electrostrictive adjusters for moderate resolution (a few arc second) imaging. Electroplated nickel/cobalt full shells are mounted together using the adjusters. The adjusters are arrayed axially and tangentially between shells, with their adjustable dimension in the radial direction. Each shell is adjusted and fixed in place during mirror assembly, starting with the innermost shell. We review finite element modeling of the adjustable optics and the application of the adjustment system to correct manufacturing errors. We discuss initial tests using electrostrictive adjusters to change the shape of flat mirror segments. This work is supported by NASA Contract NNX09AE87G and a grant from the Gordon and Betty Moore

  15. Levels of supplementation for grazing beef heifers.

    PubMed

    Cabral, Carla Heloisa Avelino; Paulino, Mario Fonseca; Detmann, Edenio; de Campos Valadares Filho, Sebastião; de Barros, Lívia Vieira; Valente, Eriton Egidio Lisboa; de Oliveira Bauer, Maristela; Cabral, Carlos Eduardo Avelino

    2014-06-01

    The objective of this experiment was to evaluate the effect of providing different levels of a supplement on the nutritional characteristics and productive performance of heifers on pasture during the rainy-dry transition and dry season in Brazil or tropical area. Thirty crossbred heifers with predominance of Zebu breed were used in a completely randomized experimental design. Treatments consisted of a mineral supplement and 0.5, 1.0, 1.5, or 2.0 kg/animal/d of a protein supplement containing 300 g crude protein (CP)/kg of dry matter (DM). In the rainy-dry transition season there was quadratic effect of the protein supplementation (p<0.10) on daily weight gain (DWG). A linear relationship (p<0.10) was found between increasing supplement intake and intakes of DM, organic matter (OM), crude protein (CP), ether extract (EE), non fibrous carbohydrates (NFC) and total digestible nutrients (TDN). Coefficients of apparent digestibility of CP, EE, and NFC increased linearly (p<0.10) with increasing supplement levels, but there was no effect on the DM apparent digestibility (p>0.10); the microbial efficiency (g CPmic/kg TDN) and the relationship of microbial nitrogen flow with nitrogen intake (g/g nitrogen intake) were negative linear profiles. In the dry season, the descriptive pattern least squares means showed a trend of stabilization of DWG from the supply of 0.98 kg of protein supplement; the intakes of DM, OM, CP, EE, NFC, and TDN showed increasing linear relationship (p<0.10) with protein supplement levels; the means of apparent digestibility coefficients of the different dietary fractions presented a linear-response-plateau (LRP); the microbial nitrogen flow (g/d) showed positive linear profile (p<0.10) for supplementation levels. It is concluded that supplementation improves the productive performance of grazing heifers and that 1.0 kg/d of supplement per animal gives the maximum increment of weight gain.

  16. Functional diversity increases ecological stability in a grazed grassland.

    PubMed

    Hallett, Lauren M; Stein, Claudia; Suding, Katharine N

    2017-03-01

    Understanding the factors governing ecological stability in variable environments is a central focus of ecology. Functional diversity can stabilize ecosystem function over time if one group of species compensates for an environmentally driven decline in another. Although intuitively appealing, evidence for this pattern is mixed. We hypothesized that diverse functional responses to rainfall will increase the stability of vegetation cover and biomass across rainfall conditions, but that this effect depends on land-use legacies that maintain functional diversity. We experimentally manipulated grazing in a California grassland to create land-use legacies of low and moderate grazing, across which we implemented rainout shelters and irrigation to create dry and wet conditions over 3 years. We found that the stability of the vegetation cover was greatly elevated and the stability of the biomass was slightly elevated across rainfall conditions in areas with histories of moderate grazing. Initial functional diversity-both in the seed bank and aboveground-was also greater in areas that had been moderately grazed. Rainfall conditions in conjunction with this grazing legacy led to different functional diversity patterns over time. Wet conditions led to rapid declines in functional diversity and a convergence on resource-acquisitive traits. In contrast, consecutively dry conditions maintained but did not increase functional diversity over time. As a result, grazing practices and environmental conditions that decrease functional diversity may be associated with lasting effects on the response of ecosystem functions to drought. Our results demonstrate that theorized relationships between diversity and stability are applicable and important in the context of working grazed landscapes.

  17. Near grazing scattering from non-Gaussian ocean surfaces

    NASA Technical Reports Server (NTRS)

    Kim, Yunjin; Rodriguez, Ernesto

    1993-01-01

    We investigate the behavior of the scattered electromagnetic waves from non-Gaussian ocean surfaces at near grazing incidence. Even though the scattering mechanisms at moderate incidence angles are relatively well understood, the same is not true for near grazing rough surface scattering. However, from the experimental ocean scattering data, it has been observed that the backscattering cross section of a horizontally polarized wave can be as large as the vertical counterpart at near grazing incidence. In addition, these returns are highly intermittent in time. There have been some suggestions that these unexpected effects may come from shadowing or feature scattering. Using numerical scattering simulations, it can be shown that the horizontal backscattering cannot be larger than the vertical one for the Gaussian surfaces. Our main objective of this study is to gain a clear understanding of scattering mechanisms underlying the near grazing ocean scattering. In order to evaluate the backscattering cross section from ocean surfaces at near grazing incidence, both the hydrodynamic modeling of ocean surfaces and an accurate near grazing scattering theory are required. For the surface modeling, we generate Gaussian surfaces from the ocean surface power spectrum which is derived using several experimental data. Then, weakly nonlinear large scale ocean surfaces are generated following Longuet-Higgins. In addition, the modulation of small waves by large waves is included using the conservation of wave action. For surface scattering, we use MOM (Method of Moments) to calculate the backscattering from scattering patches with the two scale shadowing approximation. The differences between Gaussian and non-Gaussian surface scattering at near grazing incidence are presented.

  18. The effects of timing of grazing on plant and arthropod communities in high-elevation grasslands.

    PubMed

    Davis, Stacy C; Burkle, Laura A; Cross, Wyatt F; Cutting, Kyle A

    2014-01-01

    Livestock grazing can be used as a key management tool for maintaining healthy ecosystems. However, the effectiveness of using grazing to modify habitat for species of conservation concern depends on how the grazing regime is implemented. Timing of grazing is one grazing regime component that is less understood than grazing intensity and grazer identity, but is predicted to have important implications for plant and higher trophic level responses. We experimentally assessed how timing of cattle grazing affected plant and arthropod communities in high-elevation grasslands of southwest Montana to better evaluate its use as a tool for multi-trophic level management. We manipulated timing of grazing, with one grazing treatment beginning in mid-June and the other in mid-July, in two experiments conducted in different grassland habitat types (i.e., wet meadow and upland) in 2011 and 2012. In the upland grassland experiment, we found that both early and late grazing treatments reduced forb biomass, whereas graminoid biomass was only reduced with late grazing. Grazing earlier in the growing season versus later did not result in greater recovery of graminoid or forb biomass as expected. In addition, the density of the most ubiquitous grassland arthropod order (Hemiptera) was reduced by both grazing treatments in upland grasslands. A comparison of end-of-season plant responses to grazing in upland versus wet meadow grasslands revealed that grazing reduced graminoid biomass in the wet meadow and forb biomass in the upland, irrespective of timing of grazing. Both grazing treatments also reduced end-of-season total arthropod and Hemiptera densities and Hemiptera biomass in both grassland habitat types. Our results indicate that both early and late season herbivory affect many plant and arthropod characteristics in a similar manner, but grazing earlier may negatively impact species of conservation concern requiring forage earlier in the growing season.

  19. Effects of past and present livestock grazing on herpetofauna in a landscape-scale experiment.

    PubMed

    Kay, Geoffrey M; Mortelliti, Alessio; Tulloch, Ayesha; Barton, Philip; Florance, Daniel; Cunningham, Saul A; Lindenmayer, David B

    2016-06-17

    Livestock grazing is the most widespread land use on Earth and can have negative effects on biodiversity. Yet, many of the mechanisms by which grazing leads to changes in biodiversity remain unresolved. One reason is that conventional grazing studies often target broad treatments rather than specific parameters of grazing (e.g., intensity, duration, and frequency) or fail to account for historical grazing effects. We conducted a landscape-scale replicated grazing experiment (15,000 km(2) , 97 sites) to examine the impact of past grazing management and current grazing regimes (intensity, duration, and frequency) on a community of ground-dwelling herpetofauna (39 species). We analyzed community variables (species richness and composition) for all species and built multiseason patch-occupancy models to predict local colonization and extinction for the 7 most abundant species. Past grazing practices did not influence community richness but did affect community composition and patch colonization and extinction for 4 of 7 species. Present grazing parameters did not influence community richness or composition, but 6 of the 7 target species were affected by at least one grazing parameter. Grazing frequency had the most consistent influence, positively affecting 3 of 7 species (increased colonization or decreased extinction). Past grazing practice affected community composition and population dynamics in some species in different ways, which suggests that conservation planners should examine the different grazing histories of an area. Species responded differently to specific current grazing practices; thus, incentive programs that apply a diversity of approaches rather than focusing on a change such as reduced grazing intensity should be considered. Based on our findings, we suggest that determining fine-scale grazing attributes is essential for advancing grazing as a conservation strategy.

  20. Seeing Red

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This New Horizons image of Jupiter's volcanic moon Io was taken at 13:05 Universal Time during the spacecraft's Jupiter flyby on February 28, 2007. It shows the reddish color of the deposits from the giant volcanic eruption at the volcano Tvashtar, near the top of the sunlit crescent, as well as the bluish plume itself and the orange glow of the hot lava at its source. The relatively unprocessed image on the left provides the best view of the volcanic glow and the plume deposits, while the version on the right has been brightened to show the much fainter plume, and the Jupiter-lit night side of Io.

    New Horizons' color imaging of Io's sunlit side was generally overexposed because the spacecraft's color camera, the super-sensitive Multispectral Visible Imaging Camera (MVIC), was designed for the much dimmer illumination at Pluto. However, two of MVIC's four color filters, the blue and 'methane' filter (a special filter designed to map methane frost on the surface of Pluto at an infrared wavelength of 0.89 microns), are less sensitive than the others, and thus obtained some well-exposed views of the surface when illumination conditions were favorable. Because only two color filters are used, rather than the usual three, and because one filter uses infrared light, the color is only a rough approximation to what the human eye would see.

    The red color of the Tvashtar plume fallout is typical of Io's largest volcanic plumes, including the previous eruption of Tvashtar seen by the Galileo and Cassini spacecraft in 2000, and the long-lived Pele plume on the opposite side of Io. The color likely results from the creation of reddish three-atom and four-atom sulfur molecules (S3 and S4) from plume gases rich in two-atom sulfur molecules (S2 After a few months or years, the S3 and S4 molecules recombine into the more stable and familiar yellowish form of sulfur consisting of eight-atom molecules (S8), so these red deposits are only seen around recently-active Io

  1. Breeding bird response to cattle grazing of a cottonwood bottomland

    USGS Publications Warehouse

    Sedgwick, James A.; Knopf, Fritz L.

    1987-01-01

    We studied avian habitat relationships and the impact of grazing on breeding densities of selected migratory birds in a plains cottonwood (Populus sargentii) bottomland in northeastern Colorado. Five 16-ha plots served as controls and 5 were fenced and fall-grazed October-November 1982-84 following a season of pre-treatment study in the spring of 1982. We focused our analysis on bird species directly dependent on the grass-herb-shrub layer of vegetation for foraging, nesting, or both. The guild included house wren (Troglodytes aedon), brown thrasher (Toxostoma rufum), American robin (Turdus migratorius), common yellowthroat (Geothlypis trichas), yellow-breasted chat (Icteria virens), and rufous-sided towhee (Pipilo erythropthalmus). Moderate, late-fall grazing had no detectable impact on calculated densities of any of the 6 species, implying that proper seasonal grazing of a cottonwood floodplain is, at least initially (3 years), compatible with migratory bird use of a site for breeding. Habitat associations suggested that common yellowthroats and yellow-breasted chats were most unique and most likely to respond negatively to higher levels of grazing. We suggest that these latter 2 species are appropriate ecological indicators of the quality of ground-shrub vegetation as breeding bird habitats in lowland floodplains of the Great Plains.

  2. Suspected photosensitisation in lambs grazing birdsfoot trefoil (Lotus corniculatus).

    PubMed

    Stafford, K J; West, D M; Alley, M R; Waghorn, G C

    1995-06-01

    Suspected photosensitisation occurred in three groups of lambs grazing birdsfoot trefoil (Lotus corniculatus c.v. Grasslands Goldie). In one group, sucking lambs aged about 10 weeks, grazing birdsfoot trefoil, developed skin lesions while lambs of a similar age and from the same flock grazing lucerne (Medicago sativa) or a mixed sward of both species showed no signs of photosensitisation. Affected lambs had lesions on their backs and ears. In a few animals the tips of the ears were shortened by 2-3 cm. In the affected lambs, serum liver enzymes (gamma-glutamyltransferase, glutamate dehydrogenase), bilirubin and serum Vitamin B12 levels were within the normal range. At necropsy, no significant pathological changes were detected in the liver and histological changes in the skin were consistent with primary photosensitisation. In the second group, three of 80 weaned lambs grazing the same birdsfoot trefoil at a restricted intake were affected in the same manner as the first group. In the third group, 15 animals from 28 sets of sucking twin lambs were also affected. In only two sets of twins were both lambs affected. None of the ewes grazing with the lambs in the first or third groups showed any clinical signs of photosensitisation.

  3. Genotype effects on body temperature in dairy cows under grazing conditions in a hot climate including evidence for heterosis

    NASA Astrophysics Data System (ADS)

    Dikmen, S.; Martins, L.; Pontes, E.; Hansen, P. J.

    2009-07-01

    We compared diurnal patterns of vaginal temperature in lactating cows under grazing conditions to evaluate genotype effects on body temperature regulation. Genotypes evaluated were Holstein, Jersey, Jersey × Holstein and Swedish Red × Holstein. The comparison of Holstein and Jersey versus Jersey × Holstein provided a test of whether heterosis effects body temperature regulation. Cows were fitted with intravaginal temperature recording devices that measured vaginal temperature every 15 min for 7 days. Vaginal temperature was affected by time of day ( P < 0.0001) and genotype × time ( P < 0.0001) regardless of whether days in milk and milk yield were used as covariates. Additional analyses indicated that the Swedish Red × Holstein had a different pattern of vaginal temperatures than the other three genotypes (Swedish Red × Holstein vs others × time; P < 0.0001) and that Holstein and Jersey had a different pattern than Jersey × Holstein [(Holstein + Jersey vs Jersey × Holstein) × time, P < 0.0001]. However, Holstein had a similar pattern to Jersey [(Holstein vs Jersey) × time, P > 0.10]. These genotype × time interactions reflect two effects. First, Swedish Red × Holstein had higher vaginal temperatures than the other genotypes in the late morning and afternoon but not after the evening milking. Secondly, Jersey × Holstein had lower vaginal temperatures than other genotypes in the late morning and afternoon and again in the late night and early morning. Results point out that there are effects of specific genotypes and evidence for heterosis on regulation of body temperature of lactating cows maintained under grazing conditions and suggest that genetic improvement for thermotolerance through breed choice or genetic selection is possible.

  4. Levels of Supplementation for Grazing Beef Heifers

    PubMed Central

    Cabral, Carla Heloisa Avelino; Paulino, Mario Fonseca; Detmann, Edenio; de Campos Valadares Filho, Sebastião; de Barros, Lívia Vieira; Valente, Ériton Egidio Lisboa; de Oliveira Bauer, Maristela; Cabral, Carlos Eduardo Avelino

    2014-01-01

    The objective of this experiment was to evaluate the effect of providing different levels of a supplement on the nutritional characteristics and productive performance of heifers on pasture during the rainy-dry transition and dry season in Brazil or tropical area. Thirty crossbred heifers with predominance of Zebu breed were used in a completely randomized experimental design. Treatments consisted of a mineral supplement and 0.5, 1.0, 1.5, or 2.0 kg/animal/d of a protein supplement containing 300 g crude protein (CP)/kg of dry matter (DM). In the rainy-dry transition season there was quadratic effect of the protein supplementation (p<0.10) on daily weight gain (DWG). A linear relationship (p<0.10) was found between increasing supplement intake and intakes of DM, organic matter (OM), crude protein (CP), ether extract (EE), non fibrous carbohydrates (NFC) and total digestible nutrients (TDN). Coefficients of apparent digestibility of CP, EE, and NFC increased linearly (p<0.10) with increasing supplement levels, but there was no effect on the DM apparent digestibility (p>0.10); the microbial efficiency (g CPmic/kg TDN) and the relationship of microbial nitrogen flow with nitrogen intake (g/g nitrogen intake) were negative linear profiles. In the dry season, the descriptive pattern least squares means showed a trend of stabilization of DWG from the supply of 0.98 kg of protein supplement; the intakes of DM, OM, CP, EE, NFC, and TDN showed increasing linear relationship (p<0.10) with protein supplement levels; the means of apparent digestibility coefficients of the different dietary fractions presented a linear-response-plateau (LRP); the microbial nitrogen flow (g/d) showed positive linear profile (p<0.10) for supplementation levels. It is concluded that supplementation improves the productive performance of grazing heifers and that 1.0 kg/d of supplement per animal gives the maximum increment of weight gain. PMID:25050018

  5. Community responses of arthropods to a range of traditional and manipulated grazing in shortgrass steppe.

    PubMed

    Newbold, T A Scott; Stapp, Paul; Levensailor, Katherine E; Derner, Justin D; Lauenroth, William K

    2014-06-01

    Responses of plants to grazing are better understood, and more predictable, than those of consumers in North American grasslands. In 2003, we began a large-scale, replicated experiment that examined the effects of grazing on three important arthropod groups-beetles, spiders, and grasshoppers-in shortgrass steppe of north-central Colorado. We investigated whether modifications of the intensity and seasonality of livestock grazing alter the structure and diversity of macroarthropod communities compared with traditional grazing practices. Treatments represented a gradient of grazing intensity by cattle and native herbivores: long-term grazing exclosures; moderate summer grazing (the traditional regime); intensive spring grazing; intensive summer grazing; and moderately summer-grazed pastures also inhabited by black-tailed prairie dogs (Cynomys ludovicianus Ord). Beetles and spiders were the most common groups captured, comprising 60% and 21%, respectively, of 4,378 total pitfall captures. Grasshopper counts were generally low, with 3,799 individuals observed and densities <4 m(-2). Two years after treatments were applied, vegetation structure differed among grazing treatments, responding not only to long-term grazing conditions, but also to the short-term, more-intensive grazing manipulations. In response, arthropods were, in general, relatively insensitive to these grazing-induced structural changes. However, species-level analyses of one group (Tenebrionidae) revealed both positive and negative effects of grazing treatments on beetle richness and activity-density. Importantly, these responses to grazing were more pronounced in a year when spring-summer rainfall was low, suggesting that both grazing and precipitation-which together may create the greatest heterogeneity in vegetation structure-are drivers of consumer responses in this system.

  6. Analysis of FEL optical systems with grazing incidence mirrors

    SciTech Connect

    Knapp, C.E.; Viswanathan, V.K.; Bender, S.C.; Appert, Q.D.; Lawrence, G.; Barnard, C.

    1986-01-01

    The use of grazing incidence optics in resonators alleviates the problem of damage to the optical elements and permits higher powers in cavities of reasonable dimensions for a free electron laser (FEL). The design and manufacture of a grazing incidence beam expander for the Los Alamos FEL mock-up has been completed. In this paper, we describe the analysis of a bare cavity, grazing incidence optical beam expander for an FEL system. Since the existing geometrical and physical optics codes were inadequate for such an analysis, the GLAD code was modified to include global coordinates, exact conic representation, raytracing, and exact aberration features to determine the alignment sensitivities of laser resonators. A resonator cavity has been manufactured and experimentally setup in the Optical Evaluation Laboratory at Los Alamos. Calculated performance is compared with the laboratory measurements obtained so far.

  7. Grazing increases the concentration of CLA in dairy cow milka.

    PubMed

    Lahlou, M N; Kanneganti, R; Massingill, L J; Broderick, G A; Park, Y; Pariza, M W; Ferguson, J D; Wu, Z

    2014-07-01

    An experiment was conducted to examine whether increased CLA in milk of dairy cows fed fresh pasture compared with alfalfa and corn silages was because of ruminal or endogenous synthesis. Eight Holsteins were fed a total mixed ration using alfalfa and corn silages as the forage source in confinement or grazed in a replicated crossover design. The proportion of total fatty acids as CLA (primarily c9, t11-18:2) in g/100 g was 0.44 v. 0.28 in ruminal digesta, 0.89 v. 0.53 in omasal digesta and 0.71 v. 1.06 in milk during confinement feeding and grazing, respectively. Blood plasma CLA was 0.54 v. 1.05 mg/l for the two treatments, respectively. The increased concentration of CLA in milk with grazing likely resulted from increased synthesis through desaturation of t11-18:1 in the mammary gland.

  8. Changes in vegetation and grazing capacity following honey mesquite control

    USGS Publications Warehouse

    McDaniel, Kirk C.; Brock, John H.; Haas, Robert H.

    1982-01-01

    Honey mesquite kill and suppression, vegetation response, and changes in grazing use and capacity were evaluated following brush control in north-central Texas. Tree grubbing was most effective for eliminating honey mesquite, but because of soil and plant damage the treatment did not increase grazing capacity or improve range condition compared to nontreated rangeland. Aerial application of 2,4,5-T + picloram was more effective in klllmg and defoliating honey mesquite than 2,4,5-T alone, but both treatments significantly increased forage production. The 2,4,5-T + picloram and 2,4,5-T sprays provided a 7 to 16% increase in grazing capacity over a 4-year period on light and heavy honey mesquite infested pastures, respectively.

  9. Wildfire: It's Economic Impact on Grazing Livestock in Northern Nevada

    NASA Astrophysics Data System (ADS)

    Honeycutt, S.

    2015-12-01

    As the climate changes and Nevada experiences long severe drought, a key understanding of the economic impacts of wildfire on grazing livestock is essential in the assurance of livestock production in future management of Nevada's rangeland. The focus of this research is to determine the economic impact in the reduction of rangeland available for livestock grazing due to wildfires. The datasets utilized in this research are from 2007 & 2012 and include Bureau of Land Management wildfire, grazing allotments and herd management area geospatial data along with USDA Census of Agriculture, Inventory & Sales Information for cattle & calves, sheep & lambs, and goats. Presented in the results will be the direct, indirect, and induced economic effects of wildfires on rangeland production.

  10. [Effect of grazing on sandy grassland ecosystem in Inner Mongolia].

    PubMed

    Zhao, Halin; Zhang, Tonghui; Zhao, Xueyong; Zhou, Ruilian

    2004-03-01

    This experiment was carried out for 5 years in Horqin sandy land, lnner Mongolia, which had 4 treatments: Non-grazing (NG), light grazing (LG), moderate grazing (MG) and over grazing (OG). The results showed that different grazing intensities resulted in different development trend of the pasture ecosystem, of which, the injury of OG on pasture ecosystem was very great. The plant diversity, vegetation coverage, plant height and primary productivity under continuous overgrazing for 5 year were 87.9%, 82.1%, 94.0% and 57.0%, respectively, lower than those in NG. The biomass on the OG pasture was only 2.1% of NG, and the contents of soil clay, C and N as well as the quantities of soil microbes and small animals in OG were respectively 6.0%, 31.9%, 25.0%, 95.0% and 75.9% lower than those in NG, but the soil hardness was raised by 274.0%. Especially, the secondary productivity of the pasture became negative from the third year, and the productive foundation of the pasture ecosystem was completely destroyed. Non-grazing was beneficial to pasture, and enclosure caused an increase in vegetation coverage, plant height and primary productivity. The vegetation coverage, plant height and soil status in LG and MG were not as good as those in NG, but were stable and didn't show worsening trend. Based on the above results, it's considered that on the sandy pasture in the semi-arid area of Inner Mongolia, the rational grass utilization ratio is 45%-50%, and the suitable loading capacity is 3-4 sheep unit.hm-2.

  11. Microzooplankton grazing in the Eastern Bering Sea in summer

    NASA Astrophysics Data System (ADS)

    Stoecker, Diane K.; Weigel, Alison; Goes, Joaquim I.

    2014-11-01

    Dilution experiments to estimate microzooplankton grazing on phytoplankton were conducted during the summers of 2008, 2009, and 2010 in the Eastern Bering Sea as part of the BEST-BSIERP integrated ecosystem project. All three summers followed cold springs in the Bering Sea. Average microzooplankton grazing coefficients were relatively similar among regions, ranging from 0.16 to 0.34 d-1 in simulated in situ incubations with mixed-layer water collected from the depth of the 55% Io isolume. In Off Shelf and Outer Shelf domains, microzooplankton consumed 67-78% of phytoplankton daily growth but in the Middle and Inner Shelf domains, microzooplankton grazing exceeded phytoplankton daily growth. Regional estimates of microzooplankton ingestion of phytoplankton carbon ranged from 4.4 to 11.0 μg C d-1, with highest ingestion in the Off Shelf, Outer Shelf, and Alaska Peninsula regions and, lower ingestion in the Middle Shelf and Inner Shelf regions. On the northern Middle Shelf, a deep chlorophyll maximum (DCM) occurred at most stations. Grazing coefficients in the DCM were similar in magnitude to coefficients in the corresponding mixed layer. However, because of the higher phytoplankton biomass in the DCM, estimated microzooplankton ingestion and secondary production per liter were higher in the DCM than in the mixed layer. Measurements of photosynthetic quantum yields (Fv/Fm) in whole seawater and diluted treatments indicated that with some plankton assemblages, dilution had a negative effect on phytoplankton physiology and could have compromised their growth rates. This could have also resulted in an underestimation of microzooplankton grazing. Nevertheless, it is clear that microzooplankton grazing consumed most of the phytoplankton production in summer, and that microzooplankton were an important link in food webs supporting larger zooplankton and in carbon flow in the Eastern Bering Sea.

  12. High motility reduces grazing mortality of planktonic bacteria.

    PubMed

    Matz, Carsten; Jürgens, Klaus

    2005-02-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated that the number of predator-prey contacts increased with bacterial swimming speed, but ingestion rates dropped at speeds of >25 microm s(-1) as a result of handling problems with highly motile cells. Comparative studies of a moderately motile strain (<25 microm s(-1)) and a highly motile strain (>45 microm s(-1)) further revealed changes in the bacterial swimming speed distribution due to speed-selective flagellate grazing. Better long-term survival of the highly motile strain was indicated by fourfold-higher bacterial numbers in the presence of grazing compared to the moderately motile strain. Putative constraints of maintaining high swimming speeds were tested at high growth rates and under starvation with the following results: (i) for two out of three strains increased growth rate resulted in larger and slower bacterial cells, and (ii) starved cells became smaller but maintained their swimming speeds. Combined data sets for bacterial swimming speed and cell size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 microm(3). Grazing mortality was lowest for cells of >0.5 microm(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (< or =0.1 microm(3), >50 microm s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing.

  13. Development of a temporally and spatially resolved grazing incidence spectrometer

    SciTech Connect

    Dietrich, D.D.; Fortner, R.J.; Price, D.F.; Stewart, R.E.; Gilman, C.; Helava, H.

    1980-01-01

    The design considerations are presented for a grazing incidence spectrometer which will resolve both temporally and spatially the emission from a wide variety of plasmas. The basis of the design involves use of microchannel plates (MCPs) which are curved to conform to the Rowland circle of the spectrometer. The spectra are obtained when the anode is properly biased. The use of multiple anodes allows gating and with appropriate delays results in sequential time resolution of a few nanoseconds. Simultaneous gating of the anodes with spatial resolution of < 100..mu.. for any given time frame can also be obtained. The efficiency of this spectrometer is also compared with conventional grazing incidence spectrometers.

  14. Preliminary results from a shallow water benthic grazing study

    USGS Publications Warehouse

    Jones, N.L.; Monismith, Stephen G.; Thompson, Janet K.

    2005-01-01

    Despite great improvements in our knowledge on the effects of benthic grazers on seston concentrations in water columns, the effects of different hydrodynamic conditions on grazing rates has not been formulated. This makes it difficult to assess the system-wide effect of the benthic ecosystem on phytoplankton concentrations. Furthermore, it affects our ability to predict the potential success of a benthic species, such as the invasive clams Corbicula fluminea and Potamocorbula amurensis. This paper presents the preliminary results of a control volume approach to elucidate the effect of different hydrodynamic conditions on the grazing rates of Corbicula fluminea.

  15. Effects of grazing on grassland soil carbon: a global review.

    PubMed

    McSherry, Megan E; Ritchie, Mark E

    2013-05-01

    Soils of grasslands represent a large potential reservoir for storing CO2 , but this potential likely depends on how grasslands are managed for large mammal grazing. Previous studies found both strong positive and negative grazing effects on soil organic carbon (SOC) but explanations for this variation are poorly developed. Expanding on previous reviews, we performed a multifactorial meta-analysis of grazer effects on SOC density on 47 independent experimental contrasts from 17 studies. We explicitly tested hypotheses that grazer effects would shift from negative to positive with decreasing precipitation, increasing fineness of soil texture, transition from dominant grass species with C3 to C4 photosynthesis, and decreasing grazing intensity, after controlling for study duration and sampling depth. The six variables of soil texture, precipitation, grass type, grazing intensity, study duration, and sampling depth explained 85% of a large variation (±150 g m(-2)  yr(-1) ) in grazing effects, and the best model included significant interactions between precipitation and soil texture (P = 0.002), grass type, and grazing intensity (P = 0.012), and study duration and soil sampling depth (P = 0.020). Specifically, an increase in mean annual precipitation of 600 mm resulted in a 24% decrease in grazer effect size on finer textured soils, while on sandy soils the same increase in precipitation produced a 22% increase in grazer effect on SOC. Increasing grazing intensity increased SOC by 6-7% on C4 -dominated and C4 -C3 mixed grasslands, but decreased SOC by an average 18% in C3 -dominated grasslands. We discovered these patterns despite a lack of studies in natural, wildlife-dominated ecosystems, and tropical grasslands. Our results, which suggest a future focus on why C3 vs. C4 -dominated grasslands differ so strongly in their response of SOC to grazing, show that grazer effects on SOC are highly context-specific and imply that grazers in different regions might

  16. Grazing Land Management Strongly Controls Water Quality, Sediment and Channel Dynamics in Tallgrass Prairie Headwater Networks

    NASA Astrophysics Data System (ADS)

    Grudzinski, B. G.; Daniels, M. D.

    2013-12-01

    In the prairie remnants of North America, watershed sediment regimes are heavily influenced by livestock grazing practices. Despite dramatic declines in stream water quality and ecosystem function concomitant with increasing gazing pressures, there have been no studies to quantitatively assess the relationship between various grazing treatments and sediment production in natural grassland ecosystems. In this study, we evaluate suspended sediment transport and channel morphology in the Flint Hills physiographic province using a paired whole-watershed approach, including 2 replicates of high density cattle grazing, 2 replicates of low density cattle grazing, 3 replicates of bison grazing and 3 replicates of no grazing. As expected, results demonstrate that cattle grazing operations increase e-coli, sediment concentrations and increase channel width. However, no significant differences in e-coli, suspended sediment dynamics or channel geomorphology were found between bison grazed and ungrazed watersheds.

  17. Tillage Requirements Of Sweet Corn, Field Pea, and Watermelon Following Stocker Cattle Grazing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter annual grazing combined with vegetable production can potentially improve the sustainability of farming operations, particularly in the Southeast. However, winter grazing creates excessive soil compaction, which can adversely affect yields of subsequent summer crops. We initiated a study to...

  18. 78 FR 32273 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Permits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... for Navajo Partitioned Lands Grazing Permits authorized by OMB Control Number 1076-0162. This.... Data OMB Control Number: 1076-0162. Title: Navajo Partitioned Lands Grazing Permits, 25 CFR 161....

  19. 77 FR 74634 - Okanogan-Wenatchee National Forest, Okanogan County, WA Bannon, Aeneas, Revis, and Tunk Grazing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-17

    ... Grazing Allotments Environmental Impact Statement; Correction AGENCY: Forest Service, USDA. ACTION: Notice..., 2012, concerning requests for comments on the proposed grazing allotments and dates of...

  20. Ecosystem structure, function, and composition in rangelands are negatively affected by livestock grazing.

    PubMed

    Eldridge, David J; Poore, Alistair G B; Ruiz-Colmenero, Marta; Letnic, Mike; Soliveres, Santiago

    2016-06-01

    Reports of positive or neutral effects of grazing on plant species richness have prompted calls for livestock grazing to be used as a tool for managing land for conservation. Grazing effects, however, are likely to vary among different response variables, types, and intensity of grazing, and across abiotic conditions. We aimed to examine how grazing affects ecosystem structure, function, and composition. We compiled a database of 7615 records reporting an effect of grazing by sheep and cattle on 278 biotic and abiotic response variables for published studies across Australia. Using these data, we derived three ecosystem measures based on structure, function, and composition, which were compared against six contrasts of grazing pressure, ranging from low to heavy, two different herbivores (sheep, cattle), and across three different climatic zones. Grazing reduced structure (by 35%), function (24%), and composition (10%). Structure and function (but not composition) declined more when grazed by sheep and cattle together than sheep alone. Grazing reduced plant biomass (40%), animal richness (15%), and plant and animal abundance, and plant and litter cover (25%), but had no effect on plant richness nor soil function. The negative effects of grazing on plant biomass, plant cover, and soil function were more pronounced in drier environments. Grazing effects on plant and animal richness and composition were constant, or even declined, with increasing aridity. Our study represents a comprehensive continental assessment of the implications of grazing for managing Australian rangelands. Grazing effects were largely negative, even at very low levels of grazing. Overall, our results suggest that livestock grazing in Australia is unlikely to produce positive outcomes for ecosystem structure, function, and composition or even as a blanket conservation tool unless reduction in specific response variables is an explicit management objective.

  1. Enhancing Soil Productivity Using a Multi-Crop Rotation and Beef Cattle Grazing

    NASA Astrophysics Data System (ADS)

    Şentürklü, Songül; Landblom, Douglas; Cihacek, Larry; Brevik, Eric

    2016-04-01

    Agricultural production systems that include complimentary plant, soil and animal interaction contribute to sustainability. In sustainable livestock systems integrated with crop production, the soil resource is impacted positively. The goal of this research was to maximize beef cattle and crop economic yield, while improving the soil resource by increasing soil organic matter (SOM) and subsequently seasonal soil nitrogen fertility over a 5-year period (2011-2015). Each experimental crop field used in the study was 1.74 ha. Small-seeded crops were planted using a JD 1590 No-Till drill. Corn (C) and sunflowers (SF) were planted using a JD 7000 No-Till planter. The cropping sequence used in the study was SF, hard red spring wheat (HRSW), fall seeded winter triticale-hairy vetch (T-HV), spring harvested for hay/mid-June seeded 7-species cover crop (CC; SF, Everleaf Oat, Flex Winter Pea, HV, Winfred Forage Rape, Ethiopian Cabbage, Hunter Leaf Turnip), C (85-day var.), and field pea-barley intercrop (PBY). The HRSW and SF were harvested as cash crops and the PBY, C, and CC were harvested by grazing cattle. In the system, yearling beef steers grazed PBY and unharvested C before feedlot entry, and after weaning, gestating cows grazed CC. Seasonal soil nitrogen fertility was measured at 0-15, 15-30, and 30-61 cm depths approximately every two weeks from June to October, 2014. The regression illustrating the relationship between SOM and average seasonal available mineral nitrogen shows that for each percentage increase in SOM there is a corresponding N increase of 1.47 kg/ha. Nitrogen fertilizer applications for the 5-year period of the study were variable; however, the overall trend was for reduced fertilizer requirement as SOM increased. At the same time, grain, oilseed, and annual forage crop yields increased year over year (2011-2015) except for the 2014 crop year, when above average precipitation delayed seeding and early frost killed the C and SF crops prematurely

  2. Above- and below-ground grass growth responds to grazing management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    How is grass productivity above- and below-ground affected by grazing at different heights or by leaving different residuals after grazing? A recent study found no simple answer to this question. Meadow fescue and orchardgrass were grazed by Holstein heifers to remove 50 or 100% of above-ground fora...

  3. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false How are grazing permits allocated within each range unit... allocated within each range unit? (a) Initial allocation of the number of animal units authorized in each... grazing permits and the current authorized stocking rate on a given range unit. (b) Grazing...

  4. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false How are grazing permits allocated within each range unit... allocated within each range unit? (a) Initial allocation of the number of animal units authorized in each... grazing permits and the current authorized stocking rate on a given range unit. (b) Grazing...

  5. 25 CFR 161.403 - How are grazing permits allocated within each range unit?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true How are grazing permits allocated within each range unit... allocated within each range unit? (a) Initial allocation of the number of animal units authorized in each... grazing permits and the current authorized stocking rate on a given range unit. (b) Grazing...

  6. 43 CFR 4180.2 - Standards and guidelines for grazing administration.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Standards and guidelines for grazing...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Fundamentals of Rangeland Health and Standards and Guidelines for Grazing...

  7. 43 CFR 4180.2 - Standards and guidelines for grazing administration.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Standards and guidelines for grazing...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Fundamentals of Rangeland Health and Standards and Guidelines for Grazing...

  8. [Microbial community structure of the alpine meadow under different grazing styles in Naqu prefecture of Tibet].

    PubMed

    Niu, Lei; Liu, Ying-hui; Li, Yue; Ouyang, Sheng-nan

    2015-08-01

    To clarify the effects of grazing styles on the soil microbial community in the alpine meadow, we explored the changes of soil microbial community structure in the alpine meadow located in Naqu district of Tibet Autonomous Region by analyzing the soil chemical properties and phospholipid fatty acids (PLFAs). The results showed that the contents of soil total organic carbon, total phosphate and nitrate nitrogen under the different grazing styles followed the trend of 7-year rest grazing > free grazing > grazing prohibition. Except for the ratio of fungal PLFAs/bacterial PLFAs, total PLFAs, the bacterial PLFAs, the fungal PLFAs, the gram negative bacterial and the gram positive bacterial PLFAs over the different grazing types were in the order of 7-year rest grazing > 5-year grazing prohibition > 7-year and 9-year grazing prohibition. The principal component analysis (PCA) presented that the first principal component (PC1 = 74.6%) was mainly composed of monounsaturated fatty acids, polyunsaturated fatty acids and branched fatty acids, and the second principal component (PC2 = 13.2%) was mainly composed of saturated fatty acids and some monounsaturated fatty acids. Total PLFAs content was significantly positively correlated with microbial biomass carbon content. Compared with grazing prohibition, fallow grazing was best for the alpine meadow in Naqu district, and free grazing with light intensity was good for the alpine meadow.

  9. 78 FR 15036 - Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing Permits

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-08

    ... Bureau of Indian Affairs Renewal of Agency Information Collection for Navajo Partitioned Lands Grazing... for Navajo Partitioned Lands Grazing Permits authorized by OMB Control Number 1076-0162. This..., modify, or assign a grazing permit on Navajo Partitioned Lands is eligible and complies with...

  10. Effects of timing of grazing on arthropod communities in semi-natural grasslands.

    PubMed

    Lenoir, Lisette; Lennartsson, Tommy

    2010-01-01

    Arthropod communities were investigated in two Swedish semi-natural grasslands, each subject to two types of grazing regime: conventional grazing from May to September (continuous grazing) and traditional late management from mid-July (late grazing). Pitfall traps were used to investigate abundance of carabids, spiders, and ants over the grazing season. Ant abundance was also measured by mapping nest density during three successive years. Small spiders, carabids and ants (Myrmica spp.) were more abundant in continuous grazing than in late grazing while larger spiders, carabids, and ants (Formica spp.) were more abundant in late grazing. The overall abundance of carabids was higher in continuous grazing in the early summer but higher in late grazing in the late summer. The switch of preference from continuous to late grazing coincided with the time for larvae hibernating species replacing adult hibernating. We discuss possible explanations for the observed responses in terms of effects of grazing season on a number of habitat variables for example temperature, food resources, structure of vegetation, litter layer, competition, and disturbance.

  11. Sheep grazing effect on dryland soil carbon and nitrogen in the wheat-fallow system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control by sheep grazing during fallow periods in the dryland wheat-fallow system may influence soil C and N levels. The effects of fallow management for weed control and soil water conservation [sheep grazing (grazing), herbicide application (chemical), and tillage (mechanical)] and cropping s...

  12. Ruminant Grazing of Cover Crops: Effects on Soil Properties and Agricultural Production

    ERIC Educational Resources Information Center

    Poffenbarger, Hanna

    2010-01-01

    Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops…

  13. 25 CFR 166.409 - How is my grazing rental payment determined?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How is my grazing rental payment determined? 166.409 Section 166.409 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.409 How is...

  14. 25 CFR 166.413 - To whom are grazing rental payments made?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false To whom are grazing rental payments made? 166.413 Section 166.413 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.413 To whom are...

  15. 25 CFR 166.401 - How does the BIA establish grazing rental rates?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How does the BIA establish grazing rental rates? 166.401 Section 166.401 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination...

  16. 43 CFR 4300.40 - How long can I graze reindeer with my permit?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false How long can I graze reindeer with my...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION; ALASKA; REINDEER; GENERAL Conditions of Your Approved Permit § 4300.40 How long can I graze reindeer...

  17. 25 CFR 166.410 - When are grazing rental payments due?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When are grazing rental payments due? 166.410 Section 166.410 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.410 When are...

  18. 25 CFR 173.17 - Agricultural and grazing permits and leases.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Agricultural and grazing permits and leases. 173.17... Agricultural and grazing permits and leases. (a) Permits or leases may be granted after the lands set forth in.... Permits for grazing lands suitable for division into range units shall be granted in accordance with...

  19. 25 CFR 173.17 - Agricultural and grazing permits and leases.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Agricultural and grazing permits and leases. 173.17... Agricultural and grazing permits and leases. (a) Permits or leases may be granted after the lands set forth in.... Permits for grazing lands suitable for division into range units shall be granted in accordance with...

  20. 43 CFR 4170.2-1 - Penal provisions under the Taylor Grazing Act.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Penal provisions under the Taylor Grazing...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Penalties § 4170.2-1 Penal provisions under the Taylor Grazing Act. Under section 2...

  1. 25 CFR 166.418 - When is a grazing rental payment late?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When is a grazing rental payment late? 166.418 Section 166.418 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.418 When is a...

  2. 25 CFR 166.409 - How is my grazing rental payment determined?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How is my grazing rental payment determined? 166.409 Section 166.409 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.409 How is...

  3. 25 CFR 166.410 - When are grazing rental payments due?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false When are grazing rental payments due? 166.410 Section 166.410 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.410 When are...

  4. 25 CFR 166.306 - Can the BIA adjust the grazing capacity?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Can the BIA adjust the grazing capacity? 166.306 Section 166.306 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.306 Can the BIA adjust the grazing capacity? Yes. In...

  5. 43 CFR 9264.1 - Grazing administration-exclusive of Alaska.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing administration-exclusive of Alaska... Management § 9264.1 Grazing administration—exclusive of Alaska. Persons performing the following prohibited... animals to graze on or be driven across those lands without a permit or lease or in violation of the...

  6. 43 CFR 2711.1-3 - Sales requiring grazing permit or lease cancellations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Sales requiring grazing permit or lease... POLICY AND MANAGEMENT ACT Sales: Procedures § 2711.1-3 Sales requiring grazing permit or lease cancellations. When lands are identified for disposal and such disposal will preclude livestock grazing,...

  7. 25 CFR 161.100 - Do tribal laws apply to grazing permits?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Do tribal laws apply to grazing permits? 161.100 Section... LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.100 Do tribal laws apply to grazing permits? Navajo Nation laws generally apply to land under the jurisdiction of the Navajo...

  8. 36 CFR 251.103 - Mediation of term grazing permit disputes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Mediation of term grazing... Lands § 251.103 Mediation of term grazing permit disputes. (a) Decisions subject to mediation. In those States with Department of Agriculture certified mediation programs, any holder of a term grazing...

  9. 25 CFR 166.413 - To whom are grazing rental payments made?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false To whom are grazing rental payments made? 166.413 Section 166.413 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.413 To whom are...

  10. 25 CFR 166.401 - How does the BIA establish grazing rental rates?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How does the BIA establish grazing rental rates? 166.401 Section 166.401 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination...

  11. 36 CFR 251.103 - Mediation of term grazing permit disputes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Mediation of term grazing... Lands § 251.103 Mediation of term grazing permit disputes. (a) Decisions subject to mediation. In those States with Department of Agriculture certified mediation programs, any holder of a term grazing...

  12. 25 CFR 166.418 - When is a grazing rental payment late?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When is a grazing rental payment late? 166.418 Section 166.418 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.418 When is a...

  13. 25 CFR 161.100 - Do tribal laws apply to grazing permits?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.100 Do tribal laws apply to grazing permits? Navajo Nation laws generally apply to land under the jurisdiction of the Navajo Nation... 25 Indians 1 2010-04-01 2010-04-01 false Do tribal laws apply to grazing permits? 161.100...

  14. 77 FR 6534 - Malheur National Forest; Oregon; Summit Logan Grazing Authorization Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-08

    ... Forest Service Malheur National Forest; Oregon; Summit Logan Grazing Authorization Project AGENCY: Forest... authorize livestock grazing on all or portions of the Lake Creek, Logan Valley, McCoy Creek and Summit... watersheds. The Summit Logan Grazing Authorization Project area is located south and west of Prairie...

  15. The science behind the use of prescribed grazing as a conservation practice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation Practice Standard 528 of the Natural Resource Conservation Service (NRCS) defines prescribed grazing as “managing the harvest of vegetation with grazing and/or browsing animals”. Prescribed grazing or browsing incorporates a variety of management actions. For the purposes of this presen...

  16. Effects of Timing of Grazing on Arthropod Communities in Semi-Natural Grasslands

    PubMed Central

    Lenoir, Lisette; Lennartsson, Tommy

    2010-01-01

    Arthropod communities were investigated in two Swedish semi-natural grasslands, each subject to two types of grazing regime: conventional grazing from May to September (continuous grazing) and traditional late management from mid-July (late grazing). Pitfall traps were used to investigate abundance of carabids, spiders, and ants over the grazing season. Ant abundance was also measured by mapping nest density during three successive years. Small spiders, carabids and ants (Myrmica spp.) were more abundant in continuous grazing than in late grazing while larger spiders, carabids, and ants (Formica spp.) were more abundant in late grazing. The overall abundance of carabids was higher in continuous grazing in the early summer but higher in late grazing in the late summer. The switch of preference from continuous to late grazing coincided with the time for larvae hibernating species replacing adult hibernating. We discuss possible explanations for the observed responses in terms of effects of grazing season on a number of habitat variables for example temperature, food resources, structure of vegetation, litter layer, competition, and disturbance. PMID:20569138

  17. Monitoring riparian response to prescription grazing with low-altitude aerial surveys

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prescription grazing (controlling grazing animals to achieve a specified conservation objective) is a USDA Natural Resources Conservation Service approved practice. But, there is no approved means for assessing the success or failure of extensive-area grazing prescriptions. In 2003 a prescription gr...

  18. 25 CFR 166.301 - How is Indian land for grazing purposes described?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How is Indian land for grazing purposes described? 166.301 Section 166.301 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.301 How is Indian land for grazing purposes...

  19. 25 CFR 166.306 - Can the BIA adjust the grazing capacity?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Can the BIA adjust the grazing capacity? 166.306 Section 166.306 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.306 Can the BIA adjust the grazing capacity? Yes. In...

  20. Grazing sericea lespedeza for control of gastrointestinal nematodes in lambs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alternatives to chemical dewormers are needed to counter anthelmintic resistance and improve organic management systems. The objective was to examine the effectiveness of grazing sericea lespedeza (SL) compared with grass pastures for control of gastrointestinal nematodes (GIN) in lambs. In Experi...

  1. Temperate grass response to extent and timing of grazing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Considerable differences exist among cool-season grass species in their production potential and response to management variables. We examined the effects of grazing management on forage and root production of two temperate perennial grasses, meadow fescue [Schedonoruspratensis (Huds.) P. Beauv.] an...

  2. Methane emissions measured directly from grazing livestock in New Zealand

    NASA Astrophysics Data System (ADS)

    Lassey, Keith R.; Ulyatt, Marcus J.; Martin, Ross J.; Walker, Carolyn F.; David Shelton, I.

    We report measurements of methane emissions from individual ruminant livestock-both sheep and dairy cows-grazing pasture typical of New Zealand lowlands in the temperate southwest Pacific. These are the first measurements reported from grazing sheep, and among the first from grazing cattle. The measurement technique, developed at Washington State University, enables emission rates to be determined from analyses of "breath" samples collected while grazing. More than 250 measurements of daily methane emission from 50 sheep (8 months old) were made, with flock-mean emission 18.9 ± 0.8 g hd -1 d -1. Although emissions were weakly correlated with feed intake, they represented a 4.6 ± 0.1 % average loss of gross dietary energy. The corresponding mean emission based on 40 measurements of daily emissions from 10 lactating dairy cows was 263 ± 10 g hd -1 d -1, approximately 6.2% of estimated gross energy intake. A notable feature was the large inter-sheep variability in daily methane emission (factor of 1.4 range) that could not be attributed to variable intake. This would appear to suggest an appreciable diversity of methanogenetic response to digestion, and may be significant in the search for strategies to control emissions of this greenhouse gas.

  3. Phytoplankton growth and microzooplankton grazing in the subtropical Northeast Atlantic.

    PubMed

    Cáceres, Carlos; Taboada, Fernando González; Höfer, Juan; Anadón, Ricardo

    2013-01-01

    Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2-5 µm and >5 µm) and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth rates were high (0.11-1.60 d(-1)), especially in the case of the large fraction. Grazing rates were also high (0.15-1.29 d(-1)), suggesting high turnover rates within the phytoplankton community. The integrated balances between phytoplankton growth and grazing losses were close to zero, although deviations were detected at several depths. Also, O2 supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres.

  4. Consequences of prescribed fire and grazing on grassland ant communities.

    PubMed

    Underwood, Emma C; Christian, Caroline E

    2009-04-01

    Prescribed fire and livestock grazing are used for the management and restoration of native grasslands the world over; however, the effects of these management techniques on ant communities are unclear. We examined the response of ants to these disturbances in grasslands in northern California. Twenty-four 30 by 30 m plots were established across two sites that received one of four treatments: grazing, fire, grazing and fire, or no treatment. Ants were censused using 240 pitfall traps with one preburn and two postburn samples (14 d and 1 yr after burning). We analyzed ant abundance using broadly defined groups based on feeding habit and/or habitat use and detected no grazing effect but a significant fire effect that differed by group. Immediate postfire sampling showed an increase in cryptic species (particularly Brachymyrmex depilis). One year after the fire, no response was detected for cryptic species, but burned plots had greater abundance of seed harvesters. Analysis of vegetation showed burned plots had significantly greater forb cover, which might have provided greater food resources, and also lower biomass, which might have facilitated foraging. Understanding the effects of these management tools on ant abundance complements our understanding of their effect on vegetation and assists conservation practitioners effectively manage grassland ecosystems both in California and beyond.

  5. Butterfly responses to prairie restoration through fire and grazing

    USGS Publications Warehouse

    Vogel, Jennifer A.; Debinski, Diane M.; Koford, Rolf R.; Miller, J.R.

    2007-01-01

    The development of land for modern agriculture has resulted in losses of native prairie habitat. The small, isolated patches of prairie habitat that remain are threatened by fire suppression, overgrazing, and invasion by non-native species. We evaluated the effects of three restoration practices (grazing only, burning only, and burning and grazing) on the vegetation characteristics and butterfly communities of remnant prairies. Total butterfly abundance was highest on prairies that were managed with burning and grazing and lowest on those that were only burned. Butterfly species richness did not differ among any of the restoration practices. Butterfly species diversity was highest on sites that were only burned. Responses of individual butterfly species to restoration practices were highly variable. In the best predictive regression model, total butterfly abundance was negatively associated with the percent cover of bare ground and positively associated with the percent cover of forbs. Canonical correspondence analysis revealed that sites with burned only and grazed only practices could be separated based on their butterfly community composition. Butterfly communities in each of the three restoration practices are equally species rich but different practices yield compositionally different butterfly communities. Because of this variation in butterfly species responses to different restoration practices, there is no single practice that will benefit all species or even all species within habitat-specialist or habitat-generalist habitat guilds. ?? 2007 Elsevier Ltd. All rights reserved.

  6. Analysis of a new class of grazing incidence spectroscopic telescope

    NASA Technical Reports Server (NTRS)

    Green, J. C.; Bowyer, S.

    1986-01-01

    The throughput and imaging properties of one of a new class of grazing incidence spectroscopic telescope are examined with a Monte Carlo ray tracing technique. The results are compared with Wolter Schwarzschild type II telescopes of similar size. The image quality of this telescope is comparable, and the control of the off-axis light is superior to the Wolter Schwarzschild design.

  7. Crassostrea virginica grazing on toxic and non-toxic diatoms.

    PubMed

    Thessen, A E; Soniat, T M; Dortch, Q; Doucette, G J

    2010-01-01

    Despite high abundances of toxic Pseudo-nitzschia spp. over Louisiana oyster beds (Crassostrea virginica; eastern oyster) there have been no documented cases of amnesic shellfish poisoning (ASP) in the state. Two possible explanations are that oysters do not readily feed on long pointed chains of Pseudo-nitzschia cells or they discriminate against toxic cells while grazing. To test these hypotheses, short-term grazing experiments were conducted with several diatoms, including the domoic acid (DA)-producing Pseudo-nitzschia multiseries (1.31+/-0.057 pg DA cell(-1)) and the non-toxic Pseudo-nitzschia delicatissima, Thalassiosira weissflogii, and Ditylum brightwellii. Grazing rates on the small centric species T. weissflogii were significantly higher than on the larger and pointier D. brightwellii and either Pseudo-nitzschia species. Grazing on toxic P. multiseries and non-toxic P. delicatissima was not significantly different. Pseudofeces production was higher and feces production was occasionally lower in oysters fed Pseudo-nitzschia spp. than in oysters fed the other two diatoms. Our data demonstrate lower filtration rates of C. virginica on Pseudo-nitzschia spp. relative to the other diatoms tested and comparable filtration on toxic and non-toxic Pseudo-nitzschia spp. These findings suggest that eastern oysters do not discriminate amongst food types due to DA content.

  8. Challenges to Predicting Productivity of Grazing Ruminants. Where to now?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Fourth Grazing Livestock Nutrition Conference was convened at Estes Park July 9 and 10.There were over 28 poster presentations and 12 conference papers presented. The papers were organized in 6 topical sessions ranging from microbiology to supplementation. The first session covered the potential...

  9. Stockpiled Prairie Grass For Fall-Grazing Lambs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New varieties of prairiegrass (Bromus catharticus Vahl. = B. willdenowii Kunth.) exhibit improved persistence over 'Matua' under USA growing conditions, but animal performance data is lacking. Therefore, we evaluated performance of lambs grazing fall-stockpiled 'Dixon' prairiegrass on a West Virgin...

  10. STOCKPILED PRAIRIEGRASS PROVIDES HIGH-QUALITY FALL GRAZING FOR LAMBS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New varieties of prairiegrass (Bromus catharticus Vahl. = B. willdenowii Kunth.) exhibit improved persistence over ‘Matua’ under USA growing conditions, but animal performance data is lacking. We evaluated performance of lambs grazing stockpiled ‘Dixon’ prairiegrass on West Virginia hill pasture in...

  11. Getting more information from your grazing research beyond cattle performance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research examining the nutrition of grazing ungulates can be a rewarding career, however it poses many challenges. This type of science requires the scientist to make many assumptions, deal with numerous variables across a landscape, and requires careful planning to manage these unknowns and produc...

  12. Polioencephalomalacia in adult sheep grazing pastures with prostrate pigweed

    PubMed Central

    2005-01-01

    Abstract Polioencephalomalacia was diagnosed in 2 animals from different farms. In apparently healthy animals from same farms, fecal thiaminase and a significant reduction in erythrocyte transketolase activity was observed. The presence of thiaminase in Amaranthus blitoides could have contributed to the development of polioencephalomalacia in sheep grazing on natural pastures. PMID:15759830

  13. Hydrologic variability enhances stream biofilm grazing by invertebrates

    NASA Astrophysics Data System (ADS)

    Ceola, S.; Hödl, I.; Adlboller, M.; Singer, G.; Bertuzzo, E.; Mari, L.; Botter, G.; Battin, T. J.; Gatto, M.; Rinaldo, A.

    2012-12-01

    The temporal variability of streamflows is a key feature structuring and controlling ecological communities and ecosystem processes. The magnitude, frequency and predictability of streamflows, and thus of velocity and near-bed shear stress fields, control structure and function of benthic invertebrates and biofilms - attached and matrix-enclosed microbial communities at the base of the food chain. Although alterations of streamflow regime due to climate change, habitat fragmentation or other anthropogenic factors are ubiquitous, their ecological implications remain poorly understood. Here, by experimenting with two contrasting flow regimes in stream microcosms, we show how flow variability affects invertebrate grazing of phototrophic biofilms (i.e. periphyton). In both flow regimes, we manipulated light availability as a key control on biofilm algal productivity and grazer activity, thereby allowing the test of flow regime effects across various biofilm biomass to grazing activity ratios. Average grazing rates were significantly enhanced under variable flow conditions and highest at intermediate light availability. Our results suggest that stochastic flow regime offers increased opportunity for grazing under more favorable shear stress conditions, with implications for trophic carbon transfer in stream food webs.

  14. ANT COMMUNITIES AND LIVESTOCK GRAZING IN THE GREAT BASIN, USA

    EPA Science Inventory

    The objectives of this study were to determine if metrics for ant species assemblages can be used as indicators of rangeland condition, and to determine the influence of vegetation and ground cover variables, factors often influenced by livestock grazing, on ant communities. The ...

  15. Large animal grazing and temporal patterns in ecosystem services

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The shortgrass steppe ecosystem has a long evolutionary history of large animal grazing by bison, which were replaced by domesticated livestock in the mid 1800s. In addition, this ecosystem is characterized by a semi-arid environment with low annual precipitation amounts, but high inter- and intra-a...

  16. Manatee grazing impacts on a mixed species seagrass bed

    USGS Publications Warehouse

    Lefebvre, Lynn W.; Provancha, Jane A.; Slone, Daniel H.; Kenworthy, W. Judson

    2017-01-01

    The endangered manatee Trichechus manatus is one of few large grazers in seagrass systems. To assess the long-term impacts of repeated grazing on seagrasses, we selected a study site within Kennedy Space Center in the northern Banana River, Brevard County, Florida, that was typically grazed by large numbers of manatees in spring. Two 13x13 m manatee exclosures and 2 paired open plots of equal size were established at the study site in October 1990. Shoot counts, biomass, and species composition of the co-dominant seagrass species, Syringodium filiforme and Halodule wrightii, were sampled 3 times per year in all 4 plots between October 1990 and October 1994. We used a Bayesian modelling approach, accounting for the influence of depth, to detect treatment (exclosed vs. open) effects. S. filiforme shoot counts, total biomass, and frequency of occurrence significantly increased in the exclosures. By July 1993, mean biomass values in the exclosures (167 g dry wt m-2) greatly exceeded those in the open plots (28 g dry wt m-2). H. wrightii decreased in the exclosures by 1994. Initially, both S. filiforme and H. wrightii responded positively to release from manatee grazing pressure. As S. filiforme continued to become denser in the exclosures, it gradually replaced H. wrightii. Our findings may be helpful to biologists and managers interested in predicting seagrass recovery and manatee carrying capacity of repeatedly grazed seagrass beds in areas of special significance to manatees and seagrass conservation.

  17. Post-fire grazing management in the Great Basin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing wildfire size and frequency in the Great Basin call for post-fire grazing management practices that ensure sagebrush steppe communities are productive and resilient to disturbances such as drought and species invasions. We provide guidelines for maintaining productive sagebrush steppe co...

  18. Cyclic Sommerfeld resonances in nanorods at grazing incidences.

    PubMed

    Feng, Simin; Halterman, Klaus; Overfelt, Pamela L; Bowling, Donald

    2009-10-26

    We investigate electromagnetic scattering from nanoscale wires and reveal the emergence of a family of exotic resonances for source waves close to grazing incidence. These grazing resonances have a much higher Q-bandwidth product and thus, a much higher Q factor and broader bandwidth than the pure plasmonic resonances found in metal nanowires. Furthermore, these grazing resonances are much less susceptible to material losses than surface plasmon resonances. Contrary to the process of exciting surface plasmon resonances, these grazing resonances can arise in both dielectric and metallic nanowires and appear near to the cutoff wavelength of the circular waveguide. This peculiar resonance effect originates from the excitation of long range guided surface waves through the interplay of coherently scattered continuum modes coupled with first-order azimuthal propagating modes of the cylindrical nanowire. These first-order cyclic Sommerfeld waves and associated cyclic Sommerfeld resonances revealed here opens up the possibility of an alternative scheme of enhanced fields with a better merit (higher Q-bandwidth product and lower loss) than conventional surface plasmon resonances in the nano-regime. This nanowire resonance phenomenon can be utilized in broad scientific areas, including: metamaterial designs, nanophotonic integration, nanoantennas, and nanosensors.

  19. Distribution of cattle grazing in a northeastern Oregon riparian pasture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock grazing of a northeastern Oregon riparian pasture was monitored using high-frequency GPS tracking of cattle and high-resolution aerial photography. Tracking collars recorded positions, velocity, date, and time at 1-sec intervals. Areas where animals rested and moved were identified and re...

  20. Multi-fluid MHD model for Sun-grazing comets

    NASA Astrophysics Data System (ADS)

    Jia, Y.-D.; Russell, C. T.; Liu, W.; Gombosi, T. I.

    2013-09-01

    Sun-grazing comets are comets that dive into the lower corona. Recent advances in spacecraft capabilities have enabled us to observe these comets with high resolution both in time and space. These comets exhibit rich tail activity, even multiple tails. This study investigates a collection of these activities, models the cometary plasma with model-generated coronal conditions.

  1. Does livestock grazing influence spatial patterns of woody plant proliferation?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Patterns of woody plant proliferation in grasslands and savannas influence rates of erosion, spread of disturbance, and nutrient pools.  Spatial pattern is the outcome of plant dispersal, recruitment, competition/facilitation, and disturbance. We quantified effects of livestock grazing, a widely cit...

  2. Livestock grazing and sage-grouse habitat: impacts and opportunities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sage-grouse obtain resources from sagebrush communities for breeding, summer, and winter life stages. Grazing changes the productivity, composition, and structure of herbaceous plants in sagebrush communities, thus directly influencing the productivity of nesting and early brood-rearing habitats. In...

  3. Pasture-scale methane emissions of grazing cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing cattle are mobile point sources of methane and present challenges to quantify emissions using noninterfering micrometeorological methods. Stocking density is low and cattle can bunch up or disperse over a wide area, so knowing cattle locations is critical. The methane concentration downwind ...

  4. Estimating carbon fluxes on small rotationally grazed pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Satellite-based Normalized Difference Vegetation Index (NDVI) data have been extensively used for estimating gross primary productivity (GPP) and yield of grazing lands throughout the world. Large-scale estimates of GPP are a necessary component of efforts to monitor the soil carbon balance of grazi...

  5. Environmental Assessment of Beale AFB Grazing Lease Program

    DTIC Science & Technology

    2012-12-01

    benefit the vernal pool crustaceans by removing thatch, controlling invasive grasses, and improving the hydrology of the vernal pools and swales in the...an opinion to Beale AFB that grazing will benefit vernal pool crustaceans by removing thatch, controlling invasive grasses, and improving the

  6. Grazing Behavior of Heifers Measured by Handheld GPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to assess how previous grazing experience affects animal movement on pasture. Portable GPS units were used to monitor movements of 32 Holstein (n=21) and Holstein-Jersey (n=11) yearlings. Total distance walked was measured and analyzed as a randomized complete block e...

  7. Phanerozoic stromatolites: noncompetitive ecologic restriction by grazing and burrowing animals.

    PubMed

    Garrett, P

    1970-07-10

    The abundance of stromatolites (algal laminated sedimentary structures) in the Precambrian followed by a decline in the Phanerozoic is explained by the evolution and diversification during the Phanerozoic of grazing animals which feed on surface algal mats and of burrowing animals which destroy sedimentary laminations.

  8. Cattle as ecosystem engineers: New grazing management enhances rangeland biodiversity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A confluence of factors has shaped the composition and structure of vegetation on rangelands in the American West. These factors include climate, soils, topography, history of grazing and fire (both wildfire and prescribed fire) as well as legacy effects from prior land management practices. Despite...

  9. 43 CFR 4710.5 - Closure to livestock grazing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... FREE-ROAMING HORSES AND BURROS Management Considerations § 4710.5 Closure to livestock grazing. (a) If necessary to provide habitat for wild horses or burros, to implement herd management actions, or to protect wild horses or burros, to implement herd management actions, or to protect wild horses or burros...

  10. Thermal balance of cattle grazing winter range: model application.

    PubMed

    Keren, E N; Olson, B E

    2006-05-01

    Beef cattle grazing semiarid foothill rangeland of the Northern Rockies during winter may be exposed to cold temperatures and high winds while grazing pastures with low nutritional value. Cattle can physiologically and behaviorally respond to the changing environment to lower their metabolic requirements and reduce the effects of cold exposure. Requirements of grazing cattle may be overpredicted with models developed in controlled settings that do not account for energy-conserving behaviors. We refined a simple thermal balance equation to model heat exchange of free-ranging cattle. We accounted for the complex interactions between animal behavior and the changing natural environment by applying the insulation characteristics of the cattle's tissue and coat to a simple geometric shape of an asymmetric ellipsoid at different orientations to the sun and wind. We compared the model predictions with heat production measured in 3 studies, and in all cases the model predictions were similar to those reported. Model simulations indicate behaviors, such as lying and orientation to the sun, mitigated the effects of extreme weather. For many combinations of winter weather variables, metabolic requirements increased only slightly due to cold exposure of mature beef cattle in a near-maintenance state. The results indicate that solar radiation contributes strongly to the thermal balance of a cow. Thus, previous models that do not account for the irradiative environment may overestimate metabolic requirements of cattle acclimated to grazing winter range.

  11. Sound management may sequester methane in grazed rangeland ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Considering their contribution to global warming, the sources and sinks of methane (CH4) should be accounted when undertaking a greenhouse gas inventory for grazed rangeland ecosystems. The aim of this study was to evaluate the mitigation potential of current ecological management programs implement...

  12. Design and performance analysis of multilayer nested grazing incidence optics

    NASA Astrophysics Data System (ADS)

    Zuo, Fuchang; Deng, Loulou; Mei, Zhiwu; Li, Liansheng; Lv, Zhengxin

    2014-10-01

    We have developed X-ray grazing incidence optics with a single mirror. Although t can be used to demonstrate and test on the ground to verify the feasibility of X-ray detection system, it is unable to meet the requirements of X-ray pulsar navigation due to small effective area and large mass. There is an urgent need to develop multilayer nested grazing incidence optics, which consists of multilayer mirrors to form a coaxial and confocal system to maximize the use of space and increase the effective area. In this paper, aiming at the future demand of X-ray pulsar navigation, optimization and analysis of nested X-ray grazing incidence optics was carried out, the recurrence relations between the layers of mirrors were derived, reasonable initial structural parameters and stray light reduction method was given, and theoretical effective collection area was calculated. The initial structure and stray light eliminating structure are designed. The optical-mechanical-thermal numerical model was established using optical analysis software and finite element software for stray light analysis, focusing performance analysis, tolerance analysis, and mechanical analysis, providing evidence and guidance for the processing and alignment of nested X-ray grazing incidence optics.

  13. Cultivar Preference of Lambs Grazing Forage Chicory in Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This project compared grazing preferences of lambs between seven cultivars of forage chicory (Cichorium intybus L.). This on-farm trial was conducted in central Ohio (40.53 degrees N, 82.46 degrees W, 1089 ft above sea level). The chicory was established by using conventional tillage in Bogart Silt...

  14. Effects of shade on welfare and meat quality of grazing sheep under high ambient temperature.

    PubMed

    Liu, H W; Cao, Y; Zhou, D W

    2012-12-01

    This study was conducted to evaluate the effects of providing shade on growth performance, welfare, and meat quality of grazing sheep under high ambient temperature. A total of 120 healthy male Ujumqin wool sheep (a local breed; BW = 18.7 ± 1.27 kg; 14 wk old) were randomly and equally divided into shaded and unshaded treatments with 3 pens per treatment. Sheep were grazed on an unshaded pastureland from 0600 to 1000 h and 1400 to 1800 h. During other times, sheep were confined in shaded or unshaded pens. Body weight was recorded on d 1 and 42 of the experiment. Rectal temperature and respiration rate were recorded on d 7, 14, 21, 28, 35, and 42. At end of the trial, sheep were blood sampled and slaughtered to collect meat samples. Respiration rate was greater (P < 0.05) in the unshaded sheep than shaded sheep on d 14, 21, 28, 35, and 42 of the trial whereas no significant differences were found on d 7. Moreover, no differences were observed in final BW, ADG, or rectal temperature throughout the trial. The pH at 24 h postmortem (pH(24)) and cooking loss were greater (P < 0.01) in unshaded than shaded sheep. On the contrary, lightness (L*), redness (a*) and yellowness (b*) values at 24 h postmortem were lower (P < 0.05) in unshaded versus shaded sheep. The sheep in the unshaded group had a greater (P < 0.05) cortisol concentration compared with the shaded group. Sheep in the shaded group had lower creatine kinase activity (P < 0.01) as well as observed for glucose (P < 0.05), triiodothyronine (P < 0.01), and thyroxine (P < 0.05) concentrations and white blood cell count (P < 0.05). Compared with the unshaded group, sheep in the shaded group had a greater lymphocytes (LYM) count (P < 0.05). In contrast, the opposite was true for neutrophils (NEU) count (P < 0.01) and NEU:LYM ratio (P < 0.01). In conclusion, the shade cloth, although not enhancing ADG, improved meat quality traits and certain stress parameters in grazing sheep reared under high ambient temperature.

  15. Impacts of livestock grazing and tree clearing on birds of woodland and riparian habitats.

    PubMed

    Martin, Tara G; McIntyre, S

    2007-04-01

    We investigated the impact of pastoral management on birds in subtropical grassy eucalypt woodland in southeastern Queensland, Australia, where the patterns of land management have made it possible to disentangle the effects of livestock grazing from those of tree clearing. We recorded changes in bird species composition, density, and relative abundance across two woodland habitat types (riparian and nonriparian) and two levels of clearing (wooded and nonwooded) and three levels of livestock grazing (low, moderate, and high) replicated over space (1000 km(2)) and time (2001-2002). We predicted that species that depend on understory vegetation would be most negatively affected by livestock grazing. A Bayesian generalized linear model showed that the level of grazing had the greatest effect when trees were present. When trees were absent, the impact of grazing was overshadowed by the effects of a lack of trees. Over 65% of species responded to different levels of grazing, and the abundance of 42% of species varied markedly with habitat and grazing. The most common response to grazing was high species relative abundance under low levels of grazing (28% of species), species absence at high levels of grazing (20%), and an increase in abundance with increasing grazing (18%). Despite having similar bird assemblages, the effect of grazing was stronger in riparian habitat than in adjacent woodland habitat. Our results suggest that any level of commercial livestock grazing is detrimental to some woodland birds, particularly the understory-dependant species, as predicted. Nevertheless, provided trees are not cleared, a rich and abundant bird fauna can coexist with moderate levels of grazing. Habitats with high levels of grazing, on the other hand, resulted in a species-poor bird assemblage dominated by birds that are increasing in abundance nationally.

  16. Vegetation responses to the first 20 years of cattle grazing in an Australian desert.

    PubMed

    Fensham, R J; Fairfax, R J; Dwyer, J M

    2010-03-01

    Existing theoretical frameworks suggest three predictions relevant to grazing effects in Australian aridlands: grazing has a negative but moderate effect on plant species richness; a separate "state" resulting from degradation caused by extreme grazing will be evident; some plant species will have a strong association with grazing relief refuges that have only ever been subject to light grazing. These predictions were examined in the dune swales of an Australian desert, with data on herbaceous species collected along transects up to 14 km from artificial water points between four and 33 years old. A cumulative grazing index was constructed utilizing both the spatial occupation patterns of cattle and the length of exposure. Despite restricting sampling to a narrow habitat, silt/clay content and soil pH influence floristic patterns independent of grazing. The analysis of quadrat data in relation to grazing revealed almost no patterns in plant cover, species richness (at two different scales), or abundance across plant life-form groups. Five species had an increasing response, and seven a decreasing response, while the only species restricted to areas of extremely low grazing pressure was sufficiently rare that it could have occurred there by chance. The dominant annual grass, the most common shrub, and a perennial tussock-forming sedge all decrease with high levels of grazing. Most species exhibit an ephemeral life strategy in response to unreliable rainfall, and this boom and bust strategy effectively doubles as an adaptation to grazing. After 20 years of exposure to managed grazing with domestic stock in Australian dune swales, patterns in species richness have not emerged in response to grazing pressure, the ecosystem has not been transformed to another degradation "state," and there is no evidence that grazing relief refuges provide havens for species highly sensitive to grazing.

  17. Impact of grazing management with large herbivores on forest ground flora and bramble understorey

    NASA Astrophysics Data System (ADS)

    Van Uytvanck, Jan; Hoffmann, Maurice

    2009-07-01

    We investigated whether grazing management with large herbivores is appropriate to reduce expanding bramble ( Rubus sp.) in an ancient forest in Flanders (N. Belgium). We further studied interaction effects of four years (all year-round) grazing and Rubus cover on the presence, cover, and flowering of five forest ground flora species (unpalatable: Anemone nemorosa and Primula elatior; palatable: Hyacinthoides non-scripta, Vinca minor and Hedera helix). We collected data on eight transects and in 412 plots in adjacent grazed and ungrazed forest and used baseline datasets of 1996 and 2002 in the same area (i.e. before grazing). In a field experiment, we simulated grazing (by clipping) and trampling (by pressing a weight) in eight homogeneous A. nemorosa vegetation stands. Large Rubus thickets had a clear negative impact on cover and flowering of A. nemorosa due to competition for light. Four years of cattle grazing reduced bramble cover by more than 50%, but then the limiting factor for A. nemorosa cover and flowering shifted to trampling damage. We also found lower cover and flowering of H. non-scripta in grazed plots, as a consequence of direct grazing. The evergreen species V. minor and H. helix totally disappeared from the grazed forest. Simulated once-only effects of grazing and trampling had a small and short term negative impact on cover of A. nemorosa, but flowering was strongly reduced. Grazing reduced biomass with 25-30% in the following years. Year-round grazing with large herbivores is an appropriate measure for bramble control in forests, but negative effects on ground flora are possible if grazing pressure is high. A low or moderate grazing pressure (<0.25 animal units ha -1 y -1) should be maintained in landscape mosaics with grassland and forest; or intermittent periods of non-grazing should be provided to maintain forest ground flora diversity.

  18. Measuring grazing-angle DHR with the infrared grazing angle reflectometer

    NASA Astrophysics Data System (ADS)

    Benson, Michael R.; Marciniak, Michael A.; Burks, Jeffrey W.

    2012-10-01

    The Infrared Grazing Angle Reflectometer allows measurement of Directional Hemispherical Reflectance (DHR) at very high angles of incidence (30 to 85 degrees) and at wavelengths ranging from 4.3 to 10.8 microns. A hemi-ellipsoidal mirror redirects the reflected light and reflects it on to a novel five-sided pyroelectric detector. The incident light intensity is measured and used in calculating the DHR of the sample. In this paper, the theory of operation of this detector is derived, and used to simulate the operation of the system. This simulation of the detector shows errors of 3% or less for both diffuse and specular samples, compared to the theoretical DHR. The calibration method defined in this paper allows for high accuracy and ease of use without knowing the specific attributes of the optics used in the system. Finally, collected DHR data is compared with the simulated data for comparison. Comparing the measured data to the simulation shows that the model correctly predicts the locations and trends of the scattered energy.

  19. Feedback dynamics of grazing lawns: Coupling vegetation change with animal growth

    USGS Publications Warehouse

    Person, Brian T.; Herzog, M.P.; Ruess, Roger W.; Sedinger, J.S.; Anthony, R. Michael; Babcock, C.A.

    2003-01-01

    We studied the effects of grazing by Black Brant (Branta bernicla nigricans) geese (hereafter Brant) on plant community zonation and gosling growth between 1987 and 2000 at a nesting colony in southwestern Alaska. The preferred forage of Brant, Carex subspathacea, is only found as a grazing lawn. An alternate forage species, C. ramenskii, exists primarily as meadow but also forms grazing lawns when heavily grazed. We mowed plots of ungrazed C. ramenskii meadows to create swards that Brant could select and maintain as grazing lawns. Fecal counts were higher on mowed plots than on control plots in the year after plots were mowed. Both nutritional quality and aboveground biomass of C. ramenskii in mowed plots were similar to that of C. subspathacea grazing lawns. The areal extent of grazing lawns depends in part on the population size of Brant. High Brant populations can increase the areal extent of grazing lawns, which favors the growth of goslings. Grazing lawns increased from 3% to 8% of surface area as the areal extent of C. ramenskii meadows declined between 1991 and 1999. Gosling mass was lower early in this time period due to density dependent effects. As the goose population stabilized, and area of grazing lawns increased, gosling mass increased between 1993 and 1999. Because larger goslings have increased survival, higher probability of breeding, and higher fecundity, herbivore-mediated changes in the distribution grazing lawn extent may result in a numerical increase of the population within the next two decades.

  20. Soil bacterial community responses to warming and grazing in a Tibetan alpine meadow.

    PubMed

    Li, Yaoming; Lin, Qiaoyan; Wang, Shiping; Li, Xiangzhen; Liu, Wentso; Luo, Caiyun; Zhang, Zhenhua; Zhu, Xiaoxue; Jiang, Lili; Li, Xine

    2016-01-01

    Warming and grazing significantly affect the structure and function of an alpine meadow ecosystem. Yet, the responses of soil microbes to these disturbances are not well understood. Controlled asymmetrical warming (+1.2/1.7°C during daytime/nighttime) with grazing experiments were conducted to study microbial response to warming, grazing and their interactions. Significant interactive effects of warming and grazing were observed on soil bacterial α-diversity and composition. Warming only caused significant increase in bacterial α-diversity under no-grazing conditions. Grazing induced no substantial differences in bacterial α-diversity and composition irrespective of warming. Warming, regardless of grazing, caused a significant increase in soil bacterial community similarity across space, but grazing only induced significant increases under no-warming conditions. The positive effects of warming on bacterial α-diversity and grazing on community similarity were weakened by grazing and warming, respectively. Soil and plant variables explained well the variations in microbial communities, indicating that changes in soil and plant properties may primarily regulate soil microbial responses to warming in this alpine meadow. The results suggest that bacterial communities may become more similar across space in a future, warmed climate and moderate grazing may potentially offset, at least partially, the effects of global warming on the soil microbial diversity.

  1. Patterns in Greater Sage-grouse population dynamics correspond with public grazing records at broad scales.

    PubMed

    Monroe, Adrian P; Aldridge, Cameron L; Assal, Timothy J; Veblen, Kari E; Pyke, David A; Casazza, Michael L

    2017-03-22

    Human land use, such as livestock grazing, can have profound yet varied effects on wildlife interacting within common ecosystems, yet our understanding of land-use effects is often generalized from short-term, local studies that may not correspond with trends at broader scales. Here we used public land records to characterize livestock grazing across Wyoming, USA, and we used Greater Sage-grouse (Centrocercus urophasianus) as a model organism to evaluate responses to livestock management. With annual counts of male Sage-grouse from 743 leks (breeding display sites) during 2004-2014, we modeled population trends in response to grazing level (represented by a relative grazing index) and timing across a gradient in vegetation productivity as measured by the Normalized Vegetation Difference Index (NDVI). We found grazing can have both positive and negative effects on Sage-grouse populations depending on the timing and level of grazing. Sage-grouse populations responded positively to higher grazing levels after peak vegetation productivity, but populations declined when similar grazing levels occurred earlier, likely reflecting the sensitivity of cool-season grasses to grazing during peak growth periods. We also found support for the hypothesis that effects of grazing management vary with local vegetation productivity. These results illustrate the importance of broad-scale analyses by revealing patterns in Sage-grouse population trends that may not be inferred from studies at finer scales, and could inform sustainable grazing management in these ecosystems.

  2. Is grazing exclusion effective in restoring vegetation in degraded alpine grasslands in Tibet, China?

    PubMed

    Yan, Yan; Lu, Xuyang

    2015-01-01

    Overgrazing is considered one of the key disturbance factors that results in alpine grassland degradation in Tibet. Grazing exclusion by fencing has been widely used as an approach to restore degraded grasslands in Tibet since 2004. Is the grazing exclusion management strategy effective for the vegetation restoration of degraded alpine grasslands? Three alpine grassland types were selected in Tibet to investigate the effect of grazing exclusion on plant community structure and biomass. Our results showed that species biodiversity indicators, including the Pielou evenness index, the Shannon-Wiener diversity index, and the Simpson dominance index, did not significantly change under grazing exclusion conditions. In contrast, the total vegetation cover, the mean vegetation height of the community, and the aboveground biomass were significantly higher in the grazing exclusion grasslands than in the free grazed grasslands. These results indicated that grazing exclusion is an effective measure for maintaining community stability and improving aboveground vegetation growth in alpine grasslands. However, the statistical analysis showed that the growing season precipitation (GSP) plays a more important role than grazing exclusion in which influence on vegetation in alpine grasslands. In addition, because the results of the present study come from short term (6-8 years) grazing exclusion, it is still uncertain whether these improvements will be continuable if grazing exclusion is continuously implemented. Therefore, the assessments of the ecological effects of the grazing exclusion management strategy on degraded alpine grasslands in Tibet still need long term continued research.

  3. Plant compensation to grazing and soil carbon dynamics in a tropical grassland

    PubMed Central

    2014-01-01

    The effects of grazing on soil organic carbon (SOC) dynamics, particularly in the tropics, are still poorly understood. Plant compensation to grazing, whereby plants maintain leaf area (C input capacity) despite consumption (C removal) by grazers, has been demonstrated in tropical grasslands but its influence on SOC is largely unexplored. Here, the effect of grazing on plant leaf area index (LAI) was measured in a field experiment in Serengeti National Park, Tanzania. LAI changed little for grazing intensities up to 70%. The response curve of LAI versus grazing intensity was used in a mass balance model, called SNAP, of SOC dynamics based on previous data from the Serengeti. The model predicted SOC to increase at intermediate grazing intensity, but then to decline rapidly at the highest grazing intensities. The SNAP model predictions were compared with observed SOC stocks in the 24 grazed plots of a 10-year grazing exclosure experiment at eight sites across the park that varied in mean annual rainfall, soil texture, grazing intensity and plant lignin and cellulose. The model predicted current SOC stocks very well (R2 > 0.75), and suggests that compensatory plant responses to grazing are an important means of how herbivores might maintain or increase SOC in tropical grasslands. PMID:24498573

  4. Positive short-term effects of sheep grazing on the alpine avifauna.

    PubMed

    Loe, Leif Egil; Mysterud, Atle; Stien, Audun; Steen, Harald; Evans, Darren M; Austrheim, Gunnar

    2007-02-22

    Grazing by large herbivores may negatively affect bird populations. This is of great conservation concern in areas with intensive sheep grazing. Sheep management varies substantially between regions, but no study has been performed in less intensively grazed systems. In a fully replicated, landscape scale experiment with three levels of sheep grazing, we tested whether the abundance and diversity of an assemblage of mountain birds were negatively affected by grazing or if grazing facilitated the bird assemblage. Density of birds was higher at high sheep density compared with low sheep density or no sheep by the fourth grazing season, while there was no clear effect on bird diversity. Thus, agricultural traditions and land use politics determining sheep density may change the density of avifauna in either positive or negative directions.

  5. The influence of grazing on surface climatological variables of tallgrass prairie

    NASA Technical Reports Server (NTRS)

    Seastedt, T. R.; Dyer, M. I.; Turner, Clarence L.

    1992-01-01

    Mass and energy exchange between most grassland canopies and the atmosphere are mediated by grazing activities. Ambient temperatures can be increased or decreased by grazers. Data have been assembled from simulated grazing experiments on Konza Prairie Research Natural Area and observations on adjacent pastures grazed by cattle show significant changes in primary production, nutrient content, and bidirectional reflectance characteristics as a function of grazing intensity. The purpose of this research was to provide algorithms that would allow incorporation of grazing effects into models of energy budgets using remote sensing procedures. The approach involved: (1) linking empirical measurements of plant biomass and grazing intensities to remotely sensed canopy reflectance, and (2) using a higher resolution, mechanistic grazing model to derive plant ecophysiological parameters that influence reflectance and other surface climatological variables.

  6. Evaluating Attitudes towards Changes in Rural Landscape by Grazing Cattle on Abandoned Paddy Fields

    NASA Astrophysics Data System (ADS)

    Yasuhito, Kitai; Toshihiro, Hattori; Hiroshi, Takahashi

    The appearance of cattle grazing abandoned paddy fields can be used to evaluate attitudes towards this land-use change. The semantic differential (SD) method was used families of a university student to evaluate and compare attitudes towards five types of rural landscape: pasture, pasture grazed by cattle, rice paddy field, abandoned paddy field converted to pasture and abandoned paddy field converted to pasture grazed by cattle. Cattle grazing abandoned paddy fields were determined to have a positive effect on the landscape. However, all grazing cattle created a negative attitude because of the unclean appearance of the landscape. Grazing cattle at high stocking rates in small areas could create a negative attitude because of the oppressive appearance of the landscape. The acceptance of grazing cattle was lower if the animals ware newly introduced to the landscape.

  7. 25 CFR 166.406 - Whose grazing rental rate will be applicable for a permit on government land?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Whose grazing rental rate will be applicable for a permit... INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.406 Whose grazing rental rate will be applicable for a...

  8. 25 CFR 166.422 - What does the BIA do with grazing rental payments received from permittees?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false What does the BIA do with grazing rental payments... INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Compensation to Indian Landowners § 166.422 What does the BIA do with grazing rental payments received...

  9. 43 CFR 4.470 - How to appeal a final BLM grazing decision to an administrative law judge.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false How to appeal a final BLM grazing decision... Hearings and Appeals Grazing Procedures (inside and Outside Grazing Districts) § 4.470 How to appeal a final BLM grazing decision to an administrative law judge. (a) Any applicant, permittee, lessee,...

  10. 25 CFR 166.416 - May a permittee make a grazing rental payment in advance of the due date?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false May a permittee make a grazing rental payment in advance... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.416 May a permittee make a grazing rental payment in advance of the due date? Rent may...

  11. 25 CFR 166.422 - What does the BIA do with grazing rental payments received from permittees?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false What does the BIA do with grazing rental payments... INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Compensation to Indian Landowners § 166.422 What does the BIA do with grazing rental payments received...

  12. 43 CFR 4.471 - How to petition for a stay of a final BLM grazing decision.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... grazing decision. 4.471 Section 4.471 Public Lands: Interior Office of the Secretary of the Interior... Grazing Procedures (inside and Outside Grazing Districts) § 4.471 How to petition for a stay of a final BLM grazing decision. (a) An appellant under § 4.470 may petition for a stay of the final BLM...

  13. 25 CFR 166.411 - Will a permittee be notified when a grazing rental payment is due?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Will a permittee be notified when a grazing rental... AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.411 Will a permittee be notified when a grazing rental payment is due? Each permit states...

  14. 25 CFR 166.406 - Whose grazing rental rate will be applicable for a permit on government land?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Whose grazing rental rate will be applicable for a permit... INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.406 Whose grazing rental rate will be applicable for a...

  15. 25 CFR 166.411 - Will a permittee be notified when a grazing rental payment is due?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Will a permittee be notified when a grazing rental... AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.411 Will a permittee be notified when a grazing rental payment is due? Each permit states...

  16. 25 CFR 166.423 - How do Indian landowners receive grazing rental payments that the BIA has received from permittees?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How do Indian landowners receive grazing rental payments..., DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Compensation to Indian Landowners § 166.423 How do Indian landowners receive grazing...

  17. 43 CFR 4.470 - How to appeal a final BLM grazing decision to an administrative law judge.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false How to appeal a final BLM grazing decision... Hearings and Appeals Grazing Procedures (inside and Outside Grazing Districts) § 4.470 How to appeal a final BLM grazing decision to an administrative law judge. (a) Any applicant, permittee, lessee,...

  18. 25 CFR 166.404 - Whose grazing rental rate will be applicable for a permit on tribal land?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Whose grazing rental rate will be applicable for a permit... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.404 Whose grazing rental rate will be applicable for a permit on tribal...

  19. 25 CFR 166.423 - How do Indian landowners receive grazing rental payments that the BIA has received from permittees?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How do Indian landowners receive grazing rental payments..., DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Compensation to Indian Landowners § 166.423 How do Indian landowners receive grazing...

  20. 43 CFR 4.471 - How to petition for a stay of a final BLM grazing decision.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... grazing decision. 4.471 Section 4.471 Public Lands: Interior Office of the Secretary of the Interior... Grazing Procedures (inside and Outside Grazing Districts) § 4.471 How to petition for a stay of a final BLM grazing decision. (a) An appellant under § 4.470 may petition for a stay of the final BLM...

  1. 25 CFR 166.416 - May a permittee make a grazing rental payment in advance of the due date?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false May a permittee make a grazing rental payment in advance... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments § 166.416 May a permittee make a grazing rental payment in advance of the due date? Rent may...

  2. 25 CFR 166.404 - Whose grazing rental rate will be applicable for a permit on tribal land?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Whose grazing rental rate will be applicable for a permit... LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Rate Determination and Adjustment § 166.404 Whose grazing rental rate will be applicable for a permit on tribal...

  3. 43 CFR 4130.4 - Authorization of temporary changes in grazing use within the terms and conditions of permits and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... grazing use within the terms and conditions of permits and leases, including temporary nonuse. 4130.4... MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Authorizing Grazing Use § 4130.4 Authorization of temporary changes in grazing use within the terms...

  4. Testing the limits of resistance: a 19-year study of Mediterranean grassland response to grazing regimes.

    PubMed

    Sternberg, Marcelo; Golodets, Carly; Gutman, Mario; Perevolotsky, Avi; Ungar, Eugene D; Kigel, Jaime; Henkin, Zalmen

    2015-05-01

    A synthesis of a long-term (19 years) study assessing the effects of cattle grazing on the structure and composition of a Mediterranean grassland in north-eastern Israel is presented, with new insights into the response of the vegetation to grazing management and rainfall. We hypothesized that the plant community studied would be resistant to high grazing intensities and rainfall variability considering the combined long history of land-use and unpredictable climatic conditions where this community evolved. Treatments included manipulations of stocking densities (moderate, heavy, and very heavy) and of grazing regimes (continuous vs. seasonal), in a factorial design. The effect of interannual rainfall variation on the expression of grazing impacts on the plant community was minor. The main effects of grazing on relative cover of plant functional groups were related to early vs. late seasonal grazing. Species diversity and equitability were remarkably stable across all grazing treatments. A reduction in tall grass cover at higher stocking densities was correlated with increased cover of less palatable groups such as annual and perennial thistles, as well as shorter and prostrate groups such as short annual grasses. This long-term study shows that interannual fluctuations in plant functional group composition could be partly accounted for by grazing pressure and timing, but not by the measured rainfall variables. Grazing affected the dominance of tall annual grasses. However, the persistence of tall grasses and more palatable species over time, despite large differences in grazing pressure and timing, supports the idea that Mediterranean grasslands are highly resistant to prolonged grazing. Indeed, even under the most extreme grazing conditions applied, there were no signs of deterioration or collapse of the ecosystem. This high resistance to grazing intensity and interannual fluctuation in climatic conditions should favor the persistence of the plant community under

  5. Red blood cell production

    MedlinePlus

    ... hemocytoblasts give rise to all of the formed elements in blood. If a hemocytoblast commits to becoming a cell called a proerythroblast, it will develop into a new red blood cell. The formation of a red ...

  6. [Effect of grazing on grassland under protective plantation in the ecotone between agriculture and animal husbandry or Songnen plain].

    PubMed

    He, Nianpeng; Wu, Ling; Zhou, Daowei

    2004-05-01

    Based on the current special position that grassland under protective plantation is one of the most important grazing spaces of the ecotone between agriculture and animal husbandry in Songnen plain, an experiment was conducted to investigate the effect of grazing on grassland under protective plantation. The results showed that no-grazing grassland in the grassland under protective plantation was seriously degenerated, but light and moderate grazing could stimulate the growth of grass and the product and quality of grassland. The index of grassland quality (IGQ) of no-grazing grassland was the lowest (15.51), attributing to serious degradation, while that of light grazing grassland was the highest (86.41), and the IGQ was decreased with increasing grazing intensity. Therefore, in order to stimulate the grass growth of the grassland, fully utilize the leaves of poplar, and increase the available forage resources, light and moderate grazing intensity should be advocated, but no-grazing and extreme grazing should be avoided.

  7. RED-LETTER DAYS

    EPA Science Inventory

    The word "red-letter" is an adjective meaning "of special significance." It's origin is from the practice of marking Christian holy days in red letters on calendars. The "red-letter days" to which I refer occurred while I was a graduate student of ...

  8. Free-grazing ducks and highly pathogenic avian influenza, Thailand.

    PubMed

    Gilbert, Marius; Chaitaweesub, Prasit; Parakamawongsa, Tippawon; Premashthira, Sith; Tiensin, Thanawat; Kalpravidh, Wantanee; Wagner, Hans; Slingenbergh, Jan

    2006-02-01

    Thailand has recently had 3 epidemic waves of highly pathogenic avian influenza (HPAI); virus was again detected in July 2005. Risk factors need to be identified to better understand disease ecology and assist HPAI surveillance and detection. This study analyzed the spatial distribution of HPAI outbreaks in relation to poultry, land use, and other anthropogenic variables from the start of the second epidemic wave (July 2004-May 2005). Results demonstrate a strong association between H5N1 virus in Thailand and abundance of free-grazing ducks and, to a lesser extent, native chickens, cocks, wetlands, and humans. Wetlands used for double-crop rice production, where free-grazing duck feed year round in rice paddies, appear to be a critical factor in HPAI persistence and spread. This finding could be important for other duck-producing regions in eastern and southeastern Asian countries affected by HPAI.

  9. Simulating the onset of grazing envelope evolution of binary stars

    NASA Astrophysics Data System (ADS)

    Shiber, Sagiv; Kashi, Amit; Soker, Noam

    2017-02-01

    We present the first three-dimensional gas-dynamical simulations of the grazing envelope evolution (GEE) of stars, with the goal of exploring the basic flow properties and the role of jets at the onset of the GEE. In the simulated runs, a secondary main-sequence star grazes the envelope of the primary asymptotic giant branch (AGB) star. The orbit is circular at the radius of the AGB primary star on its equator. We inject two opposite jets perpendicular to the equatorial plane from the location of the secondary star, and follow the evolution for several orbital periods. We explore the flow pattern by which the jets eject the outskirts of the AGB envelope. After one orbit, the jets start to interact with gas ejected in previous orbits and inflate hot low-density bubbles.

  10. Grazing-activated chemical defence in a unicellular marine alga

    NASA Astrophysics Data System (ADS)

    Wolfe, Gordon V.; Steinke, Michael; Kirst, Gunter O.

    1997-06-01

    Marine plankton use a variety of defences against predators, some of which affect trophic structure and biogeochemistry. We have previously shown that, during grazing by the protozoan Oxyrrhis marina on the alga Emiliania huxleyi, dimethylsulphoniopropionate (DMSP) from the prey is converted to dimethyl sulphide (DMS) when lysis of ingested prey cells initiates mixing of algal DMSP and the enzyme DMSP lyase. Such a mechanism is similar to macrophyte defence reactions,. Here we show that this reaction deters protozoan herbivores, presumably through the production of highly concentrated acrylate, which has antimicrobial activity. Protozoan predators differ in their ability to ingest and survive on prey with high-activity DMSP lyase, but all grazers preferentially select strains with low enzyme activity when offered prey mixtures. This defence system involves investment in a chemical precursor, DMSP, which is not self-toxic and has other useful metabolic functions. We believe this is the first report of grazing-activated chemical defence in unicellular microorganisms.

  11. Protozoan grazing reduces the current output of microbial fuel cells.

    PubMed

    Holmes, Dawn E; Nevin, Kelly P; Snoeyenbos-West, Oona L; Woodard, Trevor L; Strickland, Justin N; Lovley, Derek R

    2015-10-01

    Several experiments were conducted to determine whether protozoan grazing can reduce current output from sediment microbial fuel cells. When marine sediments were amended with eukaryotic inhibitors, the power output from the fuel cells increased 2-5-fold. Quantitative PCR showed that Geobacteraceae sequences were 120 times more abundant on anodes from treated fuel cells compared to untreated fuel cells, and that Spirotrichea sequences in untreated fuel cells were 200 times more abundant on anode surfaces than in the surrounding sediments. Defined studies with current-producing biofilms of Geobacter sulfurreducens and pure cultures of protozoa demonstrated that protozoa that were effective in consuming G. sulfurreducens reduced current production up to 91% when added to G. sulfurreducens fuel cells. These results suggest that anode biofilms are an attractive food source for protozoa and that protozoan grazing can be an important factor limiting the current output of sediment microbial fuel cells.

  12. Grazing-incidence antireflection films. I. Basic theory

    NASA Astrophysics Data System (ADS)

    Hannon, J. P.; Hung, N. V.; Trammell, G. T.; Gerdau, E.; Mueller, M.; Rüffer, R.; Winkler, H.

    1985-10-01

    We discuss the possibility of a new interference technique for x-ray and γ-ray optics-the simple idea of grazing-incidence antireflection films (GIAR films)-for creating high-efficiency antireflection coatings for near-grazing-incidence reflection of hard x rays and γ rays. The motivation is the possible application to producing ``ultranarrow'' bandpass filters for synchrotron radiation with frequency widths ~=10-8-10-6 eV, giving a unique high-resolution, long-coherence-length, x-ray source for probing soft inelastic excitations and opening up new possibilities in x-ray interferometry. In this first of two papers on nonresonant GIAR films, we develop the basic theory and discuss in detail the simplest ideas for achieving antireflection films-impedance-matched quarter-wave films and damping stabilized solutions-which can both be obtained by coating a high-density mirror with a single lower-density film.

  13. Properties and performance of grazing-incidence mirror systems

    NASA Astrophysics Data System (ADS)

    Aspnes, D. E.; Kelso, S. M.

    1982-04-01

    We investigate the performance of, and the origin of aberrations in, beam lines based on simple and the recently proposed CARSA mirror elements. New results include the identification of the sums of off-grazing angles and their squares as figures of merit for total reflectance and scattering losses in near-grazing-incidence systems, and the discovery that the usual image distortions and aberrations previously associated with simple elements can essentially be eliminated with pairs of elliptical mirrors having a common rotational symmetry axis. Slit throughput efficiencies and sensitivities to system stability are calculated for both horizontal and vertical dispersion for several representative beam lines using a ray-tracing program developed for CARSA systems. We find that high-resolution operation is possible with no entrance slit for CARSA combinations.

  14. Chronic parrotfish grazing impedes coral recovery after bleaching

    NASA Astrophysics Data System (ADS)

    Rotjan, Randi D.; Dimond, James L.; Thornhill, Daniel J.; Leichter, James J.; Helmuth, Brian; Kemp, Dustin W.; Lewis, Sara M.

    2006-08-01

    Coral bleaching, in which corals become visibly pale and typically lose their endosymbiotic zooxanthellae ( Symbiodinium spp.), increasingly threatens coral reefs worldwide. While the proximal environmental triggers of bleaching are reasonably well understood, considerably less is known concerning physiological and ecological factors that might exacerbate coral bleaching or delay recovery. We report a bleaching event in Belize during September 2004 in which Montastraea spp. corals that had been previously grazed by corallivorous parrotfishes showed a persistent reduction in symbiont density compared to intact colonies. Additionally, grazed corals exhibited greater diversity in the genetic composition of their symbiont communities, changing from uniform ITS2 type C7 Symbiodinium prior to bleaching to mixed assemblages of Symbiodinium types post-bleaching. These results suggest that chronic predation may exacerbate the influence of environmental stressors and, by altering the coral-zooxanthellae symbiosis, such abiotic-biotic interactions may contribute to spatial variation in bleaching processes.

  15. Active full-shell grazing-incidence optics

    NASA Astrophysics Data System (ADS)

    Roche, Jacqueline M.; Elsner, Ronald F.; Ramsey, Brian D.; O'Dell, Stephen L.; Kolodziejczak, Jeffrey J.; Weisskopf, Martin C.; Gubarev, Mikhail V.

    2016-09-01

    MSFC has a long history of developing full-shell grazing-incidence x-ray optics for both narrow (pointed) and wide field (surveying) applications. The concept presented in this paper shows the potential to use active optics to switch between narrow and wide-field geometries, while maintaining large effective area and high angular resolution. In addition, active optics has the potential to reduce errors due to mounting and manufacturing lightweight optics. The design presented corrects low spatial frequency error and has significantly fewer actuators than other concepts presented thus far in the field of active x-ray optics. Using a finite element model, influence functions are calculated using active components on a full-shell grazing-incidence optic. Next, the ability of the active optic to effect a change of optical prescription and to correct for errors due to manufacturing and mounting is modeled.

  16. Conservative deterministic spectral Boltzmann solver near the grazing collisions limit

    NASA Astrophysics Data System (ADS)

    Haack, Jeffrey R.; Gamba, Irene M.

    2012-11-01

    We present new results building on the conservative deterministic spectral method for the space homogeneous Boltzmann equation developed by Gamba and Tharkabhushaman. This approach is a two-step process that acts on the weak form of the Boltzmann equation, and uses the machinery of the Fourier transform to reformulate the collisional integral into a weighted convolution in Fourier space. A constrained optimization problem is solved to preserve the mass, momentum, and energy of the resulting distribution. Within this framework we have extended the formulation to the case of more general case of collision operators with anisotropic scattering mechanisms, which requires a new formulation of the convolution weights. We also derive the grazing collisions limit for the method, and show that it is consistent with the Fokker-Planck-Landau equations as the grazing collisions parameter goes to zero.

  17. Grazing and Metabolism of Euphausia pacifica in the Yellow Sea

    PubMed Central

    Tao, Zhencheng; Li, Chaolun; Sun, Song

    2015-01-01

    Grazing and metabolism of Euphausia pacifica in the Yellow Sea were studied from September 2006 to August 2007. Euphausia pacifica is a selective-feeding omnivore and grazing rates among different months were monitored using a Coulter Counter and batch culture feeding experiments. Euphausia pacifica mainly grazed microzooplankton in August and September, which resulted in an increase in chlorophyll a concentration. Oxygen consumption rate of E. pacifica was 38.7–42.5 μmol O2 g-1 DW h-1 in March, which was four times higher than the oxygen consumption rates in September and December. The vigorous metabolism of E. pacifica in March consumed 3.1% of body carbon daily, which is likely related to its high reproduction and grazing rate. Respiration and metabolism of E. pacifica in September and December were similar and were lower. O:N ratio of E. pacifica was the highest (17.3–23.8) in March when spawning activity occurred and when food was abundant. The energetic source of E. pacifica during September and December was mostly protein from eating a carnivorous diet, including such items as microzooplankton. Euphausia pacifica was found in cold water at the bottom of the Yellow Sea in summer and autumn and maintained a low consumption status. O:N ratios of E. pacifica in March, September, and December were negatively correlated with SSTs and no significant correlation was found between O:N ratios and chlorophyll a concentration. Seawater temperature is clearly the most important parameter influencing the metabolism of E. pacifica. PMID:25688560

  18. Backscatter from a periodic rough surface at near grazing incidence

    NASA Technical Reports Server (NTRS)

    Dominek, A. K.; Shamansky, H. T.

    1987-01-01

    The effect of periodic surface roughness on the radar cross section (RCS) was studied. The surface roughness was formed by a small sinusoidal variation in a planar surface. RCS measurements were obtained for two different sinusoidal variations near grazing incidence for both principle polarizations. Significant grating lobes were observed in the measurements which directly correspond to the roughness characteristics. A physical optics solution was generated and compared to the measurements with reasonable agreement.

  19. High Grazing Angle Sea-Clutter Literature Review

    DTIC Science & Technology

    2013-03-01

    Research, 1986. 91(C11): p. 13065-13083. [45] Stacy, N.J.S., D. Crisp, A. Goh, D. Badger , and M. Preiss. Polarimetric Analysis of Fine Resolution X... Badger , A.S. Goh, M. Preiss, and M.L. Williams. The DSTO Ingara airbone X-Band SAR polarimetric upgrade: first results. IEEE International Geoscience...2012. [65] Rosenberg, L. Persistent Sea-spike Detection in Medium Grazing Angle X-band Sea- clutter. European SAR conference, 2012. [66] Rosenberg, L

  20. Meteoroids captured into Earth orbit by grazing atmospheric encounters

    NASA Astrophysics Data System (ADS)

    Hills, Jack G.; Goda, M. Patrick

    1997-05-01

    Some meteoroids, such as the one that produced the daytime fireball of August 10, 1972 that passed over the western United States and the European fireball of October 13, 1990, graze the atmosphere of Earth before returning to space (at reduced speed). Other grazing meteoroids, such as Peekskill, penetrate deeper into the atmosphere and lose enough energy to plunge to ground. It is evident that if a grazing meteoroid is within some critical range of closest approach distance and speed, it is captured into a gravitationally bound orbit around Earth. It must ultimately plunge to ground after further orbital dissipation in subsequent atmospheric passages unless the gravitational pull of the Moon and Sun or other intervention raise its perigee above the atmosphere. A spherical atmospheric model is used to integrate the passage of meteoroids in grazing atmospheric encounters. It is found that the corridor for capture narrows with increasing values of V∞, the approach velocity of the meteoroid prior to gravitational acceleration by Earth. As an example, if V∞= 5 km s -1, stony meteoroids with closest-approach distances of h = 40 km above the Earth are captured if their radii, R, are between 3 and 9 m while if V∞ = 15 km s -1 and h = 40 km, they are only captured if R is between 1.5 and 2m. Irons with V∞ = 5 km s -1 and h = 40 km, are captured if R is between 1 and 3.5 m, while if V∞ = 15 km s -1, they are captured if R is between 0.6 and 0.9 m. The cross section for orbital capture of iron meteoroids and small stony meteoroids is about 0.001 that for directly hitting Earth. Large stones are never captured except at very low impact velocities because of the large increase in drag resulting from fragmentation.

  1. Impact of zooplankton grazing on Alexandrium blooms in the offshore Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Turner, Jefferson T.; Borkman, David G.

    2005-09-01

    Zooplankton grazing was investigated by shipboard experiments during natural blooms of Alexandrium spp. in the offshore Gulf of Maine in spring and/or summer of 1998, 2000, and 2001. Grazing studies were done in conjunction with studies of accumulation of Alexandrium toxins in the zooplankton, as part of the ECOHAB-Gulf of Maine regional program. Several species of copepods, marine cladocerans, and appendicularians were allowed to graze upon natural phytoplankton assemblages, at ambient temperatures (14-17 °C). Grazing was measured by quantitative microscopic analyses of disappearance of phytoplankton cells in initial, control, and experimental food suspensions. Thus, we were able to examine grazing upon Alexandrium in comparison to grazing on other co-occurring phytoplankton taxa. Even during Alexandrium "blooms," this dinoflagellate was a minor component of the overall phytoplankton assemblage. It was present at stations where grazing experiments were conducted at levels of 0.12-7.57×10 3 cells l -1, or 0.03-3.93% of total phytoplankton cells. Maximum ingestion of Alexandrium accounted for only up to 3.2% of total cells ingested. Phytoplankton assemblages were dominated by athecate microflagellates, and to a lesser extent by diatoms and non-toxic dinoflagellates. Microflagellates were present at abundances of 159.62-793.93 cells ml -1, or 60.6-95.56% of total cells. Grazing on microflagellates accounted for 35.59-98.21% of total grazing. Grazing on Alexandrium spp. and microflagellates was generally non-selective, with these taxa being ingested in similar proportions to their availability in food assemblages. Grazing on diatoms was selective, with diatoms being disproportionately ingested, compared to their proportions in food assemblages. There were no apparent adverse effects of Alexandrium on grazers during incubations of 18-24 h, and grazer survival was 100%. Estimated daily zooplankton grazing impact on Alexandrium spp. field populations by field

  2. Species-abundance--seed-size patterns within a plant community affected by grazing disturbance.

    PubMed

    Wu, Gao-lin; Shang, Zhan-huan; Zhu, Yuan-jun; Ding, Lu-ming; Wang, Dong

    2015-04-01

    Seed size has been advanced as a key factor that influences the dynamics of plant communities, but there are few empirical or theoretical predictions of how community dynamics progress based on seed size patterns. Information on the abundance of adults, seedlings, soil seed banks, seed rains, and the seed mass of 96 species was collected in alpine meadows of the Qinghai-Tibetan Plateau (China), which had different levels of grazing disturbance. The relationships between seed-mass-abundance patterns for adults, seedlings, the soil seed bank, and seed rain in the plant community were evaluated using regression models. Results showed that grazing levels affected the relationship between seed size and abundance properties of adult species, seedlings, and the soil seed bank, suggesting that there is a shift in seed-size--species-abundance relationships as a response to the grazing gradient. Grazing had no effect on the pattern of seed-size-seed-rain-abundance at four grazing levels. Grazing also had little effect on the pattern of seed-size--species-abundance and pattern of seed-size--soil-seed-bank-abundance in meadows with no grazing, light grazing, and moderate grazing), but there was a significant negative effect in meadows with heavy grazing. Grazing had little effect on the pattern of seed-size--seedling-abundance with no grazing, but had significant negative effects with light, moderate, and heavy grazing, and the |r| values increased with grazing levels. This indicated that increasing grazing pressure enhanced the advantage of smaller-seeded species in terms of the abundances of adult species, seedlings, and soil seed banks, whereas only the light grazing level promoted the seed rain abundance of larger-seeded species in the plant communities. This study suggests that grazing disturbances are favorable for increasing the species abundance for smaller-seeded species but not for the larger-seeded species in an alpine meadow community. Hence, there is a clear

  3. X-Ray Standing Wave at Grazing Incidence and Exit

    NASA Astrophysics Data System (ADS)

    Sakata, Osami; Jach, Terrence

    2013-01-01

    Grazing-angle X-ray standing waves (GAXSWs) generated dynamically are discussed under a geometry where incident, specularly reflected, and specularly diffracted waves make grazing angles to a crystal surface. The grazing angles are close to the critical angle for total external reflection. A Bragg condition is satisfied on lattice planes perpendicular to the surface. We explain all waves excited inside and outside the crystal using a three-dimensional dispersion surface. The perpendicular components of the waves are derived from the geometrical consideration on the basis of phase continuity on the boundary surface. Electric fields are formulated by solving simultaneous equations of boundary conditions for the tangential components of electric field and the normal components of the magnetic fields. The GAXSW field is formed by the interference of incident, specularly reflected, and specularly diffracted beams above the surface. The external field intensity, modulated along the surface, is expressed, while the position-dependent behaviors of the intensity are discussed. The output, proportional to the local field intensity at an adsorbed atom, is normally parametrized by the coherent position and the coherent fraction. We introduce two examples of in-plane structural analyses of iodine adsorbed on Ge(111) and 10-nm-thick Ca0.39Sr0.61F2 epilayer film on GaAs(111).

  4. Optimal phenology of annual plants under grazing pressure.

    PubMed

    Yamamura, Norio; Fujita, Noboru; Hayashi, Motoyuki; Nakamura, Yusuke; Yamauchi, Atsushi

    2007-06-07

    Plants show phenological responses to herbivory. Some enclosure experiments have demonstrated that the onset of the peak flowering season is dependent on grazing pressure. We constructed a mathematical model using Pontryargin's maximum principle to investigate changes in flowering time by examining shifts in resource allocation from vegetative to reproductive plant components. We represented a primary production of a plant individual by two types of function of vegetative part size, a linear function and a convex non-linear function. The results of a linear production model indicate that optimal phenology follows a schedule that switches from the production of vegetative parts to that of reproductive parts at a given time ('bang-bang' control). However, in a non-linear model, a singular control, wherein the plant invests in both productive and reproductive parts, may be included between obligate production and reproduction periods. We assumed that the peak of the flowering season occurs immediately following the exclusive investment in reproduction. In a linear production model, differential herbivory rates on the vegetative and reproductive parts of a plant resulted in shifts in the peak flowering time. A higher herbivory rate on the vegetative components advanced the peak, whereas it was delayed when grazing pressure focused on reproductive components of the plant. In the non-linear production model, increased grazing pressure tended to postpone the flowering peak. These results corresponded well with results of enclosure experiments, thus suggesting adaptive control of flowering time in plants.

  5. Zoonotic Echinostome Infections in Free-Grazing Ducks in Thailand

    PubMed Central

    Saijuntha, Weerachai; Duenngai, Kunyarat

    2013-01-01

    Free-grazing ducks play a major role in the rural economy of Eastern Asia in the form of egg and meat production. In Thailand, the geographical location, tropical climate conditions and wetland areas of the country are suitable for their husbandry. These environmental factors also favor growth, multiplication, development, survival, and spread of duck parasites. In this study, a total of 90 free-grazing ducks from northern, central, and northeastern regions of Thailand were examined for intestinal helminth parasites, with special emphasis on zoonotic echinostomes. Of these, 51 (56.7%) were infected by one or more species of zoonotic echinostomes, Echinostoma revolutum, Echinoparyphium recurvatum, and Hypoderaeum conoideum. Echinostomes found were identified using morphological criteria when possible. ITS2 sequences were used to identify juvenile and incomplete worms. The prevalence of infection was relatively high in each region, namely, north, central, and northeast region was 63.2%, 54.5%, and 55.3%, respectively. The intensity of infection ranged up to 49 worms/infected duck. Free-grazing ducks clearly play an important role in the life cycle maintenance, spread, and transmission of these medically important echinostomes in Thailand. PMID:24516271

  6. Understanding the spatiotemporal pattern of grazing cattle movement

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Jurdak, Raja

    2016-08-01

    Understanding the drivers of animal movement is significant for ecology and biology. Yet researchers have so far been unable to fully understand these drivers, largely due to low data resolution. In this study, we analyse a high-frequency movement dataset for a group of grazing cattle and investigate their spatiotemporal patterns using a simple two-state ‘stop-and-move’ mobility model. We find that the dispersal kernel in the moving state is best described by a mixture exponential distribution, indicating the hierarchical nature of the movement. On the other hand, the waiting time appears to be scale-invariant below a certain cut-off and is best described by a truncated power-law distribution, suggesting that the non-moving state is governed by time-varying dynamics. We explore possible explanations for the observed phenomena, covering factors that can play a role in the generation of mobility patterns, such as the context of grazing environment, the intrinsic decision-making mechanism or the energy status of different activities. In particular, we propose a new hypothesis that the underlying movement pattern can be attributed to the most probable observable energy status under the maximum entropy configuration. These results are not only valuable for modelling cattle movement but also provide new insights for understanding the underlying biological basis of grazing behaviour.

  7. Phytoplankton production and grazing balances in the Costa Rica Dome.

    PubMed

    Landry, Michael R; Selph, Karen E; Décima, Moira; Gutiérrez-Rodríguez, Andrés; Stukel, Michael R; Taylor, Andrew G; Pasulka, Alexis L

    2016-03-01

    We investigated phytoplankton production rates and grazing fates in the Costa Rica Dome (CRD) during summer 2010 based on dilution depth profiles analyzed by flow cytometry and pigments and mesozooplankton grazing assessed by gut fluorescence. Three community production estimates, from (14)C uptake (1025 ± 113 mg C m(-2) day(-1)) and from dilution experiments analyzed for total Chla (990 ± 106 mg C m(-2) day(-1)) and flow cytometry populations (862 ± 71 mg C m(-2) day(-1)), exceeded regional ship-based values by 2-3-fold. Picophytoplankton accounted for 56% of community biomass and 39% of production. Production profiles extended deeper for Prochlorococcus (PRO) and picoeukaryotes than for Synechococcus (SYN) and larger eukaryotes, but 93% of total production occurred above 40 m. Microzooplankton consumed all PRO and SYN growth and two-third of total production. Positive net growth of larger eukaryotes in the upper 40 m was balanced by independently measured consumption by mesozooplankton. Among larger eukaryotes, diatoms contributed ∼3% to production. On the basis of this analysis, the CRD region is characterized by high production and grazing turnover, comparable with or higher than estimates for the eastern equatorial Pacific. The region nonetheless displays characteristics atypical of high productivity, such as picophytoplankton dominance and suppressed diatom roles.

  8. The ability of winter grazing to reduce wildfire size, intensity ...

    EPA Pesticide Factsheets

    A recent study by Davies et al. sought to test whether winter grazing could reduce wildfire size, fire behavior metrics, and fire-induced plant mortality in shrub-grasslands. The authors concluded that ungrazed rangelands may experience more fire-induced mortality of native perennial bunchgrasses. The authors also presented several statements regarding the benefits of winter grazing on post-fire plant community responses. However, this commentary will show that the study by Davies et al. has underlying methodological flaws, lacks data necessary to support their conclusions, and does not provide an accurate discussion on the effect of grazing on rangeland ecosystems. Importantly, Davies et al. presented no data on the post-fire mortality of the perennial bunchgrasses or on the changes in plant community composition following their experimental fires. Rather, Davies et al. inferred these conclusions based off their observed fire behavior metrics of maximum temperature and a term described as the “heat load”. However, neither metric is appropriate for elucidating the heat flux impacts on plants. This lack of post-fire data, several methodological flaws, and the use of inadequate metrics describing heat cast doubts on the authors’ ability to support their stated conclusions. This article is a commentary highlights the scientific shortcomings in a forthcoming paper by Davies et al. in the International Journal of Wildland Fire. The study has methodological flaw

  9. Phytoplankton production and grazing balances in the Costa Rica Dome

    PubMed Central

    Landry, Michael R.; Selph, Karen E.; Décima, Moira; Gutiérrez-Rodríguez, Andrés; Stukel, Michael R.; Taylor, Andrew G.; Pasulka, Alexis L.

    2016-01-01

    We investigated phytoplankton production rates and grazing fates in the Costa Rica Dome (CRD) during summer 2010 based on dilution depth profiles analyzed by flow cytometry and pigments and mesozooplankton grazing assessed by gut fluorescence. Three community production estimates, from 14C uptake (1025 ± 113 mg C m−2 day−1) and from dilution experiments analyzed for total Chla (990 ± 106 mg C m−2 day−1) and flow cytometry populations (862 ± 71 mg C m−2 day−1), exceeded regional ship-based values by 2–3-fold. Picophytoplankton accounted for 56% of community biomass and 39% of production. Production profiles extended deeper for Prochlorococcus (PRO) and picoeukaryotes than for Synechococcus (SYN) and larger eukaryotes, but 93% of total production occurred above 40 m. Microzooplankton consumed all PRO and SYN growth and two-third of total production. Positive net growth of larger eukaryotes in the upper 40 m was balanced by independently measured consumption by mesozooplankton. Among larger eukaryotes, diatoms contributed ∼3% to production. On the basis of this analysis, the CRD region is characterized by high production and grazing turnover, comparable with or higher than estimates for the eastern equatorial Pacific. The region nonetheless displays characteristics atypical of high productivity, such as picophytoplankton dominance and suppressed diatom roles. PMID:27275036

  10. Understanding the spatiotemporal pattern of grazing cattle movement

    PubMed Central

    Zhao, Kun; Jurdak, Raja

    2016-01-01

    Understanding the drivers of animal movement is significant for ecology and biology. Yet researchers have so far been unable to fully understand these drivers, largely due to low data resolution. In this study, we analyse a high-frequency movement dataset for a group of grazing cattle and investigate their spatiotemporal patterns using a simple two-state ‘stop-and-move’ mobility model. We find that the dispersal kernel in the moving state is best described by a mixture exponential distribution, indicating the hierarchical nature of the movement. On the other hand, the waiting time appears to be scale-invariant below a certain cut-off and is best described by a truncated power-law distribution, suggesting that the non-moving state is governed by time-varying dynamics. We explore possible explanations for the observed phenomena, covering factors that can play a role in the generation of mobility patterns, such as the context of grazing environment, the intrinsic decision-making mechanism or the energy status of different activities. In particular, we propose a new hypothesis that the underlying movement pattern can be attributed to the most probable observable energy status under the maximum entropy configuration. These results are not only valuable for modelling cattle movement but also provide new insights for understanding the underlying biological basis of grazing behaviour. PMID:27555220

  11. Influence of elk grazing on soil properties in Rocky Mountain National Park

    USGS Publications Warehouse

    Binkley, D.; Singer, F.; Kaye, M.; Rochelle, R.

    2003-01-01

    We used three 35-year exclosures to examine the effects of high elk populations on a variety of soil properties in three vegetation types: upland sagebrush, aspen, and meadow. Grazing and hoof action by elk significantly increased bulk density (from 0.87 kg/l ungrazed to 0.94 kg/l grazed), with greater effects on soils with fewer rocks. Grazing substantially reduced extractable calcium, magnesium, potassium and phosphorus in the sagebrush type, but not in the aspen or meadow types. The only grazing effect on pH came in aspen types, where grazing prevented aspen establishment, and kept soil pH about 0.7 units higher than under aspen inside the exclosures. Grazing had no overall effect on total soil C and N across all exclosures and vegetation types. The availability of soil nitrogen, indexed by in-field resin bags and net mineralization in soil cores, showed little overall effect of grazing. Limited data on soil leaching indicated a possibility of strong increases in nitrate leaching with grazing for an aspen vegetation type at one exclosure. Although we found little effect of grazing on soil N supply, we note that N fertilization doubled the production of grasses and shrubs; if grazing eventually led to changes in soil N supply, species composition and growth would likely change. ?? 2003 Elsevier B.V. All rights reserved.

  12. Instability of development and fractal architecture in dryland plants as an index of grazing pressure

    USGS Publications Warehouse

    Alados, C.L.; Emlen, J.M.; Wachocki, B.; Freeman, D.C.

    1998-01-01

    Developmental instability has been used to monitor the well-being of natural populations exposed to physical, chemical and biological stressors. Here, we use developmental instability to assess the impact of grazing on Chrysothamnus greenii and Seriphidium novumshrubs, and Oryzopsis hymenoidesgrass, common in the arid intermountain west of the U.S.A. Statistical noise in allometric relations was used as an indicator of developmental instability arising from grazing-induced stress. Unpalatable species that are not grazed (Chrysothamnus greenii) or species that are dormant during the winter–spring grazing period (Oryzopsis hymenoides) show lower allometric variability under high grazing pressure. Palatable species (Seriphidium novum) exhibit high developmental instability under low and high grazing pressure. Grazing pressure imposed by presumably co-adapted wild herbivores enhances developmental stability in species habituated to moderate grazing, likeOryzopsis hymenoides, but stresses plants such as Chrysothamnus greenii that prefer disturbed environments. These grazing effects are probably due to the impact grazing has on competitive relationships and not to the direct action of the herbivore on the plants.

  13. Effects of cattle grazing on small mammal communities in the Hulunber meadow steppe.

    PubMed

    Cao, Chan; Shuai, Ling-Ying; Xin, Xiao-Ping; Liu, Zhi-Tao; Song, Yan-Ling; Zeng, Zhi-Gao

    2016-01-01

    Small mammals play important roles in many ecosystems, and understanding their response to disturbances such as cattle grazing is fundamental for developing sustainable land use strategies. However, how small mammals respond to cattle grazing remains controversial. A potential cause is that most of previous studies adopt rather simple experimental designs based solely on the presence/absence of grazing, and are thus unable to detect any complex relationships between diversity and grazing intensity. In this study, we conducted manipulated experiments in the Hulunber meadow steppe to survey small mammal community structures under four levels of grazing intensities. We found dramatic changes in species composition in native small mammal communities when grazing intensity reached intermediate levels (0.46 animal unit/ha). As grazing intensity increased, Spermophilus dauricus gradually became the single dominant species. Species richness and diversity of small mammals in ungrazed and lightly grazed (0.23 animal unit/ha) area were much higher than in intermediately and heavily grazed area. We did not detect a humped relationship between small mammal diversity and disturbance levels predicted by the intermediate disturbance hypothesis (IDH). Our study highlighted the necessity of conducting manipulated experiments under multiple grazing intensities.

  14. Zooplankton grazing in a eutrophic lake: implications of diel vertical migration. [Scenedesmus; Eudiaptomus; Daphnia; Ceriodaphnia; Synechococcus

    SciTech Connect

    Lampert, W.; Taylor, B.E.

    1985-02-01

    During summer and fall, depth profiles of zooplankton community grazing were determined in situ during day and night in the Schoehsee, a small eutrophic lake. Labeled algae of two different sizes were mixed with the natural suspension of phytoplankton in a grazing chamber. A small blue-green alga (Synechococcus, 1 ..mu..m) was labeled with /sup 32/P; a larger green alga (Scenedesmus, 4-15 ..mu..m) was labeled with /sup 14/C. During summer, grazing in the upper 5 m was negligible during day but strong at night. Hence, algae grow relatively unimpeded by grazing during daytime but are harvested at night. Vertical and diel differences in grazing rates disappeared when the vertical migration ceased in fall. Selectivity of grazing was controlled by the zooplankton species composition. Eudiaptomus showed a strong preference for Scenedesmus. Daphnia showed a slight preference for Scenedesmus, but Ceriodaphnia preferred Synechococcus. Cyclopoid copepodites did not ingest the small blue-green. Because Daphnia and Eudiaptomus were dominant, grazing rates on larger cells were usually higher than grazing rates on the small cells. Negative electivity indices for scenedesmus occurred only when the biomass of large crustaceans was extremely low (near the surface, during day). Zooplankton biomass was the main factor controlling both vertical and seasonal variations in grazing. Highest grazing rates (65%/d) were measured during fall when zooplankton abundance was high. Because differential losses can produce substantial errors in the results, it was necessary to process the samples on the boat immediately after collection, without preservation.

  15. Testing congruence among multiple grazing indicators: a multi-site study across the Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Wang, Yun; Lehnert, Lukas; Holzapfel, Maika; Schultz, Roland; Heberling, Gwendolyn; Görzen, Eugen; Meyer, Hanna; Seeber, Elke; Pinkert, Stefan; Ritz, Markus; Ansorge, Hermann; Bendix, Jörg; Seifert, Bernhard; Miehe, Georg; Long, Ruijun; Yang, Yongping; Wesche, Karsten

    2015-04-01

    Aim Animal husbandry is one of the most widespread land use types, and grazing is a key topic in grassland management. A wide range of indicators are employed in grazing assessments and they often yield widely differing estimates on the associated level of degradation threat. Covering Tibet as a large grassland region with long history of pastoralism, we selected representative indicators to test: (1) how grazing responses change along large-scale climatic gradients, and (2) whether their responses to both grazing intensities and local abiotic conditions are congruent. Location Tibetan Plateau Methods Biotic indicators including species and growth form compositions of vascular plants, richness and abundance of small mammals and ants, together with soil nutrients and field spectra were compared in pairs of high and low grazing intensity at 18 sites across large climatic gradients. Altitude, temperature, and precipitation were considered as potentially influential abiotic factors. Responses of indicators to grazing intensity and environmental gradients were explored by multivariate and univariate analyses. Results All indicators responded strongly to environmental changes, but the response patterns and the most influential abiotic factors varied among indicators. Grazing responses showed low overall congruence. Only vegetation cover, soil nutrient concentrations, and spectral indices were sensitive to grazing across large spatial scales. Grazing effects were significant only when local abiotic factors were taken into account. Main conclusions The results imply that grazing assessments require both appropriate indicators and local calibration. Overall, the threat of grassland degradation across the Tibetan Plateau is not as severe as is commonly assumed.

  16. Effects of cattle grazing on small mammal communities in the Hulunber meadow steppe

    PubMed Central

    Xin, Xiao-Ping; Liu, Zhi-Tao; Song, Yan-Ling

    2016-01-01

    Small mammals play important roles in many ecosystems, and understanding their response to disturbances such as cattle grazing is fundamental for developing sustainable land use strategies. However, how small mammals respond to cattle grazing remains controversial. A potential cause is that most of previous studies adopt rather simple experimental designs based solely on the presence/absence of grazing, and are thus unable to detect any complex relationships between diversity and grazing intensity. In this study, we conducted manipulated experiments in the Hulunber meadow steppe to survey small mammal community structures under four levels of grazing intensities. We found dramatic changes in species composition in native small mammal communities when grazing intensity reached intermediate levels (0.46 animal unit/ha). As grazing intensity increased, Spermophilus dauricus gradually became the single dominant species. Species richness and diversity of small mammals in ungrazed and lightly grazed (0.23 animal unit/ha) area were much higher than in intermediately and heavily grazed area. We did not detect a humped relationship between small mammal diversity and disturbance levels predicted by the intermediate disturbance hypothesis (IDH). Our study highlighted the necessity of conducting manipulated experiments under multiple grazing intensities. PMID:27635323

  17. Prescribed grazing as a secondary impact in a western riparian floodplain

    USGS Publications Warehouse

    Sedgwick, J.A.; Knopf, F.L.

    1991-01-01

    The effect of late-autumn cattle grazing on plant biomass was examined in a western Great Plains cottonwood riparian zone prone to catastrophic flooding every 5-8 years. Following 1 year of pre-treatment data collection in 1982, five 16-ha pastures were grazed from 1982 to 1984 and compared to 5 control pastures within the South Platte River floodplain in northeastern Colorado. At a prescribed grazing level of 0.46 ha/AUM, riparian vegetation proved to be resilient to the impacts of grazing. We detected only a few significant treatment effects for above-ground biomass after succeeding growing seasons. Willows (Salix spp.) responded negatively to grazing whereas biomass of prairie cordgrass (Spartina pectinata Link) was greater on grazed plots. Yearly changes in above-ground biomass, especially dramatic following a severe flood in 1983, suggest that periodic, catastrophic flooding is a major perturbation to the ecosystem, and in conjunction with our results on grazing impacts, indicate that dormant-season grazing within Soil Conservation Service (SCS) guidelines is a comparatively minor impact within the floodplain. In addition, grazing impacts were probably further mitigated by a major forage supplement of cottonwood leaves which was available at the time of cattle introductions. This local forage supplement ultimately created a lighter grazing treatment than that originally prescribed.

  18. [Effect of grazing on the temperature sensitivity of soil respiration in Hulunber meadow steppe].

    PubMed

    Wang, Xu; Yan, Rui-Rui; Deng, Yu; Yan, Yu-Chun; Xin, Xiao-Ping

    2014-05-01

    Grazing is one of the major human activities which lead to disturbance on grassland ecosystem. Quantifying the effect of grazing on the temperature sensitivity of soil respiration ( Q10 ) is essential for accurate assessment of carbon budget in grassland ecosystem. This study was conducted on the grazing gradients experiment platform in Hulunber meadow steppe. Soil respiration was measured by a dynamic closed chamber method (equipped with Li 6400-09, Lincoln, NE, USA) during the growing season in 2011. The results showed that soil respiration had significant seasonal variation and the maximum occurred in July, which was mainly dominated by temperature. The order of average soil respiration during the period from May to September in different treatments was G1 > GO > G2 > G3 > G4 > G5. Comparing with non-grazing treatment, Q10 under heavy grazing conditions (0. 92 Au hm-2) was reduced by about 10% , and was increased a little under light grazing conditions (0. 23 Au hm-2). There was a significant negative correlation between Q15 and grazing intensities (r = 0. 944, P <0. 05) . Grazing could decrease the temperature sensitivity of soil respiration to different degrees. The Q10 under different grazing gradients had positive linear regression relationships with aboveground biomass, belowground biomass, soil organic carbon and soil moisture. They could explain 71.0%-85.2% variations of Q10. It was suggested that the variation of Q10 was mainly determined by the change of biotic and environmental factors due to grazing.

  19. Saharan dust and Florida red tides: The cyanophyte connection

    NASA Astrophysics Data System (ADS)

    Walsh, John J.; Steidinger, Karen A.

    2001-06-01

    Prediction of the consequences of harmful algal blooms for humans and other vertebrates is constrained by an inadequate understanding of the factors that promote their initiation. A simple exponential growth model of net production is used for analysis of four time series at different sampling intervals over ˜40 years of red tide strandings, associated fish kills, and concomitant dust loadings on the West Florida shelf. At least large summer blooms of a toxic dinoflagellate Gymnodinium breve appear to be primed regularly by an aeolian supply of nutrients. Wet deposition of Saharan mineral aerosols may alleviate iron limitation of diazotrophic cyanophytes, which in turn fuel the nitrogen economy of red tides in the eastern Gulf of Mexico. Vagaries of the wind-induced circulation and of selective grazing pressure on phytoplankton competitors within phosphorus replete coastal waters then determine each year the residence times for exposure of G. breve-mediated neurotoxins to fish, manatees, and humans along the southeastern United States.

  20. Protist Community Grazing on Prokaryotic Prey in Deep Ocean Water Masses.

    PubMed

    Rocke, Emma; Pachiadaki, Maria G; Cobban, Alec; Kujawinski, Elizabeth B; Edgcomb, Virginia P

    2015-01-01

    Oceanic protist grazing at mesopelagic and bathypelagic depths, and their subsequent effects on trophic links between eukaryotes and prokaryotes, are not well constrained. Recent studies show evidence of higher than expected grazing activity by protists down to mesopelagic depths. This study provides the first exploration of protist grazing in the bathypelagic North Atlantic Deep Water (NADW). Grazing was measured throughout the water column at three stations in the South Atlantic using fluorescently-labeled prey analogues. Grazing in the deep Antarctic Intermediate water (AAIW) and NADW at all three stations removed 3.79% ± 1.72% to 31.14% ± 8.24% of the standing prokaryote stock. These results imply that protist grazing may be a significant source of labile organic carbon at certain meso- and bathypelagic depths.

  1. 25 CFR 166.407 - If a range unit consists of tribal and individually-owned Indian lands, what is the grazing...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Indian lands, what is the grazing rental rate? 166.407 Section 166.407 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment... individually-owned Indian lands, what is the grazing rental rate? The grazing rental rate for tribal land...

  2. 25 CFR 166.407 - If a range unit consists of tribal and individually-owned Indian lands, what is the grazing...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Indian lands, what is the grazing rental rate? 166.407 Section 166.407 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment... individually-owned Indian lands, what is the grazing rental rate? The grazing rental rate for tribal land...

  3. Application of Grazing-Inspired Guidance Laws to Autonomous Information Gathering

    DTIC Science & Technology

    2014-09-01

    Application of Grazing -Inspired Guidance Laws to Autonomous Information Gathering Thomas Apker Shih-Yuan Liu Donald Sofge J. Karl Hedrick Abstract...Domestic grazing animals follow simple, scalable rules to assign themselves trajectories to cover a pasture. We explain how to adapt these rules for an...scalability and robustness to failure are required. I. INTRODUCTION Biological systems such as domestic grazing animals ex- hibit efficient and

  4. Traditional Cattle Grazing in a Mosaic Alkali Landscape: Effects on Grassland Biodiversity along a Moisture Gradient

    PubMed Central

    Török, Péter; Valkó, Orsolya; Deák, Balázs; Kelemen, András; Tóthmérész, Béla

    2014-01-01

    Extensively managed pastures are of crucial importance in sustaining biodiversity both in local- and landscape-level. Thus, re-introduction of traditional grazing management is a crucial issue in grassland conservation actions worldwide. Traditional grazing with robust cattle breeds in low stocking rates is considered to be especially useful to mimic natural grazing regimes, but well documented case-studies are surprisingly rare on this topic. Our goal was to evaluate the effectiveness of traditional Hungarian Grey cattle grazing as a conservation action in a mosaic alkali landscape. We asked the following questions: (i) How does cattle grazing affect species composition and diversity of the grasslands? (ii) What are the effects of grazing on short-lived and perennial noxious species? (iii) Are there distinct effects of grazing in dry-, mesophilous- and wet grassland types? Vegetation of fenced and grazed plots in a 200-ha sized habitat complex (secondary dry grasslands and pristine mesophilous- and wet alkali grasslands) was sampled from 2006–2009 in East-Hungary. We found higher diversity scores in grazed plots compared to fenced ones in mesophilous- and wet grasslands. Higher cover of noxious species was typical in fenced plots compared to their grazed counterparts in the last year in every studied grassland type. We found an increasing effect of grazing from the dry- towards the wet grassland types. The year-to-year differences also followed similar pattern: the site-dependent effects were the lowest in the dry grassland and an increasing effect was detected along the moisture gradient. We found that extensive Hungarian Grey cattle grazing is an effective tool to suppress noxious species and to create a mosaic vegetation structure, which enables to maintain high species richness in the landscape. Hungarian Grey cattle can feed in open habitats along long moisture gradient, thus in highly mosaic landscapes this breed can be the most suitable livestock type

  5. Density and success of bird nests relative to grazing on western Montana grasslands

    USGS Publications Warehouse

    Fondell, Thomas F.; Ball, I.J.

    2004-01-01

    Grassland birds are declining at a faster rate than any other group of North American bird species. Livestock grazing is the primary economic use of grasslands in the western United States, but the effects of this use on distribution and productivity of grassland birds are unclear. We examined nest density and success of ground-nesting birds on grazed and ungrazed grasslands in western Montana. In comparison to grazed plots, ungrazed plots had reduced forb cover, increased litter cover, increased litter depth, and increased visual obstruction readings (VOR) of vegetation. Nest density among 10 of 11 common bird species was most strongly correlated with VOR of plots, and greatest nest density for each species occurred where mean VOR of the plot was similar to mean VOR at nests. Additionally, all bird species were relatively consistent in their choice of VOR at nests despite substantial differences in VOR among plots. We suggest that birds selected plots based in part on availability of suitable nest sites and that variation in nest density relative to grazing reflected the effect of grazing on availability of nest sites. Nest success was similar between grazed plots and ungrazed plots for two species but was lower for nests on grazed plots than on ungrazed plots for two other species because of increased rates of predation, trampling, or parasitism by brown-headed cowbirds (Molothrus ater). Other species nested almost exclusively on ungrazed plots (six species) or grazed plots (one species), precluding evaluation of the effects of grazing on nest success. We demonstrate that each species in a diverse suite of ground-nesting birds preferentially used certain habitats for nesting and that grazing altered availability of preferred nesting habitats through changes in vegetation structure and plant species composition. We also show that grazing directly or indirectly predisposed some bird species to increased nesting mortality. Management alternatives that avoid

  6. Excretion of Eimeria alabamensis oocysts in grazing calves and young stock.

    PubMed

    Svensson, C

    2000-03-01

    The aims of the present study were to investigate the excretion of Eimeria alabamensis oocysts by young cattle during their first grazing season and during the first 16 days of their second grazing period. In trial 1, nine first-season grazing heifers were studied and found to have become infected with E. alabamensis shortly after turnout. The next grazing period they were turned out on to a permanent pasture together with two first-season grazing calves. Faecal samples were collected before turnout and then daily from day 3 to day 16. The second-season grazing heifers excreted insignificant numbers of E. alabamensis oocysts, whereas one of the two first-season grazing calves excreted up to 703,000 oocysts/g of faeces (OPG), indicating that the pasture was contaminated. In trial 2, faecal samples were collected from 12 calves before their first turnout in May, daily from day 2 to day 20 after turnout and then once a week until the end of September. The calves grazed pastures used in previous years by first-season grazing calves. Nine of the calves developed clinical E. alabamensis coccidiosis 4-7 days after turnout and excreted more than 950,000 OPG on days 9-10. By day 17 the oocyst excretion had decreased below 900 OPG and remained low throughout the rest of the grazing season. The results of the two studies indicate that reinfections with E. alabamensis are of little clinical importance in calves grazing contaminated pastures, and that young stock infected with E. alabamensis during their first grazing season may be used to cleanse contaminated pastures without risk of developing clinical coccidiosis.

  7. Traditional cattle grazing in a mosaic alkali landscape: effects on grassland biodiversity along a moisture gradient.

    PubMed

    Török, Péter; Valkó, Orsolya; Deák, Balázs; Kelemen, András; Tóthmérész, Béla

    2014-01-01

    Extensively managed pastures are of crucial importance in sustaining biodiversity both in local- and landscape-level. Thus, re-introduction of traditional grazing management is a crucial issue in grassland conservation actions worldwide. Traditional grazing with robust cattle breeds in low stocking rates is considered to be especially useful to mimic natural grazing regimes, but well documented case-studies are surprisingly rare on this topic. Our goal was to evaluate the effectiveness of traditional Hungarian Grey cattle grazing as a conservation action in a mosaic alkali landscape. We asked the following questions: (i) How does cattle grazing affect species composition and diversity of the grasslands? (ii) What are the effects of grazing on short-lived and perennial noxious species? (iii) Are there distinct effects of grazing in dry-, mesophilous- and wet grassland types? Vegetation of fenced and grazed plots in a 200-ha sized habitat complex (secondary dry grasslands and pristine mesophilous- and wet alkali grasslands) was sampled from 2006-2009 in East-Hungary. We found higher diversity scores in grazed plots compared to fenced ones in mesophilous- and wet grasslands. Higher cover of noxious species was typical in fenced plots compared to their grazed counterparts in the last year in every studied grassland type. We found an increasing effect of grazing from the dry- towards the wet grassland types. The year-to-year differences also followed similar pattern: the site-dependent effects were the lowest in the dry grassland and an increasing effect was detected along the moisture gradient. We found that extensive Hungarian Grey cattle grazing is an effective tool to suppress noxious species and to create a mosaic vegetation structure, which enables to maintain high species richness in the landscape. Hungarian Grey cattle can feed in open habitats along long moisture gradient, thus in highly mosaic landscapes this breed can be the most suitable livestock type.

  8. Floristic composition, biomass, and aboveground net plant production in grazed and protected sites in a mountain grassland of central Argentina

    NASA Astrophysics Data System (ADS)

    Pucheta, Eduardo; Cabido, Marcelo; Díaz, Sandra; Funes, Guillermo

    1998-04-01

    Changes in plant community composition, diversity, aboveground biomass, and aboveground net primary production (ANPP) of different plant growth-forms were assessed in sites protected from livestock grazing for 2, 4, and 15 years, and in a heavily-grazed site. Species richness was maximum at the grazed site and decreased significantly after 4 years of protection. Diversity decreased significantly only after 15 years of protection. No alien or weedy species were found at grazed or protected sites. Grazing exclusion produced a shift from grazing-tolerant or grazing-avoiding species with a graminoid or prostrate growth-form to taller species with a tall tussock growth-form. Grazing produced a 33% decrease in standing biomass but little change in ANPP when compared to the site protected from grazing for 2 years, but important changes in both biomass and ANPP respect to the sites protected for 4 and 15 years. Consumption was near 35% of ANPP.

  9. Improved grazing management may increase soil carbon sequestration in temperate steppe

    NASA Astrophysics Data System (ADS)

    Chen, Wenqing; Huang, Ding; Liu, Nan; Zhang, Yingjun; Badgery, Warwick B.; Wang, Xiaoya; Shen, Yue

    2015-07-01

    Different grazing strategies impact grassland plant production and may also regulate the soil carbon formation. For a site in semiarid temperate steppe, we studied the effect of combinations of rest, high and moderate grazing pressure over three stages of the growing season, on the process involved in soil carbon sequestration. Results show that constant moderate grazing (MMM) exhibited the highest root production and turnover accumulating the most soil carbon. While deferred grazing (RHM and RMH) sequestered less soil carbon compared to MMM, they showed higher standing root mass, maintained a more desirable pasture composition, and had better ability to retain soil N. Constant high grazing pressure (HHH) caused diminished above- and belowground plant production, more soil N losses and an unfavorable microbial environment and had reduced carbon input. Reducing grazing pressure in the last grazing stage (HHM) still had a negative impact on soil carbon. Regression analyses show that adjusting stocking rate to ~5SE/ha with ~40% vegetation utilization rate can get the most carbon accrual. Overall, the soil carbon sequestration in the temperate grassland is affected by the grazing regime that is applied, and grazing can be altered to improve soil carbon sequestration in the temperate steppe.

  10. Functional trait responses to grazing are mediated by soil moisture and plant functional group identity

    PubMed Central

    Zheng, Shuxia; Li, Wenhuai; Lan, Zhichun; Ren, Haiyan; Wang, Kaibo

    2015-01-01

    Abundant evidence has shown that grazing alters plant functional traits, community structure and ecosystem functioning of grasslands. Few studies, however, have tested how plant responses to grazing are mediated by resource availability and plant functional group identity. We examined the effects of grazing on functional traits across a broad range of species along a soil moisture gradient in Inner Mongolia grassland. Our results showed that trait syndromes of plant size (individual biomass) and shoot growth (leaf N content and leaf density) distinguished plant species responses to grazing. The effects of grazing on functional traits were mediated by soil moisture and dependent on functional group identity. For most species, grazing decreased plant height but increased leaf N and specific leaf area (SLA) along the moisture gradient. Grazing enhanced the community-weighted attributes (leaf NCWM and SLACWM), which were triggered mainly by the positive trait responses of annuals and biennials and perennial grasses, and increased relative abundance of perennial forbs. Our results suggest that grazing-induced species turnover and increased intraspecific trait variability are two drivers for the observed changes in community weighted attributes. The dominant perennial bunchgrasses exhibited mixed tolerance–resistance strategies to grazing and mixed acquisitive–conservative strategies in resource utilization. PMID:26655858

  11. Using digital photography to examine grazing in montane meadows

    USGS Publications Warehouse

    McIlroy, Susan K.; Allen-Diaz, Barbara H.; Berg, Alexander C.

    2011-01-01

    Cattle (Bos taurus) numbers on national forests are allocated based on allotment grazing capacity, but spatial patterns of timing and density at smaller scales are difficult to assess. However, it is often in meadows or riparian areas that grazing may affect hydrology, biodiversity, and other important ecosystem characteristics. To explore real-time animal presence in montane meadows we distributed 18 digital cameras across nine sites in the Sierra National Forest, California. Our objectives were to document seasonal and diurnal presence of both cattle and mule deer (Odocoileus hemionus), identify the effects of three fencing treatments on animal distribution, and test digital photography as a tool for documenting cattle presence. We recorded 409 399 images during daylight hours for two grazing seasons, and we identified 5 084 and 24 482 cattle "marks" (instances of animal occurrence) in 2006 and 2007, respectively. Deer presence was much lower, with 331 marks in 2006 and 598 in 2007. Morning cattle presence was highest before 0800 hours both years (13.7% and 15.4% of total marks for 2006 and 2007, respectively). Marks decreased until 1100 hours and then increased around 1400 hours and remained relatively stable until 1900 hours. Marks then rose precipitously, with >20% of total marks recorded after 1900 hours both years. Deer presence was less than 10% per hour until 1800 hours, when >20% of total marks were recorded after this time both years. Among treatments, cattle marks were highest outside fences at partially fenced meadows, and deer were highest within completely fenced meadows. Our experience suggests that cameras are not viable tools for meadow monitoring due to variation captured within meadows and the time and effort involved in image processing and review.

  12. Seasonal Carbon Dioxide Exchange of a Grazed Grassland in California

    NASA Astrophysics Data System (ADS)

    Xu, L.; Baldocchi, D. D.

    2001-12-01

    An new Ameriflux site was established in late 2000 to study the exchange of carbon dioxide over an oak/grass savanna and a nearby grazed grassland at the foothill of Sierra Nevada in California. Only data from the grazed grassland will be presented here. The flux measurement, along with measurements of meteorological and soil parameters, were start at the end of October 2000. Results from almost one year's data indicated that most of variance of the CO2 flux can be explained by changes in soil water content and leaf area index (LAI). The grass started to growth around middle of October after receiving substantial rainfall. Midday net ecosystem CO2 exchange (NEE) increased slowly from near zero in early November to about -10 μ mol m-2 s-1 (downward flux is negative) in the middle of March. While the nighttime NEE was around 1 to 3 μ mol m-2 s-1. In the spring, there was a peak growth period when photosynthesis and respiration both accelerated. The maximum LAI was 2.0, reached at this peak period. Midday NEE reached a maximum value of -18 μ mol m-2 s-1, and averaged nighttime NEE ranged from 2 to 5 μ mol m-2 s-1. Then as the soil dried out in the early summer, both daytime photosynthesis and night respiration plummeted to near zero. In the dry summer, small value of soil CO2 efflux during daytime only was observed. From almost one season's data, we found that nighttime ecosystem respiration followed closely to the daytime photosynthetic rate, indicating the importance of photosynthetic assimilates allocation for respiration. Annual integrated carbon exchange over this grazed grassland was estimated to be around -120 g C m-2. Results also show that the seasonality of NEE and growth of grasses are quite different from those mid-western grasslands.

  13. Spherical mirror grazing incidence x-ray optics

    NASA Technical Reports Server (NTRS)

    Cash, Jr., Webster C. (Inventor)

    1997-01-01

    An optical system for x-rays combines at least two spherical or near spherical mirrors for each dimension in grazing incidence orientation to provide the functions of a lens in the x-ray region. To focus x-ray radiation in both the X and the Y dimensions, one of the mirrors focusses the X dimension, a second mirror focusses the Y direction, a third mirror corrects the X dimension by removing comatic aberration and a fourth mirror corrects the Y dimension. Spherical aberration may also be removed for an even better focus. The order of the mirrors is unimportant.

  14. An Evaluation of Grazing-Incidence Optics for Neutron Imaging

    NASA Technical Reports Server (NTRS)

    Gubarev, M. V.

    2007-01-01

    The refractive index for most materials is slightly less than unity, which opens an opportunity to develop the grazing incidence neutron imaging optics. The ideal material for the optics would be natural nickel and its isotopes. Marshall Space Flight Center (MSFC) has active development program on the nickel replicated optics for use in x-ray astronomy. Brief status report on the program is presented. The results of the neutron focusing optic test carried by the MSFC team at National Institute of Standards and Technology (NIST) are also presented. Possible applications of the optics are briefly discussed.

  15. Steering-Enhanced Roughening during Metal Deposition at Grazing Incidence

    NASA Astrophysics Data System (ADS)

    van Dijken, Sebastiaan; Jorritsma, Louis C.; Poelsema, Bene

    1999-05-01

    It is shown that steering may have an important influence on the morphology of growing films. Steering originates from long-range attractive forces between incoming atoms and substrate atoms and leads to preferential arrival of atoms on top of islands. This phenomenon is most pronounced for grazing incidence deposition and results in significantly increased roughness of the growing film. Steering, which is expected to be generally valid but has so far been disregarded in growth studies, is illustrated for the growth of Cu/Cu(001).

  16. Soil degradation in semi-arid grasslands due to intensive grazing in Northern China

    NASA Astrophysics Data System (ADS)

    Wiesmeier, M.; Steffens, M.; Kölbl, A.; Kögel-Knabner, I.

    2012-04-01

    Degradation of semi-arid grasslands is a global environmental problem, particularly in Inner Mongolia, Northern China, where up to 70% of the total area is classified as degraded steppe. The main cause of grassland degradation in Northern China is overgrazing as a result of increasing stocking rates and a static grazing management during the last 50 years. The aim of this study was to investigate the impact of intensive grazing on the stabilization processes, the amount and the spatial distribution of soil organic matter (SOM) in the grasslands of Inner Mongolia. Within the Xilin River Catchment, intensively grazed sites were compared with ungrazed experimental sites at different spatial and temporal scales. In order to determine short-term effects of intensive grazing, a controlled grazing experiment was established in 2005. Topsoil samples were taken in 2005 and again in 2008 from ungrazed (UG05), moderately grazed (MG) and heavily grazed plots (HG) and analyzed for chemical and physical soil properties. The effects of long-term grazing were investigated in detail at continuously grazed sites (CG) and compared to adjacent ungrazed sites that were fenced in 1979 (UG79). To elucidate the spatial structure of selected topsoil parameters at the field scale, 100 grid points with spacings of 5 m and 15 m were sampled. For detection of small-scale variability at the plant scale, 40 randomly selected points were sampled inside areas of 2 m × 2 m at each plot. Semivariances were calculated for the determined soil properties. To quantify the contribution of single soil fractions to total SOC stocks, a combined density and particle size fractionation was applied. Carbon mineralization was determined in an incubation experiment for a period of one month for UG79 and CG sites. Grazing exclusion led to a significant decrease of SOC in the topsoil already three years after grazing exclusion and resulted in 25-30% lower amounts after 30 years. This decrease was related to lower

  17. The impact of cattle and goats grazing on vegetation in oak stands of varying coppicing age

    NASA Astrophysics Data System (ADS)

    Papachristou, Thomas G.; Platis, Panayiotis D.

    2011-01-01

    The effects of cattle and goats grazing on oak shoot growth and herbaceous vegetation in three oak forest stands with different coppicing age (1, 4 and 7 yrs after the clear cutting) were investigated. In April 1997, an experimental area was chosen with three forest stands, which were clear cut in 1996 (CL1996), 1993 (CL1993), and 1990 (CL1990). All stands were grazed by cattle and goats after they were clear cut. In each forest stand, five 10 m × 10 m paired plots were located, which represented grazed and protected patches. Herbage biomass within protected and grazed plots was measured four times each year (spring: May-June, summer: July-August, autumn: September-October, and winter: November-December). Behavioural observations on grazing animals were conducted in the same periods. In both protected and open plots the height and basal diameter of all oak shoots on 5 preselected stumps were measured at the end of five growing periods from 1997 to 2001. All forest stands carried a similar amount of available herbage (averaged over forest stands and growing season, 2614 kg/ha). Grazing animals removed on average 1057 kg/ha throughout the growing period. Cattle mainly consumed herbage (97% of bites) while goats consumed a mixture of oak browse (41% bites), herbaceous species (34% bites), and other woody species browse (25% bites). The height, diameter and volume of oak shoots were affected by grazing. The three forest stands had similar shoot heights in the protected plots in 2001 after 5 years of grazing protection. The volume of oak shoots of the grazed plots were 146.7 cm3 for CL1996, 232.9 cm3 for CL1993, and 239.1 cm3 for CL1990 in 2001 (i.e. 5, 8, and 11 years grazing after the clear cuttings, respectively). The protected plots carried greater volumes of oak shoots, CL1996: 496.0 cm3 (few months grazing before protection), CL1993: 690.0 cm3 (4 years grazing before protection), and CL1990: 344.0 cm3 (7 years grazing before protection). In conclusion, almost

  18. Effects of Introduced Grasses, Grazing and Fire on Regional Biogeochemistry in Hawaii

    NASA Astrophysics Data System (ADS)

    Elmore, A. J.; Asner, G. P.

    2003-12-01

    African grasses introduced for grazing have expanded in geographic extent in mesic tropical systems of Hawaii and other regions of the world. Grassland expansion leads to increases in fire frequency, speeding woodland and forest destruction at greater geographic scales than occurs with grazing alone. At Pu'uwa'awa'a Ranch, Hawaii, restoration of the native woodland habitat has become a critical objective following the introduction and dominance of the African grass species Pennisetum clandestinum and P. setaceum. Grazing and grass-fueled fires have destroyed over 60% of the original forest. To stabilize these communities, managers must balance the combined effects of grazing and fire. Grazing reduces the recruitment success of native tropical trees, but grazing also reduces fire risk by moderating grass fuel conditions and restricting the extent and density of the most flammable grass species. Our study focuses on two questions: (1) What grazing intensity is necessary to change the fire conditions of a region given in situ soil and precipitation conditions? (2) Have long-term grazing conditions altered soil carbon and nitrogen stocks? We used high resolution imaging spectrometer data to measure photosynthetic and non-photosynthetic vegetation cover, analysis of soil carbon and nitrogen stocks, and measurements of plant community composition along gradients in grazing intensity. P. setaceum, the more flammable alien grass, was dominant where grazing intensity was low and at lower elevations where precipitation is low. The less flammable grass, P. clandestinum, occurred in regions of high grazing intensity and higher precipitation. Grazing influenced the dominance of P. setaceum and P. clandestinum only where precipitation and soil characteristics were suitable for both grasses to occur. At suitable sites, grazing reduced fire conditions through a species sift towards P. clandestinum. Soil carbon and nitrogen stocks decreased with grazing intensity, which was

  19. Grazing intensity differentially regulates ANPP response to precipitation in North American semiarid grasslands.

    PubMed

    Irisarri, J Gonzalo N; Derner, Justin D; Porensky, Lauren M; Augustine, David J; Reeves, Justin L; Mueller, Kevin E

    2016-07-01

    Grazing intensity elicits changes in the composition of plant functional groups in both shortgrass steppe (SGS) and northern mixed-grass prairie (NMP) in North America. How these grazing intensity-induced changes control aboveground net primary production (ANPP) responses to precipitation remains a central open question, especially in light of predicted climate changes. Here, we evaluated effects of four levels (none, light, moderate, and heavy) of long-term (>30 yr) grazing intensity in SGS and NMP on: (1) ANPP; (2) precipitation-use efficiency (PUE, ANPP : precipitation); and (3) precipitation marginal response (PMR; slope of a linear regression model between ANPP and precipitation). We advance prior work by examining: (1) the consequences of a range of grazing intensities (more grazed vs. ungrazed); and (2) how grazing-induced changes in ANPP and PUE are related both to shifts in functional group composition and physiological responses within each functional group. Spring (April-June) precipitation, the primary determinant of ANPP, was only 12% higher in NMP than in SGS, yet ANPP and PUE were 25% higher. Doubling grazing intensity in SGS and nearly doubling it in NMP reduced ANPP and PUE by only 24% and 33%, respectively. Increased grazing intensity reduced C3 graminoid biomass and increased C4 grass biomass in both grasslands. Functional group shifts affected PUE through biomass reductions, as PUE was positively associated with the relative abundance of C3 species and negatively with C4 species across both grasslands. At the community level, PMR was similar between grasslands and unaffected by grazing intensity. However, PMR of C3 graminoids in SGS was eightfold higher in the ungrazed treatment than under any grazed level. In NMP, PMR of C3 graminoids was only reduced under heavy grazing intensity. Knowing the ecological consequences of grazing intensity provides valuable information for mitigation and adaptation strategies in response to predicted climate

  20. Grazing effects on species composition in different vegetation types (La Palma, Canary Islands)

    NASA Astrophysics Data System (ADS)

    Arévalo, J. R.; de Nascimento, L.; Fernández-Lugo, S.; Mata, J.; Bermejo, L.

    2011-05-01

    Grazing management is probably one of the most extensive land uses, but its effects on plant communities have in many cases been revealed to be contradictory. Some authors have related these contradictions to the stochastic character of grazing systems. Because of that, it is necessary to implement specific analyses of grazing effects on each community, especially in natural protected areas, in order to provide the best information to managers. We studied the effects of grazing on the species composition of the main vegetation types where it takes place (grasslands, shrublands and pine forests) on the island of La Palma, Canary Islands. We used the point-quadrat intersect method to study the species composition of grazed and ungrazed areas, which also were characterized by their altitude, distance to farms, distance to settlements, year of sampling, herbaceous aboveground biomass and soil organic matter. The variables organic matter, productivity and species richness were not significantly affected by grazing. The species composition of the analyzed plant communities was affected more by variables such as altitude or distance to farms than by extensive grazing that has been traditionally carried out on the island of La Palma involving certain practices such as continuous monitoring of animals by goat keepers, medium stocking rates adjusted to the availability of natural pastures, supplementation during the dry season using local forage shrubs or mown pastures and rotating animals within grazing areas Although some studies have shown a negative effect of grazing on endangered plant species, these results cannot be freely extrapolated to the traditional grazing systems that exert a low pressure on plant communities (as has been found in this study). We consider extensive grazing as a viable way of ensuring sustainable management of the studied ecosystems.

  1. FORAGES AND PASTURES SYMPOSIUM: Improving soil health and productivity on grasslands using managed grazing of livestock.

    PubMed

    Russell, J R; Bisinger, J J

    2015-06-01

    Beyond grazing, managed grasslands provide ecological services that may offer economic incentives for multifunctional use. Increasing biodiversity of plant communities may maximize net primary production by optimizing utilization of available light, water, and nutrient resources; enhance production stability in response to climatic stress; reduce invasion of exotic species; increase soil OM; reduce nutrient leaching or loading in surface runoff; and provide wildlife habitat. Strategically managed grazing may increase biodiversity of cool-season pastures by creating disturbance in plant communities through herbivory, treading, nutrient cycling, and plant seed dispersal. Soil OM will increase carbon and nutrient sequestration and water-holding capacity of soils and is greater in grazed pastures than nongrazed grasslands or land used for row crop or hay production. However, results of studies evaluating the effects of different grazing management systems on soil OM are limited and inconsistent. Although roots and organic residues of pasture forages create soil macropores that reduce soil compaction, grazing has increased soil bulk density or penetration resistance regardless of stocking rates or systems. But the effects of the duration of grazing and rest periods on soil compaction need further evaluation. Because vegetative cover dissipates the energy of falling raindrops and plant stems and tillers reduce the rate of surface water flow, managing grazing to maintain adequate vegetative cover will minimize the effects of treading on water infiltration in both upland and riparian locations. Through increased diversity of the plant community with alterations of habitat structure, grazing systems can be developed that enhance habitat for wildlife and insect pollinators. Although grazing management may enhance the ecological services provided by grasslands, environmental responses are controlled by variations in climate, soil, landscape position, and plant community

  2. Shaping the Herders' "Mental Maps": Participatory Mapping with Pastoralists' to Understand Their Grazing Area Differentiation and Characterization.

    PubMed

    Wario, Hussein T; Roba, Hassan G; Kaufmann, Brigitte

    2015-09-01

    Understanding the perception of environmental resources by the users is an important element in planning its sustainable use and management. Pastoralist communities manage their vast grazing territories and exploit resource variability through strategic mobility. However, the knowledge on which pastoralists' resource management is based and their perception of the grazing areas has received limited attention. To improve this understanding and to document this knowledge in a way that can be communicated with 'outsiders', we adopted a participatory mapping approach using satellite imagery to explore how Borana pastoralists of southern Ethiopia differentiated and characterized their grazing areas. The Borana herders conceptualized their grazing areas as set of distinctive grazing units each having specific names and characteristics. The precise location and the borders of each grazing unit were identified on the satellite image. In naming of the grazing units, the main differentiating criteria were landforms, vegetation types, prevalence of wildlife species, and manmade features. Based on the dominant soil type, the grazing units were aggregated into seasonal grazing areas that were described using factors such as soil drainage properties, extent of woody cover, main grass species, and prevalence of ecto-parasites. Pastoralists ranking of the seasonal grazing areas according to their suitability for cattle grazing matched with vegetation assessment results on the abundance of desirable fodder varieties. Approaching grazing area differentiation from the pastoralists' perspectives improves the understanding of rangeland characteristics that pastoralists considered important in their grazing management and visualization of their mental representation in digital maps eases communication of this knowledge.

  3. Shaping the Herders' "Mental Maps": Participatory Mapping with Pastoralists' to Understand Their Grazing Area Differentiation and Characterization

    NASA Astrophysics Data System (ADS)

    Wario, Hussein T.; Roba, Hassan G.; Kaufmann, Brigitte

    2015-09-01

    Understanding the perception of environmental resources by the users is an important element in planning its sustainable use and management. Pastoralist communities manage their vast grazing territories and exploit resource variability through strategic mobility. However, the knowledge on which pastoralists' resource management is based and their perception of the grazing areas has received limited attention. To improve this understanding and to document this knowledge in a way that can be communicated with `outsiders', we adopted a participatory mapping approach using satellite imagery to explore how Borana pastoralists of southern Ethiopia differentiated and characterized their grazing areas. The Borana herders conceptualized their grazing areas as set of distinctive grazing units each having specific names and characteristics. The precise location and the borders of each grazing unit were identified on the satellite image. In naming of the grazing units, the main differentiating criteria were landforms, vegetation types, prevalence of wildlife species, and manmade features. Based on the dominant soil type, the grazing units were aggregated into seasonal grazing areas that were described using factors such as soil drainage properties, extent of woody cover, main grass species, and prevalence of ecto-parasites. Pastoralists ranking of the seasonal grazing areas according to their suitability for cattle grazing matched with vegetation assessment results on the abundance of desirable fodder varieties. Approaching grazing area differentiation from the pastoralists' perspectives improves the understanding of rangeland characteristics that pastoralists considered important in their grazing management and visualization of their mental representation in digital maps eases communication of this knowledge.

  4. Effect of grazing on plant attributes and hydrological properties in the sloping lands of the East African highlands.

    PubMed

    Taddese, Girma; Saleem, M A Mohamed; Astatke, Abyie; Ayaleneh, Wagnew

    2002-09-01

    Extending livestock grazing to the steep slopes has led to unstable grazing systems in the East African Highlands, and new solutions and approaches are needed to ameliorate the current situation. This work was aimed at studying the effect of livestock grazing on plant attributes and hydrological properties. The study was conducted from 1996 to 2000 at the International Livestock Research Institute at Debre Ziet Research Station. Two sites were selected: one at 0-4% slope, and the other at 4-8% slope. The treatments were: (1) no grazing (control); (2) light grazing, 0.6 animal unit months per hectare (aum/ha); (3) moderate grazing, 1.8 aum/ha; (4) heavy grazing, 3.0 aum/ha; (5) very heavy grazing, 4.2 aum/ha; (6) initially plowed and continuously very heavily grazed, 4.2 aum/ha. The result showed that species richness, infiltration rate, bare ground, and soil loss significantly varied with grazing pressure. Species richness was higher in grazed plots compared to nongrazed plots. Biomass yield improved on heavily grazed plots as cow dung accumulated over years. Cynodon dactylon plant species persisted with livestock grazing pressure in both sites. Infiltration rate improved and soil erosion declined in all treatments after the first year.

  5. Combined effects of climatic gradient and domestic livestock grazing on reptile community structure in a heterogeneous agroecosystem.

    PubMed

    Rotem, Guy; Gavish, Yoni; Shacham, Boaz; Giladi, Itamar; Bouskila, Amos; Ziv, Yaron

    2016-01-01

    Grazing plays an important role in shaping ecological communities in human-related ecosystems. Although myriad studies have explored the joint effect of grazing and climate on plant communities, this interactive effect has rarely been studied in animals. We hypothesized that the effect of grazing on the reptile community varies along a climatic gradient in relation to the effect of grazing on habitat characteristics, and that grazing differentially affects reptiles of different biogeographic regions. We tested our hypotheses by collecting data on environmental characteristics and by trapping reptiles in four heterogeneous landscapes experiencing differing grazing intensities and distributed along a sharp climatic gradient. We found that while reptile diversity increased with grazing intensity at the mesic end of the gradient, it decreased with grazing intensity at the arid end. Moreover, the proportion of reptile species of differing biogeographic origins varied with the interactive effect of climate and grazing. The representation of species originating in arid biogeographic zones was highest at the arid end of the climatic gradient, and representation increased with grazing intensity within this area. Regardless of the climatic context, increased grazing pressure results in a reduction in vegetation cover and thus in changes in habitat characteristics. By reducing vegetation cover, grazing increased habitat heterogeneity in the dense mesic sites and decreased habitat heterogeneity in the arid sites. Thus, our results suggest that the same direction of habitat alteration caused by grazing may have opposite effects on biodiversity and community composition in different climatic contexts.

  6. Cobb's Red Cabbage Indicator.

    ERIC Educational Resources Information Center

    Cobb, Vicki

    1998-01-01

    Describes the use of an indicator made from the pigment in red cabbage. Cabbage is grated then soaked in water. When the water is a strong red, the cabbage is strained out. The cabbage-juice indicator is then used to test for acids and bases. Includes a list of good foods to test for acidity and alkalinity. (PVD)

  7. Low frequency seabed scattering at low grazing angles.

    PubMed

    Zhou, Ji-Xun; Zhang, Xue-Zhen

    2012-04-01

    Low-frequency (LF) seabed scattering at low grazing angles (LGA) is almost impossible to directly measure in shallow water (SW), except through inversion from reverberation. The energy flux method for SW reverberation is briefly introduced in this paper. The closed-form expressions of reverberation in an isovelocity waveguide, derived from this method, indicate that in the three-halves law range interval multimode/ray sea bottom scattering with different incident and scattering angles in forming the reverberation may equivalently be represented by the bottom backscattering at a single range-dependent angle. This equivalent relationship is used to derive the bottom backscattering strength (BBS) as a function of angle and frequency. The LF&LGA BBS is derived in a frequency band of 200-2500 Hz and in a grazing angle range of 1.1°-14.0° from reverberation measurements at three sites with sandy bottoms. This is based on three previous works: (1) The closed-form expressions of SW reverberation [Zhou, (Chinese) Acta Acustica 5, 86-99 (1980)]; (2) the effective geo-acoustic model of sandy bottoms that follows the Biot model [Zhou et al., J. Acoust. Soc. Am. 125, 2847-2866 (2009)] and (3) A quality database of wideband reverberation level normalized to source level [Zhou and Zhang, IEEE J. Oceanic Eng. 30, 832-842 (2005)].

  8. Design and development of grazing incidence x-ray mirrors

    NASA Astrophysics Data System (ADS)

    Zuo, Fuchang; Mei, Zhiwu; Ma, Tao; Deng, Loulou; Shi, Yongqiang; Li, Liansheng

    2016-01-01

    X-ray pulsar navigation has attracted extensive attentions from academy and engineering domains. The navigation accuracy is can be enhanced through design of X-ray mirrors to focus X-rays to a small detector. The Wolter-I optics, originally proposed based on a paraboloid mirror and a hyperboloid mirror for X-ray imaging, has long been widely developed and employed in X-ray observatory. Some differences, however, remain in the requirements on optics between astronomical X-ray observation and pulsar navigation. The simplified Wolter-I optics, providing single reflection by a paraboloid mirror, is more suitable for pulsar navigation. In this paper, therefore, the grazing incidence X-ray mirror was designed further based on our previous work, with focus on the reflectivity, effective area, angular resolution and baffles. To evaluate the performance of the manufactured mirror, the surface roughness and reflectivity were tested. The test results show that the grazing incidence mirror meets the design specifications. On the basis of this, the reflectivity of the mirror in the working bandwidth was extrapolated to evaluate the focusing ability of the mirror when it works together with the detector. The purpose of our current work to design and develop a prototype mirror was realized. It can lay a foundation and provide guidance for the development of multilayer nested X-ray mirror with larger effective area.

  9. Fluence thresholds for grazing incidence hard x-ray mirrors

    SciTech Connect

    Aquila, A.; Ozkan, C.; Sinn, H.; Tschentscher, T.; Mancuso, A. P.; Gaudin, J.; Sobierajski, R.; Klepka, M. T.; Dłużewski, P.; Morawiec, K.; Störmer, M.; Bajt, S.; Ohashi, H.; Koyama, T.; Tono, K.; Inubushi, Y. [RIKEN and others

    2015-06-15

    X-ray Free Electron Lasers (XFELs) have the potential to contribute to many fields of science and to enable many new avenues of research, in large part due to their orders of magnitude higher peak brilliance than existing and future synchrotrons. To best exploit this peak brilliance, these XFEL beams need to be focused to appropriate spot sizes. However, the survivability of X-ray optical components in these intense, femtosecond radiation conditions is not guaranteed. As mirror optics are routinely used at XFEL facilities, a physical understanding of the interaction between intense X-ray pulses and grazing incidence X-ray optics is desirable. We conducted single shot damage threshold fluence measurements on grazing incidence X-ray optics, with coatings of ruthenium and boron carbide, at the SPring-8 Angstrom compact free electron laser facility using 7 and 12 keV photon energies. The damage threshold dose limits were found to be orders of magnitude higher than would naively be expected. The incorporation of energy transport and dissipation via keV level energetic photoelectrons accounts for the observed damage threshold.

  10. Evaporative cooling for Holstein dairy cows under grazing conditions.

    PubMed

    Valtorta, Silvia E; Gallardo, Miriam R

    2004-05-01

    Twenty-four grazing Holstein cows in mid and late lactation were randomly assigned to two treatment groups: control and cooled. The trial was performed at the Experimental Dairy Unit, Rafaela Agricultural Experimental Station (INTA), Argentina. The objective was to evaluate the effects of sprinkler and fan cooling before milkings on milk production and composition. The effects of the cooling system on rectal temperature and respiration rate were also evaluated. Cooled cows showed higher milk production (1.04 l cow(-1) day(-1)). The concentration and yield of milk fat and protein increased in response to cooling treatment. The cooling system also reduced rectal temperature and respiration rate. No effects were observed on body condition. It was concluded that evaporative cooling, which is efficient for housed animals, is also appropriate to improve yields and animal well-being under grazing systems. These results are impressive since the cooling system was utilized only before milkings, in a system where environmental control is very difficult to achieve. This trial was performed during a mild summer. The results would probably be magnified during hotter weather.

  11. Evaporative cooling for Holstein dairy cows under grazing conditions

    NASA Astrophysics Data System (ADS)

    Valtorta, Silvia E.; Gallardo, Miriam R.

    . Twenty-four grazing Holstein cows in mid and late lactation were randomly assigned to two treatment groups: control and cooled. The trial was performed at the Experimental Dairy Unit, Rafaela Agricultural Experimental Station (INTA), Argentina. The objective was to evaluate the effects of sprinkler and fan cooling before milkings on milk production and composition. The effects of the cooling system on rectal temperature and respiration rate were also evaluated. Cooled cows showed higher milk production (1.04 l cow-1 day-1). The concentration and yield of milk fat and protein increased in response to cooling treatment. The cooling system also reduced rectal temperature and respiration rate. No effects were observed on body condition. It was concluded that evaporative cooling, which is efficient for housed animals, is also appropriate to improve yields and animal well-being under grazing systems. These results are impressive since the cooling system was utilized only before milkings, in a system where environmental control is very difficult to achieve. This trial was performed during a mild summer. The results would probably be magnified during hotter weather.

  12. Milk from cows grazing on cool-season pastures provides an enhanced profile of bioactive fatty acids compared to those grazed on a monoculture of pearl millet.

    PubMed

    Bainbridge, Melissa L; Egolf, Emily; Barlow, John W; Alvez, Juan P; Roman, Joe; Kraft, Jana

    2017-02-15

    The demand for dairy products from grass-fed cows is driven, in part, by their more desirable fatty acid (FA) profile, containing more n-3 FA and conjugated linoleic acids (CLA) than conventionally produced dairy products. This study investigated the effects of pearl millet (PM) vs. cool-season pasture (CSP) on animal performance and milk FA in a grazing system. Eight Holstein dairy cows were used in a repeated measures design with four-week periods. Forage type had no effect on animal performance (estimated dry matter intake, milk production, fat, or protein). The contents of CLA and n-3 FA in a serving of whole milk (3.25% fat) increased when cows grazed CSP compared to PM. A serving of whole milk from cows grazing PM had a higher content of saturated FA and branched-chain FA. In conclusion, the contents of various bioactive FA were higher in milk fat of cows grazing a CSP compared to PM.

  13. Predicting grass dry matter intake, milk yield and milk fat and protein yield of spring calving grazing dairy cows during the grazing season.

    PubMed

    O'Neill, B F; Lewis, E; O'Donovan, M; Shalloo, L; Galvin, N; Mulligan, F J; Boland, T M; Delagarde, R

    2013-08-01

    Predicting the grass dry matter intake (GDMI), milk yield (MY) or milk fat and protein yield (milk solids yield (MSY)) of the grazing dairy herd is difficult. Decisions with regard to grazing management are based on guesstimates of the GDMI of the herd, yet GDMI is a critical factor influencing MY and MSY. A data set containing animal, sward, grazing management and concentrate supplementation variables recorded during weeks of GDMI measurement was used to develop multiple regression equations to predict GDMI, MY and MSY. The data set contained data from 245 grazing herds from 10 published studies conducted at Teagasc, Moorepark. A forward stepwise multiple regression technique was used to develop the multiple regression equations for each of the dependent variables (GDMI, MY, MSY) for three periods during the grazing season: spring (SP; 5 March to 30 April), summer (SU; 1 May to 31 July) and autumn (AU; 1 August to 31 October). The equations generated highlighted the importance of different variables associated with GDMI, MY and MSY during the grazing season. Peak MY was associated with an increase in GDMI, MY and MSY during the grazing season with the exception of GDMI in SU when BW accounted for more of the variation. A higher body condition score (BCS) at calving was associated with a lower GDMI in SP and SU and a lower MY and MSY in all periods. A higher BCS was associated with a higher GDMI in SP and SU, a higher MY in SU and AU and a higher MSY in all periods. The pre-grazing herbage mass of the sward (PGHM) above 4 cm was associated with a quadratic effect on GDMI in SP, on MY in SP and SU and on MSY in SU. An increase in daily herbage allowance (DHA) above 4 cm was associated with an increase in GDMI in AU, an increase in MY in SU and AU and MSY in AU. Supplementing grazing dairy cows with concentrate reduced GDMI and increased MY and MSY in all periods. The equations generated can be used by the Irish dairy industry during the grazing season to predict the

  14. 25 CFR 161.300 - When is a permit needed to authorize grazing use?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false When is a permit needed to authorize grazing use? 161.300 Section 161.300 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Permit Requirements § 161.300 When is a permit needed to authorize...

  15. 36 CFR 222.3 - Issuance of grazing and livestock use permits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... written permit. (H) Paid permits to holders of grazing permits for breeding animals used to service... prior to the end of ten years, or it will be in the best interest of sound land management to specify a... capacity exists to graze specified numbers of animals. (ii) A term permit holder has first priority...

  16. 36 CFR 222.3 - Issuance of grazing and livestock use permits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... written permit. (H) Paid permits to holders of grazing permits for breeding animals used to service... prior to the end of ten years, or it will be in the best interest of sound land management to specify a... capacity exists to graze specified numbers of animals. (ii) A term permit holder has first priority...

  17. 36 CFR 222.3 - Issuance of grazing and livestock use permits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... written permit. (H) Paid permits to holders of grazing permits for breeding animals used to service... prior to the end of ten years, or it will be in the best interest of sound land management to specify a... capacity exists to graze specified numbers of animals. (ii) A term permit holder has first priority...

  18. 36 CFR 222.3 - Issuance of grazing and livestock use permits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... written permit. (H) Paid permits to holders of grazing permits for breeding animals used to service... prior to the end of ten years, or it will be in the best interest of sound land management to specify a... capacity exists to graze specified numbers of animals. (ii) A term permit holder has first priority...

  19. 36 CFR 222.3 - Issuance of grazing and livestock use permits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... written permit. (H) Paid permits to holders of grazing permits for breeding animals used to service... prior to the end of ten years, or it will be in the best interest of sound land management to specify a... capacity exists to graze specified numbers of animals. (ii) A term permit holder has first priority...

  20. Linking pasture and animal processes. Grazing few hours during the afternoon and evening

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cattle instinctively concentrate grazing during dusk, when pasture is more nutritive. Afternoon allocations of fresh pasture (PM) increase duration and intensity of dusk grazing bouts and consequently pasture intake at that time of day, which certainly has demonstrated to improve animal performance ...

  1. 36 CFR 222.53 - Grazing fees in the East-noncompetitive procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... livestock grazing use and occupancy on National Forest System (NFS) lands in the States of New York..., fair market value procedures. These rules do not apply to grazing fees on National Forest System lands... permittees in the Eastern and Southern Regions on National Forest System lands, including...

  2. Evidence targeted grazing benefits to invaded rangelands can increase over extended time frames

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prescribed grazing uses livestock to address rangeland management issues such as woody plant encroachment, accumulations of flammable biomass and exotic weed invasions. Invasive weed responses to prescribed grazing have proven variable. For instance, a given livestock species can sharply reduce ab...

  3. Targeted grazing of white locoweed: Short-term effects of herbivory regime on vegetation and sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White locoweed (Oxytropis sericea Nuttall) and non-target vegetation response to two years of targeted grazing by sheep, one treatment of picloram plus 2, 4-D (HER) or no treatment (CON) were compared. Serum of sheep that grazed locoweed intermittently (IGZ, five days on locoweed followed by three d...

  4. Grassland fire and cattle grazing regulate reptile and amphibian assembly among patches.

    PubMed

    Larson, Danelle M

    2014-12-01

    Fire and grazing are common management schemes of grasslands globally and are potential drivers of reptilian and amphibian (herpetofauna) metacommunity dynamics. Few studies have assessed the impacts of fire and cattle grazing on herpetofauna assemblages in grasslands. A patch-burn grazing study at Osage Prairie, MO, USA in 2011-2012 created landscape patches with treatments of grazing, fire, and such legacies. Response variables were measured before and after the application of treatments, and I used robust-design occupancy modeling to estimate patch occupancy and detection rate within patches, and recolonization and extinction (i.e., dispersal) across patches. I conducted redundancy analysis and a permuted multivariate analysis of variance to determine if patch type and the associated environmental factors explained herpetofauna assemblage. Estimates for reptiles indicate that occupancy was seasonally constant in Control patches (ψ ~ 0.5), but declined to ψ ~ 0.15 in patches following the applications of fire and grazing. Local extinctions for reptiles were higher in patches with fire or light grazing (ε ~ 0.7) compared to the controls. For the riparian herpetofaunal community, patch type and grass height were important predictors of abundance; further, the turtles, lizards, snakes, and adult amphibians used different patch types. The aquatic amphibian community was predicted by watershed and in-stream characteristics, irrespective of fire or grazing. The varying responses from taxonomic groups demonstrate habitat partitioning across multiple patch types undergoing fire, cattle grazing, and legacy effects. Prairies will need an array of patch types to accommodate multiple herpetofauna species.

  5. Crop yields and soil organic matter responses to sheep grazing in US northern Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep (Ovis aries L.) grazing, a cost-effective method of controlling weeds compared to herbicide application and tillage, may influence soil C and N levels by consuming plant residue and returning feces and urine to the soil. Little is known about the effect of sheep grazing on soil C and N storage...

  6. Net greenhouse gas emissions affected by sheep grazing under dryland cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep grazing to control weeds during fallow may influence greenhouse gas (GHG) emissions by consuming crop residue and returning feces and urine to the soil. We evaluated the effect of sheep grazing compared to herbicide application for weed control on soil temperature and water content at the 0- t...

  7. Soil greenhouse gas emissions affected by sheep grazing under dryland cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep grazing to control weeds during fallow may influence soil greenhouse gas (CO2, N2O, and CH4) emissions by consuming crop residue and returning feces and urine to the soil. An experiment was conducted to evaluate the effect of sheep grazing compared to herbicide application on soil temperature ...

  8. Runoff water quality from manured riparian grasslands with contrasting soil drainage and simulated grazing pressure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Globally, management of grazed riparian areas is of critical importance in terms of agricultural sustainability and environmental quality. However, the potential impacts of riparian grazing management on water quality are not well documented, particularly in the southeastern USA. The objective of ...

  9. Biogeochemical and ecological impacts of livestock grazing in semi-arid southeastern Utah, USA

    USGS Publications Warehouse

    Fernandez, D.P.; Neff, J.C.; Reynolds, R.L.

    2008-01-01

    Relatively few studies have examined the ecological and biogeochemical effects of livestock grazing in southeastern Utah. In this study, we evaluated how grazing has affected soil organic carbon and nitrogen to a depth of 50 cm in grasslands located in relict and actively-grazed sites in the Canyonlands physiographic section of the Colorado Plateau. We also evaluated differences in plant ground cover and the spatial distribution of soil resources. Results show that areas used by domestic livestock have 20% less plant cover and 100% less soil organic carbon and nitrogen compared to relict sites browsed by native ungulates. In actively grazed sites, domestic livestock grazing also appears to lead to clustered, rather than random, spatial distribution of soil resources. Magnetic susceptibility, a proxy for soil stability in this region, suggests that grazing increases soil erosion leading to an increase in the area of nutrient-depleted bare ground. Overall, these results, combined with previous studies in the region, suggest that livestock grazing affects both plant cover and soil fertility with potential long-term implications for the sustainability of grazing operations in this semi-arid landscape. ?? 2007 Elsevier Ltd. All rights reserved.

  10. Sheep Grazing Effect on Dryland Soil Properties and Wheat Yield in the Wheat-Fallow System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep (Ovis aries L.) grazing during fallow is an effective method of controlling weeds and pests in the wheat (Triticum aestivum L.)-fallow system. Little is known about the effect of sheep grazing on dryland soil properties and wheat yield. We evaluated the effects of fallow management for weed co...

  11. Sheep grazing to manage crop residues, insects and weeds in Northern Plains grain and alfalfa systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep are traditionally produced on rangelands or pasture forages and supplemented during winter with harvested feeds. In recent years, sheep producers have made great strides using commercial-scale grazing on native rangelands to control noxious weeds and excess fire fuels. Incorporating grazing in...

  12. Sheep Grazing in the Wheat-Fallow System Affects Dryland Soil Properties and Grain Yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep (Ovis aries L.) grazing during fallow is an effective method of controlling weeds and pests in the wheat (Triticum aestivum L.)-fallow system. Little is known about the effect of sheep grazing on dryland soil properties and wheat yield. We evaluated the effects of fallow management for weed co...

  13. Dryland Soil Carbon and Nitrogen Influenced by Sheep Grazing in the Wheat-Fallow System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep (Ovis aries L.) grazing during fallow for weed control in wheat (Triticum aestivum L.)-fallow systems may influence soil C and N levels and grain yields by returning part of consumed crop residue to the soil through feces and urine. We evaluated the effects of fallow management [sheep grazing ...

  14. 43 CFR 2091.7-2 - Segregative effect and opening: Taylor Grazing Act.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Segregative effect and opening: Taylor Grazing Act. 2091.7-2 Section 2091.7-2 Public Lands: Interior Regulations Relating to Public Lands... Grazing Act. Lands classified under section 7 of the Act of June 28, 1934, as amended (43 U.S.C....

  15. 43 CFR 9264.2 - Grazing administration-Alaska; livestock. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing administration-Alaska; livestock. 9264.2 Section 9264.2 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF... Management § 9264.2 Grazing administration—Alaska; livestock....

  16. 43 CFR 2091.9-3 - Lands in Alaska under grazing lease.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Lands in Alaska under grazing lease. 2091.9-3 Section 2091.9-3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU... Segregation and Opening of Lands § 2091.9-3 Lands in Alaska under grazing lease. The segregation and...

  17. 76 FR 77769 - North Finger Grazing Authorization Project, Malheur National Forest, Grant County, OR

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... Forest Service North Finger Grazing Authorization Project, Malheur National Forest, Grant County, OR... environmental effects on a proposed action to authorize grazing on all or portions of allotments within the..., Lower Fox Creek, Upper Fox Creek, and Upper Cottonwood Creek subwatersheds. The North Finger...

  18. 43 CFR 9264.3 - Grazing administration-Alaska; reindeer. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Grazing administration-Alaska; reindeer. 9264.3 Section 9264.3 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF... Management § 9264.3 Grazing administration—Alaska; reindeer....

  19. 25 CFR 166.215 - How can I find Indian land available for grazing?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false How can I find Indian land available for grazing? 166.215 Section 166.215 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Permit Requirements Obtaining A Permit § 166.215 How can I find Indian land available for...

  20. 25 CFR 166.215 - How can I find Indian land available for grazing?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false How can I find Indian land available for grazing? 166.215 Section 166.215 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Permit Requirements Obtaining A Permit § 166.215 How can I find Indian land available for...

  1. Riparian land-use and stream bank erosion within grazed pastures in southern Iowa, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian land-uses such as cropping and grazing are major agricultural practices that have impacts on stream bank erosion. The aim of this study is to assess the effects of riparian land use considered in both field and catchment scale on stream bank erosion within grazed riparian pasture sites in t...

  2. Semiarid rangeland is resilient to summer fire and post-fire grazing utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1. Most wildfires occur during summer in the northern hemisphere, the area burned annually is increasing, and fire effects during this season are least understood. Livestock grazing is a primary use of rangelands affected by wildfire, but post-fire grazing management is not well-supported with dat...

  3. EFFECTS OF INTENSE, SHORT-DURATION GRAZING ON MICROTOPOGRAPHY IN A CHIHUAHUAN DESERT GRASSLAND

    EPA Science Inventory

    We measured the effects of short-term intense grazing by domestic cattle on the microtopography of a black-grama grass (Bouteloua eriopoda) dominated desert grassland. Plots were grazed during winter or summer for 24-36 hours by 20-40 yearlings in 1995 and 1996. Soil microtopogra...

  4. Patch burn grazing management and grassland bird habitat in shortgrass steppe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Combining prescribed fire and grazing management has been recommended as a tool to generate a heterogeneous vegetation mosaic for grassland birds. Past studies addressing this interaction of fire and grazing have primarily focused on tallgrass prairies of the eastern Great Plains, while less is know...

  5. Sheep grazing enhances coarse relative to microbial organic carbon in dryland cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A cost-effective method of weed control compared with herbicide application and tillage is sheep (Ovis aries L.) grazing which may influence soil C fractions by consuming crop residue and weeds and returning C through feces and urine to the soil. Little is known about the effect of sheep grazing on ...

  6. Vegetation selection by Angus crossbred vs. Raramuri Criollo nursing cows grazing Chihuauan Desert rangeland in summer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined vegetation selection patterns of nursing Angus X Hereford crossbred (AH) and Raramuri Criollo (RC) cows grazing Chihuahuan Desert vegetation during the growing season. Eleven cows of each group grazed separately in two large pastures (1190ha, 1165ha) from mid-July until mid-August 2015 (...

  7. Cattle grazing and small mammals on the Sheldon National Wildlife Refuge, Nevada

    USGS Publications Warehouse

    Oldemeyer, John L.; Allen-Johnson, L. R.

    1988-01-01

    We studied effects of cattle grazing on small mammal microhabitat and abundance in northwestern Nevada. Abundance, diversity, and microhabitat were compared between a 375-ha cattle exclosure and a deferred-rotation grazing allotment which had a three-year history of light to moderate use. No consistent differences were found in abundance, diversity, or microhabitat between the two areas.

  8. Effects of buffer strips and grazing management on soil loss from pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intensive grazing pressure can cause soil erosion from pastures causing increased sediment loading to aquatic systems. The objectives of this work were to determine the long-term effects of grazing management and buffer strips on soil erosion from pastures fertilized with broiler litter. Field stud...

  9. Population dynamics of a monocarpic thistle: simulated effects of reproductive timing and grazing of flowering plants

    NASA Astrophysics Data System (ADS)

    Ramula, Satu

    2008-03-01

    In monocarpic plants, which die after flowering once, the timing of reproduction plays an important role. The optimal time for reproduction is when reproductive output and survival are maximized. This optimum may be altered by herbivores that consume reproductive plants of different sizes disproportionally. I examined plant survival, flowering probability, reproductive output and the probability of becoming grazed in relation to plant size in two populations of the short-lived monocarpic herb Cirsium palustre. Moreover, I simulated the consequences of changes in reproductive timing and grazing preference for population dynamics. Plant survival, flowering probability and reproductive output tended to increase with plant size, whereas the probability of becoming grazed was unaffected by plant size. According to the stochastic simulations, intense grazing would have been required to significantly reduce the stochastic population growth rate (log λs) and therefore, the observed levels of grazing had no impact on log λs in the study populations. Stochastic simulations conducted with selective grazing focusing on either early or late flowering plants and with different reproductive timings revealed that the grazing of early flowering plants had a constant effect on log λs despite the proportions of early and late flowering plants in the population, suggesting that there is no optimal time for reproduction. The grazing of late flowering plants reduced log λs with delayed reproduction, favouring reproduction early in the life cycle.

  10. Community responses of arthropods to a range of traditional and manipulated grazing in shortgrass steppe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock grazing has context-dependent impacts on grassland plant and animal communities. In grassland ecosystems that have evolved with large herbivores, such as the North American Great Plains with bison (Bison bison), responses of plants to grazing are better understood, and more predictable, th...

  11. Grassland Fire and Cattle Grazing Regulate Reptile and Amphibian Assembly Among Patches

    NASA Astrophysics Data System (ADS)

    Larson, Danelle M.

    2014-12-01

    Fire and grazing are common management schemes of grasslands globally and are potential drivers of reptilian and amphibian (herpetofauna) metacommunity dynamics. Few studies have assessed the impacts of fire and cattle grazing on herpetofauna assemblages in grasslands. A patch-burn grazing study at Osage Prairie, MO, USA in 2011-2012 created landscape patches with treatments of grazing, fire, and such legacies. Response variables were measured before and after the application of treatments, and I used robust-design occupancy modeling to estimate patch occupancy and detection rate within patches, and recolonization and extinction (i.e., dispersal) across patches. I conducted redundancy analysis and a permuted multivariate analysis of variance to determine if patch type and the associated environmental factors explained herpetofauna assemblage. Estimates for reptiles indicate that occupancy was seasonally constant in Control patches ( ψ ~ 0.5), but declined to ψ ~ 0.15 in patches following the applications of fire and grazing. Local extinctions for reptiles were higher in patches with fire or light grazing ( ɛ ~ 0.7) compared to the controls. For the riparian herpetofaunal community, patch type and grass height were important predictors of abundance; further, the turtles, lizards, snakes, and adult amphibians used different patch types. The aquatic amphibian community was predicted by watershed and in-stream characteristics, irrespective of fire or grazing. The varying responses from taxonomic groups demonstrate habitat partitioning across multiple patch types undergoing fire, cattle grazing, and legacy effects. Prairies will need an array of patch types to accommodate multiple herpetofauna species.

  12. Case study: dairies utilizing ultra-high stock density grazing in the northeast

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ultra-high stock density (UHSD) grazing (also loosely referred to as ‘mob grazing’) has attracted a lot of attention and press in the forage industry. Numerous anecdotal articles can be found in trade magazines that promote the perceived benefits of UHSD grazing. However, there is little credible re...

  13. Using Social Media to Discover Public Values, Interests, and Perceptions about Cattle Grazing on Park Lands

    NASA Astrophysics Data System (ADS)

    Barry, Sheila J.

    2014-02-01

    In the western United States, livestock grazing often co-exists with recreation, cultural resource management and biodiversity protection on federal and state protected rangelands as well as on many local government open space areas. While the value of livestock grazing for managing rangeland vegetation to reduce fire fuel loads and improve wildlife habitat is increasingly recognized by resource management professionals, public concerns, and conflict between recreationist and livestock have led to reductions in public land grazing. Traditional public input methods yield a constrained picture of people's attitudes toward cows and public land grazing. Public meetings, hearings, and surveys, the most commonly used mechanisms for public land managers to solicit public opinion, tend to foster participation of organized special interests or, in the case of surveys, focus on a specific topic. General public input is limited. This study explored the use of personal photography in social media to gain insight into public perceptions of livestock grazing in public spaces. Key findings of this study include that many recreationist in grazed San Francisco Bay Area parks shared views, interests, and concerns about cows and grazing on the photo-sharing website, FlickrTM that seldom show up at a public meeting or in surveys. Results suggest that social media analysis can help develop a more nuanced understanding of public viewpoints useful in making decisions and creating outreach and education programs for public grazing lands. This study demonstrates that using such media can be useful in gaining an understanding of public concerns about natural resource management.

  14. Using NDVI to estimate carbon fluxes from small rotationally grazed pastures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Satellite-based Normalized Difference Vegetation Index (NDVI) data have been extensively used for estimating gross primary productivity (GPP) and yield of grazing lands throughout the world. However, the usefulness of satellite-based images for monitoring rotationally-grazed pastures in the northea...

  15. Do shrubs reduce the adverse effects of grazing on soil properties?

    USGS Publications Warehouse

    Eldridge, David J.; Beecham, Genevieve; Grace, James B.

    2015-01-01

    Increases in the density of woody plants are a global phenomenon in drylands, and large aggregations of shrubs, in particular, are regarded as being indicative of dysfunctional ecosystems. There is increasing evidence that overgrazing by livestock reduces ecosystem functions in shrublands, but that shrubs may buffer the negative effects of increasing grazing. We examined changes in water infiltration and nutrient concentrations in soils under shrubs and in their interspaces in shrublands in eastern Australia that varied in the intensity of livestock grazing. We used structural equation modelling to test whether shrubs might reduce the negative effects of overgrazing on infiltration and soil carbon and nitrogen (henceforth ‘soil nutrients’). Soils under shrubs and subject to low levels of grazing were more stable and had greater levels of soil nutrients. Shrubs had a direct positive effect on soil nutrients; but, grazing negatively affected nutrients by increasing soil bulk density. Structural equation modelling showed that shrubs had a direct positive effect on water flow under ponded conditions but also enhanced water flow, indirectly, through increased litter cover. Any positive effects of shrubs on water flow under low levels of grazing waned at high levels of grazing. Our results indicate that shrubs may reduce the adverse effects of grazing on soil properties. Specifically, shrubs could restrict access to livestock and therefore protect soils and plants beneath their canopies. Low levels of grazing are likely to ensure the retention of soil water and soil carbon and nitrogen in shrubland soils.

  16. Acoustic monitoring system to quantify ingestive behavior of free-grazing cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods to estimate intake in grazing livestock include using markers, visual observation, mechanical sensors that respond to jaw movement and acoustic recording. In most of the acoustic monitoring studies, the microphone is inverted on the forehead of the grazing livestock and the skull is utilize...

  17. 36 CFR 222.53 - Grazing fees in the East-noncompetitive procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Subpart A of this part; and to any allotments advertised for competitive bidding which were not bid on... allotments created after the effective date of this rule shall be offered on a competitive bid basis as..., where sufficient market data exist, may establish the base grazing value for grazing allotments...

  18. INTERACTIONS BETWEEN NUTRIENTS,PHYTOPLANKTON GROWTH AND MICROZOOPLANKTON GRAZING RATES IN A GULF OF MEXICO ESTUARY

    EPA Science Inventory

    Juhl, Andrew R. and Michael C. Murrell. Submitted. Phytoplankton Growth and Microzooplankton Grazing in a Gulf of Mexico Estuary. Aquat. Microb. Ecol. 38(1): 147-156, 2005.(ERL,GB 1214).

    Dilution grazing experiments were conducted on 9 dates over a 16-month period in Sant...

  19. Grazing intensity differentially regulates ANPP response to precipitation in North American semiarid grasslands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grazing intensity elicits changes in the composition of plant functional groups in both short-grass steppe (SGS) and northern mixed-grass prairie (NMP) in North America. How these grazing intensity-induced changes control aboveground net primary production (ANPP) responses to precipitation remains a...

  20. POTENTIAL GRAZING IMPACT TO WATER QUALITY IN THE WESTERN UNITED STATES

    EPA Science Inventory

    Grazing is a widespread stressor on ecosystems in the western United States. As part of the US EP A's Western Environmental Monitoring and Assessment Program (EMAP), the potential for grazing impacts to surface water quality was modeled using commonly available data in a Geograph...

  1. DEMONSTRATION OF POTENTIAL GRAZING IMPACT TO WATER QUALITY IN THE WESTERN UNITED STATES

    EPA Science Inventory

    Grazing is a widespread stressor on ecosystems in the western United States. As part of the US EPA's Western Environmental Monitoring and Assessment Program (EMAP), the potential for grazing impacts to surface water quality was modeled using commonly available data in a Geograph...

  2. Grasshopper responses to fire and postfire grazing in the northern Great Plains vary among species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rangeland management practices such as burning and grazing management may affect grasshopper populations by impacting development, survival and reproduction. Experiments are lacking in the northern Great Plains examining the effects of fire and grazing intensity on grasshoppers. As part of a larger ...

  3. Invisible grazings and dangerous bifurcations in impacting systems: the problem of narrow-band chaos.

    PubMed

    Banerjee, Soumitro; Ing, James; Pavlovskaia, Ekaterina; Wiercigroch, Marian; Reddy, Ramesh K

    2009-03-01

    We discovered a narrow band of chaos close to the grazing condition for a simple soft impact oscillator. The phenomenon was observed experimentally for a range of system parameters. Through numerical stability analysis, we argue that this abrupt onset to chaos is caused by a dangerous bifurcation in which two unstable period-3 orbits, created at "invisible" grazings, take part.

  4. Bridging the management-science partnership gap: Adaptive grazing management experiment in shortgrass steppe

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Adaptive Grazing Management experiment (2013-2023) in shortgrass steppe of Colorado addresses a critical gap in grazing management: lack of management-science partnerships to more fully understand the effect of management decisions for multiple ecosystem goods and services at ranch-scales. A Sta...

  5. Using social media to discover public values, interests, and perceptions about cattle grazing on park lands.

    PubMed

    Barry, Sheila J

    2014-02-01

    In the western United States, livestock grazing often co-exists with recreation, cultural resource management and biodiversity protection on federal and state protected rangelands as well as on many local government open space areas. While the value of livestock grazing for managing rangeland vegetation to reduce fire fuel loads and improve wildlife habitat is increasingly recognized by resource management professionals, public concerns, and conflict between recreationist and livestock have led to reductions in public land grazing. Traditional public input methods yield a constrained picture of people's attitudes toward cows and public land grazing. Public meetings, hearings, and surveys, the most commonly used mechanisms for public land managers to solicit public opinion, tend to foster participation of organized special interests or, in the case of surveys, focus on a specific topic. General public input is limited. This study explored the use of personal photography in social media to gain insight into public perceptions of livestock grazing in public spaces. Key findings of this study include that many recreationist in grazed San Francisco Bay Area parks shared views, interests, and concerns about cows and grazing on the photo-sharing website, Flickr(TM) that seldom show up at a public meeting or in surveys. Results suggest that social media analysis can help develop a more nuanced understanding of public viewpoints useful in making decisions and creating outreach and education programs for public grazing lands. This study demonstrates that using such media can be useful in gaining an understanding of public concerns about natural resource management.

  6. 25 CFR 166.306 - Can the BIA adjust the grazing capacity?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Can the BIA adjust the grazing capacity? 166.306 Section... Land and Operations Management § 166.306 Can the BIA adjust the grazing capacity? Yes. In consultation... capacity using the best evaluation method(s) relevant to the ecological region....

  7. 25 CFR 166.306 - Can the BIA adjust the grazing capacity?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Can the BIA adjust the grazing capacity? 166.306 Section... Land and Operations Management § 166.306 Can the BIA adjust the grazing capacity? Yes. In consultation... capacity using the best evaluation method(s) relevant to the ecological region....

  8. 25 CFR 166.306 - Can the BIA adjust the grazing capacity?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Can the BIA adjust the grazing capacity? 166.306 Section... Land and Operations Management § 166.306 Can the BIA adjust the grazing capacity? Yes. In consultation... capacity using the best evaluation method(s) relevant to the ecological region....

  9. 25 CFR 161.100 - Do tribal laws apply to grazing permits?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Do tribal laws apply to grazing permits? 161.100 Section 161.100 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.100 Do tribal laws apply...

  10. 25 CFR 161.100 - Do tribal laws apply to grazing permits?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Do tribal laws apply to grazing permits? 161.100 Section 161.100 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.100 Do tribal laws apply...

  11. 25 CFR 161.100 - Do tribal laws apply to grazing permits?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Do tribal laws apply to grazing permits? 161.100 Section 161.100 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.100 Do tribal laws apply...

  12. MICROTOPOGRAPHY AND GRAZING IN DESERT RANGE LAND: A LESSON IN STATISTICS VERSUS REALITY IN THE FIELD

    EPA Science Inventory

    This presentation summarizes two experiments on the effects of grazing on soil microtopography in a Chihuahuan Desert rangeland. In the first experiment, we measured the effect of three consecutive years of short duration <48 hours per year) intense grazing (20--40 yearling cows ...

  13. Soil water response to slope aspect and grazing in silvopasture during drought

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Silvopasture is receiving increasing attention as a robust management system for production of forage for livestock grazing on the diverse landscapes of the Appalachian region. Little knowledge about soil water response to slope aspect and grazing pressure in silvopasture systems of the Region is a...

  14. Heifer body weight gain and reproductive achievement in response to protein and energy supplementation while grazing dormant range forage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Heifers grazing winter range require supplemental nutrients to compliment dormant forage to achieve optimal growth and performance. A study was conducted to evaluate nutritional environment and effect of different supplementation strategies for developing heifers grazing dormant winter range. Eigh...

  15. The impact of grazing on plant fractal architecture and fitness of a mediterranean shrub (Anthyllis cytisoidesL.)

    USGS Publications Warehouse

    Escos, J.; Alados, C.L.; Emlen, J.M.

    1997-01-01

    1. We examined natural grazing by livestock (sheep and goats) on Albaida Anthyllis cytisoides L. with the aim of determining whether variation in the allometric relationships between plant parts provides a sensitive indicator of the impact of grazing.2. The intra-individual variation in translatory symmetry with scale and increased complexity of fractal structures reflect environmental disturbance under heavy grazing pressure and lack of grazing.3. Fitness consequences of grazing were also investigated. Grazing promotes growth and adult survival, and a drop in seed production as a consequence of consumption. In spite of that, total inclusive fitness (population rate of change) tends to increase with grazing.4. Moderate grazing, while promoting growth, also enhances stability of vegetative structures. The favourable effect of moderate levels of herbivory on A. cytisoides is reflected in the homeostatic maintenance of its translatory symmetry and in the increased complexity of its fractal structures.

  16. 25 CFR 166.411 - Will a permittee be notified when a grazing rental payment is due?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Rental Payments... schedule of rental payments agreed to by the parties. We will issue an invoice to the permittee 30 to...

  17. Dairy cows increase ingestive mastication and reduce ruminative chewing when grazing chicory and plantain.

    PubMed

    Gregorini, P; Minnee, E M K; Griffiths, W; Lee, J M

    2013-01-01

    Although the nutritive value of chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.) has been thoroughly studied, little is known about the grazing behavior of cattle feeding on chicory and plantain swards. The objective of the present study was to assess and describe the grazing behavior of dairy cows as affected by dietary proportions of chicory and plantain fed as monocultures for part of the day. Ninety Holstein-Friesian cows (489±42 kg of body weight; 4.1±0.3 body condition score, and 216±15 d in milk) were randomly assigned to 15 groups (6 cows per group) and grazed according to 7 treatments: control (CTL, 3 groups), perennial ryegrass (Lolium perenne L.) dominant sward (24-h pasture strip); 3 chicory treatments comprising 20, 40, and 60% of the diet, strip-grazing a monoculture of chicory to a fixed postgrazing residual before strip-grazing a perennial ryegrass dominant sward (2 groups of cows per treatment); and 3 plantain treatments comprising 20, 40, and 60% of the diet, strip-grazing a monoculture of plantain to a fixed postgrazing residual before strip-grazing a perennial ryegrass dominant sward (2 groups of cows per treatment). Four focal animals per group were equipped with 3-dimensional motion sensors, which provided the number of steps taken at each minute of the day. These cows were also fitted with automatic jaw-movement recorders that identified bites, mastication during ingestion, chewing during rumination, and determined grazing, rumination and idling times and bouts. Daily grazing time and bouts were not affected by treatments but rumination time differed and was reduced by up to 90 min when cows were allocated to chicory and plantain as 60% of their diet. Ruminative chewing was reduced in cows grazing chicory and plantain by up to 20% in cows allocated to the 60% treatments. Compared with perennial ryegrass, as the dietary proportion of chicory and plantain increased, cows spent more time idling and less time ruminating

  18. Limb profiles of the Moon from grazing occultation observations collected at RGO

    NASA Astrophysics Data System (ADS)

    Soma, Mitsuru; Kato, Yuji

    2002-09-01

    From lunar grazing occultation observations it is shown that the present lunar limb profile data have sometimes large errors, and therefore it is apparent that they need to be modified. For that purpose observations of grazing occultations collected at the Royal Greenwich Observatory until 1980 were analyzed and lunar limb profile data were obtained. As a result the number of the luanr limb profile data obtained from grazing occultations was almost doubled. These profile data are being used for the predictions of lunar grazing occultations in order to locate observers at better positions, so that they can also get good grazing occultation data to improve the lunar limb profiles. These profile data will be used in the future analyses of solar eclipse observations and of the possible errors of the Hipparcos proper motion system.

  19. Molecular-based analysis of changes in indigenous milk microflora during the grazing period.

    PubMed

    Hagi, Tatsuro; Kobayashi, Miho; Nomura, Masaru

    2010-01-01

    Variations in milk microflora caused by changes in the cow feeding environment (from inside to outside grazing) were analyzed using a molecular-based approach comprising denaturing gradient gel electrophoresis and real-time PCR. After 8 d of outside grazing, changes in milk microflora were observed. Denaturing gradient gel electrophoresis analysis showed that the predominant bacterial group in the milk belonged to the Lactobacillus species during the experimental period, whereas the genus Staphylococcus gained in numbers during the outside grazing period in addition to Lactobacillus. To investigate the quantitative dynamics of staphylococci, real-time PCR was performed using staphylococcal-specific primers. Real-time PCR analysis revealed that the population of staphylococci increased during the outside grazing period. Our combined denaturing gradient gel electrophoresis and real-time PCR approach enables precise monitoring of the dynamics of both total bacteria and specific bacterial species in milk. Our results provide information on grazing management and the manufacture of dairy products.

  20. Effect of grazing flow on steady-state resistance of isolated square-edged orifices

    NASA Technical Reports Server (NTRS)

    Rogers, T.

    1976-01-01

    Steady state diagnostic testing of an isolated orifice has shown the nature of the interaction between grazing and orifice flow causing the large increase in orifice resistance for both inflow and outflow. A simple inviscid interaction model is developed which uses thin aerofoil theory to account for pressure forces exerted at the interface between the orifice and grazing flow together with a one-dimensional discharge coefficient concept. The effect of grazing flow boundary layer thickness is also included in the model. Resistance measurements for each orifice tested, over a wide range of grazing flow speeds and flow rates, collapse into a single curve when plotted in terms of effective discharge coefficient against orifice to grazing velocity ratio. The correlation curves for inflow and outflow are different. Data for clustered orifices collapse in the same way as those for the single orifice. The effect of boundary layer thickness is compared with model predictions.

  1. Visual study of the effect of grazing flow on the oscillatory flow in a resonator orifice

    NASA Technical Reports Server (NTRS)

    Baumeister, K. J.; Rice, E. J.

    1975-01-01

    Grazing flow and oscillatory flow in an orifice were studied in a plexiglass flow channel with a single side branch Helmholtz resonator using water as the fluid medium. An oscillatory flow was applied to the resonatory cavity, and color dyes were injected in both the orifice and the grazing flow field to record the motion of the fluid. The flow regimes associated with linear and nonlinear (high sound pressure level) impedances with and without grazing flows were recorded by a high-speed motion-picture camera. Appreciable differences in the oscillatory flow field were seen in the various flow regimes. With high grazing flows, the outflow and inflow from the resonator cavity are found to be asymmetric. The visual study confirms that jet energy loss during flow into a resonator cavity is much larger than the loss for ejection from the cavity into the grazing flow. For inflow into the resonator cavity, the effective orifice area was significantly reduced.

  2. High Red Blood Cell Count

    MedlinePlus

    Symptoms High red blood cell count By Mayo Clinic Staff A high red blood cell count is an increase in oxygen-carrying cells in your bloodstream. Red blood cells transport oxygen from your lungs to tissues throughout ...

  3. Effect of grazing on vegetation and soil of the heuweltjieveld in the Succulent Karoo, South Africa

    NASA Astrophysics Data System (ADS)

    Schmiedel, Ute; Röwer, Inga Ute; Luther-Mosebach, Jona; Dengler, Jürgen; Oldeland, Jens; Gröngröft, Alexander

    2016-11-01

    We asked how historical and recent grazing intensity affect the patchy landscape of the heuweltjieveld in the semi-arid biodiversity hotspot Succulent Karoo. The study was carried out on a communal farmland 80 km south-west of Springbok, in Namaqualand. Heuweltjies are roughly circular earth mounds that are regularly distributed in this landscape. We sampled plant species and life-form composition, diversity measures, habitat and soil variables in 100 m2 plots, placed in three visually distinguishable heuweltjie zones (centre, fringe, and matrix) and distributed across grazing camps with different recent and historic grazing intensities. Differences between heuweltjie zones were assessed with ANOVAs and multiple linear regressions. The effect of past and recent grazing intensity on soil and plant variables was analysed by Generalized Linear Models for each heuweltjie zone separately. The three zones constituted clearly distinguishable units in terms of vegetation and soil characteristics. Soil pH and cover of annual plants increased from matrix to centres, while total vegetation cover, species richness and perennial plant cover decreased in the same direction. Historic (pre-2000) grazing patterns had the strongest effects on fringes, showing the strongest soil and vegetation-related signs of overutilization with increased stocking density. Centres showed signs of overutilization irrespective of the stocking density. The much shorter exposure to recent grazing pattern (post-2000), which was nearly inverse to the historic grazing pattern, showed increase of vegetation cover (centres) and species richness (matrix) with recent grazing intensity. We interpret these effects as still visible responses of the lower grazing intensity in these camps during the historic period. No recovery under recent grazing was observed at any of the zones. We conclude that irrespective of their conducive growing conditions, once transformed to a disturbed state, heuweltjie centres recover

  4. Grazing responses in herbs in relation to herbivore selectivity and plant traits in an alpine ecosystem.

    PubMed

    Evju, Marianne; Austrheim, Gunnar; Halvorsen, Rune; Mysterud, Atle

    2009-08-01

    Herbivores shape plant communities through selective foraging. However, both herbivore selectivity and the plant's ability to tolerate or resist herbivory may depend on the density of herbivores. In an alpine ecosystem with a long history of grazing, plants are expected to respond to both enhanced and reduced grazing pressures, and the interaction between plant traits and changes in species abundance are expected to differ between the two types of alteration of grazing regime. To understand the mechanisms behind species response, we investigated the relationship between sheep selectivity (measured in situ), plant traits and experimentally derived measures of change in species abundance as a response to the enhancement (from low to high density) or cessation (from low to zero density) of sheep grazing pressure over a six-year time period for 22 abundant herb species in an alpine habitat in south Norway. Sheep selected large, late-flowering herbs with a low leaf C/N ratio. Species that increased in abundance in response to enhanced grazing pressure were generally small and had high root/shoot ratios, thus exhibiting traits that reflect both resistance (through avoidance) and tolerance (through regrowth capacity) strategies. The abundance of selected species remained stable during the study period, and also under the enhanced grazing pressure treatment. There was, however, a tendency for selected species to respond positively to cessation of grazing, although overall responses to cessation of grazing were much less pronounced than responses to enhanced grazing. Avoidance through short stature (probably associated with increased light availability through the removal of tall competitors) as well as a certain amount of regrowth capacity appear to be the main mechanisms behind a positive response to enhanced grazing pressure in this study. The plant trait perspective clearly improves our insight into the mechanisms behind observed changes in species abundance when the

  5. Multi-decadal impacts of grazing on soil physical and biogeochemical properties in southeast Utah

    USGS Publications Warehouse

    Neff, J.C.; Reynolds, R.L.; Belnap, J.; Lamothe, P.

    2005-01-01

    Many soils in southeastern Utah are protected from surface disturbance by biological soil crusts that stabilize soils and reduce erosion by wind and water. When these crusts are disturbed by land use, soils become susceptible to erosion. In this study, we compare a never-grazed grassland in Canyonlands National Park with two historically grazed sites with similar geologic, geomorphic, and geochemical characteristics that were grazed from the late 1800s until 1974. We show that, despite almost 30 years without livestock grazing, surface soils in the historically grazed sites have 38-43% less silt, as well as 14-51% less total elemental soil Mg, Na, P, and Mn content relative to soils never exposed to livestock disturbances. Using magnetic measurement of soil magnetite content (a proxy for the stabilization of far-traveled eolian dust) we suggest that the differences in Mg, Na, P, and Mn are related to wind erosion of soil fine particles after the historical disturbance by livestock grazing. Historical grazing may also lead to changes in soil organic matter content including declines of 60-70% in surface soil C and N relative to the never-grazed sites. Collectively, the differences in soil C and N content and the evidence for substantial rock-derived nutrient loss to wind erosion implies that livestock grazing could have long-lasting effects on the soil fertility of native grasslands in this part of southeastern Utah. This study suggests that nutrient loss due to wind erosion of soils should be a consideration for management decisions related to the long-term sustainability of grazing operations in arid environments.

  6. Climate change and grazing interact to alter flowering patterns in the Mongolian steppe.

    PubMed

    Spence, Laura A; Liancourt, Pierre; Boldgiv, Bazartseren; Petraitis, Peter S; Casper, Brenda B

    2014-05-01

    Socio-economic changes threaten nomadic pastoralism across the world, changing traditional grazing patterns. Such land-use changes will co-occur with climate change, and while both are potentially important determinants of future ecosystem functioning, interactions between them remain poorly understood. We investigated the effects of grazing by large herbivores and climate manipulation using open-top chambers (OTCs) on flower number and flowering species richness in mountain steppe of northern Mongolia. In this region, sedentary pastoralism is replacing nomadic pastoralism, and temperature is predicted to increase. Grazing and OTCs interacted to affect forb flowering richness, which was reduced following grazing removal, and reduced by OTCs in grazed plots only. This interaction was directly linked to the soil moisture and temperature environments created by the experimental treatments: most species flowered when both soil moisture and temperature levels were high (i.e. in grazed plots without OTCs), while fewer species flowered when either temperature, or moisture, or both, were low. Removal of grazing increased the average number of graminoid flowers produced at peak flowering in Year 1, but otherwise grazing removal and OTCs did not affect community-level flower composition. Of four abundant graminoid species examined individually, three showed increased flower number with grazing removal, while one showed the reverse. Four abundant forb species showed no significant response to either treatment. Our results highlight how climate change effects on mountain steppe could be contingent on land-use, and that studies designed to understand ecosystem response to climate change should incorporate co-occurring drivers of change, such as altered grazing regimes.

  7. Mollusc grazing may constrain the ecological niche of the old forest lichen Pseudocyphellaria crocata.

    PubMed

    Gauslaa, Y

    2008-11-01

    This study reports on mollusc grazing of two epiphytic cyanobacterial lichens (Pseudocyphellaria crocata and Lobaria pulmonaria) transplanted within three Picea abies-dominated boreal rain forest stands (clear-cut, young and old forests) in west central Norway. Grazing was particularly high in transplants located in the old forest and was almost absent in clear-cut transplants. Grazing marks were absent on natural thalli on nearby spruce twigs (required creeping distance for mollusc from the ground >4 m). Transplantation of lichens from twigs to artificial transplantation frames reduced the creeping distance to 1.2 m, and caused a significant increase in grazing damage in P. crocata. Given a paired choice under transplantation, molluscs consistently preferred P. crocata and avoided L. pulmonaria, implying species-specific differences in herbivore defence. Pseudocyphellaria crocata has a much lower content of the medullary depsidones stictic and constictic acid than L. pulmonaria. Heavy grazing occurred in the P. crocata thalli lowest in these two depsidones. The upper part of the medulla hosting the photobiont was the preferred fodder for grazing molluscs. Molluscs avoided the yellow soralia in P. crocata (localised pulvinic acid), suggesting a role for pulvinic acid in preventing grazing of detached soredia and early establishment stages. The preference of P. crocata for thin spruce twigs is probably a result of a lower grazing pressure on twigs compared to e.g. deciduous stems that frequently support the better defended L. pulmonaria. Ongoing climate changes with increased annual rainfall and milder winters have presumably increased mollusc grazing, particularly in SW parts of Norway which have more species of lichen-feeding molluscs than the boreal sites studied. These temperate areas lacking natural spruce populations have recently experienced reported extinctions of the poorly defended P. crocata from rocks and deciduous stems prone to mollusc grazing. Lichen

  8. Increasing native, but not exotic, biodiversity increases aboveground productivity in ungrazed and intensely grazed grasslands.

    PubMed

    Isbell, Forest I; Wilsey, Brian J

    2011-03-01

    Species-rich native grasslands are frequently converted to species-poor exotic grasslands or pastures; however, the consequences of these changes for ecosystem functioning remain unclear. Cattle grazing (ungrazed or intensely grazed once), plant species origin (native or exotic), and species richness (4-species mixture or monoculture) treatments were fully crossed and randomly assigned to plots of grassland plants. We tested whether (1) native and exotic plots exhibited different responses to grazing for six ecosystem functions (i.e., aboveground productivity, light interception, fine root biomass, tracer nitrogen uptake, biomass consumption, and aboveground biomass recovery), and (2) biodiversity-ecosystem functioning relationships depended on grazing or species origin. We found that native and exotic species exhibited different responses to grazing for three of the ecosystem functions we considered. Intense grazing decreased fine root biomass by 53% in exotic plots, but had no effect on fine root biomass in native plots. The proportion of standing biomass consumed by cattle was 16% less in exotic than in native grazed plots. Aboveground biomass recovery was 30% less in native than in exotic plots. Intense grazing decreased aboveground productivity by 25%, light interception by 14%, and tracer nitrogen uptake by 54%, and these effects were similar in native and exotic plots. Increasing species richness from one to four species increased aboveground productivity by 42%, and light interception by 44%, in both ungrazed and intensely grazed native plots. In contrast, increasing species richness did not influence biomass production or resource uptake in ungrazed or intensely grazed exotic plots. These results suggest that converting native grasslands to exotic grasslands or pastures changes ecosystem structure and processes, and the relationship between biodiversity and ecosystem functioning.

  9. Grazing intensity significantly affects belowground carbon and nitrogen cycling in grassland ecosystems: a meta-analysis.

    PubMed

    Zhou, Guiyao; Zhou, Xuhui; He, Yanghui; Shao, Junjiong; Hu, Zhenhong; Liu, Ruiqiang; Zhou, Huimin; Hosseinibai, Shahla

    2017-03-01

    Livestock grazing activities potentially alter ecosystem carbon (C) and nitrogen (N) cycles in grassland ecosystems. Despite the fact that numerous individual studies and a few meta-analyses had been conducted, how grazing, especially its intensity, affects belowground C and N cycling in grasslands remains unclear. In this study, we performed a comprehensive meta-analysis of 115 published studies to examine the responses of 19 variables associated with belowground C and N cycling to livestock grazing in global grasslands. Our results showed that, on average, grazing significantly decreased belowground C and N pools in grassland ecosystems, with the largest decreases in microbial biomass C and N (21.62% and 24.40%, respectively). In contrast, belowground fluxes, including soil respiration, soil net N mineralization and soil N nitrification increased by 4.25%, 34.67% and 25.87%, respectively, in grazed grasslands compared to ungrazed ones. More importantly, grazing intensity significantly affected the magnitude (even direction) of changes in the majority of the assessed belowground C and N pools and fluxes, and C : N ratio as well as soil moisture. Specifically,light grazing contributed to soil C and N sequestration whereas moderate and heavy grazing significantly increased C and N losses. In addition, soil depth, livestock type and climatic conditions influenced the responses of selected variables to livestock grazing to some degree. Our findings highlight the importance of the effects of grazing intensity on belowground C and N cycling, which may need to be incorporated into regional and global models for predicting effects of human disturbance on global grasslands and assessing the climate-biosphere feedbacks.

  10. Grazing effects on surface energy fluxes in a desert steppe on the Mongolian Plateau.

    PubMed

    Shao, Changliang; Chen, Jiquan; Li, Linghao; Dong, Gang; Han, Juanjuan; Abraha, Michael; John, Ranjeet

    2017-03-01

    Quantifying the surface energy fluxes of grazed and ungrazed steppes is essential to understand the roles of grasslands in local and global climate and in land use change. We used paired eddy-covariance towers to investigate the effects of grazing on energy balance (EB) components: net radiation (Rn ), latent heat (LE), sensible heat (H), and soil heat (G) fluxes on adjacent grazed and ungrazed areas in a desert steppe of the Mongolian Plateau for a two-year period (2010-2012). Near 95% of Rn was partitioned as LE and H, whereas the contributions of G and other components of the EB were 5% at an annual scale. H dominated the energy partitioning and shared ~50% of Rn . When comparing the grazed and the ungrazed desert steppe, there was remarkably lower Rn and a lower H, but higher G at the grazed site than at the ungrazed site. Both reduced available energy (Rn - G) and H indicated a "cooling effect" feedback onto the local climate through grazing. Grazing reduced the dry year LE but enhanced the wet year LE. Energy partitioning of LE/Rn was positively correlated with the canopy conductivity, leaf area index, and soil moisture. H/Rn was positively correlated with the vapor pressure deficit but negatively correlated with the soil moisture. Boosted regression tree results showed that LE/Rn was dominated by soil moisture in both years and at both sites, while grazing shifted the H/Rn domination from temperature to soil moisture in the wet year. Grazing not only caused an LE shift between the dry and the wet year, but also triggered a decrease in the H/Rn because of changes in vegetation and soil properties, indicating that the ungrazed area had a greater resistance while the grazed area had a greater sensitivity of EB components to the changing climate.

  11. Bison grazing increases arthropod abundance and diversity in a tallgrass prairie.

    PubMed

    Moran, Matthew D

    2014-10-01

    How grazing-induced ecosystem changes by ungulates indirectly affect other consumers is a question of great interest. I investigated the effect of grazing by American Bison (Bos bison L.) on an arthropod community in tallgrass prairie. Grazing increased the abundance of arthropods, an increase that was present in both herbivorous and carnivorous assemblages, but not in detritivores. The increase in herbivores and reduction in plant biomass from grazing resulted in an arthropod herbivore load almost three times higher in grazed plots compared with controls. Among herbivores, the sap-feeding insect guild was dramatically more abundant, while chewing herbivores were not affected. Herbivorous and carnivorous arthropod richness was higher in grazed plots, although the response was strongest among herbivores. Arthropod abundance on individual grasses and forbs was significantly higher in grazed areas, while plant type had no effect on abundance, indicating that the change was ecosystem-wide and not simply in response to a reduction in grass biomass from grazing. The response of arthropods to grazing was strongest in the early part of the growing season. Published research shows that ungulate grazing, although decreasing available biomass to other consumers, enhances plant quality by increasing nitrogen level in plants. The arthropod results of this study suggest higher plant quality outweighs the potential negative competitive effects of plant biomass removal, although other activities of bison could not be ruled out as the causative mechanism. Because arthropods are extremely abundant organisms in grasslands and a food source for other consumers, bison may represent valuable management tools for maintaining biodiversity.

  12. Herbage intake and ruminal digestion of dairy cows grazed on perennial ryegrass pasture either in the morning or evening.

    PubMed

    Ueda, Koichiro; Mitani, Tomohiro; Kondo, Seiji

    2016-08-01

    This study aimed to clarify diurnal fluctuations of herbage intake, ruminal fermentation of herbage carbohydrates and proteins, and digesta particulate weight in the rumen of grazing dairy cows. Six ruminally cannulated, non-lactating dairy cows were grazed on perennial ryegrass/white clover pasture either in the morning (04.00 to 08.00 hours) or the evening (16.00 to 20.00 hours). Cows grazed in the evening spent more time (P < 0.01) and consumed more herbage (P < 0.01) compared with cows grazed in the morning. Higher (P < 0.05) daily mean concentrations of total volatile fatty acid, propionate and n-butyrate in rumen fluid were observed for cows grazed in the evening compared with cows grazed in the morning. Although cows grazed in the evening ingested more crude protein compared with cows grazed in the morning, no significant difference in NH3 -N concentration in rumen fluid was observed between them. The ratio of purine-derivative concentration to creatinine concentrations was higher (P < 0.01) in the urine of cows grazed in the evening than in cows grazed in the morning. These results clearly indicated that evening grazing was advantageous for dairy cows compared with morning grazing, in terms of ruminal fermentable energy intake and nitrogen utilization efficiency.

  13. 25 CFR 166.200 - When is a permit needed to authorize possession of Indian land for grazing purposes?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... land for grazing purposes? 166.200 Section 166.200 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Permit Requirements General Requirements § 166.200 When is a permit needed to authorize possession of Indian land for grazing purposes? (a) Unless otherwise provided for...

  14. 25 CFR 161.102 - What notifications are required that tribal laws apply to grazing permits on the Navajo...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... grazing permits on the Navajo Partitioned Lands? 161.102 Section 161.102 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER NAVAJO PARTITIONED LANDS GRAZING PERMITS Tribal Policies and Laws Pertaining to Permits § 161.102 What notifications are required that tribal laws apply to grazing permits...

  15. 25 CFR 166.200 - When is a permit needed to authorize possession of Indian land for grazing purposes?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... land for grazing purposes? 166.200 Section 166.200 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Permit Requirements General Requirements § 166.200 When is a permit needed to authorize possession of Indian land for grazing purposes? (a) Unless otherwise provided for...

  16. 43 CFR 4120.3-9 - Water rights for the purpose of livestock grazing on public lands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... grazing on public lands. 4120.3-9 Section 4120.3-9 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR RANGE MANAGEMENT (4000) GRAZING ADMINISTRATION-EXCLUSIVE OF ALASKA Grazing Management § 4120.3-9 Water rights for the purpose of...

  17. 25 CFR 166.420 - Will any special fees be assessed on delinquent grazing rental payments due under a permit?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Will any special fees be assessed on delinquent grazing... OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Late Rental Payment Collections § 166.420 Will any special fees be assessed on delinquent...

  18. 25 CFR 166.420 - Will any special fees be assessed on delinquent grazing rental payments due under a permit?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Will any special fees be assessed on delinquent grazing... OF THE INTERIOR LAND AND WATER GRAZING PERMITS Grazing Rental Rates, Payments, and Late Payment Collections Late Rental Payment Collections § 166.420 Will any special fees be assessed on delinquent...

  19. Non-traditional Forages in a Managed Grazing System for Control of Gastrointestinal Parasites in Sheep: Preliminary Work

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This project compared lambs grazing forage chicory (Cichorium intybus L.) with lambs grazing brown mid-rib forage sorghum (Sorghum bicolor (L.) Moench.) x sudangrass (Sorghum sudanense Piper) hybrid (BMR) to determine if anti-parasitic effects of chicory could be demonstrated. Lambs grazed these fo...

  20. Synechococcus production and grazing loss rates in nearshore tropical waters.

    PubMed

    Heng, Pei Li; Lim, Joon Hai; Lee, Choon Weng

    2017-03-01

    Temporal variation of Synechococcus, its production (μ) and grazing loss (g) rates were studied for 2 years at nearshore stations, i.e. Port Dickson and Port Klang along the Straits of Malacca. Synechococcus abundance at Port Dickson (0.3-2.3 × 10(5) cell ml(-1)) was always higher than at Port Klang (0.3-7.1 × 10(4) cell ml(-1)) (p < 0.001). μ ranged up to 0.98 day(-1) (0.51 ± 0.29 day(-1)), while g ranged from 0.02 to 0.31 day(-1) (0.15 ± 0.07 day(-1)) at Port Klang. At Port Dickson, μ and g averaged 0.47 ± 0.13 day(-1) (0.29-0.82 day(-1)) and 0.31 ± 0.14 day(-1) (0.13-0.63 day(-1)), respectively. Synechococcus abundance did not correlate with temperature (p > 0.25), but nutrient and light availability were important factors for their distribution. The relationship was modelled as log Synechococcus = 0.37Secchi - 0.01DIN + 4.52 where light availability (as Secchi disc depth) was a more important determinant. From a two-factorial experiment, nutrients were not significant for Synechococcus growth as in situ nutrient concentrations exceeded the threshold for saturated growth. However, light availability was important and elevated Synechococcus growth rates especially at Port Dickson (F = 5.94, p < 0.05). As for grazing loss rates, they were independent of either nutrients or light intensity (p > 0.30). In nearshore tropical waters, an estimated 69 % of Synechococcus production could be grazed.