Blue Oak Canopy Effect on Seasonal Forage Production and Quality

Science.gov (United States)

William E. Frost; Neil K. McDougald; Montague W. Demment

1991-01-01

Forage production and forage quality were measured seasonally beneath the canopy of blue oak (Quercus douglasii) and in open grassland at the San Joaquin Experimental Range. At the March and peak standing crop sampling dates forage production was significantly greater (p=.05) beneath blue oak compared to open grassland. At most sampling dates, the...

Productivity and carbon footprint of perennial grass-forage legume intercropping strategies with high or low nitrogen fertilizer input.

Science.gov (United States)

Hauggaard-Nielsen, Henrik; Lachouani, Petra; Knudsen, Marie Trydeman; Ambus, Per; Boelt, Birte; Gislum, René

2016-01-15

A three-season field experiment was established and repeated twice with spring barley used as cover crop for different perennial grass-legume intercrops followed by a full year pasture cropping and winter wheat after sward incorporation. Two fertilization regimes were applied with plots fertilized with either a high or a low rate of mineral nitrogen (N) fertilizer. Life cycle assessment (LCA) was used to evaluate the carbon footprint (global warming potential) of the grassland management including measured nitrous oxide (N2O) emissions after sward incorporation. Without applying any mineral N fertilizer, the forage legume pure stand, especially red clover, was able to produce about 15 t above ground dry matter ha(-1) year(-1) saving around 325 kg mineral Nfertilizer ha(-1) compared to the cocksfoot and tall fescue grass treatments. The pure stand ryegrass yielded around 3t DM more than red clover in the high fertilizer treatment. Nitrous oxide emissions were highest in the treatments containing legumes. The LCA showed that the low input N systems had markedly lower carbon footprint values than crops from the high N input system with the pure stand legumes without N fertilization having the lowest carbon footprint. Thus, a reduction in N fertilizer application rates in the low input systems offsets increased N2O emissions after forage legume treatments compared to grass plots due to the N fertilizer production-related emissions. When including the subsequent wheat yield in the total aboveground production across the three-season rotation, the pure stand red clover without N application and pure stand ryegrass treatments with the highest N input equalled. The present study illustrate how leguminous biological nitrogen fixation (BNF) represents an important low impact renewable N source without reducing crop yields and thereby farmers earnings. Copyright © 2015. Published by Elsevier B.V.

Genetic resources of perennial forage grasses in Serbia: Current state, broadening and evaluation

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Sokolović Dejan

2017-01-01

Full Text Available Due to historical background of vegetation development, geographical position, climate and relief, Serbia represents one of the 158 world biodiversity centres, based upon the number of plant species and territory size (biodiversity index 0.72. Large areas in Serbia are under natural grasslands and pastures, composed of forage grass species, and important as source of natural plant genetic diversity and germplasm for breeding. These eco-systems represent basic prerequisites for sustainable forage production, but very low potential of them is utilized and genetic resources are not protected. Family Poaceae is present in Serbia flora with 70 genera and among them from the aspect of forage production and quality, the most important are perennial Festuca, Lolium, Dactylis, Phleum, Bromus, Arrhenatherum, Poa and Agrostis species. Most of these grasses have been bred in Serbia and lot of cultivars were released. These cultivars contain autochthonous Serbian material and represent great and important resource of genetic variability. Therefore, collecting of new samples which are acclimatised to local eco-geographical conditions and including them in plant ex situ gene bank is of exceptional importance for further utilization in different plant breeding programmes as well as genetic resources protection. These autochthonous populations have natural variability and very often have satisfactory yielding performance in comparison with introduced cultivars, which referred them for direct phenotypic selection for cultivars release. Broadening of forage grasses genotypes collection is permanent objective of Serbian scientists. Collected accessions are being characterized and evaluated for important phenological, morphological and agronomical traits. In this paper genetic resources of forage grass species, their diversity and potentials, state of the grasses gene banks, as well as possibility for breeding of new cultivars has been analysed.

Effects of seasonal advancement on the forage availability, quality ...

African Journals Online (AJOL)

Effects of seasonal advancement on the forage availability, quality and acceptability by grazing gudali cattle in the humid zone of Nigeria. ... There were significant (p<0.05) differences in the dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF) contents of all the forages. DM content ranged from 9.6% (Tridax ...

Cool-Season Turfgrass Species and Cultivars: Response to Simulated Traffic in Central Italy

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Carlo F. Cereti

2010-03-01

Full Text Available Turfgrass species differ greatly in their ability to withstand the abrasion and compaction of traffic. Wear tolerance of turfgrass species and cultivars has been evaluated abroad by many researchers, while only few and partial studies have been conducted in Italy. Field experiment was carried out in Viterbo in 2001, 2002 and 2003 to evaluate the effect of the simulated traffic on 110 varieties belonging to four turfgrass cool-season species: tall fescue (Festuca arundinacea Schreb., fine fescues (Festuca rubra L. ssp. rubra Gaud., ssp. commutata Gaud., ssp. tricophylla Gaud., perennial ryegrass (Lolium perenne L. and Kentucky bluegrass (Poa pratensis L.. Shoot density, visual turfgrass quality and thatch thickness were the major characters recorded to estimate wear tolerance. Traffic was simulated using a device containing three rollers pulled by a small tractor. The traffic simulator weighed 564 kg and applied a pressure of about 3 MPa. Results indicated that perennial ryegrass and tall fescue had high wear tolerance and low statistical variation among cultivars. Kentucky bluegrass showed an average wear tolerance owing to its shoot density and good recovery potential. In spite of their high shoot density, fine fescues exhibited poor wear tolerance because of their scarce resistance to high temperatures which are typical of the Mediterranean climate in late spring and summer. This study enabled a preliminary selection of the most suitable cool-season grasses and cultivars for trafficked and non-trafficked areas in Central Italy and highlighted that different turfgrass species have different wear tolerance mechanisms.

Effects of foraging mode and season on the energetics of the Marine Iguana, Amblyrhynchus cristatus

NARCIS (Netherlands)

Drent, J; Lichtenbelt, WDV; Wikelski, M

1, Marine Iguanas (Amblyrhynchus cristatus) inhabiting the rocky shores of the Galapagos Islands apply two foraging strategies, intertidal and subtidal foraging, in a seasonal climate. Effects of both foraging strategy and seasonality on the daily energy expenditure (DEE) were measured using doubly

Effect of season on the quality of forages selected by sheep in citrus plantations in Ghana

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Leonard K. Adjorlolo

2014-09-01

Full Text Available The study aimed at assessing the effects of season on chemical composition of forages selected by sheep grazing in a citrus plantation. Forage species growing in a sweet orange (Citrus sinensis plantation were identified and sampled monthly for 2 years. Samples were bulked on monthly basis for chemical analysis. The average dry matter content of the forages increased from the rainy to the dry season but effects of season on the chemical components were inconsistent. Some species, such as Asystasia gangetica, had a higher crude protein concentration in the dry season, whereas for others, such as Panicum repens, the reverse occurred. However, average concentrations of crude protein, detergent fiber and components of fiber for all species for the rainy season were not significantly different from the dry season values. It was concluded that there were differences among forage species in their responses to changing seasons, such that grazing ruminants may select a diet to enable them to meet their nutritional requirements, provided forage biomass is adequate.Keywords: Crop-livestock integration, tree plantations, chemical composition, seasonal effects, forage quality.DOI: 10.17138/TGFT(2271-277

Considerations for Managing Agricultural Co-Existence between Transgenic and Non-Transgenic Cultivars of Outcrossing Perennial Forage Plants in Dairy Pastures

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Kevin F. Smith

2016-11-01

Full Text Available Many of the major forage species used in agriculture are outcrossing and rely on the exchange of pollen between individuals for reproduction; this includes the major species used for dairy production in grazing systems: perennial ryegrass (Lolium perenne L. and white clover (Trifolium repens L.. Cultivars of these species have been co-existing since contrasting cultivars were developed using plant breeding, but the consequences and need for strategies to manage co-existence have been made more prominent with the advent of genetic modification. Recent technological developments have seen the experimental evaluation of genetically modified (GM white clover and perennial ryegrass, although there is no current commercial growing of GM cultivars of these species. Co-existence frameworks already exist for two major cross-pollinated grain crops (canola and maize in Europe, and for alfalfa (Medicago sativa L. in the US, so many of the principles that the industry has developed for co-existence in these crops such as detection techniques, segregation, and agronomic management provide lessons and guidelines for outcrossing forage species, that are discussed in this paper.

Foraging decisions, patch use, and seasonality in egrets (Aves: ciconiiformes)

Science.gov (United States)

Erwin, R.M.

1985-01-01

Feeding snowy (Egretta thula) and great (Casmerodius albus) egrets were observed during 2 breeding seasons in coastal New Jersey and 2 brief winter periods in northeast Florida (USA). A number of tests based on assumptions of foraging models, predictions from foraging theory, and earlier empirical tests concerning time allocation and movement in foraging patches was made. Few of the expectations based on foraging theory and/or assumptions were supported by the empirical evidence. Snowy egrets fed with greater intensity and efficiency during the breeding season (when young were being fed) than during winter. They also showed some tendency to leave patches when their capture rate declined, and they spent more time foraging in patches when other birds were present nearby. Great egrets showed few of these tendencies, although they did leave patches when their intercapture intervals increased. Satiation differences had some influence on feeding rates in snowy egrets, but only at the end of feeding bouts. Some individuals of both species revisited areas in patches that had recently been exploited, and success rates were usually higher after the 2nd visit. Apparently, for predators of active prey, short-term changes in resource availability ('resource depression') may be more important than resource depletion, a common assumption in most optimal foraging theory models.

Dry season mapping of savanna forage quality, using the hyperspectral Carnegie

NARCIS (Netherlands)

Knox, N.; Skidmore, A.K.; Prins, H.H.T.; Asner, P.; Werff, van der H.M.A.; Boer, de W.F.; Waal, van der C.; Knegt, de H.J.; Kohi, E.; Slotow, R.; Grant, R.C.

2011-01-01

Forage quality within an African savanna depends upon limiting nutrients (nitrogen and phosphorus) and nutrients that constrain the intake rates (non-digestible fibre) of herbivores. These forage quality nutrients are particularly crucial in the dry season when concentrations of limiting nutrients

Seasonal/Interannual Variations of Carbon Sequestration and Carbon Emission in a Warm-Season Perennial Grassland

OpenAIRE

Deepa Dhital; Tomoharu Inoue; Hiroshi Koizumi

2014-01-01

Carbon sequestration and carbon emission are processes of ecosystem carbon cycling that can be affected while land area converted to grassland resulting in increased soil carbon storage and below-ground respiration. Discerning the importance of carbon cycle in grassland, we aimed to estimate carbon sequestration in photosynthesis and carbon emission in respiration from soil, root, and microbes, for four consecutive years (2007–2010) in a warm-season perennial grassland, Japan. Soil carbon emi...

Alcohol consumption and the risk of self-reported perennial and seasonal allergic rhinitis in young adult women in a population-based cohort study

DEFF Research Database (Denmark)

Bendtsen, P; Grønbæk, M; Kjær, S. K.

2008-01-01

Background Alcohol consumption has been suggested to be associated with the development of allergic rhinitis (AR), but there is limited data on the topic. Objectives The objective of this study was to investigate the association between alcohol consumption and the risk of developing AR among young...... women. Methods Five thousand eight hundred and seventy Danish women aged 20-29 years participated in a prospective cohort study, and were free of seasonal and perennial AR at baseline (1991-1993). Alcohol consumption was assessed by a food frequency questionnaire. The main outcome measures were self......-reported information on seasonal and perennial AR debuting during a mean follow-up period of 7.8 years. Results During follow-up, 831 women developed seasonal AR and 523 women developed perennial AR, corresponding to 14% and 9%. Alcohol consumption was positively associated with the risk of developing perennial AR...

More milk from forage: Milk production, blood metabolites, and forage intake of dairy cows grazing pasture mixtures and spatially adjacent monocultures.

Science.gov (United States)

Pembleton, Keith G; Hills, James L; Freeman, Mark J; McLaren, David K; French, Marion; Rawnsley, Richard P

2016-05-01

There is interest in the reincorporation of legumes and forbs into pasture-based dairy production systems as a means of increasing milk production through addressing the nutritive value limitations of grass pastures. The experiments reported in this paper were undertaken to evaluate milk production, blood metabolite concentrations, and forage intake levels of cows grazing either pasture mixtures or spatially adjacent monocultures containing perennial ryegrass (Lolium perenne), white clover (Trifolium repens), and plantain (Plantago lanceolata) compared with cows grazing monocultures of perennial ryegrass. Four replicate herds, each containing 4 spring-calving, cross-bred dairy cows, grazed 4 different forage treatments over the periods of early, mid, and late lactation. Forage treatments were perennial ryegrass monoculture (PRG), a mixture of white clover and plantain (CPM), a mixture of perennial ryegrass, white clover, and plantain (RCPM), and spatially adjacent monocultures (SAM) of perennial ryegrass, white clover, and plantain. Milk volume, milk composition, blood fatty acids, blood β-hydroxybutyrate, blood urea N concentrations, live weight change, and estimated forage intake were monitored over a 5-d response period occurring after acclimation to each of the forage treatments. The acclimation period for the early, mid, and late lactation experiments were 13, 13, and 10 d, respectively. Milk yield (volume and milk protein) increased for cows grazing the RCPM and SAM in the early lactation experiment compared with cows grazing the PRG, whereas in the mid lactation experiment, milk fat increased for the cows grazing the RCPM and SAM when compared with the PRG treatments. Improvements in milk production from grazing the RCPM and SAM treatments are attributed to improved nutritive value (particularly lower neutral detergent fiber concentrations) and a potential increase in forage intake. Pasture mixtures or SAM containing plantain and white clover could be a

Association of Candidate Genes With Submergence Response in Perennial Ryegrass

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Xicheng Wang

2017-05-01

Full Text Available Perennial ryegrass is a popular cool-season grass species due to its high quality for forage and turf. The objective of this study was to identify associations of candidate genes with growth and physiological traits to submergence stress and recovery after de-submergence in a global collection of 94 perennial ryegrass accessions. Accessions varied largely in leaf color, plant height (HT, leaf fresh weight (LFW, leaf dry weight (LDW, and chlorophyll fluorescence (Fv/Fm at 7 days of submergence and in HT, LFW and LDW at 7 days of recovery in two experiments. Among 26 candidate genes tested by various models, single nucleotide polymorphisms (SNPs in 10 genes showed significant associations with traits including 16 associations for control, 10 for submergence, and 8 for recovery. Under submergence, Lp1-SST encoding sucrose:sucrose 1-fructosyltransferase and LpGA20ox encoding gibberellin 20-oxidase were associated with LFW and LDW, and LpACO1 encoding 1-aminocyclopropane-1-carboxylic acid oxidase was associated with LFW. Associations between Lp1-SST and HT, Lp6G-FFT encoding fructan:fructan 6G-fructosyltransferase and Fv/Fm, LpCAT encoding catalase and HT were also detected under submergence stress. Upon de-submergence, Lp1-SST, Lp6G-FFT, and LpPIP1 encoding plasma membrane intrinsic protein type 1 were associated with LFW or LDW, while LpCBF1b encoding C-repeat binding factor were associated with HT. Nine significant SNPs in Lp1-SST, Lp6G-FFT, LpCAT, and LpACO1 resulted in amino acid changes with five substitutions found in Lp1-SST under submergence or recovery. The results indicated that allelic diversity in genes involved in carbohydrate and antioxidant metabolism, ethylene and gibberellin biosynthesis, and transcript factor could contribute to growth variations in perennial ryegrass under submergence stress and recovery after de-submergence.

Annual warm-season grasses vary for forage yield, quality, and competitiveness with weeds

Science.gov (United States)

Warm-season annual grasses may be suitable as herbicide-free forage crops. A two-year field study was conducted to determine whether tillage system and nitrogen (N) fertilizer application method influenced crop and weed biomass, water use, water use efficiency (WUE), and forage quality of three war...

Seasonal variations of cadmium and zinc in Arrhenatherum elatius, a perennial grass species from highly contaminated soils

International Nuclear Information System (INIS)

Deram, Annabelle; Denayer, Franck-Olivier; Petit, Daniel; Van Haluwyn, Chantal

2006-01-01

There is interest in studying bioaccumulation in plants because they form the base of the food chain as well as their potential use in phytoextraction. From this viewpoint, our study deals with the seasonal variation, from January to July, of Cd and Zn bioaccumulation in three metallicolous populations of Arrhenatherum elatius, a perennial grass with a high biomass production. In heavily polluted soils, while Zn bioaccumulation is weak, A. elatius accumulates more Cd than reported gramineous plants, with concentration of up to 100 μg g -1 . Our results also showed seasonal variations of bioaccumulation, underlying the necessity for in situ studies to specify the date of sampling and also the phenology of the collected plant sample. In our experimental conditions, accumulation is lower in June, leading us to the hypothesis of restriction in heavy metals translocation from roots to aerial parts during seed production. - Cd and Zn bioaccumulation varies seasonally in a perennial grass

Seasonal variations of cadmium and zinc in Arrhenatherum elatius, a perennial grass species from highly contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Deram, Annabelle [Institut Lillois d' Ingenierie de la Sante, Universite Droit et Sante de Lille, EA 2690, 42 rue Ambroise Pare, 59120 Loos (France)]. E-mail: aderam@ilis.univ-lille2.fr; Denayer, Franck-Olivier [Institut Lillois d' Ingenierie de la Sante, Universite Droit et Sante de Lille, EA 2690, 42 rue Ambroise Pare, 59120 Loos (France); Petit, Daniel [Laboratoire de Genetique et Evolution des Populations Vegetales, UPRESA-CNRS 8016, Bat SN2, Universite des Sciences et Techniques de Lille, 59655 Villeneuve d' Ascq, F59655 France (France); Van Haluwyn, Chantal [Faculte des Sciences Pharmaceutiques et Biologiques, Departement de Botanique, Universite Droit et Sante de Lille, EA 2690, B.P. 83, 59006 Lille Cedex (France)

2006-03-15

There is interest in studying bioaccumulation in plants because they form the base of the food chain as well as their potential use in phytoextraction. From this viewpoint, our study deals with the seasonal variation, from January to July, of Cd and Zn bioaccumulation in three metallicolous populations of Arrhenatherum elatius, a perennial grass with a high biomass production. In heavily polluted soils, while Zn bioaccumulation is weak, A. elatius accumulates more Cd than reported gramineous plants, with concentration of up to 100 {mu}g g{sup -1}. Our results also showed seasonal variations of bioaccumulation, underlying the necessity for in situ studies to specify the date of sampling and also the phenology of the collected plant sample. In our experimental conditions, accumulation is lower in June, leading us to the hypothesis of restriction in heavy metals translocation from roots to aerial parts during seed production. - Cd and Zn bioaccumulation varies seasonally in a perennial grass.

Seasonal nutrient yield and digestibility of deer forage from a young pine plantation

Science.gov (United States)

Robert M. Blair; Henry L. Short; E.A. Epps

1977-01-01

Six classes of current herbaceous and woody forage were collected seasonally from a 5-year-old mixed loblolly (Pinus taeda)-shortleaf pine (Pinus echinata) plantation (in Texas) and subjected to nutrient analyses and nylon bag dry-matter digestion trials. Forages were most nutritious and digestible in the spring when tissues were succulent and growing rapidly. Browse...

Foraging strategy switch of a top marine predator according to seasonal resource differences

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Malcolm Daniel O'Toole

2015-04-01

Full Text Available The spatio-temporal variability in marine resources influences the foraging behaviour and success of top marine predators. However, little is known about the links between these animals and ocean productivity, specifically, how plankton density influences their foraging behaviour. Southern elephant seals (Mirounga leonina have two annual at-sea foraging trips: a two month post-breeding foraging trip (Nov – Jan that coincides with elevated summer productivity; and an eight month post-moulting foraging trip (Feb – Oct over winter, when productivity is low. Physical parameters are often used to describe seal habitat, whereas information about important biological parameters is lacking. We used electronic tags deployed on elephant seals during both trips to determine their movement and foraging behaviour. The tags also recorded light, which measured the bio-optical properties of the water column, the bulk of which is presumably influenced by phytoplankton. We investigated the relationship between plankton density and seal foraging behaviour; comparing trends between summer and winter trips. We found a positive relationship between plankton density and foraging behaviour, which did not vary seasonally. We propose that profitable concentrations of seal prey are more likely to coincide with planktonic aggregations, but we also acknowledge that trophic dynamics may shift in response to seasonal trends in productivity. Seal prey (mid-trophic level and plankton (lower-trophic level are expected to overlap in space and time during summer trips when peak phytoplankton blooms occur. In contrast, aggregated patches of lower trophic levels are likely to be more dispersed during winter trips when plankton density is considerably lower and heterogeneous. These results show that southern elephant seals are able to exploit prey resources in different ways throughout the year as demonstrated by the variation observed between seal foraging behaviour and trophic

Forage yield and nitrogen nutrition dynamics of warm-season native forage genotypes under two shading levels and in full sunlight

OpenAIRE

Barro,Raquel Santiago; Varella,Alexandre Costa; Lemaire,Gilles; Medeiros,Renato Borges de; Saibro,João Carlos de; Nabinger,Carlos; Bangel,Felipe Villamil; Carassai,Igor Justin

2012-01-01

The successful achievement of a highly productive understorey pasture in silvopastoral systems depends on the use of well-adapted forage genotypes, showing good agronomic performance and persistence under shading and grazing. In this study, the herbage dry matter yield (DMY) and nitrogen nutrition dynamics were determined in three native warm-season grasses (Paspalum regnellii, Paspalum dilatatum and Paspalum notatum) and a forage legume (Arachis pintoi) under two shading levels compared with...

Development of Perennial Grain Sorghum

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Stan Cox

2018-01-01

Full Text Available Perennial germplasm derived from crosses between Sorghum bicolor and either S. halepense or S. propinquum is being developed with the goal of preventing and reversing soil degradation in the world’s grain sorghum-growing regions. Perennial grain sorghum plants produce subterranean stems known as rhizomes that sprout to form the next season’s crop. In Kansas, breeding perennial sorghum involves crossing S. bicolor cultivars or breeding lines to S. halepense or perennial S. bicolorn × S. halepense breeding lines, selecting perennial plants from F2 or subsequent populations, crossing those plants with S. bicolor, and repeating the cycle. A retrospective field trial in Kansas showed that selection and backcrossing during 2002–2009 had improved grain yields and seed weights of breeding lines. Second-season grain yields of sorghum lines regrowing from rhizomes were similar to yields in the first season. Further selection cycles have been completed since 2009. Many rhizomatous lines that cannot survive winters in Kansas are perennial at subtropical or tropical locations in North America and Africa. Grain yield in Kansas was not correlated with rhizomatousness in either Kansas or Uganda. Genomic regions affecting rhizome growth and development have been mapped, providing new breeding tools. The S. halepense gene pool may harbor many alleles useful for improving sorghum for a broad range of traits in addition to perenniality.

Perennial peanut (Arachis glabrata Benth.) contains polyphenol oxidase (PPO) and PPO substrates that can reduce post-harvest proteolysis.

Science.gov (United States)

Sullivan, Michael L; Foster, Jamie L

2013-08-15

Studies of perennial peanut (Arachis glabrata Benth.) suggest its hay and haylage have greater levels of rumen undegraded protein (RUP) than other legume forages such as alfalfa (Medicago sativa L.). Greater RUP can result in more efficient nitrogen utilization by ruminant animals with positive economic and environmental effects. We sought to determine whether, like red clover (Trifolium pretense L.), perennial peanut contains polyphenol oxidase (PPO) and PPO substrates that might be responsible for increased RUP. Perennial peanut extracts contain immunologically detectible PPO protein and high levels of PPO activity (>100 nkatal mg(-1) protein). Addition of caffeic acid (PPO substrate) to perennial peanut extracts depleted of endogenous substrates reduced proteolysis by 90%. Addition of phenolics prepared from perennial peanut leaves to extracts of either transgenic PPO-expressing or control (non-expressing) alfalfa showed peanut phenolics could reduce proteolysis >70% in a PPO-dependent manner. Two abundant likely PPO substrates are present in perennial peanut leaves including caftaric acid. Perennial peanut contains PPO and PPO substrates that together are capable of inhibiting post-harvest proteolysis, suggesting a possible mechanism for increased RUP in this forage. Research related to optimizing the PPO system in other forage crops will likely be applicable to perennial peanut. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Omalizumab Is Equally Effective in Persistent Allergic Oral Corticosteroid-Dependent Asthma Caused by Either Seasonal or Perennial Allergens: A Pilot Study.

Science.gov (United States)

Domingo, Christian; Pomares, Xavier; Navarro, Albert; Rudi, Núria; Sogo, Ana; Dávila, Ignacio; Mirapeix, Rosa M

2017-02-28

Omalizumab is marketed for chronic severe asthma patients who are allergic to perennial allergens. Our purpose was to investigate whether omalizumab is also effective in persistent severe asthma due to seasonal allergens. Thirty patients with oral corticosteroid-dependent asthma were treated with Omalizumab according to the dosing table. For each patient with asthma due to seasonal allergens, we recruited the next two consecutive patients with asthma due to perennial allergens. The dose of oral methyl prednisolone was tapered at a rate of 2 mg every two weeks after the start of treatment with omalizumab depending on tolerance. At each monthly visit, a forced spirometry and fractional exhaled nitric oxide (FeNO) measurement were performed and the accumulated monthly methyl prednisolone dose was calculated. At entry, there were no differences between groups in terms of gender, body mass index or obesity, year exacerbation rate, monthly dose of methyl-prednisolone (MP), FeNO and blood immunoglobuline E (IgE) MP, FeNO and IgE values, or spirometry (perennial: FVC: 76%; FEV₁: 62%; seasonal: FVC: 79%; FEV₁: 70%). The follow-up lasted 76 weeks. One patient in each group was considered a non-responder. Spirometry did not worsen in either group. There was a significant intragroup reduction in annual exacerbation rate and methyl prednisolone consumption but no differences were detected in the intergroup comparison. Omalizumab offered the same clinical benefits in the two cohorts regardless of whether the asthma was caused by a seasonal or a perennial allergen. These results strongly suggest that allergens are the trigger in chronic asthma but that it is the persistent exposure to IgE that causes the chronicity.

Omalizumab Is Equally Effective in Persistent Allergic Oral Corticosteroid-Dependent Asthma Caused by Either Seasonal or Perennial Allergens: A Pilot Study

Directory of Open Access Journals (Sweden)

Christian Domingo

2017-02-01

Full Text Available Omalizumab is marketed for chronic severe asthma patients who are allergic to perennial allergens. Our purpose was to investigate whether omalizumab is also effective in persistent severe asthma due to seasonal allergens. Thirty patients with oral corticosteroid-dependent asthma were treated with Omalizumab according to the dosing table. For each patient with asthma due to seasonal allergens, we recruited the next two consecutive patients with asthma due to perennial allergens. The dose of oral methyl prednisolone (MP was tapered at a rate of 2 mg every two weeks after the start of treatment with omalizumab depending on tolerance. At each monthly visit, a forced spirometry and fractional exhaled nitric oxide (FeNO measurement were performed and the accumulated monthly MP dose was calculated. At entry, there were no differences between groups in terms of gender, body mass index or obesity, year exacerbation rate, monthly dose of MP, FeNO and blood immunoglobuline E (IgE values, or spirometry (perennial: FVC: 76%; FEV1: 62%; seasonal: FVC: 79%; FEV1: 70%. The follow-up lasted 76 weeks. One patient in each group was considered a non-responder. Spirometry did not worsen in either group. There was a significant intragroup reduction in annual exacerbation rate and MP consumption but no differences were detected in the intergroup comparison. Omalizumab offered the same clinical benefits in the two cohorts regardless of whether the asthma was caused by a seasonal or a perennial allergen. These results strongly suggest that allergens are the trigger in chronic asthma but that it is the persistent exposure to IgE that causes the chronicity.

Rendimento de forragem e valor nutritivo de gramíneas anuais de estação fria submetidas a sombreamento por Pinus elliottii e ao sol pleno Forage yield and nutritive value of cool-season annual forage grasses shaded by Pinus elliottii trees and at full-sun

Directory of Open Access Journals (Sweden)

Raquel Santiago Barro

2008-10-01

Full Text Available Avaliou-se o efeito do sombreamento provocado por duas densidades arbóreas em uma floresta de Pinus elliottii Engelm. com 10 anos de idade sobre o rendimento e o valor nutritivo da forragem de três gramíneas de ciclo hibernal. Como tratamentos, avaliou-se a combinação de dois fatores (3 x 3 em um delineamento experimental de parcelas subdivididas com três repetições, no qual as parcelas foram as condições luminosas (proporcionadas por duas densidades arbóreas: 555 e 333 árvores/ha e luz solar plena e as subparcelas as espécies forrageiras azevém-anual (Lolium multiflorum Lam.; aveia-preta (Avena strigosa Schreb.; e aveia-branca (A. sativa L. cv. Fapa 2. A semeadura foi realizada entre 25/7/2005 e 5/8/2005 e entre 26 e 27/4/2006. O rendimento de matéria seca foi estimado em avaliações durante o estádio vegetativo (aos 104 dias após a semeadura em 2006 e em pleno florescimento (aos 132 e 170 dias, em 2005 e 2006, respectivamente. O valor nutritivo da forragem foi avaliado considerando os teores médios de proteína bruta (PB e a digestibilidade in vitro da matéria orgânica (DIVMO. O sombreamento moderado reduziu em 57% o rendimento médio de forragem dos três genótipos avaliados, mas aumentou em 2,3% o teor de proteína bruta (PB e em 5,5% a digestibilidade in vitro (DIVMO quando as plantas estavam em florescimento pleno. Entre as espécies forrageiras avaliadas, a aveia-branca e a aveia-preta apresentam maior potencial para utilização em sistemas silvipastoris na Região Sul.It was evaluated the shading effect induced by two tree densities of a ten-year-old slash pine (Pinus elliottii Engelm. forest, and at full sun, on forage dry matter yield and nutritive value of three cool-season annual grasses. Treatments were a combination of two main factors: a three light conditions induced by two tree densities (333 e 555 stems/ha and at full sun; b three cool-season annual forage grasses: Italian ryegrass (Lolium multiflorum Lam

Semeadura direta de forrageiras de estação fria em campo natural com aplicação de herbicidas: I. Produção de forragem e contribuição relativa das espécies No-till seeding of cool season forages on native pasture with herbicides application: I. Forage yield and relative contribution of plant species

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Enrique Pérez Gomar

2004-06-01

Full Text Available Os campos naturais apresentam estacionalidade na sua produção forrageira, a qual pode ser atenuada com a introdução de espécies de estação fria através de semeadura direta, aumentando a produção forrageira no inverno. Durante quatro anos, conduziu-se um experimento de semeadura direta de forragem de inverno, sobre campo nativo, em um Argissolo Vermelho-Amarelo, de textura superficial arenosa do norte do Uruguai. Em delineamento de blocos ao acaso com parcelas sub-subdivididas, foram testadas doses de herbicidas (glifosate 1L ha-1, glifosate 4L ha-1, paraquat 3L ha-1 e testemunha, como tratamento principal, aplicadas no ano 1994. A repetição ou não das mesmas doses no ano 1995 constituiu-se na subparcela, e a aplicação ou não das mesmas doses no ano 1996 constituiu-se na sub-subparcela. Os resultados mostraram que o maior distúrbio sobre a produção de forrageiras e contribuição das espécies do campo nativo foi provocado com a aplicação continuada de herbicidas sistêmicos na maior dose. Quando não foi aplicado herbicida (testemunha havia onze espécies e com aplicação de glifosate 4L ha-1 havia seis espécies, bem como ocorreu uma substituição de espécies perenes por anuais. O herbicida paraquat e a dose baixa de glifosate mostraram efeitos intermediários entre o observado no campo nativo semeado com triticale e azevém sem tratar com herbicida e os provocados com glifosate na dose alta. Por outro lado, os rendimentos de matéria seca das espécies forrageiras invernais semeadas foram 63% maiores na dose mais alta de glifosate do que na testemunha, devido a um maior controle da competição que exercia o campo nativo.Natural grasslands have great seasonal fluctuation of forage production. The winter forage production may be increased using cool-season forage species established with no-till, reducing seasonal fluctuations. An experiment with winter grasses (black oat and rye grass no-till sown on native grasses, was

Effects of Seasonal and Perennial Grazing on Soil Fauna Community and Microbial Biomass Carbon in the Subalpine Meadows of Yunnan, Southwest China

Institute of Scientific and Technical Information of China (English)

LIU Shengjie; YANG Xiaodong; Anthony R.IVES; FENG Zhili; SHA Liqing

2017-01-01

Grazing and over-grazing may drive changes in the diversity and functioning of below-ground meadow ecosystems.A field soil survey was conducted to compare microbial biomass carbon (Cmin) and soil fauna communities in the two main grassland management systems in subalpine regions of Yunnan Province,China:perennial grazing currently practiced due to increasing herd sizes and traditional seasonal grazing.A three-year exclosure experiment was then conducted to further compare the effects of different grazing practices,including treatments of no mowing,perennial grazing (NM + G),mowing followed by seasonal grazing (M + G),mowing and no grazing (M + NG),and no mowing or grazing (NM + NG).The comparative survey result revealed that Cmin and total density of soil fauna were significantly lower at a perennially grazed site than at a seasonally grazed site.The experiment results showed that in comparison to non-grazing treatments (M + NG and NM + NG),grazing (NM + G and M + G) reduced total fauna density (by 150 individuals m-2) and the number of taxonomic groups present (by 0.32 taxa m-2).Mowing decreased Cmin (by 0.31 mg g-1).Furthermore,the NM + G treatment (perennial grazing) had the lowest density of Collembola (16.24 individuals m-2),one of the two most common taxonomic groups,although other taxonomic groups responded differently to the treatments.Treatment effects on soil fauna were consistent with those on above-ground grasses,in which C:N ratios were greatly reduced by grazing,with this effect being the greatest for the NM + G treatment.In contrast,different grazing treatments had little effect on C:N ratio of soil.Furthermore,the traditional grazing method (mowing followed by seasonal grazing) may have less severe effects on some taxonomic groups than perennial grazing.Therefore,an appropriate management should aim to protect soil fauna and microbes in this area from over-grazing and against further degradation.

Pollen foraging in colonies of Melipona bicolor (Apidae, Meliponini): effects of season, colony size and queen number.

Science.gov (United States)

Hilário, S D; Imperatriz-Fonseca, V L

2009-01-01

We evaluated the ratio between the number of pollen foragers and the total number of bees entering colonies of Melipona bicolor, a facultative polygynous species of stingless bees. The variables considered in our analysis were: seasonality, colony size and the number of physogastric queens in each colony. The pollen forager ratios varied significantly between seasons; the ratio was higher in winter than in summer. However, colony size and number of queens per colony had no significant effect. We conclude that seasonal differences in pollen harvest are related to the production of sexuals and to the number of individuals and their body size.

Forage seeding in rangelands increases production and prevents weed invasion

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Josh Davy

2017-07-01

Full Text Available Increasing forage productivity in the Sierra foothill rangelands would help sustain the livestock industry as land availability shrinks and lease rates rise, but hardly any studies have been done on forage selections. From 2009 to 2014, in one of the first long-term and replicated studies of seeding Northern California's Mediterranean annual rangeland, we compared the cover of 22 diverse forages to determine their establishment and survivability over time. Among the annual herbs, forage brassica (Brassica napus L. and chicory (Cichorium intybus L. proved viable options. Among the annual grasses, soft brome (Bromus hordeaceus and annual ryegrass (Lolium multiflorum performed well. However, these species will likely require frequent reseeding to maintain dominance. Long-term goals of sustained dominant cover (> 3 years are best achieved with perennial grasses. Perennial grasses that persisted with greater than 50% cover were Berber orchardgrass (Dactylis glomerata, Flecha tall fescue (Lolium arundinaceum and several varieties of hardinggrass (Phalaris aquatica L., Perla koleagrass, Holdfast, Advanced AT. In 2014, these successful perennials produced over three times more dry matter (pounds per acre than the unseeded control and also suppressed annual grasses and yellow starthistle (Centaurea solstitialis L. cover.

Effect of sociality and season on gray wolf (Canis lupus) foraging behavior: implications for estimating summer kill rate.

Science.gov (United States)

Metz, Matthew C; Vucetich, John A; Smith, Douglas W; Stahler, Daniel R; Peterson, Rolf O

2011-03-01

Understanding how kill rates vary among seasons is required to understand predation by vertebrate species living in temperate climates. Unfortunately, kill rates are only rarely estimated during summer. For several wolf packs in Yellowstone National Park, we used pairs of collared wolves living in the same pack and the double-count method to estimate the probability of attendance (PA) for an individual wolf at a carcass. PA quantifies an important aspect of social foraging behavior (i.e., the cohesiveness of foraging). We used PA to estimate summer kill rates for packs containing GPS-collared wolves between 2004 and 2009. Estimated rates of daily prey acquisition (edible biomass per wolf) decreased from 8.4±0.9 kg (mean ± SE) in May to 4.1±0.4 kg in July. Failure to account for PA would have resulted in underestimating kill rate by 32%. PA was 0.72±0.05 for large ungulate prey and 0.46±0.04 for small ungulate prey. To assess seasonal differences in social foraging behavior, we also evaluated PA during winter for VHF-collared wolves between 1997 and 2009. During winter, PA was 0.95±0.01. PA was not influenced by prey size but was influenced by wolf age and pack size. Our results demonstrate that seasonal patterns in the foraging behavior of social carnivores have important implications for understanding their social behavior and estimating kill rates. Synthesizing our findings with previous insights suggests that there is important seasonal variation in how and why social carnivores live in groups. Our findings are also important for applications of GPS collars to estimate kill rates. Specifically, because the factors affecting the PA of social carnivores likely differ between seasons, kill rates estimated through GPS collars should account for seasonal differences in social foraging behavior.

Nitrogen Fertilization Effect on Phosphorus Remediation Potential of Three Perennial Warm-Season Forages

NARCIS (Netherlands)

Newman, Y.C.; Agyin-Birikorang, S.; Adjei, M.B.; Scholberg, J.M.S.; Silveira, M.L.; Vendramini, J.M.B.; Rechcigl, J.E.; Sollenberger, L.E.

2009-01-01

Warm-season C-4 grasses are capable of removing excess soil nutrients because of their high Yield potential and nutrient uptake efficiency. Bahiagrass (Paspalum notatum Flugge), limpograss [Hemarthria altissima (Poir.) Stapf& Hubb], and stargrass (Cynodon nlemfuensis Vanderyst), three commonly

Extreme Effects of Season on the Foraging Activities and Colony Productivity of a Stingless Bee (Melipona asilvai Moure, 1971 in Northeast Brazil

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Daniela Lima do Nascimento

2012-01-01

Full Text Available This study reports the influence of season on foraging activities and internal colonial parameters of Melipona asilvai in an Atlantic forest area of northeast Brazil. We used video cameras connected to a PC to monitor all departures and returns of foragers and the types of materials they carried. Foraging activities decreased almost 90% from dry to rainy seasons, but temperature and humidity were not the main factors influencing departures. Observed honey storage and an extreme cutback in activities during the rainy period suggest a seasonal diapause in this species.

Effect of forage type, harvesting time and exogenous enzyme application on degradation characteristics measured using in vitro technique

DEFF Research Database (Denmark)

Moharrery, Ali; Hvelplund, Torben; Weisbjerg, Martin Riis

2009-01-01

Five forage species cut at different harvest times were studied for their degradation characteristics using in vitro digestibility technique. The forage species were two grasses and three legumes growing in two seasons (spring growth and second re-growth). Grass and legume forages were harvested...... at three harvesting times being early (E), middle (M) and late (L), both during the spring growth and the second re-growth. The grasses included perennial ryegrass (Lolium perenne), and festulolium (XFestulolium), and the legumes included white clover (Trifolium repens), red clover (Trifolium pratense......) and neutral detergent fibre (aNDFom) degradation profiles were fitted to an exponential equation. The fractional rate of degradation (c) of DM or aNDFom did vary among the forage species and was highest for the legumes. The potential degradability ranged from 580 to 870 g/kg for DM and from 380 to 900 g...

The genome and transcriptome of perennial ryegrass mitochondria

DEFF Research Database (Denmark)

Islam, Md. Shofiqul; Studer, Bruno; Byrne, Stephen

2013-01-01

Background: Perennial ryegrass (Lolium perenne L.) is one of the most important forage and turf grass species of temperate regions worldwide. Its mitochondrial genome is inherited maternally and contains genes that can influence traits of agricultural importance. Moreover, the DNA sequence...... and annotation of the complete mitochondrial genome from perennial ryegrass. Results: Intact mitochondria from perennial ryegrass leaves were isolated and used for mtDNA extraction. The mitochondrial genome was sequenced to a 167-fold coverage using the Roche 454 GS-FLX Titanium platform, and assembled...... of mitochondrial genomes has been established and compared for a large number of species in order to characterize evolutionary relationships.Therefore, it is crucial to understand the organization of the mitochondrial genome and how it varies between and within species. Here, we report the first de novo assembly...

African Journal of Range and Forage Science - Vol 11, No 1 (1976)

African Journals Online (AJOL)

African Journal of Range and Forage Science. ... Changes of biomass in some perennial grass species. ... The use of shoot dimensions to estimate the leaf mass or shoot area of certain indigenous ... Italian ryegrass as a perennial fodder crop.

The perennial ryegrass GenomeZipper: targeted use of genome resources for comparative grass genomics.

Science.gov (United States)

Pfeifer, Matthias; Martis, Mihaela; Asp, Torben; Mayer, Klaus F X; Lübberstedt, Thomas; Byrne, Stephen; Frei, Ursula; Studer, Bruno

2013-02-01

Whole-genome sequences established for model and major crop species constitute a key resource for advanced genomic research. For outbreeding forage and turf grass species like ryegrasses (Lolium spp.), such resources have yet to be developed. Here, we present a model of the perennial ryegrass (Lolium perenne) genome on the basis of conserved synteny to barley (Hordeum vulgare) and the model grass genome Brachypodium (Brachypodium distachyon) as well as rice (Oryza sativa) and sorghum (Sorghum bicolor). A transcriptome-based genetic linkage map of perennial ryegrass served as a scaffold to establish the chromosomal arrangement of syntenic genes from model grass species. This scaffold revealed a high degree of synteny and macrocollinearity and was then utilized to anchor a collection of perennial ryegrass genes in silico to their predicted genome positions. This resulted in the unambiguous assignment of 3,315 out of 8,876 previously unmapped genes to the respective chromosomes. In total, the GenomeZipper incorporates 4,035 conserved grass gene loci, which were used for the first genome-wide sequence divergence analysis between perennial ryegrass, barley, Brachypodium, rice, and sorghum. The perennial ryegrass GenomeZipper is an ordered, information-rich genome scaffold, facilitating map-based cloning and genome assembly in perennial ryegrass and closely related Poaceae species. It also represents a milestone in describing synteny between perennial ryegrass and fully sequenced model grass genomes, thereby increasing our understanding of genome organization and evolution in the most important temperate forage and turf grass species.

Effect of sociality and season on gray wolf (Canis lupus foraging behavior: implications for estimating summer kill rate.

Directory of Open Access Journals (Sweden)

Matthew C Metz

Full Text Available BACKGROUND: Understanding how kill rates vary among seasons is required to understand predation by vertebrate species living in temperate climates. Unfortunately, kill rates are only rarely estimated during summer. METHODOLOGY/PRINCIPAL FINDINGS: For several wolf packs in Yellowstone National Park, we used pairs of collared wolves living in the same pack and the double-count method to estimate the probability of attendance (PA for an individual wolf at a carcass. PA quantifies an important aspect of social foraging behavior (i.e., the cohesiveness of foraging. We used PA to estimate summer kill rates for packs containing GPS-collared wolves between 2004 and 2009. Estimated rates of daily prey acquisition (edible biomass per wolf decreased from 8.4±0.9 kg (mean ± SE in May to 4.1±0.4 kg in July. Failure to account for PA would have resulted in underestimating kill rate by 32%. PA was 0.72±0.05 for large ungulate prey and 0.46±0.04 for small ungulate prey. To assess seasonal differences in social foraging behavior, we also evaluated PA during winter for VHF-collared wolves between 1997 and 2009. During winter, PA was 0.95±0.01. PA was not influenced by prey size but was influenced by wolf age and pack size. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that seasonal patterns in the foraging behavior of social carnivores have important implications for understanding their social behavior and estimating kill rates. Synthesizing our findings with previous insights suggests that there is important seasonal variation in how and why social carnivores live in groups. Our findings are also important for applications of GPS collars to estimate kill rates. Specifically, because the factors affecting the PA of social carnivores likely differ between seasons, kill rates estimated through GPS collars should account for seasonal differences in social foraging behavior.

SEASONALITY OF ANNUAL PLANT ESTABLISHMENT INFLUENCES THE INTERACTIONBETWEEN THE NON-NATIVE ANNUAL GRASS BROMUS MADRITENSIS SSP. RUBENS AND MOJAVE DESERT PERENNIALS

Energy Technology Data Exchange (ETDEWEB)

L A. DEFALCO; G. C. FERNANDEZ; R. S. NOWAK

2004-01-01

Competition between native and non-native species can change the composition and structure of plant communities, but in deserts the timing of non-native plant establishment can modulate their impacts to native species. In a field experiment, we varied densities of the non-native annual grass Bromus madritensis ssp. rubens around individuals of three native perennials--Larrea iridentata, Achnatherum hymenoides, and Pleuraphis rigida--in either winter or spring. Additional plots were prepared for the Same perennial species and seasons, but with a mixture of native annual species. Relative growth rates of perennial shoots (RGRs) declined with increasing Bromus biomass when Bromus that was established in winter had 2-3 mo of growth and high water use before perennial growth began. However, this high water use did not significantly reduce water potentials for the perennials, suggesting Bromus that established earlier depleted other soil resources, such as N, otherwise used by perennial plants. Spring-established Bromus had low biomass even at higher densities and did not effectively reduce RGRs, resulting in an overall lower impact to perennials than when Bromus was established in winter. Similarly, growth and reproduction of perennials with mixed annuals as neighbors did not differ from those with Bromus neighbors of equivalent biomass, but densities of these annuals did not support the high biomass necessary to reduce perennial growth. Thus, impacts of native Mojave Desert annuals to perennials are expected to be lower than those of Bromus because seed dormancy and narrow requirements for seedling survivorship produce densities and biomass lower than those achieved by Bromus. In comparing the effects of Bromus among perennial species, the impact of increased Bromus biomass on RGR was lower for Larrea than for the two perennial grasses, probably because Lurrea maintains low growth rates throughout the year, even after Bromus has completed its life cycle. This contrasts

Dry season forages for improving dairy production in smallholder systems in Uganda

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Jolly Kabirizi

2013-12-01

Full Text Available Economically feasible strategies for year-round feed supply to dairy cattle are needed to improve feed resource availability, milk yield and household income for the smallholder dairy farming systems that predominate in the rural Eastern and Central African region. Currently, Napier grass (Pennisetum purpureum is the major forage in zero-grazing production systems, but dry-season production is often constrained. Our results from 24 farms show that sowing forage legumes, including Centrosema molle (formerly C. pubescens and Clitoria ternatea, with Napier grass and Brachiaria hybrid cv. Mulato improved both yield of forage and protein concentration. Sowing of 0.5 ha Napier-Centro plus 0.5 ha of Mulato-Clitoria increased milk yield by 80% and household income by 52% over 0.5 ha Napier grass monoculture. Possible income foregone from the crops which could have been grown on the additional 0.5 ha must be considered in assessing the economic viability of the system.

Lambs Fed Fresh Winter Forage Rape (Brassica napus L.) Emit Less Methane than Those Fed Perennial Ryegrass (Lolium perenne L.), and Possible Mechanisms behind the Difference

Science.gov (United States)

Sun, Xuezhao; Henderson, Gemma; Cox, Faith; Molano, German; Harrison, Scott J.; Luo, Dongwen; Janssen, Peter H.; Pacheco, David

2015-01-01

The objectives of this study were to examine long-term effects of feeding forage rape (Brassica napus L.) on methane yields (g methane per kg of feed dry matter intake), and to propose mechanisms that may be responsible for lower emissions from lambs fed forage rape compared to perennial ryegrass (Lolium perenne L.). The lambs were fed fresh winter forage rape or ryegrass as their sole diet for 15 weeks. Methane yields were measured using open circuit respiration chambers, and were 22-30% smaller from forage rape than from ryegrass (averages of 13.6 g versus 19.5 g after 7 weeks, and 17.8 g versus 22.9 g after 15 weeks). The difference therefore persisted consistently for at least 3 months. The smaller methane yields from forage rape were not related to nitrate or sulfate in the feed, which might act as alternative electron acceptors, or to the levels of the potential inhibitors glucosinolates and S-methyl L-cysteine sulfoxide. Ruminal microbial communities in forage rape-fed lambs were different from those in ryegrass-fed lambs, with greater proportions of potentially propionate-forming bacteria, and were consistent with less hydrogen and hence less methane being produced during fermentation. The molar proportions of ruminal acetate were smaller and those of propionate were greater in forage rape-fed lambs, consistent with the larger propionate-forming populations and less hydrogen production. Forage rape contained more readily fermentable carbohydrates and less structural carbohydrates than ryegrass, and was more rapidly degraded in the rumen, which might favour this fermentation profile. The ruminal pH was lower in forage rape-fed lambs, which might inhibit methanogenic activity, shifting the rumen fermentation to more propionate and less hydrogen and methane. The significance of these two mechanisms remains to be investigated. The results suggest that forage rape is a potential methane mitigation tool in pastoral-based sheep production systems. PMID:25803688

Pronounced Seasonal Changes in the Movement Ecology of a Highly Gregarious Central-Place Forager, the African Straw-Coloured Fruit Bat (Eidolon helvum.

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Jakob Fahr

Full Text Available Straw-coloured fruit bats (Eidolon helvum migrate over vast distances across the African continent, probably following seasonal bursts of resource availability. This causes enormous fluctuations in population size, which in turn may influence the bats' impact on local ecosystems. We studied the movement ecology of this central-place forager with state-of-the-art GPS/acceleration loggers and concurrently monitored the seasonal fluctuation of the colony in Accra, Ghana. Habitat use on the landscape scale was assessed with remote sensing data as well as ground-truthing of foraging areas.During the wet season population low (~ 4000 individuals, bats foraged locally (3.5-36.7 km in urban areas with low tree cover. Major food sources during this period were fruits of introduced trees. Foraging distances almost tripled (24.1-87.9 km during the dry season population peak (~ 150,000 individuals, but this was not compensated for by reduced resting periods. Dry season foraging areas were random with regard to urban footprint and tree cover, and food consisted almost exclusively of nectar and pollen of native trees.Our study suggests that straw-coloured fruit bats disperse seeds in the range of hundreds of meters up to dozens of kilometres, and pollinate trees for up to 88 km. Straw-coloured fruit bats forage over much larger distances compared to most other Old World fruit bats, thus providing vital ecosystem services across extensive landscapes. We recommend increased efforts aimed at maintaining E. helvum populations throughout Africa since their keystone role in various ecosystems is likely to increase due to the escalating loss of other seed dispersers as well as continued urbanization and habitat fragmentation.

Pronounced Seasonal Changes in the Movement Ecology of a Highly Gregarious Central-Place Forager, the African Straw-Coloured Fruit Bat (Eidolon helvum).

Science.gov (United States)

Fahr, Jakob; Abedi-Lartey, Michael; Esch, Thomas; Machwitz, Miriam; Suu-Ire, Richard; Wikelski, Martin; Dechmann, Dina K N

2015-01-01

Straw-coloured fruit bats (Eidolon helvum) migrate over vast distances across the African continent, probably following seasonal bursts of resource availability. This causes enormous fluctuations in population size, which in turn may influence the bats' impact on local ecosystems. We studied the movement ecology of this central-place forager with state-of-the-art GPS/acceleration loggers and concurrently monitored the seasonal fluctuation of the colony in Accra, Ghana. Habitat use on the landscape scale was assessed with remote sensing data as well as ground-truthing of foraging areas. During the wet season population low (~ 4000 individuals), bats foraged locally (3.5-36.7 km) in urban areas with low tree cover. Major food sources during this period were fruits of introduced trees. Foraging distances almost tripled (24.1-87.9 km) during the dry season population peak (~ 150,000 individuals), but this was not compensated for by reduced resting periods. Dry season foraging areas were random with regard to urban footprint and tree cover, and food consisted almost exclusively of nectar and pollen of native trees. Our study suggests that straw-coloured fruit bats disperse seeds in the range of hundreds of meters up to dozens of kilometres, and pollinate trees for up to 88 km. Straw-coloured fruit bats forage over much larger distances compared to most other Old World fruit bats, thus providing vital ecosystem services across extensive landscapes. We recommend increased efforts aimed at maintaining E. helvum populations throughout Africa since their keystone role in various ecosystems is likely to increase due to the escalating loss of other seed dispersers as well as continued urbanization and habitat fragmentation.

Effects of Nitrogen Rate and Regrowth Interval on Perennial Ryegrass Fatty Acid Content during the Growing Season

NARCIS (Netherlands)

Witkowska, I.M.; Wever, C.J.G.; Gort, G.; Elgersma, A.

2008-01-01

The content of fatty acids (FA) in herbage is important for forage quality and animal-source foods, but there is a lack of knowledge on effects of agronomic practices, and on environmental factors related to seasonal variation in FA concentrations and FA composition. This research investigated the

Comparison of three techniques for estimating the forage intake of lactating dairy cows on pasture.

Science.gov (United States)

Macoon, B; Sollenberger, L E; Moore, J E; Staples, C R; Fike, J H; Portier, K M

2003-09-01

Quantifying DMI is necessary for estimation of nutrient consumption by ruminants, but it is inherently difficult on grazed pastures and even more so when supplements are fed. Our objectives were to compare three methods of estimating forage DMI (inference from animal performance, evaluation from fecal output using a pulse-dose marker, and estimation from herbage disappearance methods) and to identify the most useful approach or combination of approaches for estimating pasture intake by lactating dairy cows. During three continuous 28-d periods in the winter season, Holstein cows (Bos taurus; n = 32) grazed a cool-season grass or a cool-season grass-clover mixture at two stocking rates (SR; 5 vs. 2.5 cows/ha) and were fed two rates of concentrate supplementation (CS; 1 kg of concentrate [as-fed] per 2.5 or 3.5 kg of milk produced). Animal response data used in computations for the animal performance method were obtained from the latter 14 d of each period. For the pulse-dose marker method, chromium-mordanted fiber was used. Pasture sampling to determine herbage disappearance was done weekly throughout the study. Forage DMI estimated by the animal performance method was different among periods (P forage mass. The pulse-dose marker method generally provided greater estimates of forage DMI (as much as 11.0 kg/d more than the animal performance method) and was not correlated with the other methods. Estimates of forage DMI by the herbage disappearance method were correlated with the animal performance method. The difference between estimates from these two methods, ranging from -4.7 to 5.4 kg/d, were much lower than their difference from pulse-dose marker estimates. The results of this study suggest that, when appropriate for the research objectives, the animal performance or herbage disappearance methods may be useful and less costly alternatives to using the pulse-dose method.

Cumulative drought and land-use impacts on perennial vegetation across a North American dryland region

Science.gov (United States)

Munson, Seth M.; Long, A. Lexine; Wallace, Cynthia; Webb, Robert H.

2016-01-01

Question The decline and loss of perennial vegetation in dryland ecosystems due to global change pressures can alter ecosystem properties and initiate land degradation processes. We tracked changes of perennial vegetation using remote sensing to address the question of how prolonged drought and land-use intensification have affected perennial vegetation cover across a desert region in the early 21st century? Location Mojave Desert, southeastern California, southern Nevada, southwestern Utah and northwestern Arizona, USA. Methods We coupled the Moderate-Resolution Imaging Spectroradiometer Enhanced Vegetation Index (MODIS-EVI) with ground-based measurements of perennial vegetation cover taken in about 2000 and about 2010. Using the difference between these years, we determined perennial vegetation changes in the early 21st century and related these shifts to climate, soil and landscape properties, and patterns of land use. Results We found a good fit between MODIS-EVI and perennial vegetation cover (2000: R2 = 0.83 and 2010: R2 = 0.74). The southwestern, far southeastern and central Mojave Desert had large declines in perennial vegetation cover in the early 21st century, while the northeastern and southeastern portions of the desert had increases. These changes were explained by 10-yr precipitation anomalies, particularly in the cool season and during extreme dry or wet years. Areas heavily impacted by visitor use or wildfire lost perennial vegetation cover, and vegetation in protected areas increased to a greater degree than in unprotected areas. Conclusions We find that we can extrapolate previously documented declines of perennial plant cover to an entire desert, and demonstrate that prolonged water shortages coupled with land-use intensification create identifiable patterns of vegetation change in dryland regions.

Predicting foraging wading bird populations in Everglades National Park from seasonal hydrologic statistics under different management scenarios

Science.gov (United States)

Kwon, Hyun-Han; Lall, Upmanu; Engel, Vic

2011-09-01

The ability to map relationships between ecological outcomes and hydrologic conditions in the Everglades National Park (ENP) is a key building block for their restoration program, a primary goal of which is to improve conditions for wading birds. This paper presents a model linking wading bird foraging numbers to hydrologic conditions in the ENP. Seasonal hydrologic statistics derived from a single water level recorder are well correlated with water depths throughout most areas of the ENP, and are effective as predictors of wading bird numbers when using a nonlinear hierarchical Bayesian model to estimate the conditional distribution of bird populations. Model parameters are estimated using a Markov chain Monte Carlo (MCMC) procedure. Parameter and model uncertainty is assessed as a byproduct of the estimation process. Water depths at the beginning of the nesting season, the average dry season water level, and the numbers of reversals from the dry season recession are identified as significant predictors, consistent with the hydrologic conditions considered important in the production and concentration of prey organisms in this system. Long-term hydrologic records at the index location allow for a retrospective analysis (1952-2006) of foraging bird numbers showing low frequency oscillations in response to decadal fluctuations in hydroclimatic conditions. Simulations of water levels at the index location used in the Bayesian model under alternative water management scenarios allow the posterior probability distributions of the number of foraging birds to be compared, thus providing a mechanism for linking management schemes to seasonal rainfall forecasts.

The Perennial Ryegrass GenomeZipper: Targeted Use of Genome Resources for Comparative Grass Genomics1[C][W

Science.gov (United States)

Pfeifer, Matthias; Martis, Mihaela; Asp, Torben; Mayer, Klaus F.X.; Lübberstedt, Thomas; Byrne, Stephen; Frei, Ursula; Studer, Bruno

2013-01-01

Whole-genome sequences established for model and major crop species constitute a key resource for advanced genomic research. For outbreeding forage and turf grass species like ryegrasses (Lolium spp.), such resources have yet to be developed. Here, we present a model of the perennial ryegrass (Lolium perenne) genome on the basis of conserved synteny to barley (Hordeum vulgare) and the model grass genome Brachypodium (Brachypodium distachyon) as well as rice (Oryza sativa) and sorghum (Sorghum bicolor). A transcriptome-based genetic linkage map of perennial ryegrass served as a scaffold to establish the chromosomal arrangement of syntenic genes from model grass species. This scaffold revealed a high degree of synteny and macrocollinearity and was then utilized to anchor a collection of perennial ryegrass genes in silico to their predicted genome positions. This resulted in the unambiguous assignment of 3,315 out of 8,876 previously unmapped genes to the respective chromosomes. In total, the GenomeZipper incorporates 4,035 conserved grass gene loci, which were used for the first genome-wide sequence divergence analysis between perennial ryegrass, barley, Brachypodium, rice, and sorghum. The perennial ryegrass GenomeZipper is an ordered, information-rich genome scaffold, facilitating map-based cloning and genome assembly in perennial ryegrass and closely related Poaceae species. It also represents a milestone in describing synteny between perennial ryegrass and fully sequenced model grass genomes, thereby increasing our understanding of genome organization and evolution in the most important temperate forage and turf grass species. PMID:23184232

Forage mass and stocking rate of elephant grass pastures managed under agroecological and conventional systems

OpenAIRE

Clair Jorge Olivo; Carlos Alberto Agnolin; Priscila Flôres Aguirre; Cláudia Marques de Bem; Tiago Luís da Ros de Araújo; Michelle Schalemberg Diehl; Gilmar Roberto Meinerz

2014-01-01

The objective was to evaluate elephant grass (Pennisetum purpureum Schum.) pastures, under the agroecological and conventional systems, as forage mass and stocking rate. In the agroecological system, the elephant grass was established in rows spaced by 3.0 m from each other. During the cool season ryegrass (Lolium multiflorum Lam.) was established between these rows, which allowed the development of spontaneous growth species during the warm season. In the conventional system the elephant gra...

Seasonal Variation of Provitamin D2 and Vitamin D2 in Perennial Ryegrass (Lolium perenne L.)

DEFF Research Database (Denmark)

Jäpelt, Rie Bak; Didion, Thomas; Smedsgaard, Jørn

2011-01-01

Ergosterol (provitamin D(2)) is converted to vitamin D(2) in grass by exposure to UV light. Six varieties of perennial ryegrass (Lolium perenne L.) were harvested four times during the season, and the contents of vitamin D(2) and ergosterol were analyzed by a sensitive and selective liquid...... chromatography tandem mass spectrometry method. Weather factors were recorded, and a principal component analysis was performed to study which factors were important for the formation of vitamin D(2). The results suggest that a combination of weather factors is involved and that the contents of ergosterol...... and vitamin D(2) change more than a factor of 10 during the season. These results demonstrate that grass potentially can be a significant source of vitamin D for grazing animals and animals fed on silage and hay....

Complete chloroplast genome sequence of a major allogamous forage species, perennial ryegrass (Lolium perenne L.).

Science.gov (United States)

Diekmann, Kerstin; Hodkinson, Trevor R; Wolfe, Kenneth H; van den Bekerom, Rob; Dix, Philip J; Barth, Susanne

2009-06-01

Lolium perenne L. (perennial ryegrass) is globally one of the most important forage and grassland crops. We sequenced the chloroplast (cp) genome of Lolium perenne cultivar Cashel. The L. perenne cp genome is 135 282 bp with a typical quadripartite structure. It contains genes for 76 unique proteins, 30 tRNAs and four rRNAs. As in other grasses, the genes accD, ycf1 and ycf2 are absent. The genome is of average size within its subfamily Pooideae and of medium size within the Poaceae. Genome size differences are mainly due to length variations in non-coding regions. However, considerable length differences of 1-27 codons in comparison of L. perenne to other Poaceae and 1-68 codons among all Poaceae were also detected. Within the cp genome of this outcrossing cultivar, 10 insertion/deletion polymorphisms and 40 single nucleotide polymorphisms were detected. Two of the polymorphisms involve tiny inversions within hairpin structures. By comparing the genome sequence with RT-PCR products of transcripts for 33 genes, 31 mRNA editing sites were identified, five of them unique to Lolium. The cp genome sequence of L. perenne is available under Accession number AM777385 at the European Molecular Biology Laboratory, National Center for Biotechnology Information and DNA DataBank of Japan.

Native herbaceous perennials as ornamentals

DEFF Research Database (Denmark)

Larsen, Bjarne; Ørgaard, Marian

2013-01-01

Gardening with native perennials is a way to bring nature closer to urban citizens and bring up reflections on nature in a busy world. During three seasons of trialing Salvia pratensis, Dianthus deltoides, Campanula trachelium, Vincetoxicum hirundinaria, Saxifraga granulata, Plantago media and P...

Contrasts in Sea Ice Formation and Production in the Arctic Seasonal and Perennial Ice Zones

Science.gov (United States)

Kwok, R.

2006-01-01

Four years (1997-2000) of RADARSAT Geophysical Processor System (RGPS) data are used to contrast the sea ice deformation and production regionally, and in the seasonal (SIZ) and perennial (PIZ) ice zones. Ice production is of seasonal ice in openings during the winter. 3-day estimates of these quantities are provided within Lagrangian elements initially 10 km on a side. A distinct seasonal cycle is seen in both zones with these estimates highest in the late fall and with seasonal minimums in the mid-winter. Regional divergence over the winter could be up to 30%. Spatially, the highest deformation is in the SIZ north of coastal Alaska. Both ice deformation and production are higher in the SIZ: deformation-related ice production in the SIZ (approx.0.5 m) is 1.5-2.3 times that of the PIZ (approx.0.3 m) - this is connected to ice strength and thickness. Atmospheric forcing and boundary layer structure contribute to only the seasonal and interannual variability. Seasonal ice growth in ice fractures accounts for approx.25-40% of the total ice production of the Arctic Ocean. By itself, this deformation-ice production relationship could be considered a negative feedback when thickness is perturbed. However, the overall effect on ice production in the face of increasing seasonal and thinner/weaker ice coverage could be modified by: local destabilization of the water column promoting overturning of warmer water due to increased brine rejection; and, the upwelling of the pynocline associated with increased occurrence of large shear motion in sea ice.

Genes and quantitative trait loci (QTL) controlling trace element concentrations in perennial grasses grown on phytotoxic soil contaminated with heavy metals

Science.gov (United States)

Perennial grasses cover diverse soils throughout the world, including sites contaminated with heavy metals, producing forages that must be safe for livestock and wildlife. Chromosome regions known as quantitative trait loci (QTLs) controlling forage mineral concentrations were mapped in a populatio...

Season and landscape composition affect pollen foraging distances and habitat use of honey bees.

Science.gov (United States)

Danner, Nadja; Molitor, Anna Maria; Schiele, Susanne; Härtel, Stephan; Steffan-Dewenter, Ingolf

2016-09-01

Honey bees (Apis mellifera L.) show a large variation in foraging distances and use a broad range of plant species as pollen resources, even in regions with intensive agriculture. However, it is unknown how increasing areas of mass-flowering crops like oilseed rape (Brassica napus; OSR) or a decrease of seminatural habitats (SNH) change the temporal and spatial availability of pollen resources for honey bee colonies, and thus foraging distances and frequency in different habitat types. We studied pollen foraging of honey bee colonies in 16 agricultural landscapes with independent gradients of OSR and SNH area within 2 km and used waggle dances and digital geographic maps with major land cover types to reveal the distance and visited habitat type on a landscape level. Mean pollen foraging distance of 1347 decoded bee dances was 1015 m (± 26 m; SEM). In spring, increasing area of flowering OSR within 2 km reduced mean pollen foraging distances from 1324 m to only 435 m. In summer, increasing cover of SNH areas close to the colonies (within 200 m radius) reduced mean pollen foraging distances from 846 to 469 m. Frequency of pollen foragers per habitat type, measured as the number of dances per hour and hectare, was equally high for SNH, grassland, and OSR fields, but lower for other crops and forests. In landscapes with a small proportion of SNH a significantly higher density of pollen foragers on SNH was observed, indicating that pollen resources in such simple agricultural landscapes are more limited. Overall, we conclude that SNH and mass-flowering crops can reduce foraging distances of honey bee colonies at different scales and seasons with possible benefits for the performance of honey bee colonies. Further, mixed agricultural landscapes with a high proportion of SNH reduce foraging densities of honey bees in SNH and thus possible competition for pollen resources. © 2016 by the Ecological Society of America.

A systems approach for the evaluation of ethanol production based on forages

Energy Technology Data Exchange (ETDEWEB)

Alvo, P. [McGill Univ., Ste. Anne de Bellevue, PQ (Canada). Macdonald Coll.; Savoie, P. [Agriculture and Agri-Food Canada, Quebec, PQ (Canada). Saine-Foy Research Centre; Tremblay, D. [Laval Univ., Quebec, PQ (Canada). Dept. de Genie Rural; Emond, J.-P.; Turcotte, G. [Laval Univ., Quebec City, PQ (Canada). Dept. de Sciences et Technologie des Aliments

1996-04-01

A systems approach is proposed to simultaneously consider the agronomic aspects of forage production and the processing aspects related to the extraction of a glucose or xylose substrate, its fermentation into ethanol and the optimal utilization of co-products (protein meal, fibrous residue). The energy to produce and transport forage on the farm was estimated to be only 375 MJ/t dry matter (DM) when liquid manure was used and 1165 MJ/t DM when mineral fertilizer was used. An additional 126 MJ/t DM would be required to transport it to a processing plant. In contrast, whole-plant corn production using mineral fertilizer required about 3211 MJ/t DM, but it had a potential ethanol yield 3.2 times greater per unit area than perennial forage. A forage system with mechanical juice extraction resulted in 8-20% of the original forage dry matter available in a liquid substrate with subsequent protein meal separation and the fermentation of soluble sugars into ethanol. Another forage system with relatively complete conversion of cellulose and hemicellulose into simple sugars by thermal, acidic and enzymatic treatments was estimated to produce 12-28 times more ethanol per unit area than the mechanically extracted juice. Complete conversion of perennial forages would meet the petroleum industry`s needs more consistently than simple extraction of soluble components. (Author)

Cool seasons are related to poor prognosis in patients with infective endocarditis

Science.gov (United States)

Chen, Su-Jung; Chao, Tze-Fan; Lin, Yenn-Jiang; Lo, Li-Wei; Hu, Yu-Feng; Tuan, Ta-Chuan; Hsu, Tsui-Lieh; Yu, Wen-Chung; Leu, Hsin-Bang; Chang, Shih-Lin; Chen, Shih-Ann

2012-09-01

Many cardiac diseases demonstrate seasonal variations in the incidence and mortality. This study was designed to investigate whether the mortality of infective endocarditis (IE) was higher in cool seasons and to evaluate the effects of cool climate for IE. We enrolled 100 IE patients with vegetations in our hospital. The temperatures of the IE episodes were defined as the monthly average temperatures of the admission days. The average temperatures in the cool (fall/winter) and warm seasons (spring/summer) were 19.2°C and 27.6°C, respectively. In addition, patients admitted with the diagnosis of IE were identified from the National Health Insurance Research Database (NHIRD) and the in-hospital mortality rates in cool and warm seasons were compared to validate the findings derived from the data of our hospital. The mortality rate for IE was significantly higher in fall/winter than in spring/summer which presents consistently in the patient population of our hospital (32.7% versus 12.5%, p = 0.017) and from NHIRD (10.4% versus 4.6%, p = 0.019). IE episodes which occurred during cool seasons presented with a higher rate of heart failure (44.2% versus 22.9%, p = 0.025) and D-dimer level (5.5 ± 3.8 versus 2.4 ± 1.8 μg/ml, p = 0.017) at admission than that of warm seasons. These results may reflect the impact of temperatures during the pre-hospitalized period on the disease process. In the multivariate analysis, Staphylococcal infection, left ventricular hypertrophy, left ventricular systolic dysfunction and temperature were the independent predictors of mortalities in IE patients.

Diet variability of forage fishes in the Northern California Current System

Science.gov (United States)

Hill, Andrew D.; Daly, Elizabeth A.; Brodeur, Richard D.

2015-06-01

As fisheries management shifts to an ecosystem-based approach, understanding energy pathways and trophic relationships in the Northern California Current (NCC) will become increasingly important for predictive modeling and understanding ecosystem response to changing ocean conditions. In the NCC, pelagic forage fishes are a critical link between seasonal and interannual variation in primary production and upper trophic groups. We compared diets among dominant forage fish (sardines, anchovies, herring, and smelts) in the NCC collected in May and June of 2011 and June 2012, and found high diet variability between and within species on seasonal and annual time scales, and also on decadal scales when compared to results of past studies conducted in the early 2000s. Copepoda were a large proportion by weight of several forage fish diets in 2011 and 2012, which differed from a preponderance of Euphausiidae found in previous studies, even though all years exhibited cool ocean conditions. We also examined diet overlap among these species and with co-occurring subyearling Chinook salmon and found that surf smelt diets overlapped more with subyearling Chinook diets than any other forage fish. Herring and sardine diets overlapped the most with each other in our interdecadal comparisons and some prey items were common to all forage fish diets. Forage fish that show plasticity in diet may be more adapted to ocean conditions of low productivity or anomalous prey fields. These findings highlight the variable and not well-understood connections between ocean conditions and energy pathways within the NCC.

Changes of biomass in some perennial grass species. | M.C. ...

African Journals Online (AJOL)

Patterns of seasonal herbaceous biomass change in a burned, ungrazed savanna woodland are reported. A standard clipping technique was used and material farmed in the current season was separated from that formed in the previous season for three perennial grass species: Brachiaria nigropedata, Andropogon ...

Towards in vitro fertilization, gametosomatic cybridization and DNA transfer in perennial ryegrass (Lolium perenne L.)

NARCIS (Netherlands)

Maas, van der H.M.

1994-01-01

In this thesis, research towards invitro fertilization, gametosomatic cybridization andDNAtransfer in perennial ryegrass ( Loliumperenne L.), the most important forage

Forage mass and the nutritive value of pastures mixed with forage peanut and red clover

Directory of Open Access Journals (Sweden)

Ricardo Lima de Azevedo Junior

2012-04-01

Full Text Available The objective of this research was to estimate three pasture-based systems mixed with elephantgrass + spontaneous growth species, annual ryegrass, for pasture-based system 1; elephantgrass + spontaneous growth species + forage peanut, for pasture-based system 2; and elephantgrass + spontaneous growth species + annual ryegrass + red clover, for pasture-based system 3. Elephantgrass was planted in rows 4 m apart from each other. During the cool-season, annual ryegrass was sown in the alleys between the rows of elephantgrass; forage peanut and red clover were sown in the alleys between the elephantgrass according to the respective treatment. The experimental design was totally randomized in the three treatments (pasture-based systems, two replicates (paddocks in completely split-plot time (grazing cycles. Holstein cows receiving 5.5 kg-daily complementary concentrate feed were used in the evaluation. Pre-grazing forage mass, botanical composition and stocking rate were evaluated. Samples of simulated grazing were collected to analyze organic matter (OM, neutral detergent fiber (NDF, crude protein (CP and organic matter in situ digestibility (OMISD. Nine grazing cycles were performed during the experimental period (341 days. The average dry matter values for pre-grazing and stocking rate were 3.34; 3.46; 3.79 t/ha, and 3.28; 3.34; 3.60 AU/ha for each respective pasture-based system. Similar results were observed between the pasture-based systems for OM, NDF, CP and OMISD. Considering forage mass, stocking rate and nutritive value, the pasture-based system intercropped with forage legumes presented better performance.

Optimal foraging in seasonal environments: implications for residency of Australian flying foxes in food-subsidized urban landscapes.

Science.gov (United States)

Páez, David J; Restif, Olivier; Eby, Peggy; Plowright, Raina K

2018-05-05

Bats provide important ecosystem services such as pollination of native forests; they are also a source of zoonotic pathogens for humans and domestic animals. Human-induced changes to native habitats may have created more opportunities for bats to reside in urban settings, thus decreasing pollination services to native forests and increasing opportunities for zoonotic transmission. In Australia, fruit bats ( Pteropus spp. flying foxes) are increasingly inhabiting urban areas where they feed on anthropogenic food sources with nutritional characteristics and phenology that differ from native habitats. We use optimal foraging theory to investigate the relationship between bat residence time in a patch, the time it takes to search for a new patch (simulating loss of native habitat) and seasonal resource production. We show that it can be beneficial to reside in a patch, even when food productivity is low, as long as foraging intensity is low and the expected searching time is high. A small increase in the expected patch searching time greatly increases the residence time, suggesting nonlinear associations between patch residence and loss of seasonal native resources. We also found that sudden increases in resource consumption due to an influx of new bats has complex effects on patch departure times that again depend on expected searching times and seasonality. Our results suggest that the increased use of urban landscapes by bats may be a response to new spatial and temporal configurations of foraging opportunities. Given that bats are reservoir hosts of zoonotic diseases, our results provide a framework to study the effects of foraging ecology on disease dynamics.One contribution of 14 to a theme isssue 'Anthropogenic resource subsidies and host-parasite dynamics in wildlife'. © 2018 The Author(s).

Peripartal rumination dynamics and health status in cows calving in hot and cool seasons.

Science.gov (United States)

Paudyal, S; Maunsell, F; Richeson, J; Risco, C; Donovan, A; Pinedo, P

2016-11-01

Our objective was to evaluate the effect of season of calving, associated with variable levels of heat stress, on the dynamics of rumination during the prepartum period and early lactation of cows that were healthy or affected by peripartal health disorders. Three weeks before the estimated due date, 210 multiparous Holstein cows at the University of Florida Dairy Unit were affixed with a neck collar containing rumination loggers, providing rumination time (RT) in 2-h periods. One blood sample was collected in a subpopulation of cows (n=76) at 12 to 48h postcalving to assess metabolic status by determining serum calcium, nonesterified fatty acid, and β-hydroxybutyrate concentrations. The occurrence of peripartal health disorders (dystocia, clinical ketosis, clinical hypocalcemia, metritis, and mastitis) was assessed by University of Florida veterinarians and trained farm personnel. We analyzed the dynamics of daily RT over ± 14d relative to parturition in cows that were healthy or affected by specific health disorders by season of calving [hot season, June to September (n=77); cool season, November to April (n=118)] using repeated measures analysis and comparison of least squares means at different time points relative to calving. Rumination was consistently reduced on the day of calving in both healthy and sick cows in both the hot and cool seasons. Only hot-season calvings had shorter average daily RT prepartum and postpartum in cows affected by severe negative energy balance and subclinical ketosis. Dystocia during the hot season was associated with shorter daily RT prepartum; for cool-season calvings, cows with dystocia had reduced RT postpartum. We also observed reduced RT in cows with ketosis prepartum and postpartum in both the hot and cool seasons. Daily RT was reduced postpartum in cows with hypocalcemia and mastitis that calved during the cool season, and it was shorter in cows with metritis in both the hot and cool seasons. Our results indicated that

Determination of Cardinal Temperatures for Cool Season Turfgrass and Two Common Weed Species

Directory of Open Access Journals (Sweden)

Marjan Diayanat

2018-02-01

Full Text Available Introduction The presence of broadleaf weeds not only reduces the aesthetic quality of the turfgrass, but more importantly they compete with desired turfgrass for water, nutrients, and light. Weed management after seeding is an important component to successfully establishing a healthy stand of cool season turfgrass. Weed seed germination is a key process because determines both the number of weeds that could potentially emerge and the timing of their appearance in the turfgrass. Temperature is of the most important factor regulating germination of non-dormant seeds in irrigated, annual agroecosystems at the beginning of the growth season where light, nutrients, and moisture are typically not growth limiting. Also prostrate knotweed (Polygonum aviculare L. and annual sowthistle (Sonchus oleraceus L. are two annual common broad leaf weeds in cool season turfgrass. Prostrate knotweed is very competitive in infertile and compacted soils and often invades turfgrasses along driveways, sidewalks, and beaten paths across lawns. Annual sowthistle is found in open habitats that include waste areas, turf, and roadsides. The aim of this study was to evaluate different nonlinear regression models to describe response of germination rate to different temperatures in perennial ryegrass (Lolium perenne L., fescue (Festuca rubra L., prostrate knotweed and annual sowthistle. Materials and Methods This experiment was based on completely randomized design with 4 replications at Islamic Azad University in the laboratory of Science Research Branch in 2015. The seeds were treated with different temperatures (2, 5, 10, 15, 20, 25, 30, 35, 40 and 45oC Twenty five seeds were placed in each petri dish for each species in per replication. Ten milliliters of distilled water were added to each petri dish and the filter papers were regularly moistened to ensure saturation throughout the germination tests. Petri dishes were placed in germinator with 16 hour day, 8 hour night

Comparative seasonal variations of spectral signatures of broad-leaved and coniferous stands from Landsat data. Comparison with other perennial environments

International Nuclear Information System (INIS)

Chaume, R.; Combeau, A.

1984-01-01

Spectral signatures of two distinct forest test areas were identified from digital data including 15 LANDSAT scenes covering the same geographical area: a broad-leaved forest (oak and beech) and a coniferous forest (scotch pine). Seasonal variations of the signatures were examined and were expressed in terms of various data: date, solar height and phenological state of vegetation cover. Results were compared to these obtained from other perennial surface conditions (grassland, bare soils) . Range of the seasonal variations of radiance is noted, as well as evolutionary peculiarities on each band and between themes. Rationing of spectral bands (particularly MSS 5 and 7) and their variation with time are specified [fr

Evaluation of Perennial Forage Legumes and Herbs in Six Mediterranean Environments Evaluación de Leguminosas y Hierbas Forrajeras Perennes en Seis Medioambientes Mediterráneos

Directory of Open Access Journals (Sweden)

Daniel Real

2011-09-01

Full Text Available There is an absence of drought tolerant herbaceous perennial forage legume and herb options other than lucerne (Medicago sativa L. for environments with Mediterranean-like climates common in extensive areas of Southern Australia, the Mediterranean basin, and Chile. Therefore, a collection of 174 forage perennial legume and herb entries from 103 species and 32 genera was evaluated for adaptation in a diverse range of Mediterranean climatic environments in Southern Australia. The seasonal rainfall distribution varied from moderately to highly winter dominant with long term average annual rainfall ranging from 318 to 655 mm. The entries were rated for productivity and persistence over 3 yr. The 12 entries identified as the most promising for winter, summer, or all-year round production included Bituminaria bituminosa (L. C.H. Stirt. var. albomarginata; Cichorium intybus L.; Cullen australasicum (Schltdl. J.W. Grimes; Dorycnium hirsutum (L. Ser.; Kennedia prostrata R. Br.; Lotononis bainesii Baker, Lotus pedunculatus Cav.; L. corniculatus L.; L. cytisoides L.; Medicago sativa subsp. sativa L.; Medicago sativa subsp. caerulea (Less. ex Ledeb. Schmalh., and M. sativa subsp. falcata (L. Arcang. These entries maintained production and persisted for the period of the evaluation, with the exception of C. intybus and L. corniculatus that declined in persistence over time. The potential role of these species in extensive grazing systems in Mediterranean climatic zones, their attributes and limitations, and current progress in developing them as useful forage plants was discussed.Existe una escasez de leguminosas y hierbas perennes herbáceas además de alfalfa (Medicago sativa L. tolerantes a sequía para ambientes con clima mediterráneo como los que se encuentran en el Sur de Australia, el Mediterráneo y Chile. Por lo tanto, una colección de 174 leguminosas perennes y hierbas correspondientes a 103 especies y 32 géneros fue evaluada por su adaptaci

Subalpine bumble bee foraging distances and densities in relation to flower availability.

Science.gov (United States)

Elliott, Susan E

2009-06-01

Bees feed almost exclusively on nectar and pollen from flowers. However, little is known about how food availability limits bee populations, especially in high elevation areas. Foraging distances and relationships between forager densities and resource availability can provide insights into the potential for food limitation in mobile consumer populations. For example, if floral resources are limited, bee consumers should fly farther to forage, and they should be more abundant in areas with more flowers. I estimated subalpine bumble bee foraging distances by calculating forager recapture probabilities at increasing distances from eight marking locations. I measured forager and flower densities over the flowering season in six half-hectare plots. Because subalpine bumble bees have little time to build their colonies, they may forage over short distances and forager density may not be constrained by flower density. However, late in the season, when floral resources dwindle, foraging distances may increase, and there may be stronger relationships between forager and flower densities. Throughout the flowering season, marked bees were primarily found within 100 m (and never >1,000 m) from their original marking location, suggesting that they typically did not fly far to forage. Although the density of early season foraging queens increased with early-season flower density, the density of mid- and late-season workers and males did not vary with flower density. Short foraging distances and no relationships between mid- and late-season forager and flower densities suggest that high elevation bumble bees may have ample floral resources for colony growth reproduction.

Assessing Water-use Relationships in a Perennial Kernza Field

Science.gov (United States)

De Oliveira, G.; Brunsell, N. A.; Sutherlin, C. E.; Crews, T.; Vico, G.

2017-12-01

Perennial grain/forage crops can sustain high yields without replanting for 3-10 years or more, resulting in potentially important environmental benefits. Although previous research has been conducted in perennial food crops, the coupling between these ecosystems and the atmosphere is not well understood. The objective of this study was to evaluate the magnitude and temporal variability of the water-use relationships in a perennial Kernza wheatgrass crop in Salina, north-central region of Kansas (KS), USA. The study period comprised approximately 4.5 years (May 2012-October 2016) of eddy covariance observations collected at the US-KLS AmeriFlux tower. In particular, we examine the water-use efficiency, carbon and water fluxes in relation to the local environmental factors, such as vapor pressure deficit, soil moisture, air temperature, etc. An analysis of the correspondence between accumulated precipitation (PPT) and ET in the perennial crop indicated a most likely low surface runoff and that there were other sources of water for plant intake in addition to the annual PPT, i.e., deep water. In this sense, we highlight that the long roots observed in perennial crops may facilitate the water uptake in the deeper soil layers, providing extra resources for the plant growth especially when the rainfall indices are low. The results obtained in this work are important in order to better understand the hydrologic cycle of perennial agroecosystems as well as to understand the benefits and disadvantages in relation to annual crops particularly under changing climatic conditions.

Genetic markers for flowering in perennial ryegrass

DEFF Research Database (Denmark)

Paina, Cristiana; Byrne, Stephen; Andersen, Jeppe Reitan

2011-01-01

Perennial ryegrass (Lolium perenne L.) is the principal forage grass utilized in Danish agriculture and underpins the beef and dairy sectors. It is characterized as having high digestibility, high nutritional value, and high productivity during vegetative growth. However, at the reproductive growth...... genes will be converted to molecular markers and mapped in an existing mapping population previously characterized for flowering time and vernalization response. References: Amasino, R.M., Michaels S.D. (2010). The Timing of Flowering. Plant Physiology 154: 516–520 Greenup, A., W. Peacock, W.J., Dennis...

Seasonal variation of the Cs137 contamination of the tree forage of wild hoofed animals of the Pripyat National Park

International Nuclear Information System (INIS)

Uglyanets, A.V.

2011-01-01

In the conditions of the Republic of Belarus there were presented the results of studies of the 137Cs contamination of the tree forage of wild hoofed animals in the Pripyat national park. The parameters of this radioisotope accumulation in the shoots of different trees, shrubs, dwarf shrubs and bushes were studied in the seasonal and edaphic aspects, and their influencing factors were specified. The 137Cs contamination of the tree forage of wild hoofed animals was determined to be dependent on the soil pollution degree, growth conditions and species composition of plants and their proportion in the phytocenosis, as well as on the edaphic conditions and a season of the year

Importance and condition of forage crops seed production in agriculture of the Republic of Serbia

Directory of Open Access Journals (Sweden)

Đokić Dragoslav

2013-01-01

Full Text Available For contemporary and economical livestock production, especially cattle and sheep raising, it is necessary to achieve high production of livestock feed while reducing production costs. Improving the production of perennial grasses and legumes creates a good basis for the development of livestock production in different agro-ecological conditions of Serbia. It also establishes a link between farming and animal husbandry, which is of particular importance for the preservation and higher fertility of arable land and the protection of agro-ecosystems. An important factor for the cheaper production of livestock feed is the possibility to provide sufficient quantities of quality seeds at affordable prices. Production of quality seeds of local varieties of perennial legumes is possible to obtain sufficient amounts of good quality forage. Current situation in forage crop seed production of the Republic of Serbia is unsatisfactory because the seed of perennial grasses are mostly imported. Domestic production of alfalfa, red clover and birdsfoot trefoil met domestic needs only in some years. Seed of imported varieties are often not satisfactory because those varieties are not adapted to our local agro-ecological conditions. The present results provide the basis and direction for further researches that may provide solutions to increase seed yields and which will be widely accepted in practice, which will make the production more cost-effective. Institute for forage crops Kruševac is making a significant contribution to the development of technology of seed productions, especially alfalfa, red clover and perennial grasses. Therefore the role of the Institute is very important and necessary link between production, processing and trading seeds of perennial legumes and grasses in Serbia.

Testing water-soluble carbohydrate QTL effects in perennial ryegrass (Lolium perenne L.) by marker selection

NARCIS (Netherlands)

Turner, L.B.; Farrell, M.; Humphreys, M.O.; Dolstra, O.

2010-01-01

Water-soluble carbohydrates (WSC) are an important factor determining the nutritional value of grass forage and development of genetic markers for selection of WSC traits in perennial ryegrass would benefit future breeding programmes. Quantitative trait loci (QTLs) for WSC have been published for an

Produção de forragem de gramíneas anuais semeadas no verão Forage yield of annual grasses seeded on the summer

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Rafael Orth

2012-09-01

Full Text Available No Rio Grande do Sul, a base forrageira para bovinos de corte e de leite é constituída, basicamente, por pastagens de gramíneas perenes de verão, com bom valor nutritivo (VN durante a primavera e parte do verão, quando manejadas adequadamente. Entretanto, a forragem no outono e inverno tem baixa concentração de nutrientes, o que ainda é agravado pelas geadas. Um experimento com dois anos de avaliação com parcelas divididas no delineamento em blocos casualizados, com três repetições, comparou rendimento, distribuição de forragem e valor nutritivo em três épocas de semeadura (janeiro, fevereiro e março, alocadas nas parcelas principais, e cinco genótipos (milheto comum, capim-sudão ou aveia de verão, teosinto e os híbridos de sorgo BRS 800 e AG 2501C nas subparcelas. As duas primeiras épocas de semeadura resultaram em maior rendimento de forragem (mais de 6,0Mg ha-1 de MS que a semeadura de março, com elevado valor nutritivo (>15% PB. Os sorgos forrageiros foram mais produtivos que capim-sudão e teosinto. Milheto, capim-sudão e teosinto têm maior afilhamento que os sorgos forrageiros híbridos. Milheto tem maior teor de PB (20% e menor de FDA (35% nas lâminas foliares quando comparado aos sorgos e teosinto. É possível minimizar a crise forrageira conhecida como vazio forrageiro outonal com a semeadura em múltiplas datas de forrageiras anuais de verão, até o final de fevereiro na região do Planalto Médio do RS e estender o período de pastejo em até 60 dias, em período em que as pastagens perenes de verão têm baixa oferta de forragem ou baixo valor nutritivo e as forrageiras anuais de inverno não estão estabelecidas.In the Rio Grande do Sul (RS state, southern Brazil, the forage foundation of beef and dairy cattle operations is pasture of warm-season grasses, with high nutritive value (NV during spring and part of summer seasons, if managed frequently. However, during cool-season, forage NV is very low and

Forage yield and nitrogen nutrition dynamics of warm-season native forage genotypes under two shading levels and in full sunlight

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Raquel Santiago Barro

2012-07-01

Full Text Available The successful achievement of a highly productive understorey pasture in silvopastoral systems depends on the use of well-adapted forage genotypes, showing good agronomic performance and persistence under shading and grazing. In this study, the herbage dry matter yield (DMY and nitrogen nutrition dynamics were determined in three native warm-season grasses (Paspalum regnellii, Paspalum dilatatum and Paspalum notatum and a forage legume (Arachis pintoi under two shading levels compared with full sun. The experiment was conducted in the Campanha region, Bagé, state of Rio Grande do Sul, Brazil, during two evaluation cycles (2008/2009 and 2009/2010. Three shade cloth levels (0%, 50% and 80% of light restriction were applied to the forage genotypes in a split plot design, in which shading levels were the main plot and forage genotypes were the subplots, with three replications. P. regnellii showed the highest accumulated DMY (1500 and 1700 g m-2, respectively, for the first and second evaluation cycles at all shading levels and showed no DMY decreased under the heavy shade (80%. Average DMY over the four genotypes under the 50% shade level was higher or equal compared with full sun. Influence of rainfall was observed on the DMY performance of all genotypes: the positive effect of moderate shading (50% on P. dilatatum and P. notatum DMY was associated to a low soil water availability status. Increased shading level resulted in high nitrogen nutrition index values on grasses, in comparison with full sun. All genotypes performed well under the moderate shading level, but the DMY of both P. regnellii and P. dilatatum and the herbage N content in P. notatum and A. pintoi of all genotypes stood out, showing that those main genotypes are promising to grow in silvopastoral systems at the Campanha region in southern Brazil.

Temporal effects of hunting on foraging behavior of an apex predator: Do bears forego foraging when risk is high?

Science.gov (United States)

Hertel, Anne G; Zedrosser, Andreas; Mysterud, Atle; Støen, Ole-Gunnar; Steyaert, Sam M J G; Swenson, Jon E

2016-12-01

Avoiding predators most often entails a food cost. For the Scandinavian brown bear (Ursus arctos), the hunting season coincides with the period of hyperphagia. Hunting mortality risk is not uniformly distributed throughout the day, but peaks in the early morning hours. As bears must increase mass for winter survival, they should be sensitive to temporal allocation of antipredator responses to periods of highest risk. We expected bears to reduce foraging activity at the expense of food intake in the morning hours when risk was high, but not in the afternoon, when risk was low. We used fine-scale GPS-derived activity patterns during the 2 weeks before and after the onset of the annual bear hunting season. At locations of probable foraging, we assessed abundance and sugar content, of bilberry (Vaccinium myrtillus), the most important autumn food resource for bears in this area. Bears decreased their foraging activity in the morning hours of the hunting season. Likewise, they foraged less efficiently and on poorer quality berries in the morning. Neither of our foraging measures were affected by hunting in the afternoon foraging bout, indicating that bears did not allocate antipredator behavior to times of comparably lower risk. Bears effectively responded to variation in risk on the scale of hours. This entailed a measurable foraging cost. The additive effect of reduced foraging activity, reduced forage intake, and lower quality food may result in poorer body condition upon den entry and may ultimately reduce reproductive success.

Dissecting the genetics of rhizomatousness: Towards sustainable food, forage, and bioenergy

Science.gov (United States)

Rhizomatousness is a key trait influencing both the perenniality and biomass partitioning of plants. Increased understanding of the genetic control of rhizome growth offers potential towards the creation of more sustainable grain, forage, and bioenergy cropping systems. It is also applicable to th...

Seasonal changes in chemical composition and nutritive value of native forages in a spruce-hemlock forest, southeastern Alaska.

Science.gov (United States)

Thomas A. Hanley; Jay D. McKendrick

1983-01-01

Twenty-two forages from Admiralty Island, southeastern Alaska, were monitored bimonthly for one year to assess seasonal changes in their chemical composition: neutral detergent fiber, acid detergent fiber, cellulose, lignin/cutin, invitro dry-matter digestibility, total nitrogen, phosphorus, potassium, calcium, magnesium, sodium, copper, manganese, iron, and zinc....

The Perennial Ryegrass GenomeZipper – Targeted Use of Genome Resources for Comparative Grass Genomics

DEFF Research Database (Denmark)

Pfeiffer, Matthias; Martis, Mihaela; Asp, Torben

2013-01-01

(Lolium perenne) genome on the basis of conserved synteny to barley (Hordeum vulgare) and the model grass genome Brachypodium (Brachypodium distachyon) as well as rice (Oryza sativa) and sorghum (Sorghum bicolor). A transcriptome-based genetic linkage map of perennial ryegrass served as a scaffold......Whole-genome sequences established for model and major crop species constitute a key resource for advanced genomic research. For outbreeding forage and turf grass species like ryegrasses (Lolium spp.), such resources have yet to be developed. Here, we present a model of the perennial ryegrass...... to establish the chromosomal arrangement of syntenic genes from model grass species. This scaffold revealed a high degree of synteny and macrocollinearity and was then utilized to anchor a collection of perennial ryegrass genes in silico to their predicted genome positions. This resulted in the unambiguous...

Accuracy of Genomic Prediction in a Commercial Perennial Ryegrass Breeding Program

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Dario Fè

2016-11-01

Full Text Available The implementation of genomic selection (GS in plant breeding, so far, has been mainly evaluated in crops farmed as homogeneous varieties, and the results have been generally positive. Fewer results are available for species, such as forage grasses, that are grown as heterogenous families (developed from multiparent crosses in which the control of the genetic variation is far more complex. Here we test the potential for implementing GS in the breeding of perennial ryegrass ( L. using empirical data from a commercial forage breeding program. Biparental F and multiparental synthetic (SYN families of diploid perennial ryegrass were genotyped using genotyping-by-sequencing, and phenotypes for five different traits were analyzed. Genotypes were expressed as family allele frequencies, and phenotypes were recorded as family means. Different models for genomic prediction were compared by using practically relevant cross-validation strategies. All traits showed a highly significant level of genetic variance, which could be traced using the genotyping assay. While there was significant genotype × environment (G × E interaction for some traits, accuracies were high among F families and between biparental F and multiparental SYN families. We have demonstrated that the implementation of GS in grass breeding is now possible and presents an opportunity to make significant gains for various traits.

Nutritive value, fermentation characteristics, and in situ disappearance kinetics of ensiled warm-season legumes and bahiagrass.

Science.gov (United States)

Foster, J L; Carter, J N; Sollenberger, L E; Blount, A R; Myer, R O; Maddox, M K; Phatak, S C; Adesogan, A T

2011-04-01

This study determined the nutritive value, ensiling characteristics, and in situ disappearance kinetics of bahiagrass (Paspalum notatum Flügge 'Tifton 9'), perennial peanut (Arachis glabrata Benth. 'Florigraze'), annual peanut [Arachis hypogaea (L.) 'FL MDR 98'], cowpea [Vigna unguiculata (L.) Walp. 'Iron clay'], and pigeonpea [Cajanus cajan (L.) Millsp. 'GA-2']. All forages were harvested at maturity stages that optimized dry matter (DM) yield and nutritive value. After harvest, forages were wilted to 45% DM, and 4 replicate bales of each legume and 8 bales of bahiagrass were wrapped in polyethylene and ensiled for 180 d. After each bale was opened, the forage was thoroughly mixed, and representative subsamples were taken for laboratory analysis and in situ incubation. Wilting and ensiling decreased the rumen-undegradable protein, water-soluble carbohydrate, crude protein (CP), and in vitro true digestibility (IVTD) of bahiagrass, perennial peanut, and cowpea, and increased their neutral detergent fiber (NDF) concentrations. Among haylages, CP concentration was greatest for annual peanut, followed by perennial peanut and cowpea, and least for bahiagrass. In contrast, NDF concentration was greater in bahiagrass than in legumes. Pigeonpea had the greatest NDF concentration among legumes and lowest IVTD of all haylages. All haylages were aerobically stable for at least 84 h, but pH was lower in perennial peanut and cowpea than in pigeonpea. Ammonia-N concentrations tended to be greater in legume haylages than in bahiagrass haylage. Butyrate concentration was greater in annual and perennial peanut than in bahiagrass. Total VFA concentration was greater in annual and perennial peanut and cowpea haylages than in bahiagrass haylage. Undegradable DM fractions were greater and extent of DM degradation was lower in bahiagrass and pigeonpea than in other haylages but lag time and degradation rates did not differ. Annual and perennial peanut and cowpea haylages were as

Urban gardens promote bee foraging over natural habitats and plantations.

Science.gov (United States)

Kaluza, Benjamin F; Wallace, Helen; Heard, Tim A; Klein, Alexandra-Maria; Leonhardt, Sara D

2016-03-01

Increasing human land use for agriculture and housing leads to the loss of natural habitat and to widespread declines in wild bees. Bee foraging dynamics and fitness depend on the availability of resources in the surrounding landscape, but how precisely landscape related resource differences affect bee foraging patterns remains unclear. To investigate how landscape and its interaction with season and weather drive foraging and resource intake in social bees, we experimentally compared foraging activity, the allocation of foragers to different resources (pollen, nectar, and resin) and overall resource intake in the Australian stingless bee Tetragonula carbonaria (Apidae, Meliponini). Bee colonies were monitored in different seasons over two years. We compared foraging patterns and resource intake between the bees' natural habitat (forests) and two landscapes differently altered by humans (suburban gardens and agricultural macadamia plantations). We found foraging activity as well as pollen and nectar forager numbers to be highest in suburban gardens, intermediate in forests and low in plantations. Foraging patterns further differed between seasons, but seasonal variations strongly differed between landscapes. Sugar and pollen intake was low in plantations, but contrary with our predictions, it was even higher in gardens than in forests. In contrast, resin intake was similar across landscapes. Consequently, differences in resource availability between natural and altered landscapes strongly affect foraging patterns and thus resource intake in social bees. While agricultural monocultures largely reduce foraging success, suburban gardens can increase resource intake well above rates found in natural habitats of bees, indicating that human activities can both decrease and increase the availability of resources in a landscape and thus reduce or enhance bee fitness.

Genetic variation, population structure, and linkage disequilibrium in European elite germplasm of perennial ryegrass

DEFF Research Database (Denmark)

Brazauskas, Gintaras; Lenk, Ingo; Pedersen, Morten Greve

2011-01-01

Perennial ryegrass (Lolium perenne L.) is a highly valued temperate climate grass species grown as forage crop and for amenity uses. Due to its outbreeding nature and recent domestication, a high degree of genetic diversity is expected among cultivars. The aim of this study was to assess the extent...... of linkage disequilibrium (LD) within European elite germplasm and to evaluate the appropriate methodology for genetic association mapping in perennial ryegrass. A high level of genetic diversity was observed in a set of 380 perennial ryegrass elite genotypes when genotyped with 40 SSRs and 2 STS markers...... and occurred within 0.4 cM across European varieties, when population structure was taken into consideration. However, an extended LD of up to 6.6 cM was detected within the variety Aberdart. High genetic diversity and rapid LD decay provide means for high resolution association mapping in elite materials...

Effects of fire and nitrogen addition on forage quality of Aristida purpurea

Science.gov (United States)

Purple threeawn (Aristida purpurea Nutt.) is a native perennial bunchgrass with limited forage value that dominates sites with disturbed soils and persists with continued severe grazing. Fire and nitrogen addition have been used to reduce threeawn and may increase grazing utilization of threeawn by...

Intra-seasonal variation in foraging behavior among Adélie penguins (Pygocelis adeliae) breeding at Cape Hallett, Ross Sea, Antarctica

Science.gov (United States)

Lyver, P.O.B.; MacLeod, C.J.; Ballard, G.; Karl, B.J.; Barton, K.J.; Adams, J.; Ainley, D.G.; Wilson, P.R.

2011-01-01

We investigated intra-seasonal variation in foraging behavior of chick-rearing Adélie penguins, Pygoscelis adeliae, during two consecutive summers at Cape Hallett, northwestern Ross Sea. Although foraging behavior of this species has been extensively studied throughout the broad continental shelf region of the Ross Sea, this is the first study to report foraging behaviors and habitat affiliations among birds occupying continental slope waters. Continental slope habitat supports the greatest abundances of this species throughout its range, but we lack information about how intra-specific competition for prey might affect foraging and at-sea distribution and how these attributes compare with previous Ross Sea studies. Foraging trips increased in both distance and duration as breeding advanced from guard to crèche stage, but foraging dive depth, dive rates, and vertical dive distances travelled per hour decreased. Consistent with previous studies within slope habitats elsewhere in Antarctic waters, Antarctic krill (Euphausia superba) dominated chick meal composition, but fish increased four-fold from guard to crèche stages. Foraging-, focal-, and core areas all doubled during the crèche stage as individuals shifted distribution in a southeasterly direction away from the coast while simultaneously becoming more widely dispersed (i.e., less spatial overlap among individuals). Intra-specific competition for prey among Adélie penguins appears to influence foraging behavior of this species, even in food webs dominated by Antarctic krill.

Na and K Levels in forage species from the communal grazing lands during the dry season at some locations in the Northern Region of Ghana

International Nuclear Information System (INIS)

Gomda, Y.M.; Osae, E.K.; Akaho, E.H.K.; Fianu, F.K.; Karbo, N.

1999-04-01

Forage species were taken, during the dry season, from five districts in the Northern Region of Ghana and analysed for Na and K using the Neutron Activation Analysis (NAA) technique. The Na level varied in plants species as well as location. The level ranged between 0.049 g/kg DM and 1.14 g/kg DM. This was found to be inadequate for the animals and require supplementation during the dry season. Potassium level in the forage species was between 7.8 to 91.3g/kg DM and appeared to be adequate for the grazing animals. (author)

Effects of Tall Fescue Forage Mass on Steer Ingestive Behavior and Performance

Science.gov (United States)

Tall fescue [Lolium arundinaceum (Schreb.) Darbysh] is a well adapted perennial pasture species utilized across the north-south transition zone of the United States and in similar environments worldwide. This 3-yr trial evaluated the influence of three forage masses (FM) on steer and pasture respons...

Na and K Levels in forage species from the communal grazing lands during the dry season at some locations in the Northern Region of Ghana

Energy Technology Data Exchange (ETDEWEB)

Gomda, Y M; Osae, E K; Akaho, E H.K. [Ghana Atomic Energy Commission, Accra (Ghana); Fianu, F K [University of Ghana, Legon, Accra, (Ghana); Karbo, N [Animal Research Institute, Nyankpala (Ghana)

1999-09-01

Forage species were taken, during the dry season, from five districts in the Northern Region of Ghana and analysed for Na and K using the Neutron Activation Analysis (NAA) technique. The Na level varied in plants species as well as location. The level ranged between 0.049 g/kg DM and 1.14 g/kg DM. This was found to be inadequate for the animals and require supplementation during the dry season. Potassium level in the forage species was between 7.8 to 91.3g/kg DM and appeared to be adequate for the grazing animals. (author) Technical report for year ending 1998. 2 tabs.; 18 refs.

The occurrence of large branchiopod crustaceans in perennial pans ...

African Journals Online (AJOL)

Pans are isolated, shallow depressions that are endorheic in nature. Because of the natural hydrological functioning of pans, these systems are usually restricted to arid regions and complete desiccation occurs seasonally. In the eastern provinces of South Africa many pans are perennial in nature often remaining inundated ...

Effect of Lactic Acid Lactobacillus Preservative and Moisture Level at Baling on In-situ Digestibility of Crabgrass Hay by Heifers.

Science.gov (United States)

Common crabgrass (Digitaria ciliaris [Retz.] Koel.) is a warm-season annual that offers an advantage over many perennial warm-season grasses because of its greater nutritive value and high palatability. However, little is known about how baling crabgrass hay at high moisture affects ruminal forage ...

Use of biosolids to enhance rangeland forage quality.

Science.gov (United States)

McFarland, Michael J; Vasquez, Issaak Romero; Vutran, MaiAnh; Schmitz, Mark; Brobst, Robert B

2010-05-01

Biosolids land application was demonstrated to be a potentially cost-effective means for restoring forage productivity and enhancing soil-moisture-holding capacity on disturbed rangelands. By land-applying aerobically digested, anaerobically digested, composted, and lime-stabilized biosolids on rangeland test plots at rates of up to 20 times (20X) the estimated nitrogen-based agronomic rate, forage yields were found to increase from 132.8 kg/ha (118.2 lb/ac) (control plots) to 1182.3 kg/ha (1052.8 lb/ac). Despite the environmental benefits associated with increased forage yield (e.g., reduced soil erosion, improved drainage, and enhanced terrestrial carbon sequestration), the type of forage generated both before and after biosolids land application was found to be dominated by invasive weeds, all of which were characterized as having fair to poor nutritional value. Opportunistic and shallow rooting invasive weeds not only have marginal nutritional value, they also limit the establishment of native perennial grasses and thus biodiversity. Many of the identified invasive species (e.g., Cheatgrass) mature early, a characteristic that significantly increases the fuel loads that support the increased frequency and extent of western wildfires.

Seasonal and diel patterns in cetacean use and foraging at a potential marine renewable energy site.

Science.gov (United States)

Nuuttila, Hanna K; Bertelli, Chiara M; Mendzil, Anouska; Dearle, Nessa

2018-04-01

Marine renewable energy (MRE) developments often coincide with sites frequented by small cetaceans. To understand habitat use and assess potential impact from development, echolocation clicks were recorded with acoustic click loggers (C-PODs) in Swansea Bay, Wales (UK). General Additive Models (GAMs) were applied to assess the effects of covariates including month, hour, tidal range and temperature. Analysis of inter-click intervals allowed the identification of potential foraging events as well as patterns of presence and absence. Data revealed year-round presence of porpoise, with distinct seasonal and diel patterns. Occasional acoustic encounters of dolphins were also recorded. This study provides further evidence of the need for assessing temporal trends in cetacean presence and habitat use in areas considered for development. These findings could assist MRE companies to monitor and mitigate against disturbance from construction, operation and decommissioning activities by avoiding times when porpoise presence and foraging activity is highest in the area. Copyright © 2017 Elsevier Ltd. All rights reserved.

Farmer perceptions on factors influencing water scarcity for goats in resource-limited communal farming environments.

Science.gov (United States)

Mdletshe, Zwelethu Mfanafuthi; Ndlela, Sithembile Zenith; Nsahlai, Ignatius Verla; Chimonyo, Michael

2018-05-09

The objective of the study was to compare factors influencing water scarcity for goats in areas where there are seasonal and perennial rivers under resource-limited communal farming environments. Data were collected using a structured questionnaire (n = 285) administered randomly to smallholder goat farmers from areas with seasonal and perennial rivers. Ceremonies was ranked as the major reason for keeping goats. Water scarcity was ranked the major constraint to goat production in areas with seasonal rivers when compared to areas with perennial rivers (P goat drinking in areas with seasonal and perennial river systems during cool dry and rainy seasons. Rivers were ranked as an important water source for goat drinking where there are seasonal and perennial river systems during the cool dry season. Households located close (≤ 3 km) to the nearest water source reported drinking water for goats a scarce resource. These results show that river systems, season and distance to the nearest water source from a household were factors perceived by farmers to influence water scarcity for goats in resource-limited communal farming environments. Farmers should explore water-saving strategies such as recycling wastewater from kitchens and bathrooms as an alternative water source. The government may assist farmers through sinking boreholes to supply water for both humans and livestock.

Comparing soil organic carbon dynamics in perennial grasses and shrubs in a saline-alkaline arid region, northwestern China.

Science.gov (United States)

Zhou, Yong; Pei, Zhiqin; Su, Jiaqi; Zhang, Jingli; Zheng, Yuanrun; Ni, Jian; Xiao, Chunwang; Wang, Renzhong

2012-01-01

Although semi-arid and arid regions account for about 40% of terrestrial surface of the Earth and contain approximately 10% of the global soil organic carbon stock, our understanding of soil organic carbon dynamics in these regions is limited. A field experiment was conducted to compare soil organic carbon dynamics between a perennial grass community dominated by Cleistogenes squarrosa and an adjacent shrub community co-dominated by Reaumuria soongorica and Haloxylon ammodendron, two typical plant life forms in arid ecosystems of saline-alkaline arid regions in northwestern China during the growing season 2010. We found that both fine root biomass and necromass in two life forms varied greatly during the growing season. Annual fine root production in the perennial grasses was 45.6% significantly higher than in the shrubs, and fine root turnover rates were 2.52 and 2.17 yr(-1) for the perennial grasses and the shrubs, respectively. Floor mass was significantly higher in the perennial grasses than in the shrubs due to the decomposition rate of leaf litter in the perennial grasses was 61.8% lower than in the shrubs even though no significance was detected in litterfall production. Soil microbial biomass and activity demonstrated a strong seasonal variation with larger values in May and September and minimum values in the dry month of July. Observed higher soil organic carbon stocks in the perennial grasses (1.32 Kg C m(-2)) than in the shrubs (1.12 Kg C m(-2)) might be attributed to both greater inputs of poor quality litter that is relatively resistant to decay and the lower ability of microorganism to decompose these organic matter. Our results suggest that the perennial grasses might accumulate more soil organic carbon with time than the shrubs because of larger amounts of inputs from litter and slower return of carbon through decomposition.

The foraging behavior of Japanese macaques Macaca fuscata in a forested enclosure: Effects of nutrient composition, energy and its seasonal variation on the consumption of natural plant foods

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M. Firoj JAMAN, Michael A. HUFFMAN, Hiroyuki TAKEMOTO

2010-04-01

Full Text Available In the wild, primate foraging behaviors are related to the diversity and nutritional properties of food, which are affected by seasonal variation. The goal of environmental enrichment is to stimulate captive animals to exhibit similar foraging behavior of their wild counterparts, e.g. to extend foraging time. We conducted a 12-month study on the foraging behavior of Japanese macaques in a semi-naturally forested enclosure to understand how they use both provisioned foods and naturally available plant foods and what are the nutritional criteria of their consumption of natural plants. We recorded time spent feeding on provisioned and natural plant foods and collected the plant parts ingested of their major plant food species monthly, when available. We conducted nutritional analysis (crude protein, crude lipid, neutral detergent fiber-‘NDF’, ash and calculated total non-structural carbohydrate – ‘TNC’ and total energy of those food items. Monkeys spent 47% of their feeding time foraging on natural plant species. The consumption of plant parts varied significantly across seasons. We found that leaf items were consumed in months when crude protein, crude protein-to-NDF ratio, TNC and total energy were significantly higher and NDF was significantly lower, fruit/nut items in months when crude protein and TNC were significantly higher and crude lipid content was significantly lower, and bark items in months when TNC and total energy were higher and crude lipid content was lower. This preliminary investigation showed that the forested enclosure allowed troop members to more fully express their species typical flexible behavior by challenging them to adjust their foraging behavior to seasonal changes of plant item diversity and nutritional content, also providing the possibility for individuals to nutritionally enhance their diet [Current Zoology 56 (2: 198–208, 2010].

Comparison of signaling interactions determining annual and perennial plant growth in response to low temperature

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Astrid eWingler

2015-01-01

Full Text Available Low temperature inhibits plant growth despite the fact that considerable rates of photosynthetic activity can be maintained. Instead of lower rates of photosynthesis, active inhibition of cell division and expansion is primarily responsible for reduced growth. This results in sink limitation and enables plants to accumulate carbohydrates that act as compatible solutes or are stored throughout the winter to enable re-growth in spring. Regulation of growth in response to temperature therefore requires coordination with carbon metabolism, e.g. via the signaling metabolite trehalose-6-phosphate. The phytohormones gibberellins (GA and jasmonate (JA play an important role in regulating growth in response to temperature. Growth restriction at low temperature is mainly mediated by DELLA proteins, whose degradation is promoted by GA. For annual plants, it has been shown that the GA/DELLA pathway interacts with JA signaling and C-repeat binding factor (CBF dependent cold acclimation, but these interactions have not been explored in detail for perennials. Growth regulation in response to seasonal factors is, however, particularly important in perennials, especially at high latitudes. In autumn, growth cessation in trees is caused by shortening of the daylength in interaction with phytohormone signaling. In perennial grasses seasonal differences in the sensitivity to GA may enable enhanced growth in spring. This review provides an overview of the signaling interactions that determine plant growth at low temperature and highlights gaps in our knowledge, especially concerning the seasonality of signaling responses in perennial plants.

Evaluation of new hybrid brachiaria lines in Thailand. 1. Forage production and quality

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Michael D. Hare

2015-05-01

Full Text Available Forty-three new hybrid bracharia lines were evaluated for forage accumulation and nutritive value in Northeast Thailand from 2006 to 2011 in experiments at 2 sites, using Mulato II hybrid brachiaria as a standard for comparison. The parameters evaluated were wet and dry season dry matter (DM accumulation, leaf:stem ratio, crude protein (CP concentration and fiber level [acid detergent fiber (ADF and neutral detergent fiber (NDF]. No lines consistently displayed superior dry season forage accumulation and leaf:stem ratio over Mulato II. In the wet seasons, 14 lines produced more DM than Mulato II but in only one wet season each. Mulato II produced forage with high leaf:stem ratio in all seasons. Many lines did have significantly higher CP concentrations and lower levels of ADF and NDF than Mulato II, but their forage accumulation and leaf:stem ratio were inferior. Four lines (BR02/1718, BR02/1752, BR02/1794 and BR02/0465 were granted Plant Variety Rights in 2011.Keywords: Cayman, Cobra, crude protein, dry matter yields, forage regrowth,  Mulato II.DOI: 10.17138/TGFT(383-93 

Honey bee foraging ecology: Season but not landscape diversity shapes the amount and diversity of collected pollen.

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Nadja Danner

Full Text Available The availability of pollen in agricultural landscapes is essential for the successful growth and reproduction of honey bee colonies (Apis mellifera L.. The quantity and diversity of collected pollen can influence the growth and health of honey bee colonies, but little is known about the influence of landscape structure on pollen diet. In a field experiment, we rotated 16 honey bee colonies across 16 agricultural landscapes, used traps to collect samples of collected pollen and observed intra-colonial dance communication to gain information about foraging distances. DNA metabarcoding was applied to analyze mixed pollen samples. Neither the amount of collected pollen nor pollen diversity was related to landscape diversity. However, we found a strong seasonal variation in the amount and diversity of collected pollen in all sites independent of landscape diversity. The observed increase in foraging distances with decreasing landscape diversity suggests that honey bees compensated for lower landscape diversity by increasing their pollen foraging range in order to maintain pollen amount and diversity. Our results underscore the importance of a diverse pollen diet for honey bee colonies. Agri-environmental schemes aiming to support pollinators should focus on possible spatial and temporal gaps in pollen availability and diversity in agricultural landscapes.

Cluster fescue (Festuca paradoxa Desv.): A multipurpose native cool-season grass

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Nadia E. Navarrete-Tindall; J.W. Van Sambeek; R.A. Pierce

2005-01-01

Native cool-season grasses (NCSG) are adapted to a wide range of habitats and environmental conditions, and cluster fescue (Festuca paradoxa Desv.) is no exception. Cluster fescue can be found in unplowed upland prairies, prairie draws, savannas, forest openings, and glades (Aiken et al. 1996). Although its range includes 23 states in the continental...

Chemical composition and ruminal degradation kinetics of crude protein and amino acids, and intestinal digestibility of amino acids from tropical forages

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Lidia Ferreira Miranda

2012-03-01

Full Text Available The objective of this research was to determine the chemical composition and ruminal degradation of the crude protein (CP, total and individual amino acids of leaves from tropical forages: perennial soybean (Neonotonia wightii, cassava (Manihot esculenta, leucaena (Leucaena leucocephala and ramie (Boehmeria nivea, and to estimate the intestinal digestibility of the rumen undegradable protein (RUDP and individual amino acids of leaves from the tropical forages above cited, but including pigeon pea (Cajanus cajan. Three nonlactating Holstein cows were used to determine the in situ ruminal degradability of protein and amino acids from leaves (6, 18 and 48 hours of ruminal incubation. For determination of the intestinal digestibility of RUDP, the residue from ruminal incubation of the materials was used for 18 hours. A larger concentration of total amino acids for ramie and smaller for perennial soybean were observed; however, they were very similar in leucaena and cassava. Leucine was the essential amino acid of greater concentration, with the exception of cassava, which exhibited a leucine concentration 40.45% smaller. Ramie showed 14.35 and 22.31% more lysine and methionine, respectively. The intestinal digestibility of RUDP varied from 23.56; 47.87; 23.48; 25.69 and 10.86% for leucaena, perennial soybean, cassava, ramie and pigeon pea, respectively. The individual amino acids of tropical forage disappeared in different extensions in the rumen. For the correct evaluation of those forages, one should consider their composition of amino acids, degradations and intestinal digestibility, once the amino acid composition of the forage does not reflect the amino acid profiles that arrived in the small intestine. Differences between the degradation curves of CP and amino acids indicate that degradation of amino acids cannot be estimated through the degradation curve of CP, and that amino acids are not degraded in a similar degradation profile.

Biomass accumulation and chemical composition of Massai grass intercropped with forage legumes on an integrated crop-livestock-forest system

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Tatiana da Costa Moreno Gama

2014-06-01

Full Text Available The objective was to evaluate the use of woody legumes (Albizia lebbeck, Cratylia argentea, Dipteryx Allata (Baru, a Leucaena hybrid (L. leucocephala + L. diversifolia, and Leucaena leucocephalacv. Cunningham and herbaceous legumes (Arachis pintoi intercropped with Panicum maximum cv. Massai, simultaneously implanted in a maize crop. The study made use of a randomized block experimental design with four replications. Assessments of biomass accumulation and forage nutritional value were made after the maize harvest, between June 2008 and October 2010. It was found that the residues of maize provided better growing conditions for Massai grass during the dry season. L. leucocephala cv. Cunningham and the Leucaena hybrid had the highest accumulation of all forage legumes evaluated, and provided the best nutritional value of all the arrangements tested. Of all woody legumes tested in this system, Leucaena was considered feasible for intercropping with Massai grass. The intercrop of perennial woody Baru with maize is not recommended. Albizia lebbeck and Cratylia argentea require further study, especially the yield assessment at different cutting intervals and cutting heights. Arachis pintoi had a low participation in the intercropping, showing greater performance over time, indicating slow thriving in this experimental condition.

Seasonal use of a New England estuary by foraging contingents of migratory striped bass

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Mather, Martha E.; Pautzke, Sarah M.; Finn, John T.; Deegan, Linda A.; Muth, Robert M.

2011-01-01

Using acoustic telemetry on migratory striped bass Morone saxatilis in Plum Island Estuary (PIE), Massachusetts, we found that striped bass (335–634 mm total length) tagged in the spring and summer of 2005 (n = 14) and 2006 (n = 46) stayed in the estuary for an average of 66.0 d in 2005 and 72.2 d in 2006. Striped bass spent the most time in two specific reaches: middle Plum Island Sound and lower Rowley River. In both years, three different use-groups of striped bass were observed in PIE. Short-term visitors (n = 24) stayed in the estuary only briefly (range = 5–20 d). Two groups of seasonal residents stayed for more than 30 d, either in the Rowley River (n = 14) or in Plum Island Sound (n = 22). Within PIE, the two seasonal-resident use-groups may be foraging contingents that learn how to feed efficiently in specific parts of the estuary. These distinct within-estuary use patterns could have different implications for striped bass condition and prey impact.

Effects of pasture management and off-stream water on temporal/spatial distribution of cattle and stream bank characteristics in cool-season grass pastures.

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Schwarte, K A; Russell, J R; Morrical, D G

2011-10-01

A 2-yr grazing experiment was conducted to assess the effects of grazing management on cattle distribution and pasture and stream bank characteristics. Six 12.1-ha cool-season grass pastures in central Iowa were allotted to 1 of 3 treatments: continuous stocking with unrestricted stream access (CSU), continuous stocking with stream access restricted to 4.9-m-wide stabilized crossings (CSR), or rotational stocking with stream access restricted to a riparian paddock (RP). Pastures were stocked with 15 fall-calving Angus cows (Bos taurus L.) from mid-May to mid-October for 153 d in 2008 and 2009. A global positioning system (GPS) collar recording cow position every 10 min was placed on at least 1 cow per pasture for 2 wk of each month from May through September. Off-stream water was provided to cattle in CSU and CSR treatments during the second of the 2 wk when GPS collars were on the cattle. A black globe temperature relative humidity index (BGTHI) was measured at 10-min intervals to match the time of the GPS measurements. Each month of the grazing season, forage characteristics (sward height, forage mass, and CP, IVDMD, and P concentrations) and bare and fecal-covered ground were measured. Stream bank erosion susceptibility was visually scored in May, August, and October (pre-, mid-, and post-stocking). Cattle in RP and CSR treatments spent less time (P CSR treatment reduced the probability (P CSR and RP treatments in the stream and streamside zones in September and October and in July and September. Streams in pastures with the CSU treatment had less stable banks (P CSR treatments. Results show that time spent by cattle near pasture streams can be reduced by RP or CSR treatments, thereby decreasing risks of sediment and nutrient loading of pasture streams even during periods of increased BGTHI.

Extreme precipitation variability, forage quality and large herbivore diet selection in arid environments

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Cain, James W.; Gedir, Jay V.; Marshal, Jason P.; Krausman, Paul R.; Allen, Jamison D.; Duff, Glenn C.; Jansen, Brian; Morgart, John R.

2017-01-01

Nutritional ecology forms the interface between environmental variability and large herbivore behaviour, life history characteristics, and population dynamics. Forage conditions in arid and semi-arid regions are driven by unpredictable spatial and temporal patterns in rainfall. Diet selection by herbivores should be directed towards overcoming the most pressing nutritional limitation (i.e. energy, protein [nitrogen, N], moisture) within the constraints imposed by temporal and spatial variability in forage conditions. We investigated the influence of precipitation-induced shifts in forage nutritional quality and subsequent large herbivore responses across widely varying precipitation conditions in an arid environment. Specifically, we assessed seasonal changes in diet breadth and forage selection of adult female desert bighorn sheep Ovis canadensis mexicana in relation to potential nutritional limitations in forage N, moisture and energy content (as proxied by dry matter digestibility, DMD). Succulents were consistently high in moisture but low in N and grasses were low in N and moisture until the wet period. Nitrogen and moisture content of shrubs and forbs varied among seasons and climatic periods, whereas trees had consistently high N and moderate moisture levels. Shrubs, trees and succulents composed most of the seasonal sheep diets but had little variation in DMD. Across all seasons during drought and during summer with average precipitation, forages selected by sheep were higher in N and moisture than that of available forage. Differences in DMD between sheep diets and available forage were minor. Diet breadth was lowest during drought and increased with precipitation, reflecting a reliance on few key forage species during drought. Overall, forage selection was more strongly associated with N and moisture content than energy content. Our study demonstrates that unlike north-temperate ungulates which are generally reported to be energy-limited, N and moisture

Forage mass and stocking rate of elephant grass pastures managed under agroecological and conventional systems

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Clair Jorge Olivo

2014-06-01

Full Text Available The objective was to evaluate elephant grass (Pennisetum purpureum Schum. pastures, under the agroecological and conventional systems, as forage mass and stocking rate. In the agroecological system, the elephant grass was established in rows spaced by 3.0 m from each other. During the cool season ryegrass (Lolium multiflorum Lam. was established between these rows, which allowed the development of spontaneous growth species during the warm season. In the conventional system the elephant grass was established singularly in rows spaced 1.4 m from each other. Organic and chemical fertilizers were applied at 150 kg of N/ha/year with in the pastures under agroecological and conventional systems, respectively. Lactating Holstein cows which received 5.0 kg/day supplementary concentrate feed were used for evaluation. The experimental design was completely randomized, with two treatments (agroecological and conventional systems two replications (paddocks and independent evaluations (grazing cycles. The pastures were used during the whole year for the agroecological system and for 195 days in the conventional year. The average values of forage mass were 3.5 and 4.2 t/ha and the stocking rates were 2.08 and 3.23 AU/ha for the respective systems. The results suggest that the use of the elephant grass under the agroecological system allows for best distribution of forage and stocking rate to be more uniform throughout the year than the use of elephant grass in conventional system.

De novo assembly of the perennial ryegrass transcriptome using an RNA-Seq strategy.

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Jacqueline D Farrell

Full Text Available Perennial ryegrass is a highly heterozygous outbreeding grass species used for turf and forage production. Heterozygosity can affect de-Bruijn graph assembly making de novo transcriptome assembly of species such as perennial ryegrass challenging. Creating a reference transcriptome from a homozygous perennial ryegrass genotype can circumvent the challenge of heterozygosity. The goals of this study were to perform RNA-sequencing on multiple tissues from a highly inbred genotype to develop a reference transcriptome. This was complemented with RNA-sequencing of a highly heterozygous genotype for SNP calling.De novo transcriptome assembly of the inbred genotype created 185,833 transcripts with an average length of 830 base pairs. Within the inbred reference transcriptome 78,560 predicted open reading frames were found of which 24,434 were predicted as complete. Functional annotation found 50,890 transcripts with a BLASTp hit from the Swiss-Prot non-redundant database, 58,941 transcripts with a Pfam protein domain and 1,151 transcripts encoding putative secreted peptides. To evaluate the reference transcriptome we targeted the high-affinity K+ transporter gene family and found multiple orthologs. Using the longest unique open reading frames as the reference sequence, 64,242 single nucleotide polymorphisms were found. One thousand sixty one open reading frames from the inbred genotype contained heterozygous sites, confirming the high degree of homozygosity.Our study has developed an annotated, comprehensive transcriptome reference for perennial ryegrass that can aid in determining genetic variation, expression analysis, genome annotation, and gene mapping.

Seedbed preparation influence on morphometric characteristics of perennial grasses of a semi-arid rangeland in Kenya

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Opiyo, Francis EO; Ekaya, Wellington N; Nyariki, Dickson M; Mureithi, Stephen Mwangi

2011-01-01

Semi-arid rangelands in Kenya are an important source of forage for both domestic and wild animals. However, indigenous perennial grasses notably Cenchrus ciliaris (African foxtail grass), Eragrostis superba (Maasai love grass) and Enteropogon macrostachyus (Bush rye grass) are disappearing at an alarming rate. Efforts to re-introduce them through restoration programs have often yielded little success. This can partly be attributed to failure of topsoil to capture and store scarce water to me...

Novel application of ALMANAC: Modelling a functional group, exotic warm-season perennial grasses

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Introduced perennial C4 grasses such buffelgrass (Pennisetum ciliare [(L.) Link]) and old world bluestems (OWB), including genera such as Bothriochloa Kuntze, Capillipedium Stapf, and Dichanthium Willemet have the potential to dominate landscapes. A process-based model that realistically simulates ...

Persistence of forage fish ‘hot spots’ and its association with foraging Steller sea lions (Eumetopias jubatus) in southeast Alaska

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Gende, Scott M.; Sigler, Michael F.

2006-02-01

Whereas primary and secondary productivity at oceanic 'hotspots' may be a function of upwelling and temperature fronts, the aggregation of higher-order vertebrates is a function of their ability to search for and locate these areas. Thus, understanding how predators aggregate at these productive foraging areas is germane to the study of oceanic hot spots. We examined the spatial distribution of forage fish in southeast Alaska for three years to better understand Steller sea lion ( Eumetopias jubatus) aggregations and foraging behavior. Energy densities (millions KJ/km 2) of forage fish were orders of magnitude greater during the winter months (November-February), due to the presence of schools of overwintering Pacific herring ( Clupea pallasi). Within the winter months, herring consistently aggregated at a few areas, and these areas persisted throughout the season and among years. Thus, our study area was characterized by seasonally variable, highly abundant but highly patchily distributed forage fish hot spots. More importantly, the persistence of these forage fish hot spots was an important characteristic in determining whether foraging sea lions utilized them. Over 40% of the variation in the distribution of sea lions on our surveys was explained by the persistence of forage fish hot spots. Using a simple spatial model, we demonstrate that when the density of these hot spots is low, effort necessary to locate these spots is minimized when those spots persist through time. In contrast, under similar prey densities but lower persistence, effort increases dramatically. Thus an important characteristic of pelagic hot spots is their persistence, allowing predators to predict their locations and concentrate search efforts accordingly.

Consequences of cool-season drought induced plant mortality to Chihuahuan Desert grassland ecosystem and soil respiration dynamics

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Global climate change is predicted to increase the severity and frequency of cool-season drought across the arid Southwest US. We quantified net ecosystem carbon dioxide exchange (NEE), ecosystem respiration (Reco), and gross ecosystem photosynthesis (GEP) in response to interannual seasonal precip...

Seasonal and geographical variation in heat tolerance and evaporative cooling capacity in a passerine bird.

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Noakes, Matthew J; Wolf, Blair O; McKechnie, Andrew E

2016-03-01

Intraspecific variation in avian thermoregulatory responses to heat stress has received little attention, despite increasing evidence that endothermic animals show considerable physiological variation among populations. We investigated seasonal (summer versus winter) variation in heat tolerance and evaporative cooling in an Afrotropical ploceid passerine, the white-browed sparrow-weaver (Plocepasser mahali; ∼ 47 g) at three sites along a climatic gradient with more than 10 °C variation in mid-summer maximum air temperature (Ta). We measured resting metabolic rate (RMR) and total evaporative water loss (TEWL) using open flow-through respirometry, and core body temperature (Tb) using passive integrated transponder tags. Sparrow-weavers were exposed to a ramped profile of progressively higher Ta between 30 and 52 °C to elicit maximum evaporative cooling capacity (N=10 per site per season); the maximum Ta birds tolerated before the onset of severe hyperthermia (Tb ≈ 44 °C) was considered to be their hyperthermia threshold Ta (Ta,HT). Our data reveal significant seasonal acclimatisation of heat tolerance, with a desert population of sparrow-weavers reaching significantly higher Ta in summer (49.5 ± 1.4 °C, i.e. higher Ta,HT) than in winter (46.8 ± 0.9 °C), reflecting enhanced evaporative cooling during summer. Moreover, desert sparrow-weavers had significantly higher heat tolerance and evaporative cooling capacity during summer compared with populations from more mesic sites (Ta,HT=47.3 ± 1.5 and 47.6 ± 1.3 °C). A better understanding of the contributions of local adaptation versus phenotypic plasticity to intraspecific variation in avian heat tolerance and evaporative cooling capacity is needed for modelling species' responses to changing climates. © 2016. Published by The Company of Biologists Ltd.

TrMADS3, a new MADS-box gene, from a perennial species Taihangia rupestris (Rosaceae) is upregulated by cold and experiences seasonal fluctuation in expression level.

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Du, Xiaoqiu; Xiao, Qiying; Zhao, Ran; Wu, Feng; Xu, Qijiang; Chong, Kang; Meng, Zheng

2008-06-01

In many temperate perennial plants, floral transition is initiated in the first growth season but the development of flower is arrested during the winter to ensure production of mature flowers in the next spring. The molecular mechanisms of the process remain poorly understood with few well-characterized regulatory genes. Here, a MADS-box gene, named as TrMADS3, was isolated from the overwintering inflorescences of Taihangia rupestris, a temperate perennial in the rose family. Phylogenetic analysis reveals that TrMADS3 is more closely related to the homologs of the FLOWERING LOCUS C lineage than to any of the other MIKC-type MADS-box lineages known from Arabidopsis. The TrMADS3 transcripts are extensively distributed in inflorescences, roots, and leaves during the winter. In controlled conditions, the TrMADS3 expression level is upregulated by a chilling exposure for 1 to 2 weeks and remains high for a longer period of time in warm conditions after cold treatment. In situ hybridization reveals that TrMADS3 is predominantly expressed in the vegetative and reproductive meristems. Ectopic expression of TrMADS3 in Arabidopsis promotes seed germination on the media containing relatively high NaCl or mannitol concentrations. These data indicate that TrMADS3 in a perennial species might have its role in both vegetative and reproductive meristems in response to cold.

Effect of corn dry distiller grains plus solubles supplementation level on performance and digestion characteristics of steers grazing native range during forage growing season.

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Martínez-Pérez, M F; Calderón-Mendoza, D; Islas, A; Encinias, A M; Loya-Olguín, F; Soto-Navarro, S A

2013-03-01

Two experiments were conducted to evaluate effects of corn dry distiller grains plus condensed solubles (DDGS) supplementation level on performance digestion characteristics of steers grazing native range during the forage growing season. In the performance study, 72 (206 ± 23.6 kg; 2008) and 60 (230 ± 11.3 kg; 2009) English crossbred steer calves were used in a randomized complete block design replicated over 2 yr. The grazing periods lasted 56 and 58 d and started on August 11 and 18 for 2008 and 2009, respectively. Each year, steers were blocked by BW (light, medium, and heavy), stratified by BW within blocks, and randomly assigned to 1 of 4 grazing groups. Each grazing group (6 steers in 2008 and 5 in 2009) was assigned to a DDGS supplementation levels (0, 0.2, 0.4, and 0.6% BW). Grazing group served as the experimental unit with 12 groups per year receiving 1 of 4 treatments for 2 yr (n = 6). In the metabolism study, 16 English crossbred steers (360 ± 28.9 kg) fitted with ruminal cannulas grazing native range during the summer growing season were used in a completely randomized design to evaluate treatment effects on forage intake and digestion. The experiment was conducted during the first and second weeks of October 2008. Steers were randomly assigned to supplement level (0, 0.2, 0.4, and 0.6% BW; n = 4) and grazed a single native range pasture with supplements offered individually once daily at 0700 h. In the performance study, ADG (0.64, 0.75, 0.80, and 0.86 ± 0.03 kg/d for 0, 0.2, 0.4, and 0.6% BW, respectively) increased linearly (P = 0.01) with increasing DDGS supplementation level. In the metabolism study, forage OM, NDF, CP, and ether extract (EE) intake decreased (P ≤ 0.05) linearly with increasing DDGS supplementation level. Total CP and EE intake increased (P ≤ 0.002) with increasing DDGS supplementation level. Digestibility of OM, NDF, and EE increased (linear; P ≤ 0.008) whereas the soluble CP fraction of forage masticate sample

Effects of maturity and harvest season of grass-clover silage and of forage-to-concentrate ratio on milk production of dairy cows.

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Alstrup, L; Søegaard, K; Weisbjerg, M R

2016-01-01

This study examined the effects of maturity and season of harvest of grass-clover silages and forage:concentrate ratio (FCR) on feed intake, milk production, chewing activity, digestibility, and fecal consistency of Holstein dairy cows. Comparison included 2 cuts in spring season (early and late) and 2 cuts in summer season (early and late) combined with high FCR (80:20; HFCR) and low FCR (50:50; LFCR). The experiment included 24 lactating Holstein cows arranged as 2 repeated 4 × 4 Latin squares with four 21-d periods and included measurements of feed composition, feed intake, milk production and composition, chewing activities, digestibilities, and fecal dry matter (DM) concentration and scoring. Forages were fed as two-thirds grass-clover and one-third corn silage supplemented with either 20 or 50% concentrate. Rations were fed ad libitum as total mixed rations. Early maturity cuts were more digestible than late maturity cuts, which was also reflected in a lower concentration of neutral detergent fiber (NDF) in early maturity cuts, whereas summer cuts had a higher crude protein concentration than spring cuts. Increased maturity decreased the intake of DM and energy, increased NDF intake, and decreased the yield of energy-corrected milk (ECM). Summer cuts increased the ECM yield compared with spring cuts. Milk yield (kg and kilogram of ECM) was numerically higher for cows fed early summer cut, independent of FCR in the ration. Milk protein concentration decreased, or tended to decrease, with maturity. For LFCR, the milk fat concentration increased with maturity resulting in a decreased protein:fat ratio. At HFCR, increased maturity increased the time spent chewing per kilogram of DM. Digestibility of silages was positively correlated with the fecal DM concentration. The DM intake and ECM yield showed no significant response to FCR in the ration, but the milk composition was affected. The LFCR decreased the milk fat percentage and increased the milk protein

Harvesting Effects on Species Composition and Distribution of Cover Attributes in Mixed Native Warm-Season Grass Stands

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Vitalis W. Temu

2015-05-01

Full Text Available Managing grasslands for forage and ground-nesting bird habitat requires appropriate defoliation strategies. Subsequent early-summer species composition in mixed stands of native warm-season grasses (Indiangrass (IG, Sorghastrum nutans, big bluestem (BB, Andropogon gerardii and little bluestem (LB, Schizachyrium scoparium responding to harvest intervals (treatments, 30, 40, 60, 90 or 120 d and durations (years in production was assessed. Over three years, phased May harvestings were initiated on sets of randomized plots, ≥90 cm apart, in five replications (blocks to produce one-, two- and three-year-old stands. Two weeks after harvest, the frequencies of occurrence of plant species, litter and bare ground, diagonally across each plot (line intercept, were compared. Harvest intervals did not influence proportions of dominant plant species, occurrence of major plant types or litter, but increased that of bare ground patches. Harvest duration increased the occurrence of herbaceous forbs and bare ground patches, decreased that of tall-growing forbs and litter, but without affecting that of perennial grasses, following a year with more September rainfall. Data suggest that one- or two-year full-season forage harvesting may not compromise subsequent breeding habitat for bobwhites and other ground-nesting birds in similar stands. It may take longer than a year’s rest for similar stands to recover from such changes in species composition.

Contrasting Foraging Patterns: Testing Resource-Concentration and Dilution Effects with Pollinators and Seed Predators

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Alexandria Wenninger

2016-06-01

Full Text Available Resource concentration effects occur when high resource density patches attract and support more foragers than low density patches. In contrast, resource dilution effects can occur if high density patches support fewer consumers. In this study, we examined the foraging rates of pollinators and seed predators on two perennial plant species (Rudbeckia triloba and Verbena stricta as functions of resource density. Specifically, we examined whether resource-dense patches (densities of flower and seeds on individual plants resulted in greater visitation and seed removal rates, respectively. We also examined whether foraging rates were context-dependent by conducting the study in two sites that varied in resource densities. For pollinators, we found negative relationships between the density of flowers per plant and visitation rates, suggesting dilution effects. For seed predators, we found positive relationships consistent with concentration effects. Saturation effects and differences in foraging behaviors might explain the opposite relationships; most of the seed predators were ants (recruitment-based foragers, and pollinators were mostly solitary foragers. We also found that foraging rates were site-dependent, possibly due to site-level differences in resource abundance and consumer densities. These results suggest that these two plant species may benefit from producing as many flowers as possible, given high levels of pollination and low seed predation.

Variability in cold front activities modulating cool-season evaporation from a southern inland water in the USA

International Nuclear Information System (INIS)

Liu Heping; Blanken, Peter D; Weidinger, Tamas; Nordbo, Annika; Vesala, Timo

2011-01-01

Understanding seasonal variations in the evaporation of inland waters (e.g., lakes and reservoirs) is important for water resource management as well as the prediction of the hydrological cycles in response to climate change. We analyzed eddy covariance-based evaporation measurements from the Ross Barnett Reservoir (32 deg. 26'N, 90 0 02'W; which is always ice-free) in central Mississippi during the cool months (i.e., September-March) of 2007 and 2008, and found that the variability in cold front activities (i.e., passages of cold fronts and cold/dry air masses behind cold fronts) played an important role in modulating the exchange of sensible (H) and latent (λE) heat fluxes. Our analysis showed that 2007's warmer cool season had smaller mean H and λE than 2008's cooler cool season. This implies that the warmer cool season did not accelerate evaporation and heat exchange between the water surface and the atmosphere. Instead, more frequent cold fronts and longer periods of cold/dry air masses behind the cold fronts in 2008 resulted in overall larger H and λE as compared with 2007, this primarily taking the form of sporadic short-term rapid 'pulses' of H and λE losses from the water's surface. These results suggest that future climate-induced changes in frequency of cold fronts and the meteorological properties of the air masses behind cold fronts (e.g., wind speeds, temperature, and humidity), rather than other factors of climate change, would produce significant variations in the water surface's energy fluxes and subsequent evaporation rates.

Genetic Loci Governing Androgenic Capacity in Perennial Ryegrass (Lolium perenne L.

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Rachel F. Begheyn

2018-06-01

Full Text Available Immature pollen can be induced to switch developmental pathways from gametogenesis to embryogenesis and subsequently regenerate into homozygous, diploid plants. Such androgenic production of doubled haploids is particularly useful for species where inbreeding is hampered by effective self-incompatibility systems. Therefore, increasing the generally low androgenic capacity of perennial ryegrass (Lolium perenne L. germplasm would enable the efficient production of homozygous plant material, so that a more effective exploitation of heterosis through hybrid breeding schemes can be realized. Here, we present the results of a genome-wide association study in a heterozygous, multiparental population of perennial ryegrass (n = 391 segregating for androgenic capacity. Genotyping-by-sequencing was used to interrogate gene- dense genomic regions and revealed over 1,100 polymorphic sites. Between one and 10 quantitative trait loci (QTL were identified for anther response, embryo and total plant production, green and albino plant production and regeneration. Most traits were under polygenic control, although a major QTL on linkage group 5 was associated with green plant regeneration. Distinct genetic factors seem to affect green and albino plant recovery. Two intriguing candidate genes, encoding chromatin binding domains of the developmental phase transition regulator, Polycomb Repressive Complex 2, were identified. Our results shed the first light on the molecular mechanisms behind perennial ryegrass microspore embryogenesis and enable marker-assisted introgression of androgenic capacity into recalcitrant germplasm of this forage crop of global significance.

Seasonal Variation in Parental Care Drives Sex-Specific Foraging by a Monomorphic Seabird.

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Burke, Chantelle M; Montevecchi, William A; Regular, Paul M

2015-01-01

Evidence of sex-specific foraging in monomorphic seabirds is increasing though the underlying mechanisms remain poorly understood. We investigate differential parental care as a mechanism for sex-specific foraging in monomorphic Common Murres (Uria aalge), where the male parent alone provisions the chick after colony departure. Using a combination of geolocation-immersion loggers and stable isotopes, we assess two hypotheses: the reproductive role specialization hypothesis and the energetic constraint hypothesis. We compare the foraging behavior of females (n = 15) and males (n = 9) during bi-parental at the colony, post-fledging male-only parental care and winter when parental care is absent. As predicted by the reproductive role specialization hypothesis, we found evidence of sex-specific foraging during post-fledging only, the stage with the greatest divergence in parental care roles. Single-parenting males spent almost twice as much time diving per day and foraged at lower quality prey patches relative to independent females. This implies a potential energetic constraint for males during the estimated 62.8 ± 8.9 days of offspring dependence at sea. Contrary to the predictions of the energetic constraint hypothesis, we found no evidence of sex-specific foraging during biparental care, suggesting that male parents did not forage for their own benefit before colony departure in anticipation of post-fledging energy constraints. We hypothesize that unpredictable prey conditions at Newfoundland colonies in recent years may limit male parental ability to allocate additional time and energy to self-feeding during biparental care, without compromising chick survival. Our findings support differential parental care as a mechanism for sex-specific foraging in monomorphic murres, and highlight the need to consider ecological context in the interpretation of sex-specific foraging behavior.

Seasonal Variation in Parental Care Drives Sex-Specific Foraging by a Monomorphic Seabird.

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Chantelle M Burke

Full Text Available Evidence of sex-specific foraging in monomorphic seabirds is increasing though the underlying mechanisms remain poorly understood. We investigate differential parental care as a mechanism for sex-specific foraging in monomorphic Common Murres (Uria aalge, where the male parent alone provisions the chick after colony departure. Using a combination of geolocation-immersion loggers and stable isotopes, we assess two hypotheses: the reproductive role specialization hypothesis and the energetic constraint hypothesis. We compare the foraging behavior of females (n = 15 and males (n = 9 during bi-parental at the colony, post-fledging male-only parental care and winter when parental care is absent. As predicted by the reproductive role specialization hypothesis, we found evidence of sex-specific foraging during post-fledging only, the stage with the greatest divergence in parental care roles. Single-parenting males spent almost twice as much time diving per day and foraged at lower quality prey patches relative to independent females. This implies a potential energetic constraint for males during the estimated 62.8 ± 8.9 days of offspring dependence at sea. Contrary to the predictions of the energetic constraint hypothesis, we found no evidence of sex-specific foraging during biparental care, suggesting that male parents did not forage for their own benefit before colony departure in anticipation of post-fledging energy constraints. We hypothesize that unpredictable prey conditions at Newfoundland colonies in recent years may limit male parental ability to allocate additional time and energy to self-feeding during biparental care, without compromising chick survival. Our findings support differential parental care as a mechanism for sex-specific foraging in monomorphic murres, and highlight the need to consider ecological context in the interpretation of sex-specific foraging behavior.

Variations in plant forage quality in the range of the Porcupine caribou herd

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Jill Johnstone

2002-06-01

Full Text Available Understanding potential impacts of vegetation change on caribou energetics requires information on variations in forage quality among different plant types and over time. We synthesized data on forage quality (nitrogen, neutral detergent fiber and dry matter digestibility for 10 plant growth forms from existing scientific literature and from field research in the Arctic National Wildlife Refuge, Alaska. These data describe forage quality of plant species in habitats found within the summer and winter range of the Porcupine caribou herd in northwestern Canada and northern Alaska, U.S.A. We compared mean levels of summer forage quality among growth forms and, where possible, estimated seasonal changes in forage quality. Preferred forage groups (deciduous shrubs, forbs, and cottongrass flowers had higher nitrogen and digestibility, and lower fiber content, than other growth forms. Nitrogen concentration in green biomass peaked at the onset of the growing season in forbs and deciduous shrubs, whereas graminoids reached peak nitrogen concentrations approximately 15-30 days after growth initiation. In vitro dry matter digestibility (IVDMD and concentration of neutral detergent fiber (NDF of green biomass differed among growth forms, but did not show strong seasonal changes. IVDMD and NDF concentrations were correlated with nitrogen concentrations in studies that had paired sampling.

Seasonal foraging ecology of non-migratory cougars in a system with migrating prey.

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L Mark Elbroch

Full Text Available We tested for seasonal differences in cougar (Puma concolor foraging behaviors in the Southern Yellowstone Ecosystem, a multi-prey system in which ungulate prey migrate, and cougars do not. We recorded 411 winter prey and 239 summer prey killed by 28 female and 10 male cougars, and an additional 37 prey items by unmarked cougars. Deer composed 42.4% of summer cougar diets but only 7.2% of winter diets. Males and females, however, selected different proportions of different prey; male cougars selected more elk (Cervus elaphus and moose (Alces alces than females, while females killed greater proportions of bighorn sheep (Ovis canadensis, pronghorn (Antilocapra americana, mule deer (Odocoileus hemionus and small prey than males. Kill rates did not vary by season or between males and females. In winter, cougars were more likely to kill prey on the landscape as: 1 elevation decreased, 2 distance to edge habitat decreased, 3 distance to large bodies of water decreased, and 4 steepness increased, whereas in summer, cougars were more likely to kill in areas as: 1 elevation decreased, 2 distance to edge habitat decreased, and 3 distance from large bodies of water increased. Our work highlighted that seasonal prey selection exhibited by stationary carnivores in systems with migratory prey is not only driven by changing prey vulnerability, but also by changing prey abundances. Elk and deer migrations may also be sustaining stationary cougar populations and creating apparent competition scenarios that result in higher predation rates on migratory bighorn sheep in winter and pronghorn in summer. Nevertheless, cougar predation on rare ungulates also appeared to be influenced by individual prey selection.

Effect of yearling steer sequence grazing of perennial and annual forages in an integrated crop and livestock system on grazing performance, delayed feedlot entry, finishing performance, carcass measurements, and systems economics.

Science.gov (United States)

Sentürklü, Songul; Landblom, Douglas G; Maddock, Robert; Petry, Tim; Wachenheim, Cheryl J; Paisley, Steve I

2018-06-04

In a 2-yr study, spring-born yearling steers (n = 144), previously grown to gain <0.454 kg·steer-1·d-1, following weaning in the fall, were stratified by BW and randomly assigned to three retained ownership rearing systems (three replications) in early May. Systems were 1) feedlot (FLT), 2) steers that grazed perennial crested wheatgrass (CWG) and native range (NR) before FLT entry (PST), and 3) steers that grazed perennial CWG and NR, and then field pea-barley (PBLY) mix and unharvested corn (UC) before FLT entry (ANN). The PST and ANN steers grazed 181 d before FLT entry. During grazing, ADG of ANN steers (1.01 ± SE kg/d) and PST steers (0.77 ± SE kg/d) did not differ (P = 0.31). But even though grazing cost per steer was greater (P = 0.002) for ANN vs. PST, grazing cost per kg of gain did not differ (P = 0.82). The ANN forage treatment improved LM area (P = 0.03) and percent i.m. fat (P = 0.001). The length of the finishing period was greatest (P < 0.001) for FLT (142 d), intermediate for PST (91 d), and least for ANN (66 d). Steer starting (P = 0.015) and ending finishing BW (P = 0.022) of ANN and PST were greater than FLT steers. Total FLT BW gain was greater for FLT steers (P = 0.017), but there were no treatment differences for ADG, (P = 0.16), DMI (P = 0.21), G: F (P = 0.82), and feed cost per kg of gain (P = 0.61). However, feed cost per steer was greatest for FLT ($578.30), least for ANN ($276.12), and intermediate for PST ($381.18) (P = 0.043). There was a tendency for FLT steer HCW to be less than ANN and PST, which did not differ (P = 0.076). There was no difference between treatments for LM area (P = 0.094), backfat depth (P = 0.28), marbling score (P = 0.18), USDA yield grade (P = 0.44), and quality grade (P = 0.47). Grazing steer net return ranged from an ANN system high of $9.09/steer to a FLT control system net loss of -$298 and a PST system that was slightly less than the ANN system (-$30.10). Ten-year (2003 to 2012) hedging and net return

Diallel analysis of maize hybrids for agronomic and bromatological forage traits

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Matheus Henrique Silveira Mendes

2015-05-01

Full Text Available The aim of this study was to evaluate a diallel of maize hybrids for traits related to forage production and nutritional value. Six commercial hybrids were used as parents. The crosses were made according to a complete diallel design, obtaining the F1 and reciprocal crosses. The evaluations were performed in the main and second crop seasons in the 2010/2011 crop year at the Center for Technological Development in Agriculture of the Federal University of Lavras, located in Lavras, Minas Gerais State, Brazil. The experimental precision indicated by the coefficient of variation was good for all the traits measured. Significant differences were not observed among the crosses for traits related to the nutritional value of the forage. For fresh matter yield and dehusked ear yield, the general combining ability (GCA and specific combining ability (SCA effects were significant. Sowing in the second crop season reduced the yield and nutritional value of the forage. The interaction among the crosses and sowing seasons was not significant. For the beginning of an intrapopulational breeding program, the parent BM 3061 stands out by showing high estimates of GCA for the grain and forage yields.

Determination of Phytoestrogen Content in Fresh-Cut Legume Forage

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Pavlína Hloucalová

2016-07-01

Full Text Available The aim of the study was to determine phytoestrogen content in fresh-cut legume forage. This issue has been much discussed in recent years in connection with the health and safety of feedstuffs and thus livestock health. The experiments were carried out on two experimental plots at Troubsko and Vatín, Czech Republic during June and July in 2015. Samples were collected of the four forage legume species perennial red clover (variety “Amos”, alfalfa (variety “Holyně”, and annuals Persian clover and Alexandrian clover. Forage was sampled twice at regular three to four day intervals leading up to harvest and a third time on the day of harvest. Fresh and wilted material was analyzed using liquid chromatography–mass spectrometry (LC-MS. Higher levels ( p < 0.05 of isoflavones biochanin A (3.697 mg·g −1 of dry weight and formononetin (4.315 mg·g −1 of dry weight were found in red clover than in other species. The highest isoflavone content was detected in red clover, reaching 1.001% of dry matter ( p < 0.05, representing a risk for occurrence of reproduction problems and inhibited secretion of animal estrogen. The phytoestrogen content was particularly increased in wilted forage. Significant isoflavone reduction was observed over three to four day intervals leading up to harvest.

Potential Foraging Decisions by a Desert Ungulate to Balance Water and Nutrient Intake in a Water-Stressed Environment.

Science.gov (United States)

Gedir, Jay V; Cain, James W; Krausman, Paul R; Allen, Jamison D; Duff, Glenn C; Morgart, John R

2016-01-01

Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni) populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons) and moisture (autumn and winter) during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains), female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8-55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental water during

Potential foraging decisions by a desert ungulate to balance water and nutrient intake in a water-stressed environment

Science.gov (United States)

Gedir, Jay V.; Cain, James W.; Krausman, Paul R.; Allen, Jamison D.; Duff, Glenn C.; Morgart, John R.

2016-01-01

Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni) populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons) and moisture (autumn and winter) during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains), female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8–55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental water during

Potential Foraging Decisions by a Desert Ungulate to Balance Water and Nutrient Intake in a Water-Stressed Environment.

Directory of Open Access Journals (Sweden)

Jay V Gedir

Full Text Available Arid climates have unpredictable precipitation patterns, and wildlife managers often provide supplemental water to help desert ungulates endure the hottest, driest periods. When surface water is unavailable, the only source of water for ungulates comes from the forage they consume, and they must make resourceful foraging decisions to meet their requirements. We compared two desert bighorn sheep (Ovis canadensis nelsoni populations in Arizona, USA: a treatment population with supplemental water removed during treatment, and a control population. We examined whether sheep altered their seasonal diets without supplemental water. We calculated water and nutrient intake and metabolic water production from dry matter intake and forage moisture and nitrogen content, to determine whether sheep could meet their seasonal daily water and nutrient requirements solely from forage. Diets of sheep were higher in protein (all seasons and moisture (autumn and winter during treatment compared to pretreatment. During treatment, sheep diet composition was similar between the treatment and control populations, which suggests, under the climatic conditions of this study, water removal did not influence sheep diets. We estimated that under drought conditions, without any surface water available (although small ephemeral potholes would contain water after rains, female and male sheep would be unable to meet their daily water requirements in all seasons, except winter, when reproductive females had a nitrogen deficit. We determined that sheep could achieve water and nutrient balances in all seasons by shifting their total diet proportions by 8-55% from lower to higher moisture and nitrogen forage species. We elucidate how seasonal forage quality and foraging decisions by desert ungulates allow them to cope with their xeric and uncertain environment, and suggest that, with the forage conditions observed in our study area during this study period, providing supplemental

The central and eastern Arabian Sea as a perennial source of atmospheric carbon dioxide

Digital Repository Service at National Institute of Oceanography (India)

Sarma, V.V.S.S.; DileepKumar, M.; George, M.D.

circulation and biological production. In all seasons, the pCO sub(2) is higher in surface waters of the Arabian Sea, except along the Indian coast in the southwest monsoon, than that in atmosphere, and thus this region appears to be a perennial source...

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.

Science.gov (United States)

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multi-century cool- and warm-season rainfall reconstructions for Australia's major climatic regions

Science.gov (United States)

Freund, Mandy; Henley, Benjamin J.; Karoly, David J.; Allen, Kathryn J.; Baker, Patrick J.

2017-11-01

Australian seasonal rainfall is strongly affected by large-scale ocean-atmosphere climate influences. In this study, we exploit the links between these precipitation influences, regional rainfall variations, and palaeoclimate proxies in the region to reconstruct Australian regional rainfall between four and eight centuries into the past. We use an extensive network of palaeoclimate records from the Southern Hemisphere to reconstruct cool (April-September) and warm (October-March) season rainfall in eight natural resource management (NRM) regions spanning the Australian continent. Our bi-seasonal rainfall reconstruction aligns well with independent early documentary sources and existing reconstructions. Critically, this reconstruction allows us, for the first time, to place recent observations at a bi-seasonal temporal resolution into a pre-instrumental context, across the entire continent of Australia. We find that recent 30- and 50-year trends towards wetter conditions in tropical northern Australia are highly unusual in the multi-century context of our reconstruction. Recent cool-season drying trends in parts of southern Australia are very unusual, although not unprecedented, across the multi-century context. We also use our reconstruction to investigate the spatial and temporal extent of historical drought events. Our reconstruction reveals that the spatial extent and duration of the Millennium Drought (1997-2009) appears either very much below average or unprecedented in southern Australia over at least the last 400 years. Our reconstruction identifies a number of severe droughts over the past several centuries that vary widely in their spatial footprint, highlighting the high degree of diversity in historical droughts across the Australian continent. We document distinct characteristics of major droughts in terms of their spatial extent, duration, intensity, and seasonality. Compared to the three largest droughts in the instrumental period (Federation Drought

Multi-century cool- and warm-season rainfall reconstructions for Australia's major climatic regions

Directory of Open Access Journals (Sweden)

M. Freund

2017-11-01

Full Text Available Australian seasonal rainfall is strongly affected by large-scale ocean–atmosphere climate influences. In this study, we exploit the links between these precipitation influences, regional rainfall variations, and palaeoclimate proxies in the region to reconstruct Australian regional rainfall between four and eight centuries into the past. We use an extensive network of palaeoclimate records from the Southern Hemisphere to reconstruct cool (April–September and warm (October–March season rainfall in eight natural resource management (NRM regions spanning the Australian continent. Our bi-seasonal rainfall reconstruction aligns well with independent early documentary sources and existing reconstructions. Critically, this reconstruction allows us, for the first time, to place recent observations at a bi-seasonal temporal resolution into a pre-instrumental context, across the entire continent of Australia. We find that recent 30- and 50-year trends towards wetter conditions in tropical northern Australia are highly unusual in the multi-century context of our reconstruction. Recent cool-season drying trends in parts of southern Australia are very unusual, although not unprecedented, across the multi-century context. We also use our reconstruction to investigate the spatial and temporal extent of historical drought events. Our reconstruction reveals that the spatial extent and duration of the Millennium Drought (1997–2009 appears either very much below average or unprecedented in southern Australia over at least the last 400 years. Our reconstruction identifies a number of severe droughts over the past several centuries that vary widely in their spatial footprint, highlighting the high degree of diversity in historical droughts across the Australian continent. We document distinct characteristics of major droughts in terms of their spatial extent, duration, intensity, and seasonality. Compared to the three largest droughts in the instrumental

DIMENSIONS OF CARCASS AND INTERNAL ORGANS IN YOUNG SHEEP, UNDER CONDITIONS OF GRAZING ON ASSOCIATIONS OF PERENNIAL GRAMINACEOUS AND LEGUME

Directory of Open Access Journals (Sweden)

N. DRAGOMIR

2009-05-01

Full Text Available The temporary pastures’ floristic structure influences directly the growth and development of young sheep during grazing. The associations, beside the graminaceous and perennial legume species (white clover and birdsfoot trefoil, contribute mostly to the increase of carcass dimension and organ weight. The quality of the forage from such a pasture, better balanced in terms of energy and protein, influences all growth and development parameters in young sheep.

B chromosomes are associated with redistribution of genetic recombination towards lower recombination chromosomal regions in perennial ryegrass.

Science.gov (United States)

Harper, John; Phillips, Dylan; Thomas, Ann; Gasior, Dagmara; Evans, Caron; Powell, Wayne; King, Julie; King, Ian; Jenkins, Glyn; Armstead, Ian

2018-04-09

Supernumerary 'B' chromosomes are non-essential components of the genome present in a range of plant and animal species-including many grasses. Within diploid and polyploid ryegrass and fescue species, including the forage grass perennial ryegrass (Lolium perenne L.), the presence of B chromosomes has been reported as influencing both chromosome pairing and chiasma frequencies. In this study, the effects of the presence/absence of B chromosomes on genetic recombination has been investigated through generating DArT (Diversity Arrays Technology) marker genetic maps for six perennial ryegrass diploid populations, the pollen parents of which contained either two B or zero B chromosomes. Through genetic and cytological analyses of these progeny and their parents, we have identified that, while overall cytological estimates of chiasma frequencies were significantly lower in pollen mother cells with two B chromosomes as compared with zero B chromosomes, the recombination frequencies within some marker intervals were actually increased, particularly for marker intervals in lower recombination regions of chromosomes, namely pericentromeric regions. Thus, in perennial ryegrass, the presence of two B chromosomes redistributed patterns of meiotic recombination in pollen mother cells in ways which could increase the range of allelic variation available to plant breeders.

Seasonal behavioral responses of an arid-zone passerine in a hot environment.

Science.gov (United States)

Pattinson, Nicholas B; Smit, Ben

2017-10-01

Many arid-zone animals have to forage under extremely hot conditions to maintain water and energy balance. The effect of high air temperatures (T air ) on the behavioral patterns of small endothermic animals-characterized by their high energy and water demands-will provide a valuable framework for understanding species vulnerability to climate warming. We determined the seasonal behavioral responses to changes in T air in a~10-g arid-zone passerine, the rufous-eared warbler (Malcorus pectoralis), in the Karoo semi-desert, South Africa. Rufous-eared warblers showed significant temperature-dependence in their behavior in summer, but not in winter. During summer, the warblers frequently experienced T air exceeding 40°C in the shade. For all observations 36°C, the warblers showed reductions in preening (40% decrease), foraging effort (56% decrease), and foraging success (15% decrease), as well as a significant increase in time spent engaged in evaporative cooling behavior. Moreover, as T air increased the warblers shifted increasingly off the ground and out of the full sun, into microsites in the shade (131% increase) and in shrubs (23% increase). In this regard, behavior varied seasonally, with the time spent in the shade 23% higher, and foraging effort 28% higher, in summer compared to winter across a range of moderate T air (15-30°C). Our findings emphasize the link between behavior and temperature in small birds inhabiting hot, arid environments, as well as the importance of understanding these responses for predicting biologically meaningful responses (and hence, vulnerability) of arid-zone avian communities to climactic shifts. Copyright © 2017 Elsevier Inc. All rights reserved.

Trophic ecology and foraging behavior of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata, Tropiduridae in a caatinga area of northeastern Brazil

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Leonardo B. Ribeiro

2011-09-01

Full Text Available This study aimed to analyze the seasonal variation in diet composition and foraging behavior of Tropidurus hispidus (Spix, 1825 and T. semitaeniatus (Spix, 1825, as well as measurement of the foraging intensity (number of moves, time spent stationary, distance traveled and number of attacks on prey items in a caatinga patch on the state of Rio Grande do Norte, Brazil. Hymenoptera/Formicidae and Isoptera predominated in the diet of both species during the dry season. Opportunistic predation on lepidopteran larvae, coleopteran larvae and adults, and orthopteran nymphs and adults occurred in the wet season; however, hymenopterans/Formicidae were the most important prey items. The number of food items was similar between lizard species in both seasons; however the overlap for number of prey was smaller in the wet season. Preys ingested by T. hispidus during the wet season were also larger than those consumed by T. semitaeniatus. Seasonal comparisons of foraging intensity between the two species differed, mainly in the wet season, when T. hispidus exhibited less movement and fewer attacks on prey, and more time spent stationary if compared to T. semitaeniatus. Although both lizards are sit-and-wait foragers, T. semitaeniatus is more active than T. hispidus. The diet and foraging behavior of T. hispidus and T. semitaeniatus overlap under limiting conditions during the dry season, and are segregative factors that may contribute to the coexistence of these species in the wet season.

Nutritional characteristics of forages from Niger

Directory of Open Access Journals (Sweden)

F. Infascelli

2010-04-01

Full Text Available In the production systems of the semi-arid areas low quality forages are commonly used as the basal diet (Wilkins, 2000 and, as a consequence, the nutritional status of ruminants depends mainly on the ability of rumen fermentation to yield nutrients such as the short chain fatty acids and microbial biomass (Preston and Leng, 1987. The forages browsed by the livestock can be classified into two main groups: ephemeral annual plants, which germinate and remain green for only a few weeks after rain, perennial shrubs and tree fodders. Despite their potential as feeds, little research has determined their nutritive value. In vivo evaluation is the best estimation method of feed’s nutritional value, however it is very laborious and difficult to standardize with browsing animals. O the contrary, in vitro methods are less expensive, less time consuming and allow a better control of experimental conditions than in vivo experiments. The in vitro gas production technique (IVGPT appears to be the most suitable method for use in developing countries where resources may be limited (Makkar, 2004. Increased interest in use of non-conventional feed resources has led to an increase in use of this technique, since IVGPT can provide useful data on digestion kinetics of both the soluble and insoluble fractions of feedstuffs. The aim of the present research was to evaluate twelve forages from the arid zone of Niger using the IVGPT.

Genetic linkage mapping in an F2 perennial ryegrass population using DArT markers

DEFF Research Database (Denmark)

Tomaszewski, Céline; Byrne, Stephen; Foito, Alexandra

2012-01-01

Perennial ryegrass is the principal forage grass species used in temperate agriculture. In recent years, significant efforts have been made to develop molecular marker strategies to allow cost-effective characterization of a large number of loci simultaneously. One such strategy involves using DAr......T markers, and a DArT array has recently been developed for the Lolium-Festuca complex. In this study, we report the first use of the DArTFest array to generate a genetic linkage map based on 326 markers in a Lolium perenne F2 population, consisting of 325 genotypes. For proof of concept, the map was used...

Forage fish quality: seasonal lipid dynamics of herring (Clupea harengus L.) and sprat (Sprattus sprattus L.) in the Baltic Sea

DEFF Research Database (Denmark)

Røjbek, Maria; Tomkiewicz, Jonna; Jacobsen, Charlotte

2013-01-01

seasonally with high levelstowards the end of the annual zooplankton production cycle, succeeded by a decline. Lipid content and fatty acid composition differed significantly between sprat and herring. Sprat lipid content was higher than herring, increasing with fish size and characterized by large......This study investigates lipid content and fatty acid composition of two important forage fish, sprat (Sprattus sprattus) and herring (Clupea harengus) in the Baltic Sea ecosystem. Seasonal variation in lipids was studied during three periods following the annual reproductive cycle considering...... potential differences relating to fish size, sex, and reproductive status. The isopod Saduria entomon, being at times an important prey for predatory fish, was included for comparison. In both sprat and herring, lipid content and absolute contents of essential polyunsaturated fatty acids (PUFAs) varied...

Resource selection by Indiana bats during the maternity season

Science.gov (United States)

Kathryn M. Womack; Sybill K. Amelon; Frank R. Thompson

2013-01-01

Little information exists on resource selection by foraging Indiana bats (Myotis sodalis) during the maternity season. Existing studies are based on modest sample sizes because of the rarity of this endangered species and the difficulty of radio-tracking bats. Our objectives were to determine resource selection by foraging Indiana bats during the maternity season and...

Foraging strategies of Antarctic Fulmarine petrels

NARCIS (Netherlands)

Creuwels, J.C.S.; Engelhard, G.A.; Franeker, van J.A.; Veer, van der W.; Hasperhoven, J.G.; Ruiterman, W.

2010-01-01

During breeding, procellariiform seabirds are typical central-place foragers, depending on distant pelagic resources. Especially in polar environments, where there is only a short time window to complete the breeding season, high chick provisioning rates are needed to allow chicks to fledge

Flexible Residential Test Facility: Impact of Infiltration and Ventilation on Measured Cooling Season Energy and Moisture Levels

Energy Technology Data Exchange (ETDEWEB)

Parker, Danny S. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Cummings, Jamie E. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Vieira, Robin K. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Fairey, III, Phillip W. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Sherwin, John S. [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Withers, Jr., Charles [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Hoak, David [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States); Beal, David [BA-PIRC/Florida Solar Energy Center, Cocoa, FL (United States)

2016-09-01

Air infiltration and ventilation in residential buildings is a very large part of the heating loads, but empirical data regarding the impact on space cooling has been lacking. Moreover, there has been little data on how building tightness might relate to building interior moisture levels in homes in a hot and humid climate. To address this need, BA-PIRC has conducted research to assess the moisture and cooling load impacts of airtightness and mechanical ventilation in two identical laboratory homes in the hot-humid climate over the cooling season.

Flexible Residential Test Facility: Impact of Infiltration and Ventilation on Measured Cooling Season Energy and Moisture Levels

Energy Technology Data Exchange (ETDEWEB)

Parker, D.; Kono, J.; Vieira, R.; Fairey, P.; Sherwin, J.; Withers, C.; Hoak, D.; Beal, D.

2014-05-01

Air infiltration and ventilation in residential buildings is a very large part of the heating loads, but empirical data regarding the impact on space cooling has been lacking. Moreover, there has been little data on how building tightness might relate to building interior moisture levels in homes in a hot and humid climate. To address this need, BA-PIRC has conducted research to assess the moisture and cooling load impacts of airtightness and mechanical ventilation in two identical laboratory homes in the hot-humid climate over the cooling season.

Effects of maturity and harvest season of grass-clover silage and of forage-to-concentrate ratio on milk production of dairy cows

DEFF Research Database (Denmark)

Alstrup, L; Søegaard, K; Weisbjerg, M R

2016-01-01

This study examined the effects of maturity and season of harvest of grass-clover silages and forage:concentrate ratio (FCR) on feed intake, milk production, chewing activity, digestibility, and fecal consistency of Holstein dairy cows. Comparison included 2 cuts in spring season (early and late......) and 2 cuts in summer season (early and late) combined with high FCR (80:20; HFCR) and low FCR (50:50; LFCR). The experiment included 24 lactating Holstein cows arranged as 2 repeated 4 × 4 Latin squares with four 21-d periods and included measurements of feed composition, feed intake, milk production...... digestible than late maturity cuts, which was also reflected in a lower concentration of neutral detergent fiber (NDF) in early maturity cuts, whereas summer cuts had a higher crude protein concentration than spring cuts. Increased maturity decreased the intake of DM and energy, increased NDF intake...

Root Characteristics of Perennial Warm-Season Grasslands Managed for Grazing and Biomass Production

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Rattan Lal

2013-07-01

Full Text Available Minirhizotrons were used to study root growth characteristics in recently established fields dominated by perennial C4-grasses that were managed either for cattle grazing or biomass production for bioenergy in Virginia, USA. Measurements over a 13-month period showed that grazing resulted in smaller total root volumes and root diameters. Under biomass management, root volume was 40% higher (49 vs. 35 mm3 and diameters were 20% larger (0.29 vs. 0.24 mm compared to grazing. While total root length did not differ between grazed and biomass treatments, root distribution was shallower under grazed areas, with 50% of total root length in the top 7 cm of soil, compared to 41% in ungrazed exclosures. These changes (i.e., longer roots and greater root volume in the top 10 cm of soil under grazing but the reverse at 17–28 cm soil depths were likely caused by a shift in plant species composition as grazing reduced C4 grass biomass and allowed invasion of annual unsown species. The data suggest that management of perennial C4 grasslands for either grazing or biomass production can affect root growth in different ways and this, in turn, may have implications for the subsequent carbon sequestration potential of these grasslands.

Production and supply logistics of switchgrass as an energy feedstock

Science.gov (United States)

Switchgrass (Panicum virgatum L.) is a warm-season (C4), perennial grass that is native to the tallgrass ecoregion of North America (Figure 1). Historically, switchgrass has been used for summer forage, hay, ensiling, or in conservation plantings. At the end of the 20th century, switchgrass was de...

Foraging strategies of the ant Ectatomma vizottoi (Hymenoptera, Formicidae

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Luan D. Lima

2013-12-01

Full Text Available Foraging strategies of the ant Ectatomma vizottoi (Hymenoptera, Formicidae. Foraging activity may be limited by temperature, humidity, radiation, wind, and other abiotic factors, all of which can affect energy costs during foraging. Ectatomma vizottoi's biology has only recently been studied, and no detailed information is available on its foraging patterns or diet in the field. For this reason, and because foraging activity is an important part of the ecological success of social insects, the present study aimed to investigate E. vizottoi's foraging strategies and dietary habits. First, we determined how abiotic factors constrained E. vizottoi's foraging patterns in the field by monitoring the foraging activity of 16 colonies on eight different days across two seasons. Second, we characterized E. vizottoi's diet by monitoring another set of 26 colonies during peak foraging activity. Our results show that E. vizottoi has foraging strategies that are similar to those of congeneric species. In spite of having a low efficiency index, colonies adopted strategies that allowed them to successfully obtain food resources while avoiding adverse conditions. These strategies included preying on other ant species, a foraging tactic that could arise if a wide variety of food items are not available in the environment or if E. vizottoi simply prefers, regardless of resource availability, to prey on other invertebrates and especially on other ant species.

Towards an assessment of on-farm niches for improved forages in Sud-Kivu, DR Congo

Directory of Open Access Journals (Sweden)

Birthe K. Paul

2016-10-01

Full Text Available Inadequate quantity and quality of livestock feed is a persistent constraint to productivity for mixed crop-livestock farming in eastern Democratic Republic of Congo. To assess on-farm niches of improved forages, demonstration trials and participatory on-farm research were conducted in four different sites. Forage legumes included Canavalia brasiliensis (CIAT 17009, Stylosanthes guianensis (CIAT 11995 and Desmodium uncinatum (cv. Silverleaf, while grasses were Guatemala grass (Tripsacum andersonii, Napier grass (Pennisetum purpureum French Cameroon, and a local Napier line. Within the first six months, forage legumes adapted differently to the four sites with little differences among varieties, while forage grasses displayed higher variability in biomass production among varieties than among sites. Farmers’ ranking largely corresponded to herbage yield from the first cut, preferring Canavalia, Silverleaf desmodium and Napier French Cameroon. Choice of forages and integration into farming systems depended on land availability, soil erosion prevalence and livestock husbandry system. In erosion prone sites, 55–60%of farmers planted grasses on field edges and 16–30% as hedgerows for erosion control. 43% of farmers grew forages as intercrop with food crops such as maize and cassava, pointing to land scarcity. Only in the site with lower land pressure, 71% of farmers grew legumes as pure stand. When land tenure was not secured and livestock freely roaming, 75% of farmers preferred to grow annual forage legumes instead of perennial grasses. Future research should develop robust decision support for spatial and temporal integration of forage technologies into diverse smallholder cropping systems and agro-ecologies.

Variation in sequences containing microsatellite motifs in the perennial biomass and forage grass, Phalaris arundinacea (Poaceae).

Science.gov (United States)

Barth, Susanne; Jankowska, Marta Jolanta; Hodkinson, Trevor Roland; Vellani, Tia; Klaas, Manfred

2016-03-22

Forty three microsatellite markers were developed for further genetic characterisation of a forage and biomass grass crop, for which genomic resources are currently scarce. The microsatellite markers were developed from a normalized EST-SSR library. All of the 43 markers gave a clear banding pattern on 3% Metaphor agarose gels. Eight selected SSR markers were tested in detail for polymorphism across eleven DNA samples of large geographic distribution across Europe. The new set of 43 SSR markers will help future research to characterise the genetic structure and diversity of Phalaris arundinacea, with a potential to further understand its invasive character in North American wetlands, as well as aid in breeding work for desired biomass and forage traits. P. arundinacea is particularly valued in the northern latitude as a crop with high biomass potential, even more so on marginal lands.

Exploring the Factors Driving Seasonal Farmland Abandonment: A Case Study at the Regional Level in Hunan Province, Central China

OpenAIRE

Yu, Zhonglei; Liu, Lei; Zhang, Hua; Liang, Jinshe

2017-01-01

Farmland abandonment, including perennial and seasonal abandonment, is an important process of land use change that matters most to food security. Although there is a great deal of studies on farmland abandonment, seasonal abandonment, which is as serious as perennial abandonment, has attracted little academic attention. This paper takes Hunan Province in central China as its study area and uses a spatial regression model to examine the driving factors of seasonal farmland abandonment at the ...

Physiology, phenology and behavioural strategies of forage fish

DEFF Research Database (Denmark)

Frisk, Christina

Forage fish are small individuals, and are very abundant in numbers and can form dense schools. Forage fish are important within the food webs of the oceans, as they are at the lower trophic levels. Forage fish prey on zooplankton and they are themselves preyed on by piscivore fish. The individual...... forage fish and its growth dynamics are governed by an interplay between physiological rates, e.g. metabolism and consumption and the ambient environment as the rates are temperature dependent. The topic of this thesis is to describe the strong link between the individual and the environment through....... The model includes an additional structure pool; gonads, to which energy is transferred during the spawning season. During periods of poor feeding, energy to cover metabolic costs are firstly taken from the reserve pool and secondly, if the reserves are depleted, from the somatic tissue pool. The model...

Seasonal Changes in the Caste Distribution of Foraging Populations of Formosan Subterranean Termite in New Orleans, Louisiana.

Science.gov (United States)

Cornelius, Mary L; Osbrink, Weste L A; Gallatin, Erin M

2015-01-01

This study examined the relationship between temperature, precipitation, soil composition, levels of feeding damage, and the caste distribution (workers, soldiers, nymphs) of the Formosan subterranean termite, Coptotermes formosanus Shiraki, collected in underground monitoring stations over a 12 mo period. Because nymphs are the caste that develops into alates, the seasonal abundance of nymphs was examined over a 5 yr period. Numbers of workers, soldiers, and soldier/worker ratio were significantly affected by month. Recruitment and retention of foraging termites in stations was significantly affected by the level of feeding damage. The number of nymphs collected in monitoring stations was highly variable. In the 12 mo test, there was a significant correlation between numbers of nymphs and level of feeding damage, temperature, precipitation, and soil composition. Over a 5 yr period, significantly more nymphs were collected in 2011 than in 2007 and 2008. Peak nymph collections varied from year to year. Overall, peak nymph collections were more likely to occur in Mar., Sept., and Oct. Increasing our knowledge of the environmental factors that influence recruitment and retention of foraging termites in monitoring stations could influence termite bait placement and improve baiting strategies for termite control. Identifying the key factors that cause aggregations of nymphs in underground stations could increase our ability to predict the intensity and location of alate swarms. © Crown copyright 2015.

Analysis of DNA methylation of perennial ryegrass under drought using the methylation-sensitive amplification polymorphism (MSAP) technique.

Science.gov (United States)

Tang, Xiao-Mei; Tao, Xiang; Wang, Yan; Ma, Dong-Wei; Li, Dan; Yang, Hong; Ma, Xin-Rong

2014-12-01

Perennial ryegrass (Lolium perenne), an excellent grass for forage and turf, is widespread in temperate regions. Drought is an important factor that limits its growth, distribution, and yield. DNA methylation affects gene expression and plays an important role in adaptation to adverse environments. In this study, the DNA methylation changes in perennial ryegrass under drought stress were assessed using methylation-sensitive amplified polymorphism (MSAP). After 15 days of drought stress treatment, the plant height was less than half of the control, and the leaves were smaller and darker. Genome-wide, a total of 652 CCGG sites were detected by MSAP. The total methylation level was 57.67 and 47.39 % in the control and drought treatment, respectively, indicating a decrease of 10.28 % due to drought exposure. Fifteen differentially displayed DNA fragments in MSAP profiles were cloned for sequencing analysis. The results showed that most of the genes involved in stress responses. The relative expression levels revealed that three demethylated fragments were up-regulated. The expression of a predicted retrotransposon increased significantly, changing from hypermethylation to non-methylation. Although the extent of methylation in two other genes decreased, the sites of methylation remained, and the expression increased only slightly. All of these results suggested that drought stress decreased the total DNA methylation level in perennial ryegrass and demethylation up-regulated related gene expressions and that the extent of methylation was negatively correlated with expression. Overall, the induced epigenetic changes in genome probably are an important regulatory mechanism for acclimating perennial ryegrass to drought and possibly other environmental stresses.

How Do Grass Species, Season and Ensiling Influence Mycotoxin Content in Forage?

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Adam Nawrath

2013-11-01

Full Text Available Mycotoxins are secondary metabolites produced by fungal species that have harmful effects on mammals. The aim of this study was to assess the content of mycotoxins in fresh-cut material of selected forage grass species both during and at the end of the growing season. We further assessed mycotoxin content in subsequently produced first-cutting silages with respect to the species used in this study: Lolium perenne (cv. Kentaur, Festulolium pabulare (cv. Felina, Festulolium braunii (cv. Perseus, and mixtures of these species with Festuca rubra (cv. Gondolin or Poa pratensis (Slezanka. The mycotoxins deoxynivalenol, zearalenone and T-2 toxin were mainly detected in the fresh-cut grass material, while fumonisin and aflatoxin contents were below the detection limits. July and October were the most risky periods for mycotoxins to occur. During the cold temperatures in November and December, the occurrence of mycotoxins in fresh-cut material declined. Although June was a period with low incidence of mycotoxins in green silage, contents of deoxynivalenol and zearalenone in silages from the first cutting exceeded by several times those determined in their biomass collected directly from the field. Moreover, we observed that use of preservatives or inoculants did not prevent mycotoxin production.

Recent Progress in Perennial Buckwheat Development

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Qing-Fu Chen

2018-02-01

Full Text Available Grains in the genus Fagopyrum have benefits to human health and are an excellent gluten-free raw material. Of all cereal foods, this genus has the highest total content of amino-acid nutrients necessary for humans; nutrients that are resistant to digestion (protein and starch resulting in their sustained release; higher dietary fiber content than key cereals, and is rich in a special healthy ingredient (flavonoids. Fagopyrum includes 24 species of which five are perennial. Among them, golden buckwheat (F.cymosum complex is the most important perennial buckwheat, which is not only used in Chinese medicine, but also has great potential in healthy food crop. In order to provide some clues for perennial crop studies and their industry development, this paper presents the state of perennial buckwheat research in terms of taxonomy; natural chemical products and pharmacological and health functions; genetics and evolution; breeding; and product development and utilization. The great advances such as successful interspecific crossing and its subsequent new perennial buckwheat varieties will speed up the development of the perennial buckwheat industry.

Forage Potential of Photoperiod-Sensitive millet ( Pennisetum ...

African Journals Online (AJOL)

To determine its potential as an annual forage, 'Maiwa', which is a short-day photoperiod-sensitive millet (Pennisetum americanum (Linn.) ... Improvement in the level and seasonal distribution of 'maiwa' herbage production as well as quality can be realised through suitable agronomic practices as well as breeding.

Cool-Season Turfgrass Species and Cultivars: Response to Simulated Traffic in Central Italy

OpenAIRE

Carlo F. Cereti; Roberto Ruggeri; Francesco Rossini

2010-01-01

Turfgrass species differ greatly in their ability to withstand the abrasion and compaction of traffic. Wear tolerance of turfgrass species and cultivars has been evaluated abroad by many researchers, while only few and partial studies have been conducted in Italy. Field experiment was carried out in Viterbo in 2001, 2002 and 2003 to evaluate the effect of the simulated traffic on 110 varieties belonging to four turfgrass cool-season species: tall fescue (Festuca arundinacea Schreb.), fine fes...

Foraging behaviour of pink-footed geese (Anser brachyrhynchus) during spring migration

DEFF Research Database (Denmark)

Chudzińska, Magda Ewa

and their energetic consequences are therefore of great importance to these birds. In this thesis, I have aimed to address some aspects of the foraging decisions and behaviour of pink-footed geese during their spring migration to the Arctic breeding area. I combined field techniques with telemetry technology as well...... as modelling tools to address questions about how geese forage and fuel during their spring migration. The first three presented manuscripts focus on changes in goose foraging behaviour and energetics over the course of the day, a stopover season and the entire migration. They also focus on variety of factors...... the question: which foraging decision do geese make at the Mid-Norway stopover site....

Effects of Grazing Management in Brachiaria grass-forage Peanut Pastures on Canopy Structure and Forage Intake.

Science.gov (United States)

Gomes, F K; Oliveira, M D B L; Homem, B G C; Boddey, R M; Bernardes, T F; Gionbelli, M P; Lara, M A S; Casagrande, D R

2018-06-13

Maintenance of mixed grass-legume pastures for stand longevity and improved animal utilization is a challenge in warm-season climates. The goal of this study was to assess grazing management on stand persistence, forage intake, and N balance of beef heifers grazing mixed pastures of Brachiaria brizantha and Arachis pintoi. A two-year experiment was carried out in Brazil, where four grazing management were assessed: rest period interrupted at 90%, 95%, and 100% of light interception (LI) and a fixed rest period of 42 days (90LI, 95LI, 100LI, and 42D, respectively). The LI were taken at 50 points at ground level and at five points above the canopy for each paddock using a canopy analyzer. For all treatments, the post-grazing stubble height was 15 cm. Botanical composition and canopy structure characteristics such as canopy height, forage mass, and vertical distribution of the morphological composition were evaluated pre-and post-grazing. Forage chemical composition, intake, and microbial synthesis were also determined. A randomized complete block design was used, considering the season of the year as a repeated measure over time. Grazing management and season were considered fixed, while block and year were considered random effects. In the summer, legume mass accounted for 19% of the canopy at 100LI, which was less than other treatments (a mean of 30%). The 100LI treatment had a greater grass stem mass compared with other treatments. In terms of vertical distribution for 100LI, 38.6% of the stem mass was above the stubble height, greater than the 5.7% for other treatments. The canopy structure limited neutral detergent fiber intake (P = 0.007) at 100LI (1.02% of BW/d), whereas 42D, 90LI, and 95LI treatments had NDF intake close to 1.2% of BW/d. The intake of digestible organic matter (OM; P = 0.007) and the ratio of crude protein/digestible OM (P < 0.001) were less at 100LI in relation to the other treatments. The production of microbial N (P < 0.001) and efficiency

Integração lavoura e pecuária e os atributos físicos de solo manejado sob sistema plantio direto Livestock-crop integration effects on physical attributes of a soil under no-till

Directory of Open Access Journals (Sweden)

Silvio Tulio Spera

2009-02-01

evaluated: I wheat/soybean, white oat/soybean, and common vetch/corn; II wheat/soybean, white oat/soybean, and annual forages (black oat + common vetch/corn; III perennial cool season forages (fescue + white clover + red clover + birdsfoot trefoil; and IV perennial warm season forages (bahiagrass + black oat + rye grass + white clover + red clover + birdsfoot trefoil. System V alfalfa as hay crop was established in an adjacent area in 1994. Half of the areas under the systems III, IV, and V returned to system I after the summer of 1996 (southern hemisphere. The crops, both summer and winter, were grown under no-till. The treatments were arranged in a randomized complete block design, with four replications. Soil core samples were also collected in a subtropical forest fragment adjacent to the experimental area. The variations in soil bulk density, total porosity, microporosity and macroporosity due to grain production systems with forages were not severe enough to cause soil degradation. The soil bulk density in the production systems with perennial forages was lower and total porosity and macroporosity, in the 0-2 cm layer, higher than in the production systems of grain or of grain with annual forages.

A comparative study of AMF diversity in annual and perennial plant species from semiarid gypsum soils.

Science.gov (United States)

Alguacil, M. M.; Torrecillas, E.; Roldán, A.; Díaz, G.; Torres, P.

2012-04-01

The arbuscular mycorrhizal fungi (AMF) communities composition regulate plant interactions and determine the structure of plant communities. In this study we analysed the diversity of AMF in the roots of two perennial gypsophyte plant species, Herniaria fruticosa and Senecio auricula, and an annual herbaceous species, Bromus rubens, growing in a gypsum soil from a semiarid area. The objective was to determine whether perennial and annual host plants support different AMF communities in their roots and whether there are AMF species that might be indicators of specific functional plant roles in these ecosystems. The roots were analysed by nested PCR, cloning, sequencing of the ribosomal DNA small subunit region and phylogenetic analysis. Twenty AMF sequence types, belonging to the Glomus group A, Glomus group B, Diversisporaceae, Acaulosporaceae, Archaeosporaceae and Paraglomeraceae, were identified. Both gypsophyte perennial species had differing compositions of the AMF community and higher diversity when compared with the annual species, showing preferential selection by specific AMF sequences types. B. rubens did not show host specificity, sharing the full composition of its AMF community with both perennial plant species. Seasonal variations in the competitiveness of AM fungi could explain the observed differences in AMF community composition, but this is still a working hypothesis that requires the analysis of further data obtained from a higher number of both annual and perennial plant species in order to be fully tested.

Comparative Foraging Efficiency of Two Sympatric Jackals, Silver-Backed Jackals (Canis mesomelas and Golden Jackals (Canis aureus, in the Ngorongoro Crater, Tanzania

Directory of Open Access Journals (Sweden)

S. E. Temu

2016-01-01

Full Text Available The foraging efficiency of two sympatric species of jackals, silver-backed jackals (Canis mesomelas and golden jackals (Canis aureus, was studied in the Ngorongoro crater from July 2014 through May 2015. The focal animal observation method was used and individuals of both species were followed as they foraged from morning to evening. Observations of individuals of both jackal species were made from a vehicle using binoculars and a spotting scope. Three major parameters were used for determination of foraging efficiency: distance travelled while foraging, time spent foraging, and amount of food secured in foraging period. The Mann–Whitney U test showed no significant difference (P>0.05 in distance travelled per unit time of foraging between the two species in the dry and wet seasons, respectively. Golden jackals secured a significantly higher amount of food than the silver-backed jackals in the wet season (Mann–Whitney U test, P<0.05, U=1035.4. Hunting of prey larger than Thomson’s gazelle (Eudorcas thomsonii fawns was not common. Both species mainly fed on smaller prey such as invertebrates and rodents and scavenged opportunistically. Efficient foraging is crucial for both jackal species especially during their breeding season when they are provisioning dependent pups.

Estimating Rangeland Forage Production Using Remote Sensing Data from a Small Unmanned Aerial System (sUAS)

Science.gov (United States)

Liu, H.; Jin, Y.; Devine, S.; Dahlgren, R. A.; Covello, S.; Larsen, R.; O'Geen, A. T.

2017-12-01

California rangelands cover 23 million hectares and support a $3.4 billion annual cattle industry. Rangeland forage production varies appreciably from year-to-year and across short distances on the landscape. Spatially explicit and near real-time information on forage production at a high resolution is critical for effective rangeland management, especially during an era of climatic extremes. We here integrated a multispectral MicaSense RedEdge camera with a 3DR solo quad-copter and acquired time-series images during the 2017 growing season over a topographically complex 10-hectare rangeland in San Luis Obispo County, CA. Soil moisture and temperature sensors were installed at 16 landscape positions, and vegetation clippings were collected at 36 plots to quantify forage dry biomass. We built four centimeter-level models for forage production mapping using time series of sUAS images and ground measurements of forage biomass and soil temperature and moisture. The biophysical model based on Monteith's eco-physiological plant growth theory estimated forage production reasonably well with a coefficient of determination (R2) of 0.86 and a root-mean-square error (RMSE) of 424 kg/ha when the soil parameters were included, and a R2 of 0.79 and a RMSE of 510 kg/ha when only remote sensing and topographical variables were included. We built two empirical models of forage production using a stepwise variable selection technique, one with soil variables. Results showed that cumulative absorbed photosynthetically active radiation (APAR) and elevation were the most important variables in both models, explaining more than 40% of the spatio-temporal variance in forage production. Soil moisture accounted for an additional 29% of the variance. Illumination condition was selected as a proxy for soil moisture in the model without soil variables, and accounted for 18% of the variance. We applied the remote sensing-based models to map daily forage production at 30-cm resolution for the

Hive Relocation Does Not Adversely Affect Honey Bee (Hymenoptera: Apidae Foraging

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Fiona C. Riddell Pearce

2013-01-01

Full Text Available Honey bees, Apis mellifera, face major challenges including diseases and reduced food availability due to agricultural intensification. Additionally, migratory beekeeping may subject colonies to a moving stress, both during the move itself and after the move, from the bees having to forage in a novel environment where they have no knowledge of flower locations. This study investigated the latter. We moved three colonies housed in observation hives onto the campus from a site 26 km away and compared their foraging performance to three similarly sized colonies at the same location that had not been moved. We obtained data on (1 foraging performance by calculating distance by decoding waggle dances, (2 hive foraging rate by counting forager departure rate, (3 forage quality by assessing sugar content of nectar from returning foragers, and (4 forager success by calculating the proportion of bees returning to the nest entrance with nectar in their crop. We repeated this 3 times (August 2010, October 2010, and June 2011 to encompass any seasonal effects. The data show no consistent difference in foraging performance of moved versus resident hives. Overall the results suggest that moving to a new location does not adversely affect the foraging success of honey bees.

Desert tortoises (Gopherus agassizii are selective herbivores that track the flowering phenology of their preferred food plants.

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W Bryan Jennings

Full Text Available Previous studies of desert tortoise foraging ecology in the western Mojave Desert suggest that these animals are selective herbivores, which alter their diet according to the temporal availability of preferred food plants. These studies, however, did not estimate availability of potential food plants by taking into account the spatial and temporal variability in ephemeral plant abundance that occurs within the spring season. In this study, we observed 18 free-ranging adult tortoises take 35,388 bites during the spring foraging season. We also estimated the relative abundance of potential food plants by stratifying our sampling across different phenological periods of the 3-month long spring season and by different habitats and microhabitats. This methodology allowed us to conduct statistical tests comparing tortoise diet against plant abundance. Our results show that tortoises choose food plants non-randomly throughout the foraging season, a finding that corroborates the hypothesis that desert tortoises rely on key plants during different phenological periods of spring. Moreover, tortoises only consumed plants in a succulent state until the last few weeks of spring, at which time most annuals and herbaceous perennials had dried and most tortoises had ceased foraging. Many species of food plants--including several frequently eaten species--were not detected in our plant surveys, yet tortoises located these rare plants in their home ranges. Over 50% of bites consumed were in the group of undetected species. Interestingly, tortoises focused heavily on several leguminous species, which could be nutritious foods owing to their presumably high nitrogen contents. We suggest that herbaceous perennials, which were rare on our study area but represented ~30% of tortoise diet, may be important in sustaining tortoise populations during droughts when native annuals are absent. These findings highlight the vulnerability of desert tortoises to climate change

Desert tortoises (Gopherus agassizii) are selective herbivores that track the flowering phenology of their preferred food plants

Science.gov (United States)

Jennings, Bryan W.; Berry, Kristin H.

2015-01-01

Previous studies of desert tortoise foraging ecology in the western Mojave Desert suggest that these animals are selective herbivores, which alter their diet according to the temporal availability of preferred food plants. These studies, however, did not estimate availability of potential food plants by taking into account the spatial and temporal variability in ephemeral plant abundance that occurs within the spring season. In this study, we observed 18 free-ranging adult tortoises take 35,388 bites during the spring foraging season. We also estimated the relative abundance of potential food plants by stratifying our sampling across different phenological periods of the 3-month long spring season and by different habitats and microhabitats. This methodology allowed us to conduct statistical tests comparing tortoise diet against plant abundance. Our results show that tortoises choose food plants non-randomly throughout the foraging season, a finding that corroborates the hypothesis that desert tortoises rely on key plants during different phenological periods of spring. Moreover, tortoises only consumed plants in a succulent state until the last few weeks of spring, at which time most annuals and herbaceous perennials had dried and most tortoises had ceased foraging. Many species of food plants—including several frequently eaten species—were not detected in our plant surveys, yet tortoises located these rare plants in their home ranges. Over 50% of bites consumed were in the group of undetected species. Interestingly, tortoises focused heavily on several leguminous species, which could be nutritious foods owing to their presumably high nitrogen contents. We suggest that herbaceous perennials, which were rare on our study area but represented ~30% of tortoise diet, may be important in sustaining tortoise populations during droughts when native annuals are absent. These findings highlight the vulnerability of desert tortoises to climate change if such changes

Plastid phylogenomics of the cool-season grass subfamily: clarification of relationships among early-diverging tribes.

Science.gov (United States)

Saarela, Jeffery M; Wysocki, William P; Barrett, Craig F; Soreng, Robert J; Davis, Jerrold I; Clark, Lynn G; Kelchner, Scot A; Pires, J Chris; Edger, Patrick P; Mayfield, Dustin R; Duvall, Melvin R

2015-05-04

Whole plastid genomes are being sequenced rapidly from across the green plant tree of life, and phylogenetic analyses of these are increasing resolution and support for relationships that have varied among or been unresolved in earlier single- and multi-gene studies. Pooideae, the cool-season grass lineage, is the largest of the 12 grass subfamilies and includes important temperate cereals, turf grasses and forage species. Although numerous studies of the phylogeny of the subfamily have been undertaken, relationships among some 'early-diverging' tribes conflict among studies, and some relationships among subtribes of Poeae have not yet been resolved. To address these issues, we newly sequenced 25 whole plastomes, which showed rearrangements typical of Poaceae. These plastomes represent 9 tribes and 11 subtribes of Pooideae, and were analysed with 20 existing plastomes for the subfamily. Maximum likelihood (ML), maximum parsimony (MP) and Bayesian inference (BI) robustly resolve most deep relationships in the subfamily. Complete plastome data provide increased nodal support compared with protein-coding data alone at nodes that are not maximally supported. Following the divergence of Brachyelytrum, Phaenospermateae, Brylkinieae-Meliceae and Ampelodesmeae-Stipeae are the successive sister groups of the rest of the subfamily. Ampelodesmeae are nested within Stipeae in the plastome trees, consistent with its hybrid origin between a phaenospermatoid and a stipoid grass (the maternal parent). The core Pooideae are strongly supported and include Brachypodieae, a Bromeae-Triticeae clade and Poeae. Within Poeae, a novel sister group relationship between Phalaridinae and Torreyochloinae is found, and the relative branching order of this clade and Aveninae, with respect to an Agrostidinae-Brizinae clade, are discordant between MP and ML/BI trees. Maximum likelihood and Bayesian analyses strongly support Airinae and Holcinae as the successive sister groups of a Dactylidinae

Climatic and hydrologic influences on wading bird foraging patterns in Everglades National Park

Science.gov (United States)

Kwon, H.; Lall, U.; Engel, V.

2008-05-01

The ability to map the relationship between ecological outcomes and hydrologic conditions in the Everglades National Park is a key building block for the restoration program, a primary goal of which is to improve habitat for wading bird species and to promote nesting. This paper reports on a model linking wading bird foraging numbers to hydrologic conditions in the Park We demonstrate that seasonal hydrologic statistics derived from a single water level recording site are a) well correlated with water depths throughout most areas of the Park, and b) are effective as predictors of Great Egret and White Ibis foraging numbers at the end of the nesting season when using a nonlinear Bayesian Hierarchical model that permits the estimation of a conditional distribution of bird populations given the seasonal statistics of stage at the index location. Model parameters are estimated using a Markov Chain Monte Carlo procedure. Parameter and model uncertainty are both assessed as a byproduct of the estimation process. Water depths at the beginning of the nesting season, the recession rate, and the numbers of reversals in the recession are identified as significant predictors, consistent with the hydrologic conditions considered important in the seasonal production and concentration of prey organisms in this system. Long-term hydrologic records at the index location allow for a retrospective analysis (1952-2006) of wading bird foraging numbers showing low frequency oscillations in response to decadal and multi-decadal fluctuations in hydroclimatic conditions.

The Role of Non-Foraging Nests in Polydomous Wood Ant Colonies.

Science.gov (United States)

Ellis, Samuel; Robinson, Elva J H

2015-01-01

A colony of red wood ants can inhabit more than one spatially separated nest, in a strategy called polydomy. Some nests within these polydomous colonies have no foraging trails to aphid colonies in the canopy. In this study we identify and investigate the possible roles of non-foraging nests in polydomous colonies of the wood ant Formica lugubris. To investigate the role of non-foraging nests we: (i) monitored colonies for three years; (ii) observed the resources being transported between non-foraging nests and the rest of the colony; (iii) measured the amount of extra-nest activity around non-foraging and foraging nests. We used these datasets to investigate the extent to which non-foraging nests within polydomous colonies are acting as: part of the colony expansion process; hunting and scavenging specialists; brood-development specialists; seasonal foragers; or a selfish strategy exploiting the foraging effort of the rest of the colony. We found that, rather than having a specialised role, non-foraging nests are part of the process of colony expansion. Polydomous colonies expand by founding new nests in the area surrounding the existing nests. Nests founded near food begin foraging and become part of the colony; other nests are not founded near food sources and do not initially forage. Some of these non-foraging nests eventually begin foraging; others do not and are abandoned. This is a method of colony growth not available to colonies inhabiting a single nest, and may be an important advantage of the polydomous nesting strategy, allowing the colony to expand into profitable areas.

Seasonal regulation of condensed tannin consumption by free-ranging goats in a semi-arid savanna

Science.gov (United States)

Heitkӧnig, Ignas M. A.; Scogings, Peter F.; Hattas, Dawood; Dziba, Luthando E.; Prins, Herbert H. T.; de Boer, Willem F.

2018-01-01

Although condensed tannins (CTs) are known to reduce forage intake by mammalian herbivores in controlled experiments, few studies have tested these effects in the field. Thus the role of CTs on foraging ecology of free-ranging herbivores is inadequately understood. To investigate the effects of CTs under natural savanna conditions, we pre-dosed groups of goats with polyethylene glycol (PEG, a CT-neutralising chemical), CT powder or water before observing their foraging behaviour. While accounting for the effects of season and time of the day, we tested the hypothesis that herbivores forage in ways that reduce the intake rate (g DM per minute) of CTs. We expected pre-dosing goats with CTs to reduce CT intake rates by (1) consuming diets low in CTs, (2) reducing bite rates, (3) increasing the number of foraging bouts, or (4) reducing the length of foraging bouts. Lastly, (5) expected CT to have no influence the number of dietary forage species. In both wet and dry seasons, pre-dosing goats with CTs resulted in lower CT consumption rates compared to PEG goats which seemed relieved from the stress associated with CT consumption. During dry season, the number of dietary forage species was similar across treatments, although goats that were dosed with PEG significantly increased this number in the wet season. Dosing goats with PEG increased the number and length of browsing bouts compared to goats from the other treatments. Pre-loading goats with PEG also tended to increase bite rates on browse forages, which contributed to increased consumption rates of CTs. Based on the behavioural adjustments made by goats in this study and within the constraints imposed by chemical complexity in savanna systems, we concluded that herbivores under natural conditions foraged in ways that minimised CTs consumption. More research should further elucidate the mechanism through which CTs regulated feeding behaviour. PMID:29293513

Yield and nutritive quality of forage legumes on reclaimed surface mined land

International Nuclear Information System (INIS)

Ditsch, D.C.; Collins, M.

1998-01-01

Legumes are important in the long-term nitrogen economy of surface mined lands and for establishing and maintaining quality livestock forage. Little information is available to reclamation specialists for use in selection of forage legume species based on productivity potential, persistence and nutritive quality for livestock. A study was initiated at two sites in the Appalachian coal fields of Kentucky to evaluate monocultures of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.) and birdsfoot trefoil (Lotus corniculatus L.) under management regimes suitable for livestock production. Legumes were harvested at the early bloom stage throughout the growing season for dry matter (DM) yield determination. Forage quality was determined by measuring crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose (CEL) and acid detergent lignin (ADL). High DM yields were produced by all species during the first production season (range 6.2-9.2 Mg ha -1 ) but yields of all species declined rapidly by year three. Birdsfoot trefoil demonstrated slightly greater drought tolerance during mid-season (July/August) than alfalfa and red clover. With the exception of site number-sign 1 in 1992 (4 harvests), no more than 3 harvests were made during a single growing season. Crude protein concentration of these forage legumes was found to be within the range commonly measured on undisturbed lands. However, high NDF and ADF values were observed above those reported by others for the same species. These results indicate that it may be difficult to maintain a high level of productivity throughout the five-year bonding period under hay management. Management practices such as summer stockpiling may be necessary to compensate for the rapid and wide fluctuations in DM yield and quality due to low water-holding capacity of mine spoils. 15 refs., 2 figs., 7 tabs

Seasonal and cryopreservation impacts on semen quality in boars

Science.gov (United States)

Seasonal boar infertility occurs worldwide and contributes to economic loss to the pork industry. The current study evaluated cooled vs cryopreserved semen quality of 11 Duroc boars collected in June (cool season) and August 2014 (warm season). Semen was cooled to 16°C (cooled) or frozen over liquid...

Investigating the Sustainability of Perennial Agriculture

Science.gov (United States)

Sutherlin, C. E.; Brunsell, N. A.; De Oliveira, G.; Crews, T.; Vico, G.

2017-12-01

The changing climate leads to uncertainties concerning the sustainability of certain agricultural resources, and with the additional stresses of an increasing global population, uncertainty in food security will greatly increase. To adhere to future food demands in the face of this changing climate, perennial agriculture has been a proposed solution. However, it is equally important to assure that perennial agriculture is not negatively affecting the climate in exchange for this proposed more robust food source. We chose to examine the interactions between perennial and annual agricultural crops by focusing on the efficiency of exchanges with the atmosphere. This is done using the omega decoupling factor for 4 different sites as a way of quantifying the contributions of radiation and stomatal conductance over the resulting water and carbon cycles. This gives us an indication of how the plant canopy is interacting with, and influencing the local microclimate. Ultimately, this should give us an indication of the ability of perennial crops to aid in the climate mitigation process. We hypothesized that the perennial site chosen would have omega values more similar to the omega values of a natural grassland rather than an annual crop site. Using AmeriFlux towers to determine the canopy values needed to calculate the omega decoupling factor, we focused on the Kernza perennial crops being grown at the Land Institute in Salina, Kansas (KLS), in comparison to a natural grassland in Manhattan, Kansas (KON), a typical land cover model in Lawrence, Kansas (KFS), and an annual crop site in Lamont, Oklahoma (ARM). These results will allow us to move forward in the investigation of perennial crops as a sustainable food source.

Trophic strategy of Atlantirivulus riograndensis (Cyprinodontiformes: Rivulidae, a non-annual rivulid threatened by extinction, in a perennial environment, Brazil

Directory of Open Access Journals (Sweden)

Laísa Wociechoski Cavalheiro

Full Text Available ABSTRACT Rivulidae includes non-annual fish of perennial habitats and annual fish of temporary wetlands. The objective of this research was to investigate the trophic strategy of Atlantirivulus riograndensis in a perennial environment. Sampling occurred in an environmental conservation unit in the Pampa biome, Brazil. Quantification of the diet followed the volumetric method. Consumption of autochthonous material as the main food source of the species followed the pattern of Rivulidae. Species is zooplanktonic when young. Food spectrum is broadened and insectivorousness increases with ontogeny, revealing a specialist trend in the feeding strategy of A. riograndensis. The most diverse feeding occurs in the spring and summer seasons in which the presence of larger fish was more frequent than in other seasons. The increased consumption of microcrustaceans in the fall was related to smaller individuals, captured in greater quantities in this post-reproductive period. The lowest diversity of dietary items occurs during the winter and may reflect the lower diversity of food resources available in this season or the transition from juvenile to adult diet, with consumption of autochthonous Diptera by medium sized fish.

Analysis of Inter- and Intra-individual Variation in Foraging Habits of the Endangered Hawaiian Petrel Using Stables Isotopes

Science.gov (United States)

Morra, K. E.; Ostrom, P. H.; Wiley, A. E.; James, H. F.; Stricker, C. A.; Gandhi, H.

2014-12-01

Stable isotope analysis of the endangered Hawaiian petrel's (Pterodroma sandwichensis, HAPE) feathers provides otherwise intractable information regarding non-breeding season foraging habits. Adult HAPE spend 3.5-6 months at sea during the non-breeding season, at which time they sequentially molt their flight feathers. Because feathers are metabolically inert once synthesized, they capture isotopic signals while they are grown, providing an opportunity to study foraging habits over time. Here we use stable hydrogen (δD), carbon (δ13C) and nitrogen (δ15N) isotopes to assess variation in foraging habits within and between individuals, and among four breeding colonies. δD is an indicator of prevalence of fish vs. invertebrates in the diet. In one analysis, we observed large variation in feather δD (125‰), with adults from Maui and Kauai having significantly higher δD values than corresponding hatch-year birds, indicating significant dietary differences between age groups. In a second analysis, we utilized δ13C and δ15N of Hawaii, Maui and Lanai adults, values which vary with trophic level and also at the base of the food web across HAPE's foraging range, potentially revealing information about feeding location, as well as diet. Furthermore, because the sequence of molt is known, we are able to determine whether individual foraging specialization (continued use of the same foraging behavior over time) exists in this species. To do this, we analyzed two primary feathers, P1 and P6, which reflect the beginning and the middle of the non-breeding season, respectively. We did not find significant differences in δ13C or δ15N between P1 and P6, suggesting consistent foraging habits within individuals over time. This provides evidence that individual foraging specialization exists within these populations. Analysis of a secondary feather grown late in the molt sequence would further illuminate the extent of foraging specialization. Finally, δ15N differs

Genomics: a potential panacea for the perennial problem.

Science.gov (United States)

McClure, Kendra A; Sawler, Jason; Gardner, Kyle M; Money, Daniel; Myles, Sean

2014-10-01

Perennial crops represent important fresh and processed food sources worldwide, but advancements in breeding perennials are often impeded due to their very nature. The perennial crops we rely on most for food take several years to reach production maturity and require large spaces to grow, which make breeding new cultivars costly compared with most annual crops. Because breeding perennials is inefficient and expensive, they are often grown in monocultures consisting of small numbers of elite cultivars that are vegetatively propagated for decades or even centuries. This practice puts many perennial crops at risk for calamity since they remain stationary in the face of evolving pest and disease pressures. Although there is tremendous genetic diversity available to them, perennial crop breeders often struggle to generate commercially successful cultivars in a timely and cost-effective manner because of the high costs of breeding. Moreover, consumers often expect the same cultivars to be available indefinitely, and there is often little or no incentive for growers and retailers to take the risk of adopting new cultivars. While genomics studies linking DNA variants to commercially important traits have been performed in diverse perennial crops, the translation of these studies into accelerated breeding of improved cultivars has been limited. Here we explain the "perennial problem" in detail and demonstrate how modern genomics tools can significantly improve the cost effectiveness of breeding perennial crops and thereby prevent crucial food sources from succumbing to the perils of perpetual propagation. © 2014 Botanical Society of America, Inc.

Population structure and genetic diversity in North American Hedysarum boreale Nutt.

Science.gov (United States)

Bradley S. Bushman; Steven R. Larson; Michael D. Peel; Michael E. Pfrender

2007-01-01

Hedysarum boreale Nutt. is a perennial legume native to western North America, with robust foliage in the late spring season. Due to its wide native range, forage value, and N2 fixation, H. boreale is of interest for rangeland revegetation and production. Seed cost is a major obstacle for utilization of H. boreale, primarily due to seed shattering and unreliable seed...

Forage accumulation in brachiaria grass under continuous grazing with single or variable height during the seasons of the year

Directory of Open Access Journals (Sweden)

Manoel Eduardo Rozalino Santos

2013-05-01

Full Text Available The objective of this study was to evaluate grazing management strategies of Brachiaria decumbens cv. Basilisk managed with different heights under continuous grazing with cattle. Two grazing management strategies were evaluated: maintenance of pasture with an average height of 25 cm throughout the experimental period and maintenance of pasture on the average of 15 cm in height during winter, up to 25 cm from the beginning of spring. The split-plot scheme and the randomized block design with four replications were adopted. The grazing management strategies corresponded to the primary factor, while the seasons (winter, spring and summer corresponded to secondary factor. The reduction of the average sward height to 15 cm in the winter resulted, when compared with pasture maintained at 25 cm, in overall higher growth rates (95 kg/ha.day DM and leaf blade (66.1 kg/ha.day DM, as well as higher rates of total accumulation (81.5 kg/ha.day DM and leaf blade (52.6 kg/ha.day DM. The accumulated forage production (from winter to summer was higher in the pasture lowered to 15 cm in winter (25.6 t/ha DM compared with that managed with an average height of 25 cm (22.2 t/ha DM. Regarding the seasons of the year, in the winter, there were lower rates of overall growth (6.4 kg/ha.day DM, leaf blade (5.6 kg/ha.day DM and pseudostem (0.8 kg/ha.day DM, and also lower total (-6.6 kg/ha.day DM and leaf blade (-7.5 kg/ha.day DM accumulation rates. In the spring there was a higher rate of leaf senescence (22.4 kg/ha.day DM. The accumulation of forage is incremented when the pasture of B. decumbens is lowered to 15 cm during the winter, and in the spring and summer, its average height is increased to 25 cm.

Nectar yeasts in the tall Larkspur Delphinium barbeyi (Ranunculaceae and effects on components of pollinator foraging behavior.

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Robert N Schaeffer

Full Text Available Microorganisms frequently colonize the nectar of angiosperm species. Though capable of altering a suite of traits important for pollinator attraction, few studies exist that test the degree to which they mediate pollinator foraging behavior. The objective of our study was to fill this gap by assessing the abundance and diversity of yeasts associated with the perennial larkspur Delphinium barbeyi (Ranunculaceae and testing whether their presence affected components of pollinator foraging behavior. Yeasts frequently colonized D. barbeyi nectar, populating 54-77% of flowers examined depending on site. Though common, the yeast community was species-poor, represented by a single species, Metschnikowia reukaufii. Female-phase flowers of D. barbeyi were more likely to have higher densities of yeasts in comparison to male-phase flowers. Pollinators were likely vectors of yeasts, as virgin (unvisited flowers rarely contained yeasts compared to flowers open to pollinator visitation, which were frequently colonized. Finally, pollinators responded positively to the presence of yeasts. Bombus foragers both visited and probed more flowers inoculated with yeasts in comparison to uninoculated controls. Taken together, our results suggest that variation in the occurrence and density of nectar-inhabiting yeasts have the potential to alter components of pollinator foraging behavior linked to pollen transfer and plant fitness.

Nectar Yeasts in the Tall Larkspur Delphinium barbeyi (Ranunculaceae) and Effects on Components of Pollinator Foraging Behavior

Science.gov (United States)

Schaeffer, Robert N.; Phillips, Cody R.; Duryea, M. Catherine; Andicoechea, Jonathan; Irwin, Rebecca E.

2014-01-01

Microorganisms frequently colonize the nectar of angiosperm species. Though capable of altering a suite of traits important for pollinator attraction, few studies exist that test the degree to which they mediate pollinator foraging behavior. The objective of our study was to fill this gap by assessing the abundance and diversity of yeasts associated with the perennial larkspur Delphinium barbeyi (Ranunculaceae) and testing whether their presence affected components of pollinator foraging behavior. Yeasts frequently colonized D. barbeyi nectar, populating 54–77% of flowers examined depending on site. Though common, the yeast community was species-poor, represented by a single species, Metschnikowia reukaufii. Female-phase flowers of D. barbeyi were more likely to have higher densities of yeasts in comparison to male-phase flowers. Pollinators were likely vectors of yeasts, as virgin (unvisited) flowers rarely contained yeasts compared to flowers open to pollinator visitation, which were frequently colonized. Finally, pollinators responded positively to the presence of yeasts. Bombus foragers both visited and probed more flowers inoculated with yeasts in comparison to uninoculated controls. Taken together, our results suggest that variation in the occurrence and density of nectar-inhabiting yeasts have the potential to alter components of pollinator foraging behavior linked to pollen transfer and plant fitness. PMID:25272164

Adélie penguin foraging location predicted by tidal regime switching.

Science.gov (United States)

Oliver, Matthew J; Irwin, Andrew; Moline, Mark A; Fraser, William; Patterson, Donna; Schofield, Oscar; Kohut, Josh

2013-01-01

Penguin foraging and breeding success depend on broad-scale environmental and local-scale hydrographic features of their habitat. We investigated the effect of local tidal currents on a population of Adélie penguins on Humble Is., Antarctica. We used satellite-tagged penguins, an autonomous underwater vehicle, and historical tidal records to model of penguin foraging locations over ten seasons. The bearing of tidal currents did not oscillate daily, but rather between diurnal and semidiurnal tidal regimes. Adélie penguins foraging locations changed in response to tidal regime switching, and not to daily tidal patterns. The hydrography and foraging patterns of Adélie penguins during these switching tidal regimes suggest that they are responding to changing prey availability, as they are concentrated and dispersed in nearby Palmer Deep by variable tidal forcing on weekly timescales, providing a link between local currents and the ecology of this predator.

Relationship between altitude and intensity of malaria transmission in the Usambara Mountains, Tanzania

DEFF Research Database (Denmark)

Bødker, Rene; Akida, J.; Shayo, D.

2003-01-01

the holoendemic lowland and the hypoendemic highland plateau. Lowland transmission was perennial with a significant peak in the cool season after the long rains in May, when vectors densities were high. In the highlands, low temperatures prevented parasite development in mosquitoes during the cool season rains......, and highland transmission was therefore limited to the warm dry season when vector densities were low. The primary effect of increasing altitude was a log-linear reduction in vector abundance and, to a lesser extent, a reduction in the proportion of infective mosquitoes. Highland malaria transmission...

Landscape control of nitrous oxide emissions during the transition from conservation reserve program to perennial grasses for bioenergy

Science.gov (United States)

Debasish Saha; Benjamin M. Rau; Jason P. Kaye; Felipe Montes; Paul R. Adler; Armen R. Kemanian

2016-01-01

Future liquid fuel demand from renewable sources may, in part, be met by converting the seasonally wet portions of the landscape currently managed for soil and water conservation to perennial energy crops. However, this shift may increase nitrous oxide (N2O) emissions, thus limiting the carbon (C) benefits of energy crops. Particularly high emissions may occur during...

Stable Isotopes Reveal Long-Term Fidelity to Foraging Grounds in the Galapagos Sea Lion (Zalophus wollebaeki.

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Massimiliano Drago

Full Text Available Most otariids have colony-specific foraging areas during the breeding season, when they behave as central place foragers. However, they may disperse over broad areas after the breeding season and individuals from different colonies may share foraging grounds at that time. Here, stable isotope ratios in the skull bone of adult Galapagos sea lions (Zalophus wollebaeki were used to assess the long-term fidelity of both sexes to foraging grounds across the different regions of the Galapagos archipelago. Results indicated that the stable isotope ratios (δ(13C and δ(15N of sea lion bone significantly differed among regions of the archipelago, without any significant difference between sexes and with a non significant interaction between sex and region. Moreover, standard ellipses, estimated by Bayesian inference and used as a measure of the isotopic resource use area at the population level, overlapped widely for the sea lions from the southern and central regions, whereas the overlap of the ellipses for sea lions from the central and western regions was small and non-existing for those from the western and southern regions. These results suggest that males and females from the same region within the archipelago use similar foraging grounds and have similar diets. Furthermore, they indicate that the exchange of adults between regions is limited, thus revealing a certain degree of foraging philopatry at a regional scale within the archipelago. The constraints imposed on males by an expanded reproductive season (~ 6 months, resulting from the weak reproductive synchrony among females, and those imposed on females by a very long lactation period (at least one year but up to three years, may explain the limited mobility of adult Galapagos sea lions of both sexes across the archipelago.

Drought mitigation in perennial crops by fertilization and adjustments of regional yield models for future climate variability

Science.gov (United States)

Kantola, I. B.; Blanc-Betes, E.; Gomez-Casanovas, N.; Masters, M. D.; Bernacchi, C.; DeLucia, E. H.

2017-12-01

Increased variability and intensity of precipitation in the Midwest agricultural belt due to climate change is a major concern. The success of perennial bioenergy crops in replacing maize for bioethanol production is dependent on sustained yields that exceed maize, and the marketing of perennial crops often emphasizes the resilience of perennial agriculture to climate stressors. Land conversion from maize for bioethanol to Miscanthus x giganteus (miscanthus) increases yields and annual evapotranspiration rates (ET). However, establishment of miscanthus also increases biome water use efficiency (the ratio between net ecosystem productivity after harvest and ET), due to greater belowground biomass in miscanthus than in maize or soybean. In 2012, a widespread drought reduced the yield of 5-year-old miscanthus plots in central Illinois by 36% compared to the previous two years. Eddy covariance data indicated continued soil water deficit during the hydrologically-normal growing season in 2013 and miscanthus yield failed to rebound as expected, lagging behind pre-drought yields by an average of 53% over the next three years. In early 2014, nitrogen fertilizer was applied to half of mature (7-year-old) miscanthus plots in an effort to improve yields. In plots with annual post-emergence application of 60 kg ha-1 of urea, peak biomass was 29% greater than unfertilized miscanthus in 2014, and 113% greater in 2015, achieving statistically similar yields to the pre-drought average. Regional-scale models of perennial crop productivity use 30-year climate averages that are inadequate for predicting long-term effects of short-term extremes on perennial crops. Modeled predictions of perennial crop productivity incorporating repeated extreme weather events, observed crop response, and the use of management practices to mitigate water deficit demonstrate divergent effects on predicted yields.

Intensive use of an intertidal mudflat by foraging adult American horseshoe crabs Limulus polyphemus in the Great Bay estuary, New Hampshire

Directory of Open Access Journals (Sweden)

Wan-Jean LEE

2010-10-01

Full Text Available Although concerns about harvesting levels of the American Horseshoe Crab, Limulus polyphemus have prompted increased research into its ecology, current understanding of the species’ foraging ecology is mostly limited to mid-Atlantic populations. This study elucidates the spatial and temporal pattern of Limulus foraging on an intertidal mudflat of a northern New England estuary. A novel survey method was used to monitor Limulus foraging activity without disturbing the sediment. A fixed 50 m´2 m transect was monitored with monthly surveys of the number of Limulus feeding pits from June to October 2009, May and June 2010. Snorkelling surveys were also carried out to observe individual behavior and examine the spatial scale of activity of individual animals. Results showed frequent and intensive use of the mudflat by foraging Limulus. Limulus were actively foraging within the survey area during all months surveyed. Foraging patterns exhibited a seasonal pattern with activity levels peaking in August 2009 and increased significantly towards the end of the study in June 2010. It was also shown that Limulus intertidal foraging persisted and peaked after the spring breeding season. Observations of foraging Limulus revealed that individual predators dig multiple pits within a single high tide, with little disturbance to the sediment in between. In addition to altering the perception of Limulus as a subtidal predator outside of the breeding season, findings from this study suggests a segregation of spawning and feeding habitats, thus underscoring the need to consider a wider range of critical habitats in the management of Limulus populations [Current Zoology 56 (5: 611–617, 2010].

Stem characteristics of two forage maize (Zea mays L.) cultivars varying in whole plant digestibility. IV. Changes during the growing season in anatomy and chemical composition in relation to fermentation characteristics of a lower internode

NARCIS (Netherlands)

Boon, E.J.M.C.; Struik, P.C.; Engels, F.M.; Cone, J.W.

2012-01-01

Improving digestibility of forage maize (Zea mays L.) through breeding is important to optimize the efficiency of ruminant's rations. It can partly be achieved by improving the digestibility of stem tissue, a genetically complex and diverse trait changing drastically during the growing season. We

Seasonal and inter-annual photosynthetic response of representative C4 species to soil water content and leaf nitrogen concentration across a tropical seasonal floodplain

NARCIS (Netherlands)

Mantlana, K.B.; Arneth, A.; Veenendaal, E.M.; Wohland, P.; Wolski, P.; Kolle, O.; Lloyd, J.

2008-01-01

We examined the seasonal and inter-annual variation of leaf-level photosynthetic characteristics of three C4 perennial species, Cyperus articulatus, Panicum repens and Imperata cylindrica, and their response to environmental variables, to determine comparative physiological responses of plants

Cooling system with automated seasonal freeze protection

Science.gov (United States)

Campbell, Levi A.; Chu, Richard C.; David, Milnes P.; Ellsworth, Jr., Michael J.; Iyengar, Madhusudan K.; Simons, Robert E.; Singh, Prabjit; Zhang, Jing

2016-05-24

An automated multi-fluid cooling system and method are provided for cooling an electronic component(s). The cooling system includes a coolant loop, a coolant tank, multiple valves, and a controller. The coolant loop is at least partially exposed to outdoor ambient air temperature(s) during normal operation, and the coolant tank includes first and second reservoirs containing first and second fluids, respectively. The first fluid freezes at a lower temperature than the second, the second fluid has superior cooling properties compared with the first, and the two fluids are soluble. The multiple valves are controllable to selectively couple the first or second fluid into the coolant in the coolant loop, wherein the coolant includes at least the second fluid. The controller automatically controls the valves to vary first fluid concentration level in the coolant loop based on historical, current, or anticipated outdoor air ambient temperature(s) for a time of year.

Performance and goats behavior in pasture of Andropogon grass under different forage allowances

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Daniel Louçana da Costa Araújo

2015-07-01

Full Text Available This study was accomplished to evaluate the behavior and performance of goats in to grazing on grass Andropogon gayanus Kunth var. Bisquamulatus (Hochst Hack. cv. Planaltina submitted to three forage allowances: 11, 15 and 19% BW/day, under continuous grazing. The experimental design to assess the grazing behaviour was randomized blocks in a split-plot with five replicates within the block. In the plots, we evaluated the effect of forage allowances and in the subplots, the months May and June. While for evaluation of animal performance was in complete block design with five replicates within the block. The different forage allowance did not cause structural changes in the pasture, except in height. However, there was an increase of dead material, leaf/stem ratio and reducing of height during the grazing period. The behavioral variables were not affected by forage allowance, except for the time of displacement, whereby goats spent more time in pastures with offer of 11% BW. The goats remained most part of the time in grazing and idle, corresponding to 89% and 5% of the evaluation time, respectively. Higher bit rate was observed in June, among the offerings, and 15 and 19% BW. The ingestive and grazing behaviour in goats is changed by the accumulation of dead material and stem in pasture from Andropogon grass during at rainy season. The forage supply 11% of BW increases the time of displacement of goats grazing on Andropogon grass. The management of grazing Andropogon grass with forage allowance being 11 and 19% of BW provides low weight gains in goats during the rainy season.

The State-of-the-Art for Ventilative Cooling

DEFF Research Database (Denmark)

Heiselberg, Per Kvols

2016-01-01

Ventilative cooling for buildings may lead to cooling energy savings and improvements in thermal comfort, especially in seasonally temperate and warm climates. But, codes and regulations need to better quantify its benefits.......Ventilative cooling for buildings may lead to cooling energy savings and improvements in thermal comfort, especially in seasonally temperate and warm climates. But, codes and regulations need to better quantify its benefits....

Trophic ecology and foraging behavior of Tropidurus hispidus and Tropidurus semitaeniatus (Squamata, Tropiduridae) in a caatinga area of northeastern Brazil

OpenAIRE

Ribeiro,Leonardo B.; Freire,Eliza M. X.

2011-01-01

This study aimed to analyze the seasonal variation in diet composition and foraging behavior of Tropidurus hispidus (Spix, 1825) and T. semitaeniatus (Spix, 1825), as well as measurement of the foraging intensity (number of moves, time spent stationary, distance traveled and number of attacks on prey items) in a caatinga patch on the state of Rio Grande do Norte, Brazil. Hymenoptera/Formicidae and Isoptera predominated in the diet of both species during the dry season. Opportunistic predation...

Reproductive biology of the native forage grass Trichloris crinita (Poaceae, Chloridoideae).

Science.gov (United States)

Kozub, P C; Barboza, K; Galdeano, F; Quarin, C L; Cavagnaro, J B; Cavagnaro, P F

2017-05-01

Trichloris crinita is a perennial forage grass species native to arid regions of the American continent. Due to its extensive area of distribution, good forage quality and resistance to drought and grazing, this species is widely utilised as forage and for revegetation purposes in environments with low water availability. Despite its importance, genetic improvement of T. crinita has been very limited, partly as consequence of the lack of knowledge on its mode of reproduction. In the present work, we studied the reproductive biology of T. crinita by means of embryological analyses, flow cytometric seed screen (FCSS), self-compatibility tests and progeny testing with morphological and molecular markers. Cytological analyses revealed embryo sacs with eight nuclei and of Polygonum type for all T. crinita accessions analysed. FCSS histograms exhibited two clear peaks corresponding to 2C and 3C DNA content, indicating embryo sacs of sexual origin. Controlled pollination experiments designed to evaluate seed set (%) demonstrated that T. crinita is self-compatible, whereas results from morphological and simple sequence repeat (SSR) marker analysis of progeny revealed lack of outcrossing. Together, these results indicate that T. crinita reproduces sexually. It is a self-compatible and autogamous species. It is expected that these data will have a positive impact in the genetics and breeding of this species, and therefore contribute to its proper utilisation in arid regions. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Ground water heat pumps and cooling with ground water basins as seasonal storage; Grundvandsvarmepumper og -koeling med grundvandsmagasiner som saesonlager

Energy Technology Data Exchange (ETDEWEB)

2008-04-15

Ground water temperature is constant all the year round, in Denmark approximately 9 deg. C, which is ideal for a number of cooling purposes including cooling of buildings. The structures in which the ground water flows (sand, gravel and chalk) are efficient for storing coldness and heat over longer periods. By using seasonal storage of low-temperature heat and coldness in ground water layers close to the terrain it is feasible to reach profitable energy savings of up to 90% for cooling and heating of e.g. hotels, airports, shopping malls, office buildings and other larger buildings. At the same time the large energy savings means major reduction of CO{sub 2} emissions. (BA)

Temporal pattern of foraging and microhabitat use by Galápagos marine iguanas, Amblyrhynchus cristatus.

Science.gov (United States)

Buttemer, William A; Dawson, William R

1993-10-01

We observed a colony of marine iguanas (Amblyrhynchus cristatus) on Isla Fernandina, Galápagos, Ecuador, while measuring local micrometeorological and tidal conditions. We found size-related differences in foraging mode, with smaller iguanas feeding intertidally during daytime low tides and larger iguanas feeding subtidally. Despite having greater opportunity, subtidal foragers did not time their foraging bouts or exploit their environment in ways that optimized their period at high body temperature. Instead, the foraging schedule of these iguanas served to maximize their rate of rewarming following emergence from the cool sea. Intertidal feeders, by contrast, showed much greater behavioral flexibility in attempting to exploit their thermal environment. We suggest that size-ordered differences in marine iguana thermoregulatory behavior reflect underlying ontogenetic changes in costs and benefits of thermoregulation due to differences in predator pressure, quantity of food and electrolytes taken at each feeding, mode of foraging, and agonistic tendencies.

Giant panda foraging and movement patterns in response to bamboo shoot growth.

Science.gov (United States)

Zhang, Mingchun; Zhang, Zhizhong; Li, Zhong; Hong, Mingsheng; Zhou, Xiaoping; Zhou, Shiqiang; Zhang, Jindong; Hull, Vanessa; Huang, Jinyan; Zhang, Hemin

2018-03-01

Diet plays a pivotal role in dictating behavioral patterns of herbivorous animals, particularly specialist species. The giant panda (Ailuropoda melanoleuca) is well-known as a bamboo specialist. In the present study, the response of giant pandas to spatiotemporal variation of bamboo shoots was explored using field surveys and GPS collar tracking. Results show the dynamics in panda-bamboo space-time relationships that have not been previously articulated. For instance, we found a higher bamboo stump height of foraged bamboo with increasing elevation, places where pandas foraged later in spring when bamboo shoots become more fibrous and woody. The time required for shoots to reach optimum height for foraging was significantly delayed as elevation increased, a pattern which corresponded with panda elevational migration patterns beginning from the lower elevational end of Fargesia robusta distribution and gradually shifting upward until the end of the shooting season. These results indicate that giant pandas can respond to spatiotemporal variation of bamboo resources, such as available shoots. Anthropogenic interference of low-elevation F. robusta habitat should be mitigated, and conservation attention and increased monitoring should be given to F. robusta areas at the low- and mid-elevation ranges, particularly in the spring shooting season.

Seasonality directs contrasting food collection behavior and nutrient regulation strategies in ants.

Science.gov (United States)

Cook, Steven C; Eubanks, Micky D; Gold, Roger E; Behmer, Spencer T

2011-01-01

Long-lived animals, including social insects, often display seasonal shifts in foraging behavior. Foraging is ultimately a nutrient consumption exercise, but the effect of seasonality per se on changes in foraging behavior, particularly as it relates to nutrient regulation, is poorly understood. Here, we show that field-collected fire ant colonies, returned to the laboratory and maintained under identical photoperiod, temperature, and humidity regimes, and presented with experimental foods that had different protein (p) to carbohydrate (c) ratios, practice summer- and fall-specific foraging behaviors with respect to protein-carbohydrate regulation. Summer colonies increased the amount of food collected as the p:c ratio of their food became increasingly imbalanced, but fall colonies collected similar amounts of food regardless of the p:c ratio of their food. Choice experiments revealed that feeding was non-random, and that both fall and summer ants preferred carbohydrate-biased food. However, ants rarely ate all the food they collected, and their cached or discarded food always contained little carbohydrate relative to protein. From a nutrient regulation strategy, ants consumed most of the carbohydrate they collected, but regulated protein consumption to a similar level, regardless of season. We suggest that varied seasonal food collection behaviors and nutrient regulation strategies may be an adaptation that allows long-lived animals to meet current and future nutrient demands when nutrient-rich foods are abundant (e.g. spring and summer), and to conserve energy and be metabolically more efficient when nutritionally balanced foods are less abundant.

Energy saving potential of an indirect evaporative cooler as a pre-cooling unit for mechanical cooling systems in Iran

Energy Technology Data Exchange (ETDEWEB)

Delfani, Shahram; Esmaeelian, Jafar; Karami, Maryam [Department of Installation, Building and Housing Research Center (BHRC), PO Box 13145-1696, Tehran (Iran, Islamic Republic of); Pasdarshahri, Hadi [Department of Mechanical Engineering, Tarbiat Modares University, PO Box 14115-143, Tehran (Iran, Islamic Republic of)

2010-11-15

The performance of indirect evaporative cooling system (IEC) to pre-cool air for a conventional mechanical cooling system has been investigated for four cities of Iran. For this purpose, a combined experimental setup consisting of an IEC unit followed by a packaged unit air conditioner (PUA) was designed, constructed and tested. Two air simulators were designed and used to simulate indoor heating load and outdoor design conditions. Using of experimental data and an appropriate analytical method, the performance and energy reduction capability of combined system has been evaluated through the cooling season. The results indicate IEC can reduce cooling load up to 75% during cooling seasons. Also, 55% reduction in electrical energy consumption of PUA can be obtained. (author)

The impact of grazing on forage quality of the herbaceous ...

African Journals Online (AJOL)

Reports on research conducted in the Mamoro cork oak forest of Morocco to describe the impacts of sheep grazing in March, April, May and June of 1987 and 1988 on seasonal changes in forage quality of the herbaceous vegetation. The study showed that trends in herbage quality were related mainly to plant maturity.

Multidimensional differentiation in foraging resource use during breeding of two sympatric top predators

Science.gov (United States)

Friedemann, Guilad; Leshem, Yossi; Kerem, Lior; Shacham, Boaz; Bar-Massada, Avi; McClain, Krystaal M.; Bohrer, Gil; Izhaki, Ido

2016-10-01

Ecologically-similar species were found to develop specific strategies to partition their resources, leading to niche differentiation and divergence, in order to avoid interspecific competition. Our study determines multi-dimensional differentiation of two sympatric top-predators, long-legged buzzards (LLB) and short-toed eagles (STE), which recently became sympatric during their breeding season in the Judean Foothills, Israel. By combining information from comprehensive diet and movement analyses we found four dimensions of differentiation: (1) Geographic foraging area: LLB tended to forage relatively close to their nests (2.35 ± 0.62 km), while STE forage far from their nest (13.03 ± 2.20 km) (2) Foraging-habitat type: LLBs forage at low natural vegetation, avoiding cultivated fields, whereas STEs forage in cultivated fields, avoiding low natural vegetation; (3) Diurnal dynamics of foraging: LLBs are uniformly active during daytime, whereas STEs activity peaks in the early afternoon; and (4) Food-niche: while both species largely rely on reptiles (47.8% and 76.3% for LLB and STE, respectively), LLB had a more diverse diet and consumed significantly higher percentages of lizards, while STE consumed significantly higher percentages of snakes. Our results suggest that this multidimensional differentiation allows the spatial coexistence of these two dense populations in the study area.

Legumes and forage species sole or intercropped with corn in soybean-corn succession in midwestern Brazil

Directory of Open Access Journals (Sweden)

Gessí Ceccon

2013-02-01

Full Text Available The feasibility of no-tillage in the Cerrado (Savanna-like vegetation of Brazil depends on the production of sufficient above-ground crop residue, which can be increased by corn-forage intercropping. This study evaluated how above-ground crop residue production and yields of soybean and late-season corn in a soybean-corn rotation were influenced by the following crops in the year before soybean: corn (Zea mays L. intercropped with Brachiaria (Urochloa brizantha cv. Marandu, B. decumbens cv. Basilisk, B. ruziziensis, cv. comum., Panicummaximum cv. Tanzânia, sunn hemp (Crotalaria juncea L., pigeon pea [Cajanus cajan (L. Millsp]; sole corn, forage sorghum [Sorghum bicolor (L. Moench (cv. Santa Elisa], and ruzi grass. In March 2005, corn and forage species were planted in alternate rows spaced 0.90 m apart, and sole forage species were planted in rows spaced 0.45 m apart. In October 2005, the forages were killed with glyphosate and soybean was planted. After the soybean harvest in March 2006, sole late-season corn was planted in the entire experimental area. Corn grain and stover yields were unaffected by intercropping. Above-ground crop residue was greater when corn was intercropped with Tanzania grass (10.7 Mg ha-1, Marandu (10.1 Mg ha-1, and Ruzi Grass (9.8 Mg ha-1 than when corn was not intercropped (4.0 Mg ha-1. The intercropped treatments increased the percentage of soil surface covered with crop residue. Soybean and corn grain yields were higher after sole ruzi grass and intercropped ruzi grass than after other crops. The intercropping corn with Brachiaria spp. and corn with Panicum spp. increases above-ground crop residue production and maintains nutrients in the soil without reducing late-season corn yield and the viability of no-till in the midwestern region of Brazil.

Updates to the Cool Season Food Legume Genome Database: Resources for pea, lentil, faba bean and chickpea genetics, genomics and breeding

Science.gov (United States)

The Cool Season Food Legume Genome database (CSFL, www.coolseasonfoodlegume.org) is an online resource for genomics, genetics, and breeding research for chickpea, lentil,pea, and faba bean. The user-friendly and curated website allows for all publicly available map,marker,trait, gene,transcript, ger...

Modeling plant interspecific interactions from experiments with perennial crop mixtures to predict optimal combinations.

Science.gov (United States)

Halty, Virginia; Valdés, Matías; Tejera, Mauricio; Picasso, Valentín; Fort, Hugo

2017-12-01

The contribution of plant species richness to productivity and ecosystem functioning is a longstanding issue in ecology, with relevant implications for both conservation and agriculture. Both experiments and quantitative modeling are fundamental to the design of sustainable agroecosystems and the optimization of crop production. We modeled communities of perennial crop mixtures by using a generalized Lotka-Volterra model, i.e., a model such that the interspecific interactions are more general than purely competitive. We estimated model parameters -carrying capacities and interaction coefficients- from, respectively, the observed biomass of monocultures and bicultures measured in a large diversity experiment of seven perennial forage species in Iowa, United States. The sign and absolute value of the interaction coefficients showed that the biological interactions between species pairs included amensalism, competition, and parasitism (asymmetric positive-negative interaction), with various degrees of intensity. We tested the model fit by simulating the combinations of more than two species and comparing them with the polycultures experimental data. Overall, theoretical predictions are in good agreement with the experiments. Using this model, we also simulated species combinations that were not sown. From all possible mixtures (sown and not sown) we identified which are the most productive species combinations. Our results demonstrate that a combination of experiments and modeling can contribute to the design of sustainable agricultural systems in general and to the optimization of crop production in particular. © 2017 by the Ecological Society of America.

EFFECT OF PRE-COOLING ON REPEAT-SPRINT PERFORMANCE IN SEASONALLY ACCLIMATISED MALES DURING AN OUTDOOR SIMULATED TEAM-SPORT PROTOCOL IN WARM CONDITIONS

Directory of Open Access Journals (Sweden)

Carly J. Brade

2013-09-01

Full Text Available Whether precooling is beneficial for exercise performance in warm climates when heat acclimatised is unclear. The purpose of this study was to determine the effect of precooling on repeat-sprint performance during a simulated team-sport circuit performed outdoors in warm, dry field conditions in seasonally acclimatised males (n = 10. They performed two trials, one with precooling (PC; ice slushy and cooling jacket and another without (CONT. Trials began with a 30-min baseline/cooling period followed by an 80 min repeat-sprint protocol, comprising 4 x 20-min quarters, with 2 x 5-min quarter breaks and a 10-min half-time recovery/cooling period. A clear and substantial (negative; PC slower effect was recorded for first quarter circuit time. Clear and trivial effects were recorded for overall circuit time, third and fourth quarter sprint times and fourth quarter best sprint time, otherwise unclear and trivial effects were recorded for remaining performance variables. Core temperature was moderately lower (Cohen's d=0.67; 90% CL=-1.27, 0.23 in PC at the end of the precooling period and quarter 1. No differences were found for mean skin temperature, heart rate, thermal sensation, or rating of perceived exertion, however, moderate Cohen's d effect sizes suggested a greater sweat loss in PC compared with CONT. In conclusion, repeat- sprint performance was neither clearly nor substantially improved in seasonally acclimatised players by using a combination of internal and external cooling methods prior to and during exercise performed in the field in warm, dry conditions. Of practical importance, precooling appears unnecessary for repeat-sprint performance if athletes are seasonally acclimatised or artificially acclimated to heat, as it provides no additional benefit

Effects of forage types on digestibility, methane emissions, and nitrogen utilization efficiency in two genotypes of hill ewes.

Science.gov (United States)

Zhao, Y G; Annett, R; Yan, T

2017-08-01

Thirty-six nonpregnant hill ewes (18 pure Scottish Blackface and 18 Swaledale × Scottish Blackface) aged 18 mo and weighing 48 ± 4.8 kg were allocated to 3 forage treatments balanced for genotype and BW. Each genotype was offered 3 forages (pelleted ryegrass, fresh lowland grass, and fresh hill grass) ad libitum with 6 ewes for each of the 6 genotype × diet combination treatments. Pelleted ryegrass was sourced from a commercial supplier (Drygrass South Western Ltd, Burrington, UK). Fresh lowland grass was harvested daily in the morning from a third regrowth perennial ryegrass () sward. Fresh hill grass was harvested from a seminatural hill grassland every 2 d and stored in plastic bags at 4 to 5°C until offered. The animals were individually housed in pens and offered experimental diets for 14 d before being transferred to 6 individual respiration chambers for a further 4 d, during which feed intake, fecal and urine outputs, and CH emissions were measured. There was no interaction between genotype and forage types on any variable measured. In a comparison of effects of the 3 forages, pelleted ryegrass had the greatest ( reduce CH emissions per kilogram DMI. These equations add new information in predicting enteric CH emissions and N utilization efficiency and can be used to quantify the environmental footprint of hill sheep production systems.

Soil preparation and forage sowing time for crop-livestock integration in corn culture

Directory of Open Access Journals (Sweden)

Luiz Fernando de Andrade Fritsch

2012-01-01

Full Text Available This work was carried out during the 2008/2009 crop season, in an Oxisol. It was used a split-plot arrangement design, with each plot corresponding to a different soil preparation system and each split-plot corresponding to a different sowing time of the forage Brachiaria brizantha Stapf. The soil preparation systems were: heavy harrowing (HH, disk plough (DP, chisel plough (CP and no-till (NT, and the forage sowing times were: 0, 8, 16 and 25 days after sowing (DAS of corn, arranged in 16 treatments with 3 replicates. The productive and vegetative characteristics of the corn were evaluated. Soil preparations have influenced plant height and the first ear height, with the highest value found for the heavy harrow treatment. Forage sowing time had no influence on vegetative characteristics of the corn and productive characteristics were not influenced by the soil preparations. The forage sowing time had influence on corn productivity, causing decrease in competition with corn forage from 5 DAS. The productivity was highly correlated with the number of grains per ear.

Effective rumen degradation of dry matter, crude protein and neutral detergent fibre in forage determined by near infrared reflectance spectroscopy

DEFF Research Database (Denmark)

Ohlsson, C; Houmøller, L P; Weisbjerg, Martin Riis

2007-01-01

The objective of the present study was to examine if near infrared reflectance spectroscopy (NIRS) could be used to predict degradation parameters and effective degradation from scans of original forage samples. Degradability of dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF......) of 61 samples of perennial ryegrass (Lolium perenne L.) and orchardgrass (Dactylis glomerata L.) was tested by using the in situ technique. The grass samples were harvested at three different stages, early vegetative growth, early reproductive growth and late reproductive growth. Degradability...

Dynamics of sward condition and botanical composition in mixed pastures of marandugrass, forage peanut and tropical kudzu

Directory of Open Access Journals (Sweden)

Carlos Mauricio Soares de Andrade

2012-03-01

Full Text Available This study was carried out to evaluate the dynamics of sward condition and botanical composition of a mixed pasture of marandugrass (Brachiaria brizantha cv. Marandu, forage peanut (Arachis pintoi cv. Mandobi and tropical kudzu (Pueraria phaseoloides, rotationally stocked at four daily forage allowance levels (6.6, 10.3, 14.3 and 17.9% of live weight. Sward condition was characterized in each stocking cycle by measuring pre- and post-grazing sward height, forage mass and percentage of bare ground. Botanical composition (grass, forage peanut, tropical kudzu and weeds was evaluated before each stocking period. Swards under smaller forage allowances presented lower height, forage mass and ground cover. This condition favored the growth of forage peanut, which constituted 21.1, 15.2, 8.4 and 3.8% of forage mass in the last quarter of the experimental period, from the lowest to the highest forage allowance, respectively. Tropical kudzu was sensitive to all forage allowance levels and its percentage in the botanical composition was strongly reduced along the experimental period, especially during the dry season (July to September. Forage peanut cv. Mandobi and marandugrass form a more balanced mixture when pre-grazing sward height is maintained shorter than 45 cm. Tropical kudzu is intolerant to intensive grazing management systems when associated to marandugrass.

Cooling method with automated seasonal freeze protection

Science.gov (United States)

Cambell, Levi; Chu, Richard; David, Milnes; Ellsworth, Jr, Michael; Iyengar, Madhusudan; Simons, Robert; Singh, Prabjit; Zhang, Jing

2016-05-31

An automated multi-fluid cooling method is provided for cooling an electronic component(s). The method includes obtaining a coolant loop, and providing a coolant tank, multiple valves, and a controller. The coolant loop is at least partially exposed to outdoor ambient air temperature(s) during normal operation, and the coolant tank includes first and second reservoirs containing first and second fluids, respectively. The first fluid freezes at a lower temperature than the second, the second fluid has superior cooling properties compared with the first, and the two fluids are soluble. The multiple valves are controllable to selectively couple the first or second fluid into the coolant in the coolant loop, wherein the coolant includes at least the second fluid. The controller automatically controls the valves to vary first fluid concentration level in the coolant loop based on historical, current, or anticipated outdoor air ambient temperature(s) for a time of year.

Red-cockaded woodpecker male/female foraging differences in young forest stands.

Energy Technology Data Exchange (ETDEWEB)

Franzreb, Kathleen, E.

2010-07-01

ABSTRACT The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinus spp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in contrast to earlier foraging behavior studies that focused on more mature forest. The Redcockaded Woodpecker at the Savannah River site is intensively managed including monitoring, translocation, and installation of artificial cavity inserts for roosting and nesting. Over a 3-year period, 6,407 foraging observations covering seven woodpecker family groups were recorded during all seasons of the year and all times of day. The most striking differences occurred in foraging method (males usually scaled [45% of observations] and females mostly probed [47%]),substrate used (females had a stronger preference [93%] for the trunk than males [79%]), and foraging height from the ground (mean 6 SE foraging height was higher for males [11.1 6 0.5 m] than females [9.8 6 0.5 m]). Niche overlap between males and females was lowest for substrate (85.6%) and foraging height (87.8%), and highest for tree species (99.0%), tree condition (98.3%), and tree height (96.4%). Both males and females preferred to forage in older, large pine trees. The habitat available at the Savannah River Site was considerably younger than at most other locations, but the pattern of male/female habitat partitioning observed was similar to that documented elsewhere within the range attesting to the species’ ability to adjust behaviorally.

Seasonality directs contrasting food collection behavior and nutrient regulation strategies in ants.

Directory of Open Access Journals (Sweden)

Steven C Cook

Full Text Available Long-lived animals, including social insects, often display seasonal shifts in foraging behavior. Foraging is ultimately a nutrient consumption exercise, but the effect of seasonality per se on changes in foraging behavior, particularly as it relates to nutrient regulation, is poorly understood. Here, we show that field-collected fire ant colonies, returned to the laboratory and maintained under identical photoperiod, temperature, and humidity regimes, and presented with experimental foods that had different protein (p to carbohydrate (c ratios, practice summer- and fall-specific foraging behaviors with respect to protein-carbohydrate regulation. Summer colonies increased the amount of food collected as the p:c ratio of their food became increasingly imbalanced, but fall colonies collected similar amounts of food regardless of the p:c ratio of their food. Choice experiments revealed that feeding was non-random, and that both fall and summer ants preferred carbohydrate-biased food. However, ants rarely ate all the food they collected, and their cached or discarded food always contained little carbohydrate relative to protein. From a nutrient regulation strategy, ants consumed most of the carbohydrate they collected, but regulated protein consumption to a similar level, regardless of season. We suggest that varied seasonal food collection behaviors and nutrient regulation strategies may be an adaptation that allows long-lived animals to meet current and future nutrient demands when nutrient-rich foods are abundant (e.g. spring and summer, and to conserve energy and be metabolically more efficient when nutritionally balanced foods are less abundant.

Perennial pastures for marginal farming country in southern Queensland. 2. Potential new grass cultivar evaluation

Directory of Open Access Journals (Sweden)

Richard G. Silcock

2015-01-01

Full Text Available Trials in the Condamine-Balonne basin, Australia, compared 11 promising perennial pasture grass accessions (4 Bothriochloa, 2 Cenchrus, 2 Urochloa and 1 each of Digitaria, Eragrostis and Panicum species against the best similar commercial cultivars on the basis of ease of establishment from seed, persistence once established, forage yield and ease of seed production.  Accessions sown at a site were determined by prior experience with them on a range of soils.  High quality seed was relatively easy to produce for both Urochloa species and for Eragrostis curvula CPI 30374 but problematic for the Bothriochloa spp.  Once established, all accessions persisted for 3–5 years and most were well grazed, but adequate establishment was sometimes a problem with Panicum stapfianum and Bothriochloa ewartiana.  The dry matter yield ratings of the non-commercial lines were similar to those of the commercial equivalents of the same species.  While agronomically valuable, none of the promising new grasses was considered worthy of commercialization at this point because their strengths did not warrant the setting up of a seed-production business in competition with current commercial enterprises.  Long-standing cultivars such as Gayndah buffel and Nixon sabi grass continued to exhibit their superior pasture qualities.Keywords: Herbicide tolerance, persistence, forage yield, establishment ease, commercialization, seed production.DOI: 10.17138/TGFT(315-26

Determination of microbial protein in perennial ryegrass silage

NARCIS (Netherlands)

Driehuis, F.; Wikselaar, van P.G.

2001-01-01

The microbial matter fraction was determined in perennial ryegrass silages of different dry-matter (DM) contents, ensiled with or without Lactobacillus plantarum. 15N-Leucine and the bacterial cell wall constituent diaminopimelic acid (DAPA) were used as markers for microbial-N. Perennial ryegrass

FORAGE PRODUCTIVITY IN AGROECOSYSTEMS USING TRADITIONAL AND ROTATIONAL CATTLE GRAZING IN PASO DE OVEJAS, VERACRUZ, MEXICO

Directory of Open Access Journals (Sweden)

Marcelo Bautista-Tolentino

2011-11-01

Full Text Available Forage biomass and chemical composition of Megathyrsus maximus (Jacq. B.K. Simon & S.W.L. Jacobs were assessed in monoculture (P or associated with trees of Guazuma ulmifolia Lam. (PGu or Gliricidia sepium (Jacq. Kunth ex Walp (PGs, under traditional (TG or rotational (RG cattle grazing regimes, by season of the year (windy: October-February, dry: March-June, and rainy: July-September and annually. Annual forage production (kg DM ha-1 under RG and TG was 8049±586 and 4170±319, respectively; 5441±2225 in P-TG, 2022±82 in PGs-TG, 12326±2094 in PGu-TG, 9612±1331 in PGs-RG, and 7976±737 in PGu-RG. Gliricidia sepium produced 1448±2 and 1660±3 kg DM ha-1 year-1 under PGs-TG and PGs-RG, respectively. Forage yield across plant associations and grazing regimes was higher in the rainy season (5333.6±56.7 kg DM ha-1, and decreased in the windy (2462±349.0 kg DM ha-1 and dry seasons (252.9±2 kg DM ha-1. The PGu system had the highest crude protein content annually (21.8 % and by season (23.1 %, windy, and also showed the least neutral detergent fiber content during the year (55.2 % and by season (55.2 %, rainy. Biomass production and chemical composition of M. maximus in monoculture or associated with G. ulmifolia and G. sepium can be increased by modifying the traditional grazing regimes to a more intensive rotational system during the growth period of the year.

Temperature Impact on the Forage Quality of Two Wheat Cultivars with Contrasting Capacity to Accumulate Sugars

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Máximo Lorenzo

2015-08-01

Full Text Available Wheat is increasingly used as a dual-purpose crop (for forage and grain production worldwide. Plants encounter low temperatures in winter, which commonly results in sugar accumulation. High sugar levels might have a positive impact on forage digestibility, but may also lead to an increased risk of bloat. We hypothesized that cultivars with a lower capacity to accumulate sugars when grown under cold conditions may have a lower bloat risk than higher sugar-accumulating genotypes, without showing significantly lower forage digestibility. This possibility was studied using two wheat cultivars with contrasting sugar accumulation at low temperature. A series of experiments with contrasting temperatures were performed in controlled-temperature field enclosures (three experiments and growth chambers (two experiments. Plants were grown at either cool (8.1 °C–9.3 °C or warm (15.7 °C–16.5 °C conditions in field enclosures, and at either 5 °C or 25 °C in growth chambers. An additional treatment consisted of transferring plants from cool to warm conditions in the field enclosures and from 5 °C to 25 °C in the growth chambers. The plants in the field enclosure experiments were exposed to higher irradiances (i.e., 30%–100% than those in the growth chambers. Our results show that (i low temperatures led to an increased hemicellulose content, in parallel with sugar accumulation; (ii low temperatures produced negligible changes in in vitro dry matter digestibility while leading to a higher in vitro rumen gas production, especially in the higher sugar-accumulating cultivar; (iii transferring plants from cool to warm conditions led to a sharp decrease in in vitro rumen gas production in both cultivars; and (iv light intensity (in contrast to temperature appeared to have a lower impact on forage quality.

forage systems mixed with forage legumes grazed by lactating cows

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Clair Jorge Olivo

2017-02-01

Full Text Available Current research evaluates productivity, stocking and nutritional rates of three forage systems with Elephant Grass (EG + Italian Ryegrass (IR + Spontaneous Growth Species (SGS, without forage legumes; EG + IR + SGS + Forage Peanut (FP, mixed with FP; and EG + IR + SGS + Red Clover (RC, mixed with RC, in rotational grazing method by lactating cows. IR developed between rows of EG. FP was maintained, whilst RC was sow to respective forage systems. The experimental design was completely randomized, with three treatments and two replication, subdivided into parcels over time. Mean rate for forage yield and average stocking rate were 10.6, 11.6 and 14.4 t ha-1; 3.0, 2.8 and 3.1 animal unit ha-1 day-1, for the respective systems. Levels of crude protein and total digestible nutrients were 17.8, 18.7 and 17.5%; 66.5, 66.8 and 64.8%, for the respective forage systems. The presence of RC results in better and higher forage yield in the mixture, whilst FP results in greater control of SGS. The inclusion of forage legumes in pasture systems provides better nutritional rates.

Foliar glyphosate treatment alters transcript and hormone profiles in crown buds of leafy spurge and induces dwarfed and bushy phenotypes throughout its perennial life cycle

Science.gov (United States)

Leafy spurge (Euphorbia esula) is an invasive weed of North America and its perennial nature is attributed to underground adventitious buds (UABs) that undergo seasonal cycles of para-, endo- and eco-dormancy. Recommended field rates of glyphosate (~1 kg/ha) destroys above-ground shoots of leafy spu...

Radiocesium in roe deer and wild boars and their forage in the Chernobyl area

Energy Technology Data Exchange (ETDEWEB)

Eriksson, O.; Jungskaer, W. [Uppsala Univ. (Sweden). Dept. of Ecological Botany; Gaichenko, V.; Panov, G. [Academy of Sciences of Ukraine, Kiev (Ukraine). Schmalhausen Inst. of Zoology; Goshchak, S. [RIA Pripyat, Chernobyl (Ukraine). Restoration Dept.; Jones, B. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Clinical Chemistry; Petrov, M.; Davydchuk, V. [Academy of Sciences of Ukraine, Kiev (Ukraine). Inst. of Geography; Shcherbatchenko, A. [Academy of Sciences of Ukraine, Kiev (Ukraine). Inst. of Nuclear Research

1996-12-31

Tissue samples from 67 roe deer (Capreolus capreolus) and 73 wild boars (Sus scrofa L.) were obtained from the evacuated zone around the damaged nuclear reactor in Chernobyl, Ukraine. The samplings were performed from June 1992 to February 1995 regularly during each typical season (spring in mid-May, summer in mid-August, autumn in mid-October and winter in late February). By using botanical analysis of rumen/stomach contents, dominant forage plants were identified and collected in the area where the animals had been foraging. The results show that there is a considerable individual variation in diet selection within each season for both these animal species and also a seasonal variation in the radiocesium contamination of muscular tissue. The seasonal variation is most pronounced in the wild boar. Minimum levels of 137Cs were seen during summer and autumn (mean 6kBq/kg w.w. and 2 kBq/kg w.w., resp.) and maximum levels in winter (mean 113 kBq/kg w.w.). In the roe deer, the minimum levels were seen in winter (mean 6kBq/kg w.w.) and maximum levels in autumn (mean 58 kBq/kg w.w.). These variations are caused by differences in pasture selection during different seasons of the year. One very important forage plant eaten both by roe deer and by wild boars during all seasons was evening primrose (Oenothera biennis L.). Also the underground parts of this plant are consumed by the wild boar. Also the role of soil as an intake source of radioactive contaminants has been estimated by determination of inorganic residues after ashing of rumen/stomach samples. In the winter, wild boars show the highest ash content with 32% (mean of dry matter) and the lowest in summer with 6%. In roe deer, the differences between seasons are smaller, with an average of 9% in the spring and 15% in winter. The level of 137Cs contamination in muscular tissue of these two species has not decreased noticeably in the studied area during the study period from summer 1992 to winter 1995. 18 refs, 8 figs.

Radiocesium in roe deer and wild boars and their forage in the Chernobyl area

International Nuclear Information System (INIS)

Eriksson, O.; Jungskaer, W.; Gaichenko, V.; Panov, G.; Goshchak, S.; Jones, B.; Petrov, M.; Davydchuk, V.; Shcherbatchenko, A.

1996-01-01

Tissue samples from 67 roe deer (Capreolus capreolus) and 73 wild boars (Sus scrofa L.) were obtained from the evacuated zone around the damaged nuclear reactor in Chernobyl, Ukraine. The samplings were performed from June 1992 to February 1995 regularly during each typical season (spring in mid-May, summer in mid-August, autumn in mid-October and winter in late February). By using botanical analysis of rumen/stomach contents, dominant forage plants were identified and collected in the area where the animals had been foraging. The results show that there is a considerable individual variation in diet selection within each season for both these animal species and also a seasonal variation in the radiocesium contamination of muscular tissue. The seasonal variation is most pronounced in the wild boar. Minimum levels of 137Cs were seen during summer and autumn (mean 6kBq/kg w.w. and 2 kBq/kg w.w., resp.) and maximum levels in winter (mean 113 kBq/kg w.w.). In the roe deer, the minimum levels were seen in winter (mean 6kBq/kg w.w.) and maximum levels in autumn (mean 58 kBq/kg w.w.). These variations are caused by differences in pasture selection during different seasons of the year. One very important forage plant eaten both by roe deer and by wild boars during all seasons was evening primrose (Oenothera biennis L.). Also the underground parts of this plant are consumed by the wild boar. Also the role of soil as an intake source of radioactive contaminants has been estimated by determination of inorganic residues after ashing of rumen/stomach samples. In the winter, wild boars show the highest ash content with 32% (mean of dry matter) and the lowest in summer with 6%. In roe deer, the differences between seasons are smaller, with an average of 9% in the spring and 15% in winter. The level of 137Cs contamination in muscular tissue of these two species has not decreased noticeably in the studied area during the study period from summer 1992 to winter 1995

Perennial Grass Bioenergy Cropping on Wet Marginal Land

NARCIS (Netherlands)

Das, Srabani; Teuffer, Karin; Stoof, Cathelijne R.; Walter, Michael F.; Walter, M.T.; Steenhuis, Tammo S.; Richards, Brian K.

2018-01-01

The control of soil moisture, vegetation type, and prior land use on soil health parameters of perennial grass cropping systems on marginal lands is not well known. A fallow wetness-prone marginal site in New York (USA) was converted to perennial grass bioenergy feedstock production. Quadruplicate

Liming and plant aging influence on micronutrient uptake by Brachiaria decumbens forage

International Nuclear Information System (INIS)

Armelin, Maria Jose A.; Saiki, Mitiko; Primavesi, Odo; Primavesi, Ana C.

2007-01-01

Brachiaria decumbens is the main forage in pastures of several Brazilian regions. The effects of liming and plant age on micronutrient uptake by the forage of a degraded Brachiaria decumbens pasture under restoration process, were studied in Sao Carlos - SP, southeastern Brazil, under altitude tropical climate. Experimental design was a random block (100 m 2 ), with 6 replications and 3 treatments. Each block received the following treatment: 0 t/ha of limestone with NK; 2 t/ha of limestone applied on soil surface with NK and maintenance of 1 t/ha per annum; 8 t/ha of limestone applied once on soil surface with NK. Forage samples were collected 14 cm above soil surface, each 36 days in the rain season. Instrumental neutron activation analysis (INAA) followed by gamma-ray spectrometry was the analytical method used to determine the micronutrient content. In some cases, Co Fe, Mn and Zn were negatively affected by increasing limestone doses. The opposite effect was observed for Cl. Decreases of Cl, Co and Mo uptake in forage were enhanced with plant aging. (author)

Seasonal use of conservation reserve program lands by white-tailed deer in east-central South Dakota

Science.gov (United States)

Gould, Jeffrey H.; Jenkins, Kurt J.

1993-01-01

The Conservation Reserve Program (CRP_, a provision of the 1985 Food Security Act, subsidizes landowners to take highly erodible lands out of cultivation and seed them to perennial cover for 10years. In eastern South Dakota, 0.5 million ha were enrolled in the CRP from 1985 to 1990 (Agric. Stabilization and Conserv. Serv., Brookings, S.D., unpubl. Data), which represents the largest change in conservation land-use practices in the region since the 1956 Soil Bank Program (Goetz 1987).Although the CRP is anticipated to produce substantial benefits for some wildlife species, particularly ground-nesting birds, its significance to white-tailed deer (Odocoileus virginianus) in the northern Great Plains agricultural region is poorly understood. Higgins et al. (1987) speculated that proliferation of CRP grasslands may provide a missing habitat component in intensively managed farmland, thereby enhancing several species of wildlife, including white-tailed deer. Deer managers in the region have expressed concerns that improved cover associated with DRP plantings on private land could attract deer and reduce hunter success rates or lead to increased depredation of adjacent croplands or stored winter forages (L. Rice, S.D. Dep. Game, Fish, and Parks, Rapid City, pers. comm., 1989). Our objectives were to describe variation in deer use of CRP lands by season, diel period, and deer activity class as a means of assessing seasonal importance of CRP fields to white-tailed deer in agricultural Midwest.

Dynamical Models of Interactions between Herds Forage and Water Resources in Sahelian Region

Directory of Open Access Journals (Sweden)

Jean Jules Tewa

2014-01-01

Full Text Available Optimal foraging is one of the capital topics nowadays in Sahelian region. The vast majority of feed consumed by ruminants in Sahelian region is still formed by natural pastures. Pastoral constraints are the high variability of available forage and drinking water in space and especially in time (highly seasonal, interannual variability and the scarcity of water resources. The mobility is the main functional and opportunistic adaptation to these constraints. Our goal in this paper is to formalize two dynamical models for interactions between a herd of domesticate animals, forage resources, and water resources inside a given Sahelian area, in order to confirm, explain, and predict by mathematical models some observations about pastoralism in Sahelian region. These models in some contexts can be similar to predator-prey models as forage and water resources can be considered as preys and herd’s animals as predators. These models exhibit very rich dynamics, since it predicts abrupt changes in consumer behaviour and disponibility of forage or water resources. The dynamics exhibits a possible coexistence between herd, resources, and water with alternative peaks in their trajectories.

Impact of cooling systems on Lake Michigan fishes

International Nuclear Information System (INIS)

Spigarelli, S.A.; Romberg, G.P.

1976-01-01

A comparison of data on fish mortalities due to impingement at thermal power plant water intakes on Lake Michigan with available estimates of standing crop biomass, commercial and sport fishery catches, and estimated predation mortality is presented. The striking features of these data are the proportions of total mortality due to predation and the lack of accurate basic population statistics such as standing crop biomass and natural mortality for important forage and human food fishes in Lake Michigan. Although this preliminary assessment would indicate that power plant and total impingement losses constitute an insignificant fraction of total forage biomass, the potentially unstable forage-predator ratios and the apparent high degree of annual fluctuations (year-classes) in alewife, smelt, and perch indicate the need for a more detailed assessment of cooling-system related impact on selected populations

Foraging plasticity of breeding Northern Rockhopper Penguins, Eudyptes moseleyi, in response to changing energy requirements

KAUST Repository

Booth, Jenny Marie; Steinfurth, Antje; Fusi, Marco; Cuthbert, Richard J.; McQuaid, Christopher D.

2018-01-01

During the breeding season, seabirds must balance the changing demands of self- and off-spring provisioning with the constraints imposed by central-place foraging. Recently, it was shown that Northern Rockhopper Penguins at Tristan da Cunha

Effects of stored feed cropping systems and farm size on the profitability of Maine organic dairy farm simulations.

Science.gov (United States)

Hoshide, A K; Halloran, J M; Kersbergen, R J; Griffin, T S; DeFauw, S L; LaGasse, B J; Jain, S

2011-11-01

United States organic dairy production has increased to meet the growing demand for organic milk. Despite higher prices received for milk, organic dairy farmers have come under increasing financial stress due to increases in concentrated feed prices over the past few years, which can make up one-third of variable costs. Market demand for milk has also leveled in the last year, resulting in some downward pressure on prices paid to dairy farmers. Organic dairy farmers in the Northeast United States have experimented with growing different forage and grain crops to maximize on-farm production of protein and energy to improve profitability. Three representative organic feed systems were simulated using the integrated farm system model for farms with 30, 120, and 220 milk cows. Increasing intensity of equipment use was represented by organic dairy farms growing only perennial sod (low) to those with corn-based forage systems, which purchase supplemental grain (medium) or which produce and feed soybeans (high). The relative profitability of these 3 organic feed systems was strongly dependent on dairy farm size. From results, we suggest smaller organic dairy farms can be more profitable with perennial sod-based rather than corn-based forage systems due to lower fixed costs from using only equipment associated with perennial forage harvest and storage. The largest farm size was more profitable using a corn-based system due to greater economies of scale for growing soybeans, corn grain, winter cereals, and corn silages. At an intermediate farm size of 120 cows, corn-based forage systems were more profitable if perennial sod was not harvested at optimum quality, corn was grown on better soils, or if milk yield was 10% higher. Delayed harvest decreased the protein and energy content of perennial sod crops, requiring more purchased grain to balance the ration and resulting in lower profits. Corn-based systems were less affected by lower perennial forage quality, as corn silage

Variation in the expression of ergot alkaloids between individual tillers of perennial ryegrass

Science.gov (United States)

Mace, Wade; Lunn, Kristy; Lloyd-West, Catherine

2014-11-01

Epichloë fungal endophytes of cool season grasses are well known to produce a range of alkaloids of benefit to the host. Some of these compounds are advantageous to agriculture due to qualities that promote pasture persistence (e.g. the loline class of alkaloids confer insect protection) while others are detrimental to the wellbeing of grazing livestock. The ergot alkaloids (e.g. ergovaline), produced in ryegrass and tall fescue associations, causes poor animal health in farming regions in many countries around the world and further study is required to improve our knowledge on this class of compounds. Here we present the application of a quantitative LC-MS/MS (liquid chromatography coupled to mass spectrometry) method measuring eight ergot alkaloids (chanoclavine, agroclavine, elymoclavine, lysergol, lysergic acid, ergine, lysergyl alanine, ergovaline) produced by endophyte infected grasses, to monitor levels in individual tillers from multiple plants of a single cultivar of perennial ryegrass (Lolium perenne cv. ‘Grasslands Samson’) infected with a common toxic endophyte strain (Epichloë festucae var. lolii). Monitoring the expression in individual tillers allows an estimation of the variability within a plant (between tillers) as well as between plants. The study showed that there is significant variation in the concentration of the ergot alkaloids between tillers of a single plant, at or exceeding the level of variation observed between individual plants of a population. This result emphasizes the fundamental importance of robust experimental design and sampling procedures when alkaloid expression assessment is required and these need to be rigorously tailored to the hypothesis being tested.

Variation in the expression of ergot alkaloids between individual tillers of perennial ryegrass

Directory of Open Access Journals (Sweden)

Wade Jeffray Mace

2014-11-01

Full Text Available Epichloë fungal endophytes of cool season grasses are well known to produce a range of alkaloids of benefit to the host. Some of these compounds are advantageous to agriculture due to qualities that promote pasture persistence (e.g. the loline class of alkaloids confer insect protection while others are detrimental to the wellbeing of grazing livestock. The ergot alkaloids (e.g. ergovaline, produced in ryegrass and tall fescue associations, causes poor animal health in farming regions in many countries around the world and further study is required to improve our knowledge on this class of compounds. Here we present the application of a quantitative LC-MS/MS (liquid chromatography coupled to mass spectrometry method measuring eight ergot alkaloids (chanoclavine, agroclavine, elymoclavine, lysergol, lysergic acid, ergine, lysergyl alanine, ergovaline produced by endophyte infected grasses, to monitor levels in individual tillers from multiple plants of a single cultivar of perennial ryegrass (Lolium perenne cv. ‘Grasslands Samson’ infected with a common toxic endophyte strain (Epichloë festucae var. lolii. Monitoring the expression in individual tillers allows an estimation of the variability within a plant (between tillers as well as between plants.The study showed that there is significant variation in the concentration of the ergot alkaloids between tillers of a single plant, at or exceeding the level of variation observed between individual plants of a population. This result emphasizes the fundamental importance of robust experimental design and sampling procedures when alkaloid expression assessment is required and these need to be rigorously tailored to the hypothesis being tested.

Does foraging performance change with age in female little penguins (Eudyptula minor?

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Ilka Zimmer

Full Text Available Age-related changes in breeding performance are likely to be mediated through changes in parental foraging performance. We investigated the relationship of foraging performance with age in female little penguins at Phillip Island, Australia, during the guard phase of the 2005 breeding season. Foraging parameters were recorded with accelerometers for birds grouped into three age-classes: (1 young, (2 middle age and (3 old females. We found the diving behaviour of middle-aged birds differed from young and old birds. The dive duration of middle age females was shorter than that of young and old birds while their dive effort (measure for dive and post-dive duration relation was lower than that of young ones, suggesting middle-aged birds were in better physical condition than other ones. There was no difference in prey pursuit frequency or duration between age classes, but in the hunting tactic. Females pursued more prey around and after reaching the maximum depth of dives the more experienced they were (old > middle age > young, an energy saving hunting tactic by probably taking advantage of up-thrust momentum. We suggest middle age penguins forage better than young or old ones because good physical condition and foraging experience could act simultaneously.

Heat Damaged Forages: Effects on Forage Quality

Science.gov (United States)

Traditionally, heat damage in forages has been associated with alterations in forage protein quality as a result of Maillard reactions, and most producers and nutritionists are familiar with this concept. However, this is not necessarily the most important negative consequence of spontaneous heating...

Improved fructan accumulation in perennial ryegrass transformed with the onion fructosyltransferase genes 1-SST and 6G-FFT

DEFF Research Database (Denmark)

Gadegaard, Gitte; Didion, Thomas; Foiling, Marianne

2008-01-01

Carbohydrate limitation has been identified as a main cause of inefficient nitrogen use in ruminant animals, which feed mainly on fresh forage, hay and silage. This inefficiency results in suboptimal meat and milk productivity. One important molecular breeding strategy is to improve the nutritional...... value of ryegrass (Lolium perenne) by increasing the fructan content through expression of heterologous fructan biosynthetic genes. We developed perennial ryegrass Lines expressing sucrose:sucrose 1-fructosyltransferase and fructan:fructan 6G-fructosyltransferase genes from onion (Allium cepa) which...... exhibited up to a 3-fold increased fructan content. Further, the high fructan content was stable during the growth period, whereas the fructan content in an elite variety, marketed as a high sugar variety, dropped rapidly after reaching its maximum and subsequently remained low. (c) 2007 Elsevier GmbH. ALL...

Foraging

NARCIS (Netherlands)

Ydenberg, R.C.; Prins, H.H.T.

2012-01-01

This chapter describes the role played by behavioural adjustments to foraging behaviour in accommodating rapid environmental change. It looks into the adjustments of foraging behaviour to predation danger as a result of changes in the type and array of food available. It investigates the effects of

Tradeoffs between water requirements and yield stability in annual vs. perennial crops

Science.gov (United States)

Vico, Giulia; Brunsell, Nathaniel A.

2018-02-01

Population growth and changes in climate and diets will likely further increase the pressure on agriculture and water resources globally. Currently, staple crops are obtained from annuals plants. A shift towards perennial crops may enhance many ecosystem services, but at the cost of higher water requirements and lower yields. It is still unclear when the advantages of perennial crops overcome their disadvantages and perennial crops are thus a sustainable solution. Here we combine a probabilistic description of the soil water balance and crop development with an extensive dataset of traits of congeneric annuals and perennials to identify the conditions for which perennial crops are more viable than annual ones with reference to yield, yield stability, and effective use of water. We show that the larger and more developed roots of perennial crops allow a better exploitation of soil water resources and a reduction of yield variability with respect to annual species, but their yields remain lower when considering grain crops. Furthermore, perennial crops have higher and more variable irrigation requirements and lower water productivity. These results are important to understand the potential consequences for yield, its stability, and water resource use of a shift from annual to perennial crops and, more generally, if perennial crops may be more resilient than annual crops in the face of climatic fluctuations.

Optimally frugal foraging

Science.gov (United States)

Bénichou, O.; Bhat, U.; Krapivsky, P. L.; Redner, S.

2018-02-01

We introduce the frugal foraging model in which a forager performs a discrete-time random walk on a lattice in which each site initially contains S food units. The forager metabolizes one unit of food at each step and starves to death when it last ate S steps in the past. Whenever the forager eats, it consumes all food at its current site and this site remains empty forever (no food replenishment). The crucial property of the forager is that it is frugal and eats only when encountering food within at most k steps of starvation. We compute the average lifetime analytically as a function of the frugality threshold and show that there exists an optimal strategy, namely, an optimal frugality threshold k* that maximizes the forager lifetime.

Evaulation of perennial pepperweed (Lepidium latifolium) management in a seasonal wetland in San Francisco Estuary prior to restoration of tidal hydrology

Science.gov (United States)

Herbicide applications have shown potential for control and management of invasive perennial pepperweed (Lepidium latifolium) in rangelands and tidal wetlands. However, reported efficacy of management methods varies widely, and the effects of more recently labeled aquatic herbicides on non-target ve...

Food availability and foraging near human developments by black bears

Science.gov (United States)

Merkle, Jerod A.; Robinson, Hugh S.; Krausman, Paul R.; Alaback, Paul B.

2013-01-01

Understanding the relationship between foraging ecology and the presence of human-dominated landscapes is important, particularly for American black bears (Ursus americanus), which sometimes move between wildlands and urban areas to forage. The food-related factors influencing this movement have not been explored, but can be important for understanding the benefits and costs to black bear foraging behavior and the fundamental origins of bear conflicts. We tested whether the scarcity of wildland foods or the availability of urban foods can explain when black bears forage near houses, examined the extent to which male bears use urban areas in comparison to females, and identified the most important food items influencing bear movement into urban areas. We monitored 16 collared black bears in and around Missoula, Montana, during 2009 and 2010, while quantifying the rate of change in green vegetation and the availability of 5 native berry-producing species outside the urban area, the rate of change in green vegetation, and the availability of apples and garbage inside the urban area. We used parametric time-to-event models in which an event was a bear location collected within 100 m of a house. We also visited feeding sites located near houses and quantified food items bears had eaten. The probability of a bear being located near a house was 1.6 times higher for males, and increased during apple season and the urban green-up. Fruit trees accounted for most of the forage items at urban feeding sites (49%), whereas wildland foods composed fruit trees, appear to be more important than the availability of garbage in influencing when bears forage near houses.

Nutritive value of pastures of Cynodon mixed with forage peanut in southwestern Paraná State

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Magnos Fernando Ziech

2015-08-01

Full Text Available This study evaluated the nutritive value of pastures of Coastcross-1 and Tifton 85 mixed with increasing inclusion of forage peanut (0, 25, 50, 75% occupancy area, subjected to cuts, over two study years in Southwestern Paraná State. The experimental design was factorial (three factors distributed in randomized block. The factors were cultivars (2, the occupancy area of forage peanut (4 and seasons of cuts (5, with three replications. It was evaluated the percentage of crude protein, neutral detergent fiber and in vitro digestibility of dry matter of leaf blades, stem + sheath of grasses and available forage mass of pastures. Values of crude protein ranged from 17.0 to 20.4% and from 16.8 to 19.3% for the forage mass available of Coastcross-1 and Tifton 85, respectively. Higher digestibility values were found at the beginning of evaluations. On average, the Coastcross-1 showed better nutritive value compared to Tifton 85, and, the inclusion of forage peanut increased crude protein content in leaf blades of grasses studied, in the second year after planted.

Forecasting Cool Season Daily Peak Winds at Kennedy Space Center and Cape Canaveral Air Force Station

Science.gov (United States)

Barrett, Joe, III; Short, David; Roeder, William

2008-01-01

The expected peak wind speed for the day is an important element in the daily 24-Hour and Weekly Planning Forecasts issued by the 45th Weather Squadron (45 WS) for planning operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The morning outlook for peak speeds also begins the warning decision process for gusts ^ 35 kt, ^ 50 kt, and ^ 60 kt from the surface to 300 ft. The 45 WS forecasters have indicated that peak wind speeds are a challenging parameter to forecast during the cool season (October-April). The 45 WS requested that the Applied Meteorology Unit (AMU) develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. The tool must only use data available by 1200 UTC to support the issue time of the Planning Forecasts. Based on observations from the KSC/CCAFS wind tower network, surface observations from the Shuttle Landing Facility (SLF), and CCAFS upper-air soundings from the cool season months of October 2002 to February 2007, the AMU created multiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence, the temperature inversion depth, strength, and wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft. Six synoptic patterns were identified: 1) surface high near or over FL, 2) surface high north or east of FL, 3) surface high south or west of FL, 4) surface front approaching FL, 5) surface front across central FL, and 6) surface front across south FL. The following six predictors were selected: 1) inversion depth, 2) inversion strength, 3) wind gust factor, 4) synoptic weather pattern, 5) occurrence of

Spatiotemporal heterogeneity in prey abundance and vulnerability shapes the foraging tactics of an omnivore

Science.gov (United States)

Rayl, Nathaniel; Bastille-Rousseau, Guillaume; Organ, John F.; Mumma, Matthew; Mahoney, Shane P.; Soulliere, Colleen; Lewis, Keith; Otto, Robert; Murray, Dennis; Waits, Lisette; Fuller, Todd

2018-01-01

Prey abundance and prey vulnerability vary across space and time, but we know little about how they mediate predator–prey interactions and predator foraging tactics. To evaluate the interplay between prey abundance, prey vulnerability and predator space use, we examined patterns of black bear (Ursus americanus) predation of caribou (Rangifer tarandus) neonates in Newfoundland, Canada using data from 317 collared individuals (9 bears, 34 adult female caribou, 274 caribou calves).During the caribou calving season, we predicted that landscape features would influence calf vulnerability to bear predation, and that bears would actively hunt calves by selecting areas associated with increased calf vulnerability. Further, we hypothesized that bears would dynamically adjust their foraging tactics in response to spatiotemporal changes in calf abundance and vulnerability (collectively, calf availability). Accordingly, we expected bears to actively hunt calves when they were most abundant and vulnerable, but switch to foraging on other resources as calf availability declined.As predicted, landscape heterogeneity influenced risk of mortality, and bears displayed the strongest selection for areas where they were most likely to kill calves, which suggested they were actively hunting caribou. Initially, the per‐capita rate at which bears killed calves followed a type‐I functional response, but as the calving season progressed and calf vulnerability declined, kill rates dissociated from calf abundance. In support of our hypothesis, bears adjusted their foraging tactics when they were less efficient at catching calves, highlighting the influence that predation phenology may have on predator space use. Contrary to our expectations, however, bears appeared to continue to hunt caribou as calf availability declined, but switched from a tactic of selecting areas of increased calf vulnerability to a tactic that maximized encounter rates with calves.Our results reveal that

The regulation of seasonal flowering in the Rosaceae.

Science.gov (United States)

Kurokura, Takeshi; Mimida, Naozumi; Battey, Nicholas H; Hytönen, Timo

2013-11-01

Molecular mechanisms regulating the flowering process have been extensively studied in model annual plants; in perennials, however, understanding of the molecular mechanisms controlling flowering has just started to emerge. Here we review the current state of flowering research in perennial plants of the rose family (Rosaceae), which is one of the most economically important families of horticultural plants. Strawberry (Fragaria spp.), raspberry (Rubus spp.), rose (Rosa spp.), and apple (Malus spp.) are used to illustrate how photoperiod and temperature control seasonal flowering in rosaceous crops. We highlight recent molecular studies which have revealed homologues of terminal flower1 (TFL1) to be major regulators of both the juvenile to adult, and the vegetative to reproductive transitions in various rosaceous species. Additionally, recent advances in understanding of the regulation of TFL1 are discussed.

Seasonal weather-related decision making for cattle production in the Northern Great Plains

Science.gov (United States)

High inter-annual variability of seasonal weather patterns can greatly affect forage and therefore livestock production in the Northern Great Plains. This variability can make it difficult for ranchers to set yearly stocking rates, particularly in advance of the grazing season. To better understand ...

Optimal Energy Management of Combined Cooling, Heat and Power in Different Demand Type Buildings Considering Seasonal Demand Variations

Directory of Open Access Journals (Sweden)

Akhtar Hussain

2017-06-01

Full Text Available In this paper, an optimal energy management strategy for a cooperative multi-microgrid system with combined cooling, heat and power (CCHP is proposed and has been verified for a test case of building microgrids (BMGs. Three different demand types of buildings are considered and the BMGs are assumed to be equipped with their own combined heat and power (CHP generators. In addition, the BMGs are also connected to an external energy network (EEN, which contains a large CHP, an adsorption chiller (ADC, a thermal storage tank, and an electric heat pump (EHP. By trading the excess electricity and heat energy with the utility grid and EEN, each BMG can fulfill its energy demands. Seasonal energy demand variations have been evaluated by selecting a representative day for the two extreme seasons (summer and winter of the year, among the real profiles of year-round data on electricity, heating, and cooling usage of all the three selected buildings. Especially, the thermal energy management aspect is emphasized where, bi-lateral heat trading between the energy supplier and the consumers, so-called energy prosumer concept, has been realized. An optimization model based on mixed integer linear programming has been developed for minimizing the daily operation cost of the EEN while fulfilling the energy demands of the BMGs. Simulation results have demonstrated the effectiveness of the proposed strategy.

Cool colored coating and phase change materials as complementary cooling strategies for building cooling load reduction in tropics

International Nuclear Information System (INIS)

Lei, Jiawei; Kumarasamy, Karthikeyan; Zingre, Kishor T.; Yang, Jinglei; Wan, Man Pun; Yang, En-Hua

2017-01-01

Highlights: • Cool colored coating and PCM are two complementary passive cooling strategies. • A PCM cool colored coating system is developed. • The coating reduces cooling energy by 8.5% and is effective yearly in tropical Singapore. - Abstract: Cool colored coating and phase change materials (PCM) are two passive cooling strategies often used separately in many studies and applications. This paper investigated the integration of cool colored coating and PCM for building cooling through experimental and numerical studies. Results showed that cool colored coating and PCM are two complementary passive cooling strategies that could be used concurrently in tropical climate where cool colored coating in the form of paint serves as the “first protection” to reflect solar radiation and a thin layer of PCM forms the “second protection” to absorb the conductive heat that cannot be handled by cool paint. Unlike other climate zones where PCM is only seasonally effective and cool paint is only beneficial during summer, the application of the proposed PCM cool colored coating in building envelope could be effective throughout the entire year with a monthly cooling energy saving ranging from 5 to 12% due to the uniform climatic condition all year round in tropical Singapore.

Potential of sustainable biomass production systems in Texas

International Nuclear Information System (INIS)

Sanderson, M.A.; Hussey, M.A.; Wiselogel, A.E.

1992-01-01

Biomass production for liquid fuels feedstock from systems based on warm-season perennial grasses (WSPG) offers a sustainable alternative for forage-livestock producers in Texas. Such systems also would enhance diversity and flexibility in current production systems. Research is needed to incorporate biomass production for liquid fuels, chemicals, and electrical power into current forage-livestock management systems. Our research objectives were to (i) document the potential of several WSPG in diverse Texas environments for biomass feedstock production, (ii) conduct fundamental research on morphological development of WSPG to enhance management for biomass feedstock production, (iii) examine current on-farm production systems for opportunities to incorporate biomass production, and (iv) determine feedstock quality and stability during storage

Fatty acid composition of forage herb species

DEFF Research Database (Denmark)

Warner, D.; Jensen, Søren Krogh; Cone, J.W.

2010-01-01

The use of alternative forage species in grasslands for intensive livestock production is receiving renewed attention. Data on fatty acid composition of herbs are scarce, so four herbs (Plantago lanceolata, Achillea millefolium, Cichorium intybus, Pastinaca sativa) and one grass species (timothy......, Phleum pratense) were sown in a cutting trial. The chemical composition and concentration of fatty acids (FA) of individual species were determined during the growing season. Concentrations of crude protein and FA were generally higher in the herbs than in timothy. C. intybus had the highest nutritive...

Differential metabolic responses of perennial grass Cynodon transvaalensis×Cynodon dactylon (C₄) and Poa Pratensis (C₃) to heat stress.

Science.gov (United States)

Du, Hongmei; Wang, Zhaolong; Yu, Wenjuan; Liu, Yimin; Huang, Bingru

2011-03-01

Differential metabolic responses to heat stress may be associated with variations in heat tolerance between cool-season (C₃) and warm-season (C₄) perennial grass species. The main objective of this study was to identify metabolites associated with differential heat tolerance between C₄ bermudagrass and C₃ Kentucky bluegrass by performing metabolite profile analysis using gas chromatography-mass spectrometry. Plants of Kentucky bluegrass (Poa Pratensis'Midnight') and hybrid bermudagrass (Cynodon transvaalensis x Cynodon dactylon'Tifdwarf') were grown under optimum temperature conditions (20/15 °C for Kentucky bluegrass and 30/25 °C for bermudagrass) or heat stress (35/30 °C for Kentucky bluegrass and 45/40 °C for bermudagrass). Physiological responses to heat stress were evaluated by visual rating of grass quality, measuring photochemical efficiency (variable fluorescence to maximal fluorescence) and electrolyte leakage. All of these parameters indicated that bermudagrass exhibited better heat tolerance than Kentucky bluegrass. The metabolite analysis of leaf polar extracts revealed 36 heat-responsive metabolites identified in both grass species, mainly consisting of organic acids, amino acids, sugars and sugar alcohols. Most metabolites showed higher accumulation in bermudagrass compared with Kentucky bluegrass, especially following long-term (18 days) heat stress. The differentially accumulated metabolites included seven sugars (sucrose, fructose, galactose, floridoside, melibiose, maltose and xylose), a sugar alcohol (inositol), six organic acids (malic acid, citric acid, threonic acid, galacturonic acid, isocitric acid and methyl malonic acid) and nine amino acids (Asn, Ala, Val, Thr, γ-aminobutyric acid, IIe, Gly, Lys and Met). The differential accumulation of those metabolites could be associated with the differential heat tolerance between C₃ Kentucky bluegrass and C₄ bermudagrass. Copyright © Physiologia Plantarum 2010.

Fitossociologia de uma área de floresta estacional perenifólia na fazenda Amoreiras, Querência, MT Seasonal perennial forest site phytossociology in the amareiras farm, Querência, Mato Grosso state, Brazil

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Sustanis Horn Kunz

2010-08-01

Full Text Available As florestas do sul da Amazônia, onde se encontra a Floresta Estacional Perenifólia, têm grande influência sobre a manutenção do equilíbrio físico regional e são as que mais estão ameaçadas pela ação antrópica, além de serem pouco conhecidas em relação à sua estrutura. Diante disso, objetivou-se estudar a estrutura fitossociológica de um trecho de Floresta Estacional Perenifólia na Bacia do Rio das Pacas em Querência, MT. A amostragem da vegetação consistiu na distribuição de 200 pontos quadrantes, sendo amostrados os indivíduos com diâmetro à altura de 1,30 m do solo (DAP ? 10 cm. A densidade total da área amostrada foi de 736 ind./ha, distribuídos em 58 espécies, 45 gêneros e 31 famílias. As espécies de maior Valor de Importância (VI, Ocotea leucoxylon (Sw. Laness., Trattinickia glaziovii Swart, Ouratea discophora Ducke, Xylopia amazonica R.E. Fr. e Myrcia multiflora (Lam. DC. corresponderam a 28,45% do VI total e também ocorreram em outros trechos de Floresta Estacional Perenifólia em Gaúcha do Norte, MT, porém não com a mesma representatividade. O índice de Shannon (3,51 pode ser considerado baixo por se tratar de Floresta Amazônica, mas a equabilidade de Pielou (0,86 evidenciou que a comunidade arbórea apresentava alta heterogeneidade florística.The Southern Amazon forests, where the Seasonal Perennial Forest occurs, has great influence on the maintenance of the regional physical equilibrium and they are among forests most threatened by anthropic action and are little known in relation to their structure. In this context, the objective of this work was to study phytosociological structure of a Seasonal Perennial Forest area in the Rio das Pacas Basin at Querência, state of Mato Grosso, Brazil. The vegetation sampling was composed of the distribution of 200 center quarter points, all individuals with DAP (diameter to height breast equal or superior to 10 cm were considered. The total density of

Ruminally undegradable protein content and digestibility for forages using the mobile bag in situ technique.

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Buckner, C D; Klopfenstein, T J; Rolfe, K M; Griffin, W A; Lamothe, M J; Watson, A K; MacDonald, J C; Schacht, W H; Schroeder, P

2013-06-01

Four experiments were conducted to evaluate RUP content and digestibility for smooth bromegrass, subirrigated meadow, upland native range, and warm-season grasses. Samples were collected from esophageally cannulated cows or ruminally cannulated steers. Forages were ruminally incubated in in situ bags for durations of time based on 75% of total mean retention time, which was based on IVDMD and rate of passage calculations. One-half of the bags were duodenally incubated and excreted in the feces, and NDIN was analyzed on all bags for RUP calculations. Crude protein was numerically greater early in the growing cycle for grasses compared with later as grasses matured (P ≤ 0.32). The RUP was 13.3%, 13.3%, and 19.7% of CP for smooth bromegrass, subirrigated meadow, and upland native range, respectively. These values tended to be lower early in the growth cycle and increased (linear P ≤ 0.13) as forages matured for warm-season grasses and subirrigated meadows. Because both CP and RUP content change throughout the growing season, expressing RUP as a percentage of DM gives more consistent averages compared with RUP as a percentage of CP. Coefficient of variation values for RUP as a percentage of DM averaged 0.21 over all 4 experiments compared with 0.26 for RUP as a percentage of CP. Average RUP as a percentage of DM was 2.03%, 1.53%, and 1.94% for smooth bromegrass, subirrigated meadow, and upland native range, respectively. Total tract indigestible protein (TTIDP) linearly increased with maturity for subirrigated meadow samples (P RUP varied considerably, ranging from 25% to 60%. Subirrigated meadow, native range, and smooth bromegrass samples tended to have linear decreases (P ≤ 0.11) in RUP digestibility throughout the growing season. The amount of digested RUP was fairly consistent across experiments and averages for smooth bromegrass, subirrigated meadow, and upland native range were 0.92%, 0.64%, and 0.49% of DM, respectively. Warm-season grasses in Exp. 2 had

Seasonality of the activity pattern of Callithrix penicillata (Primates, Callitrichidae in the cerrado (scrub savanna vegetation

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S. L. Vilela

Full Text Available Two wild groups of Callithrix penicillata, the Black Pincelled Marmoset, were observed from January to September 1998, in two areas, one an area of dense scrub savanna vegetation (cerrado and the other, a semidecidual woodland (cerradão, both within the boundaries of the Ecological Reserve of IBGE (Brazilian Institute of Geography and Statistics, in an environmentally protected area, the APA (Portuguese abbreviation for "environmental protected area" Gama/Cabeça-de-Veado, Brasília, DF. The behavioral data collected during the rainy (January 15 to April 15 and dry season (June 1 to September 15 were compared. Because of the proximity to the Reserve facilities, the group from the dense scrub savanna vegetation (CD was submitted to antropic impacts different from the group in the semidecidual woodland (CE, which was using as territory an area that had been suffering from man-made fires every two years as part of a long-term experimental project on fire impacts. The behavioral data was quantified by instantaneous cross-section ("scan sampling" every ten minutes with records of locomotion, rest, foraging for insects, use of exudate, and feeding. During the whole year, the greatest percentage of time spent by CE and CD was in foraging for insects, with 44% and 39%, respectively. It was evident when comparing the data for the two seasons that, for both groups, foraging for insects was more intense during the dry season, possibly to complement the shortage of food, and locomotion increased during the rainy season. The greater the availability and distribution of fruit in the areas, the greater the locomotion of the groups to obtain these resources. None of the other behavioral patterns, including the use of exudates, presented significant differences between the two seasons. Both groups foraged more frequently during the dry season and locomoted more during the rainy one.

Group foraging increases foraging efficiency in a piscivorous diver, the African penguin

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McGeorge, Cuan; Ginsberg, Samuel; Pichegru, Lorien; Pistorius, Pierre A.

2017-01-01

Marine piscivores have evolved a variety of morphological and behavioural adaptations, including group foraging, to optimize foraging efficiency when targeting shoaling fish. For penguins that are known to associate at sea and feed on these prey resources, there is nonetheless a lack of empirical evidence to support improved foraging efficiency when foraging with conspecifics. We examined the hunting strategies and foraging performance of breeding African penguins equipped with animal-borne video recorders. Individuals pursued both solitary as well as schooling pelagic fish, and demonstrated independent as well as group foraging behaviour. The most profitable foraging involved herding of fish schools upwards during the ascent phase of a dive where most catches constituted depolarized fish. Catch-per-unit-effort was significantly improved when targeting fish schools as opposed to single fish, especially when foraging in groups. In contrast to more generalist penguin species, African penguins appear to have evolved specialist hunting strategies closely linked to their primary reliance on schooling pelagic fish. The specialist nature of the observed hunting strategies further limits the survival potential of this species if Allee effects reduce group size-related foraging efficiency. This is likely to be exacerbated by diminishing fish stocks due to resource competition and environmental change. PMID:28989785

Monitoring results and analysis of thermal comfort conditions in experimental buildings for different heating systems and ventilation regimes during heating and cooling seasons

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Gendelis, S.; Jakovičs, A.; Ratnieks, J.; Bandeniece, L.

2017-10-01

This paper focuses on the long-term monitoring of thermal comfort and discomfort parameters in five small test buildings equipped with different heating and cooling systems. Calculations of predicted percentage of dissatisfied people (PPD) index and discomfort factors are provided for the room in winter season running three different heating systems - electric heater, air-air heat pump and air-water heat pump, as well as for the summer cooling with split type air conditioning systems. It is shown that the type of heating/cooling system and its working regime has an important impact on thermal comfort conditions in observed room. Recommendations for the optimal operating regimes and choice of the heating system from the thermal comfort point of view are summarized.

Influencia de la fertilización, la época y la especie forrajera en la presencia Influence of fertilization, season, and forage species in presence of arbuscular mycorrhizae in a degraded Andisoil of Colombia

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Arnulfo Gómez-Carabalí

2011-01-01

Full Text Available Para determinar la influencia de la fertilización, época, y especies forrajeras en la producción de micorrizas arbusculares se realizó un experimento con una gramínea C4, (Brachiaria dictyoneura), dos leguminosas forrajeras C3 (Arachis pintoi y Centrosema macrocarpum) y la vegetación nativa; cultivadas en dos sistemas de siembra (monocultivo y asociación), dos niveles de fertilización (alto y bajo) y cuatro edades de cosecha. Se uso un diseño de parcelas sub-sub divididas, en el cual la parcela principal fue la especie, los niveles de fertilización como subparcelas y la edad de rebrote como la sub-sub parcela. El número de esporas de hongos micorrízicos en el suelo y el porcentaje de infección en las raíces se incrementó con la edad y varió con la especie y la época del muestreo (seca o húmeda). Se encontraron diferencias en la capacidad para formar simbiosis micorrízica entre las especies de gramíneas y leguminosas bajo condiciones de campo.In the Colombian coffee zone much of the land has infertile soils with an ongoing accelerated degradation. As vegetation has changed from forest to transitory base (cassava cropping) and overgrazed pastures, ground cover has decreased resulting in increasing runoff. These changes have contributed to severe erosion, decline in soil fertility, productivity, soil structure, and water quality as well as loss of biodiversity. A field study was conducted at the farm "La Esperanza" (Mondomo, Department of Cauca, Colombia, South-America). The main objective was to determine the influence of fertilization, season and forage species in Arbuscular Mycorrhyzae in a degraded Andisol. One C4 forage grass (Brachiaria dictyoneura) and two C3 forage legumes (Arachis pintoi and Centrosema macrocarpum) and native vegetation grown under two fertilization levels, cultivated either in monoculture or in association and harvested at four different ages were evaluated. The numbers of mycorrizal spores in the soil

Breeding short-tailed shearwaters buffer local environmental variability in south-eastern Australia by foraging in Antarctic waters.

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Berlincourt, Maud; Arnould, John P Y

2015-01-01

Establishing patterns of movements of free-ranging animals in marine ecosystems is crucial for a better understanding of their feeding ecology, life history traits and conservation. As central place foragers, the habitat use of nesting seabirds is heavily influenced by the resources available within their foraging range. We tested the prediction that during years with lower resource availability, short-tailed shearwaters (Puffinus tenuirostris) provisioning chicks should increase their foraging effort, by extending their foraging range and/or duration, both when foraging in neritic (short trips) and distant oceanic waters (long trips). Using both GPS and geolocation data-loggers, at-sea movements and habitat use were investigated over three breeding seasons (2012-14) at two colonies in southeastern Australia. Most individuals performed daily short foraging trips over the study period and inter-annual variations observed in foraging parameters where mainly due to few individuals from Griffith Island, performing 2-day trips in 2014. When performing long foraging trips, this study showed that individuals from both colonies exploited similar zones in the Southern Ocean. The results of this study suggest that individuals could increase their foraging range while exploiting distant feeding zones, which could indicate that short-tailed shearwaters forage in Antarctic waters not only to maintain their body condition but may also do so to buffer against local environmental stochasticity. Lower breeding performances were associated with longer foraging trips to distant oceanic waters in 2013 and 2014 indicating they could mediate reductions in food availability around the breeding colonies by extending their foraging range in the Southern Ocean. This study highlights the importance of foraging flexibility as a fundamental aspect of life history in coastal/pelagic marine central place foragers living in highly variable environments and how these foraging strategies are use to

Monitoring Forage Production of California Rangeland Using Remote Sensing Observations

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Liu, H.; Jin, Y.; Dahlgren, R. A.; O'Geen, A. T.; Roche, L. M.; Smith, A. M.; Flavell, D.

2016-12-01

Pastures and rangeland cover more than 10 million hectares in California's coastal and inland foothill regions, providing feeds to livestock and important ecosystem services. Forage production in California has a large year-to-year variation due to large inter-annual and seasonal variabilities in precipitation and temperature. It also varies spatially due to the variability in climate and soils. Our goal is to develop a robust and cost-effective tool to map the near-real-time and historical forage productivity in California using remote sensing observations from Landsat and MODIS satellites. We used a Monteith's eco-physiological plant growth theory: the aboveground net primary production (ANPP) is determined by (i) the absorbed photosynthetically active radiation (APAR) and the (ii) light use efficiency (LUE): ANPP = APAR * LUEmax * f(T) * f(SM), where LUEmax is the maximum LUE, and f(T) and f(SM) are the temperature and soil moisture constrains on LUE. APAR was estimated with Landsat and MODIS vegetation index (VI), and LUE was calibrated with a statewide point dataset of peak forage production measurements at 75 annual rangeland sites. A non-linear optimization was performed to derive maximum LUE and the parameters for temperature and soil moisture regulation on LUE by minimizing the differences between the estimated and measured ANPP. Our results showed the satellite-derived annual forage production estimates correlated well withcontemporaneous in-situ forage measurements and captured both the spatial and temporal productivity patterns of forage productivity well. This remote sensing algorithm can be further improved as new field measurements become available. This tool will have a great importance in maintaining a sustainable range industry by providing key knowledge for ranchers and the stakeholders to make managerial decisions.

Establishing native warm season grasses on Eastern Kentucky strip mines

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Barnes, T.G.; Larkin, J.L.; Arnett, M.B. [Univ. of Kentucky, Lexington, KY (United States). Dept. of Forestry

1998-12-31

The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat.

Establishing native warm season grasses on Eastern Kentucky strip mines

International Nuclear Information System (INIS)

Barnes, T.G.; Larkin, J.L.; Arnett, M.B.

1998-01-01

The authors evaluated various methods of establishing native warm season grasses on two reclaimed Eastern Kentucky mines from 1994--1997. Most current reclamation practices incorporate the use of tall fescue (Festuca arundinacea) and other cool-season grasses/legumes that provide little wildlife habitats. The use of native warm season grasses will likely improve wildlife habitat on reclaimed strip mines. Objectives of this study were to compare the feasibility of establishing these grasses during fall, winter, or spring using a native rangeland seeder or hydroseeding; a fertilizer application at planting; or cold-moist stratification prior to hydroseeding. Vegetative cover, bare ground, species richness, and biomass samples were collected at the end of each growing season. Native warm season grass plantings had higher plant species richness compared to cool-season reclamation mixtures. There was no difference in establishment of native warm season grasses as a result of fertilization or seeding technique. Winter native warm season grass plantings were failures and cold-moist stratification did not increase plant establishment during any season. As a result of a drought during 1997, both cool-season and warm season plantings were failures. Cool-season reclamation mixtures had significantly more vegetative cover and biomass compared to native warm season grass mixtures and the native warm season grass plantings did not meet vegetative cover requirements for bond release. Forbs and legumes that established well included pale purple coneflower (Echinacea pallida), lance-leaf coreopsis (Coreopsis lanceolata), round-headed lespedeza (Lespedeza capitata), partridge pea (Cassia fasiculata), black-eyed susan (Rudbeckia hirta), butterfly milkweed (Asclepias tuberosa), and bergamot (Monarda fistulosa). Results from two demonstration plots next to research plots indicate it is possible to establish native warm season grasses on Eastern Kentucky strip mines for wildlife habitat

Behavioral and hormonal responses to the availability of forage material in Western lowland gorillas (Gorilla gorilla gorilla).

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Fuller, Grace; Murray, Anna; Thueme, Melissa; McGuire, Molly; Vonk, Jennifer; Allard, Stephanie

2018-01-01

We investigated how forage material affects indicators of welfare in three male Western lowland gorillas (Gorilla gorilla gorilla) at the Detroit Zoo. In addition to their maintenance diet and enrichment foods, the gorillas generally received forage material four times a week. From this baseline, we systematically manipulated how much forage material the group received on a weekly basis, with either daily or bi (twice)-weekly presentation of browse (mulberry, Morus sp.) or alfalfa hay. We collected behavioral data (60 hr per gorilla) and measured fecal glucocorticoid metabolites (FGM). Mixed models indicated that the presence of forage material significantly increased time feeding (F 2,351  = 9.58, p gorillas, compared to a disproportionately greater amount of time spent feeding by the dominant individual when forage material was absent. Providing forage material in addition to the regular diet likely created more opportunities for equitable feeding for the subordinate gorillas. FGM concentrations did not vary based on the presence or type of forage material available and, instead, likely reflected group social dynamics. In general, alfalfa and mulberry had similar impacts on behavior, indicating that alfalfa can be an adequate behavioral substitute during times when browse is less readily available for gorillas housed in seasonally variable climates. © 2017 Wiley Periodicals, Inc.

Belowground Water Dynamics Under Contrasting Annual and Perennial Plant Communities in an Agriculturally-Dominated Landscape

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Mora, G.; Asbjornsen, H.; Helmers, M. J.; Shepherd, G. W.

2005-12-01

The conversion from grasslands and forests to row-crops in the Midwest has affected soil water cycling because plant characteristics are one of the main parameters determining soil storage capacity, infiltration rates, and surface runoff. Little is known, however, about the extent of modification of soil water dynamics under different plant communities. To address this important issue, we are documenting soil water dynamics under contrasting perennial and annual plant communities in an agriculturally-dominated landscape. Measurements of soil moisture and depths of uptake of source water were obtained for six vegetative cover types (corn and soybean field, brome pasture, degraded savanna, restored savanna, and restored prairie) at the Neal Smith National Wildlife Refuge in Prairie City, Iowa. The depths of uptake of soil water were determined on the basis of oxygen isotope composition of soil water and stem water. Measurements were performed once a month during an entire growing season. Preliminary results indicate that soil water present under the different vegetation types show similar profiles with depth during the dry months. Soil water in the upper 5 cm is enriched in oxygen-18 by about 5 per mil relative to soil water at 100 cm. Our preliminary results also indicate that the isotopic composition of stem water from annual plants is typically higher by about 2 per mil relative to that of stem water from perennial plants during the dry period. Whereas the oxygen isotopic composition for corn stem water is -5.49 per mil, that for elm and oak stem water is -7.62 and -7.51 per mil, respectively. The higher isotope values for corn suggest that annual crop plants are withdrawing water from shallower soil horizons relative to perennial plants. Moreover, our preliminary data suggest lower moisture content in soil under annual plant cover. We propose that the presence of deeper roots in the perennial vegetation allows these plants to tap into deeper water sources when

Neutron activation analysis application for determining iron concentration in forage grasses used in intensive cattle production system

International Nuclear Information System (INIS)

Armelin, Maria Jose A.; Primavesi, Odo

2002-01-01

Iron is an essential element to the life. It is an important hemoglobin component and it is involved in the transport of oxygen to cells. A deficiency of iron results in an unsuitable synthesis of hemoglobin and a delay in the growth. Iron contents above the tolerable level in animal feed can cause serious damages to the health and the death in extreme cases. The forages are the main source of feed to cattle in grazing. It is known from the literature, that the growth and the nutritious value of the forage are influenced by specie and physiologic age of the plant, soil fertility and environmental conditions. Therefore, an agronomical evaluations of the forages are necessary before to introduce in an intensive cattle production systems to program adequate grazing management. Neutron activation analysis was applied to evaluate the Fe concentration in the main tropical forage grasses used in intensive dairy cattle production systems in Sao Carlos, SP, Brazil. Iron concentrations were smaller in the rain season than in the dry one. Comparison of results obtained in the analyses of forages with daily requirements of iron in dry matter, showed that the Fe concentration in forages was adequate. (author)

Extreme Temperature Regimes during the Cool Season and their Associated Large-Scale Circulations

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Xie, Z.

2015-12-01

In the cool season (November-March), extreme temperature events (ETEs) always hit the continental United States (US) and provide significant societal impacts. According to the anomalous amplitudes of the surface air temperature (SAT), there are two typical types of ETEs, e.g. cold waves (CWs) and warm waves (WWs). This study used cluster analysis to categorize both CWs and WWs into four distinct regimes respectively and investigated their associated large-scale circulations on intra-seasonal time scale. Most of the CW regimes have large areal impact over the continental US. However, the distribution of cold SAT anomalies varies apparently in four regimes. In the sea level, the four CW regimes are characterized by anomalous high pressure over North America (near and to west of cold anomaly) with different extension and orientation. As a result, anomalous northerlies along east flank of anomalous high pressure convey cold air into the continental US. To the middle troposphere, the leading two groups feature large-scale and zonally-elongated circulation anomaly pattern, while the other two regimes exhibit synoptic wavetrain pattern with meridionally elongated features. As for the WW regimes, there are some patterns symmetry and anti-symmetry with respect to CW regimes. The WW regimes are characterized by anomalous low pressure and southerlies wind over North America. The first and fourth groups are affected by remote forcing emanating from North Pacific, while the others appear mainly locally forced.

Dynamic oceanography determines fine scale foraging behavior of Masked Boobies in the Gulf of Mexico.

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Caroline L Poli

Full Text Available During breeding, foraging marine birds are under biological, geographic, and temporal constraints. These contraints require foraging birds to efficiently process environmental cues derived from physical habitat features that occur at nested spatial scales. Mesoscale oceanography in particular may change rapidly within and between breeding seasons, and findings from well-studied systems that relate oceanography to seabird foraging may transfer poorly to regions with substantially different oceanographic conditions. Our objective was to examine foraging behavior of a pan-tropical seabird, the Masked Booby (Sula dactylatra, in the understudied Caribbean province, a moderately productive region driven by highly dynamic currents and fronts. We tracked 135 individuals with GPS units during May 2013, November 2013, and December 2014 at a regionally important breeding colony in the southern Gulf of Mexico. We measured foraging behavior using characteristics of foraging trips and used area restricted search as a proxy for foraging events. Among individual attributes, nest stage contributed to differences in foraging behavior whereas sex did not. Birds searched for prey at nested hierarchical scales ranging from 200 m-35 km. Large-scale coastal and shelf-slope fronts shifted position between sampling periods and overlapped geographically with overall foraging locations. At small scales (at the prey patch level, the specific relationship between environmental variables and foraging behavior was highly variable among individuals but general patterns emerged. Sea surface height anomaly and velocity of water were the strongest predictors of area restricted search behavior in random forest models, a finding that is consistent with the characterization of the Gulf of Mexico as an energetic system strongly influenced by currents and eddies. Our data may be combined with tracking efforts in the Caribbean province and across tropical regions to advance

Dynamic oceanography determines fine scale foraging behavior of Masked Boobies in the Gulf of Mexico

Science.gov (United States)

Poli, Caroline L.; Harrison, Autumn-Lynn; Vallarino, Adriana; Gerard, Patrick D.; Jodice, Patrick G.R.

2017-01-01

During breeding, foraging marine birds are under biological, geographic, and temporal constraints. These contraints require foraging birds to efficiently process environmental cues derived from physical habitat features that occur at nested spatial scales. Mesoscale oceanography in particular may change rapidly within and between breeding seasons, and findings from well-studied systems that relate oceanography to seabird foraging may transfer poorly to regions with substantially different oceanographic conditions. Our objective was to examine foraging behavior of a pan-tropical seabird, the Masked Booby (Sula dactylatra), in the understudied Caribbean province, a moderately productive region driven by highly dynamic currents and fronts. We tracked 135 individuals with GPS units during May 2013, November 2013, and December 2014 at a regionally important breeding colony in the southern Gulf of Mexico. We measured foraging behavior using characteristics of foraging trips and used area restricted search as a proxy for foraging events. Among individual attributes, nest stage contributed to differences in foraging behavior whereas sex did not. Birds searched for prey at nested hierarchical scales ranging from 200 m—35 km. Large-scale coastal and shelf-slope fronts shifted position between sampling periods and overlapped geographically with overall foraging locations. At small scales (at the prey patch level), the specific relationship between environmental variables and foraging behavior was highly variable among individuals but general patterns emerged. Sea surface height anomaly and velocity of water were the strongest predictors of area restricted search behavior in random forest models, a finding that is consistent with the characterization of the Gulf of Mexico as an energetic system strongly influenced by currents and eddies. Our data may be combined with tracking efforts in the Caribbean province and across tropical regions to advance understanding of seabird

Invited review: Sustainable forage and grain crop production for the US dairy industry.

Science.gov (United States)

Martin, N P; Russelle, M P; Powell, J M; Sniffen, C J; Smith, S I; Tricarico, J M; Grant, R J

2017-12-01

A resilient US dairy industry will be underpinned by forage and crop production systems that are economically, environmentally, and socially sustainable. Land use for production of perennial and annual forages and grains for dairy cattle must evolve in response to multiple food security and environmental sustainability issues. These include increasing global populations; higher incomes and demand for dairy and other animal products; climate change with associated temperature and moisture changes; necessary reductions in carbon and water footprints; maintenance of soil quality and soil nutrient concerns; and competition for land. Likewise, maintaining producer profitability and utilizing practices accepted by consumers and society generally must also be considered. Predicted changes in climate and water availability will likely challenge current feed and dairy production systems and their national spatial distribution, particularly the western migration of dairy production in the late 20th century. To maintain and stabilize profitability while reducing carbon footprint, particularly reductions in methane emission and enhancements in soil carbon sequestration, dairy production will need to capitalize on genetic and management innovations that enhance forage and grain production and nutritive value. Improved regional and on-farm integration of feed production and manure utilization is needed to reduce environmental nitrogen and phosphorus losses and mitigate greenhouse gas emissions. Resilient and flexible feed production strategies are needed to address each of these challenges and opportunities to ensure profitable feeding of dairy cattle and a sustainable dairy industry. The Authors. Published by the Federation of Animal Science Societies and Elsevier Inc. on behalf of the American Dairy Science Association®. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).

Heavy metal concentration in forage grasses and extractability from some acid mine spoils

Energy Technology Data Exchange (ETDEWEB)

Taylor, R.W.; Ibeabuchi, I.O.; Sistani, K.R.; Shuford, J.W. (Alabama A and M University, Normal (United States). Department of Plant and Soil Science)

1993-06-01

Laboratory and greenhouse studies were conducted on several forage grasses, bermudagrass ([ital Cynodon dactylon]), creeping red fescue ([ital Festuca rubra]), Kentucky 31-tall fescue ([ital Festuca arundinacea]), oat ([ital Avena sativa]), orchardgrass ([ital Dactylis glomerata]), perennial ryegrass ([ital Lolium perenne]), sorghum ([ital Sorghum bicolor]), triticale (X. [ital triticosecale Wittmack]), and winter wheat ([ital Triticum aestivum]) grown on three Alabama acid mine spoils to study heavy metal accumulation, dry matter yield and spoil metal extractability by three chemical extractants (Mehlich 1, DTPA, and 0.1 M HCl). Heavy metals removed by these extractants were correlated with their accumulation by several forage grasses. Among the forages tested, creeping red fescue did not survive the stressful conditions of any of the spoils, while orchard grass and Kentucky 31-tall fescue did not grow in Mulberry spoil. Sorghum followed by bermudagrass generally produced the highest dry matter yield. However, the high yielding bermudagrass was most effective in accumulating high tissue levels of Mn and Zn from all spoils (compared to the other grasses) but did not remove Ni. On the average, higher levels of metals were extracted from spoils in the order of 0.1 M HCl[gt] Mehlich 1[gt] DTPA. However, DTPA extracted all the metals from spoils while Mehlich 1 did not extract Pb and 0.1 M HCl did not extract detectable levels of Ni. All of the extractants were quite effective in determining plant available Zn from the spoils. For the other metals, the effective determination of plant availability depended on the crop, the extractant, and the metal in concert. 20 refs., 6 tabs.

AUTUMNAL FORAGE YIELD AND NUTRITIVE VALUE OF THE LEGUME ARACHIS RENDIMENTO E VALOR NUTRITIVO DA FORRAGEM OUTONAL DE AMENDOIM-FORRAGEIRO

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Pedro Lima Monks

2007-09-01

Full Text Available

Dry matter yield and nutritive value of forage le-gume Arachis    pintoi (Krap. & Greg. cv. Alqueire-1 (BRA 037036, was evaluated under different cutting mana-gement regimes and levels of P and K fertilization, in a yellow-red argisoil, at CAP-UFPEL, Capão do Leão, RS, Brazil during Spring-Summer and Fall. Cutting regimes compared were: no cutting, one, two, three, four and five cuttings, at 5 cm above ground. Fertilization levels con-sisted in supplying zero, 50 and 100% of requirements for P and K recommended by Brazilian Soil Science Society, for warm season perennial forage legumes. Fertilization treatments were alocated to main plots and cutting regi-mes to subplots, in a complete splitplot randomized block design, with three replications. Data of the following va-riables were submitted to analysis of variance and polino-mial regression: dry matter yield and quality of autumnal cutting, dry matter accumulation rate of autumnal cutting and total dry matter yield. If the purpose is the utilization of the forage during Autumn, 70% of the recommended phosphorus and potassium fertilization is sufficient to ob-tain maximum forage yield. However, if the objective are cuttings during the growing season (Spring-Summer and also in Autumn, it is necessary 100% of the recommended fertilization. The increase in number of cuttings during Spring-Summer decreases in the same proportion the fo-rage yield in Autumn. Forage nutritive value in Autumn is better when greater number of cuttings are made during Spring-Summer. Spring deferments also result in higher autumnal forage quality.

KEY-WORDS: Cutting, fertilization, tropical forage.

Num Argissolo vermelho amarelo eutrófico típi-co, do Centro Agropecuário da Palma, da UFPEL, Capão do Leão, RS,  foram avaliados os efeitos de cortes esti-vais e da adubação fosfatada e potássica sobre o rendi-mento e valor nutritivo da matéria seca (MS outonal de amendoim-forrageiro (Arachis

Review on Mycotoxin Issues in Ruminants: Occurrence in Forages, Effects of Mycotoxin Ingestion on Health Status and Animal Performance and Practical Strategies to Counteract Their Negative Effects

DEFF Research Database (Denmark)

Gallo, Antonio; Giubert, Gianluca; Frisvad, Jens Christian

2015-01-01

Ruminant diets include cereals, protein feeds, their by-products as well as hay and grass, grass/legume, whole-crop maize, small grain or sorghum silages. Furthermore, ruminants are annually or seasonally fed with grazed forage in many parts of the World. All these forages could be contaminated...

Estimates of eddy turbulence consistent with seasonal variations of atomic oxygen and its possible role in the seasonal cycle of mesopause temperature

Directory of Open Access Journals (Sweden)

M. N. Vlasov

2010-11-01

Full Text Available According to current understanding, adiabatic cooling and heating induced by the meridional circulation driven by gravity waves is the major process for the cold summer and warm winter polar upper mesosphere. However, our calculations show that the upward/downward motion needed for adiabatic cooling/heating of the summer/winter polar mesopause simultaneously induces a seasonal variation in both the O maximum density and the altitude of the [O] peak that is opposite to the observed variables generalized by the MSISE-90 model. It is usually accepted that eddy turbulence can produce the [O] seasonal variations. Using this approach, we can infer the eddy diffusion coefficient for the different seasons. Taking these results and experimental data on the eddy diffusion coefficient, we consider in detail and estimate the heating and cooling caused by eddy turbulence in the summer and winter polar upper mesosphere. The seasonal variations of these processes are similar to the seasonal variations of the temperature and mesopause. These results lead to the conclusion that heating/cooling by eddy turbulence is an important component in the energy budget and that adiabatic cooling/heating induced by upward/downward motion cannot dominate in the mesopause region. Our study shows that the impact of the dynamic process, induced by gravity waves, on [O] distributions must be included in models of thermal balance in the upper mesosphere and lower thermosphere (MLT for a consistent description because (a the [O] distribution is very sensitive to dynamic processes, and (b atomic oxygen plays a very important role in chemical heating and infrared cooling in the MLT. To our knowledge, this is the first attempt to consider this aspect of the problem.

Estimated Perennial Streams of Idaho and Related Geospatial Datasets

Science.gov (United States)

Rea, Alan; Skinner, Kenneth D.

2009-01-01

The perennial or intermittent status of a stream has bearing on many regulatory requirements. Because of changing technologies over time, cartographic representation of perennial/intermittent status of streams on U.S. Geological Survey (USGS) topographic maps is not always accurate and (or) consistent from one map sheet to another. Idaho Administrative Code defines an intermittent stream as one having a 7-day, 2-year low flow (7Q2) less than 0.1 cubic feet per second. To establish consistency with the Idaho Administrative Code, the USGS developed regional regression equations for Idaho streams for several low-flow statistics, including 7Q2. Using these regression equations, the 7Q2 streamflow may be estimated for naturally flowing streams anywhere in Idaho to help determine perennial/intermittent status of streams. Using these equations in conjunction with a Geographic Information System (GIS) technique known as weighted flow accumulation allows for an automated and continuous estimation of 7Q2 streamflow at all points along a stream, which in turn can be used to determine if a stream is intermittent or perennial according to the Idaho Administrative Code operational definition. The selected regression equations were applied to create continuous grids of 7Q2 estimates for the eight low-flow regression regions of Idaho. By applying the 0.1 ft3/s criterion, the perennial streams have been estimated in each low-flow region. Uncertainty in the estimates is shown by identifying a 'transitional' zone, corresponding to flow estimates of 0.1 ft3/s plus and minus one standard error. Considerable additional uncertainty exists in the model of perennial streams presented in this report. The regression models provide overall estimates based on general trends within each regression region. These models do not include local factors such as a large spring or a losing reach that may greatly affect flows at any given point. Site-specific flow data, assuming a sufficient period of

Spatiotemporal heterogeneity in prey abundance and vulnerability shapes the foraging tactics of an omnivore.

Science.gov (United States)

Rayl, Nathaniel D; Bastille-Rousseau, Guillaume; Organ, John F; Mumma, Matthew A; Mahoney, Shane P; Soulliere, Colleen E; Lewis, Keith P; Otto, Robert D; Murray, Dennis L; Waits, Lisette P; Fuller, Todd K

2018-05-01

Prey abundance and prey vulnerability vary across space and time, but we know little about how they mediate predator-prey interactions and predator foraging tactics. To evaluate the interplay between prey abundance, prey vulnerability and predator space use, we examined patterns of black bear (Ursus americanus) predation of caribou (Rangifer tarandus) neonates in Newfoundland, Canada using data from 317 collared individuals (9 bears, 34 adult female caribou, 274 caribou calves). During the caribou calving season, we predicted that landscape features would influence calf vulnerability to bear predation, and that bears would actively hunt calves by selecting areas associated with increased calf vulnerability. Further, we hypothesized that bears would dynamically adjust their foraging tactics in response to spatiotemporal changes in calf abundance and vulnerability (collectively, calf availability). Accordingly, we expected bears to actively hunt calves when they were most abundant and vulnerable, but switch to foraging on other resources as calf availability declined. As predicted, landscape heterogeneity influenced risk of mortality, and bears displayed the strongest selection for areas where they were most likely to kill calves, which suggested they were actively hunting caribou. Initially, the per-capita rate at which bears killed calves followed a type-I functional response, but as the calving season progressed and calf vulnerability declined, kill rates dissociated from calf abundance. In support of our hypothesis, bears adjusted their foraging tactics when they were less efficient at catching calves, highlighting the influence that predation phenology may have on predator space use. Contrary to our expectations, however, bears appeared to continue to hunt caribou as calf availability declined, but switched from a tactic of selecting areas of increased calf vulnerability to a tactic that maximized encounter rates with calves. Our results reveal that generalist

Space use and resource selection by foraging Indiana bats at the northern edge of their distribution

Science.gov (United States)

Jachowski, David S.; Johnson, Joshua B.; Dobony, Christopher A.; Edwards, John W.; Ford, W. Mark

2014-01-01

Despite 4 decades of conservation concern, managing endangered Indiana bat (Myotis sodalis) populations remains a difficult wildlife resource issue facing natural resource managers in the eastern United States. After small signs of population recovery, the recent emergence of white-nose syndrome has led to concerns of local and/or regional extirpation of the species. Where Indiana bats persist, retaining high-quality foraging areas will be critical to meet physiological needs and ensure successful recruitment and overwinter survival. However, insight into foraging behavior has been lacking in the Northeast of the USA. We radio-tracked 12 Indiana bats over 2 summers at Fort Drum, New York, to evaluate factors influencing Indiana bat resource selection during night-time foraging. We found that foraging space use decreased 2% for every 100 m increase in distance to water and 6% for every 100 m away from the forest edge. This suggests high use of riparian areas in close proximity to forest and is somewhat consistent with the species’ foraging ecology in the Midwest and upper South. Given the importance of providing access to high-quality foraging areas during the summer maternity season, Indiana bat conservation at the northern extent of the species’ range will be linked to retention of forested habitat in close proximity to riparian zones. 

Foraging flight distances of wintering ducks and geese: a review

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William P. Johnson

2014-12-01

Full Text Available The distance covered by foraging animals, especially those that radiate from a central area when foraging, may affect ecosystem, community, and population dynamics, and has conservation and landscape planning implications for multiple taxa, including migratory waterfowl. Migrating and wintering waterfowl make regular foraging flights between roosting and feeding areas that can greatly impact energetic resources within the foraging zone near roost sites. We reviewed published studies and gray literature for one-way foraging flight distances (FFDs of migrating and wintering dabbling ducks and geese. Thirty reviewed studies reported FFDs and several reported values for multiple species or locations. We obtained FFD values for migration (n = 7 and winter (n = 70. We evaluated the effects of body mass, guild, i.e., dabbling duck or goose, and location, i.e., Nearctic or Palearctic, on FFDs. We used the second-order Akaike's Information Criterion for model selection. We found support for effects of location and guild on FFDs. FFDs of waterfowl wintering in the Nearctic (7.4 ± 6.7 km, mean ± SD; n = 39 values were longer than in the Palearctic (4.2 ± 3.2 km; n = 31 values. The FFDs of geese (7.8 ± 7.2 km, mean ± SD; n = 24 values were longer than FFDs of dabbling ducks (5.1 ± 4.4 km, mean ± SD; n = 46 values. We found mixed evidence that distance flown from the roost changed, i.e., increased or decreased, seasonally. Our results can be used to refine estimates of energetic carrying capacity around roosts and in biological and landscape planning efforts.

Establishment techniques in under-sown perennial ryegrass for seed production

DEFF Research Database (Denmark)

Deleuran, Lise C; Boelt, Birte

2009-01-01

Establishment methods have proven to be of major importance for grass-seed production. The objective of this research was to test the effect of different sowing techniques on plant establishment and the subsequent seed yield. Perennial ryegrass (Lolium perenne L.) is used as the model grass due...... to its large importance in Danish agriculture. In a three-year trial six different methods of under-sowing of perennial ryegrass in a spring barley cover crop were employed. Perennial ryegrass was either sown directly at different depths within the spring barley (Hordeum vulgare L.) rows or placed 2, 6......, or 12 cm from the spring barley rows. Results of dry-matter yield indicate that the best establishment of the grass occurred when placing the grass 6 or 12 cm from the cover-crop row, and this is of importance in less vigorous grasses. Overall, no seed-yield difference has been observed for perennial...

The importance of warm season warming to western U.S. streamflow changes

Science.gov (United States)

Das, T.; Pierce, D.W.; Cayan, D.R.; Vano, J.A.; Lettenmaier, D.P.

2011-01-01

Warm season climate warming will be a key driver of annual streamflow changes in four major river basins of the western U.S., as shown by hydrological model simulations using fixed precipitation and idealized seasonal temperature changes based on climate projections with SRES A2 forcing. Warm season (April-September) warming reduces streamflow throughout the year; streamflow declines both immediately and in the subsequent cool season. Cool season (October-March) warming, by contrast, increases streamflow immediately, partially compensating for streamflow reductions during the subsequent warm season. A uniform warm season warming of 3C drives a wide range of annual flow declines across the basins: 13.3%, 7.2%, 1.8%, and 3.6% in the Colorado, Columbia, Northern and Southern Sierra basins, respectively. The same warming applied during the cool season gives annual declines of only 3.5%, 1.7%, 2.1%, and 3.1%, respectively. Copyright 2011 by the American Geophysical Union.

Beneficial Effects of Temperate Forage Legumes that Contain Condensed Tannins

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Jennifer W. MacAdam

2015-07-01

Full Text Available The two temperate forage legumes containing condensed tannins (CT that promote ruminant production are birdsfoot trefoil (Lotus corniculatus L.; BFT and sainfoin (Onobrychis viciifolia Scop.; SF. Both are well-adapted to the cool-temperate climate and alkaline soils of the Mountain West USA. Condensed tannins comprise a diverse family of bioactive chemicals with multiple beneficial functions for ruminants, including suppression of internal parasites and enteric methane. Birdsfoot trefoil contains 10 to 40 g·CT·kg−1 dry matter (DM, while SF contains 30 to 80 g·CT·kg−1 DM. Our studies have focused on these two plant species and have demonstrated consistently elevated rates of gain for beef calves grazing both BFT and SF. Novel results from our BFT research include carcass dressing percentages and consumer sensory evaluations equivalent to feedlot-finished steers and significantly greater than grass-finished steers, but with omega-3 fatty acid concentrations equal to grass-finished beef. We have further demonstrated that ruminants fed BFT or SF will consume more endophyte-infected tall fescue (Schedonorus arundinaceus (Schreb. Dumort. forage or seed than ruminants fed a non-CT forage legume. There is great potential value for sustainable livestock production in the use of highly digestible, nitrogen-fixing legumes containing tannins demonstrated to improve ruminant productivity.

Livestock forage and mineral relations on a shrub-steppe rangeland in northwestern United States of America

International Nuclear Information System (INIS)

Uresk, D.W.; Rickard, W.H.

1976-01-01

The study area is the Arid Lands Ecology (ALE) Reserve, a portion of the United States Energy Research and Development Administration's Hanford Reservation located in the semi-arid region of south-central Washington. Small experimental pastures were subjected to four consecutive years of moderate spring grazing by yearling steers. These pastures are unique in that they represent grazing stresses imposed upon previously ungrazed (by livestock) plant communities. These communities had been protected from grazing by livestock for more than 30 years under ERDA management. Bluebunch wheatgrass (Agropyron spicatum), the dominant species, was the major forage plant in the diet of the steers during the 1974 grazing season, followed by Cusick's bluegrass (Poa cusickii), Thurber's needlegrass (Stipa thurberiania) and hawksbeard (Crepis atrabarba). These four species made up approximately 93% of the total diet. The forage intake ranged from 9.9 kg/head daily to 10.9 kg/head daily during the grazing season. During this period, these steers gained a total of 21.6 kg/ha live weight. Fifteen kg of forage consumed produces 1 kg of live steer for a 6.7% conversion. The conversion rate for crude protein was 12.7%, 83.3% for phosphorus and 25.6% for calcium. (author)

CHEMICAL COMPOSITION OF CAATINGA POTENTIAL FORAGES SPECIES

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Dynara Layza de Souza da Silva

2015-12-01

Full Text Available Chemical composition of some potential forages species, natives from Caatinga region, were evaluated. Samples of Macroptilium heterophyllum, Stylosanthes humilis, Rhynchosia mínima, Desmodium tortuosum Sw. Dc, Merremia aegyptia, Mimosa tenuiflora Wild, Bauhinia cheilantha and as well Macroptilium lathyroides, Caesalpinia pyramidalis and Mimosa tenuiflora hays were collected in Rio Grande do Norte Stated, during 2011 rainy season. The analyses: dry matter (DM, crude protein (CP mineral matter (MM ether extract  (EE neutral detergent fiber (NDF, acid detergent fiber (ADF, lignin (LIG, insoluble neutral detergent nitrogen, (INDN insoluble acid detergent nitrogen, (ADIN, total phenol (TF and total tannin (TT were done at Embrapa Caprinos e Ovinos in Ceará State. Plants analyzed, as expected, for tropical species, exhibited high level of cell wall constituents, high lignifications rate and revealed substantial presence of anti nutritional compounds. However, regardless of this data, the main problem, for grazing animals, is due to its xerophytes characteristics. Most of the shrubs and trees are deciduous, losing its leaves during the dry season. In addition, herbaceous presents a very rapid lifetime cycle, germinating and senescing during the brief wet season.

Environmental characterization of seasonal trends and foraging habitat of bottlenose dolphins (Tursiops truncatus) in northern Gulf of Mexico bays

OpenAIRE

Miller, Cara E.; Baltz, Donald M.

2010-01-01

A description of the foraging habitat of a cetacean species is critical for conservation and effective management. We used a fine-scale microhabitat approach to examine patterns in bottlenose dolphin (Tursiops truncatus) foraging distribution in relation to dissolved oxygen, turbidity, salinity, water depth, water temperature, and distance from shore measurements in a highly turbid estuary on the northern Gulf of Mexico. In general, environmental variation in the Barataria Basin marine env...

A new way of assessing foraging behaviour at the individual level using faeces marking and satellite telemetry.

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Marie-Andrée Giroux

Full Text Available Heterogeneity in foraging behaviour can profoundly influence ecological processes shaping populations. To scale-up from individual foraging behaviour to processes occurring at the population scale, one needs to sample foraging behaviour at the individual level, and over large temporal scales or during critical seasons known to influence life-history traits. We developed an innovative technique to monitor foraging behaviour at the individual level in secretive species, a technique that can be ultimately used to investigate the links between foraging behaviour and life-history traits. First, the technique used a novel approach, namely the combination of telemetry tracking and biomarking of faeces with food dyes to locate fresh signs of presence left by individuals equipped with GPS collars. Second, the technique is based on the simultaneous or successive sampling of life-history traits and individual foraging behaviour, using tracks with high probabilities of recovery of dyed faeces. We first describe our methodological approach, using a case study of a large herbivore, and then provide recommendations and guidelines for its use. Sampling single snow tracks of individuals equipped with a GPS collar was a reliable way to assess individual winter foraging behaviour in a white-tailed deer (Odocoileus virginianus Zimmermann population. During that period, the probability of recovery of dyed faeces within the range of the collar precision was very high for single snow tracks of equipped deer (97%. Our approach is well suited to study individual foraging behaviour, and could ultimately be used to investigate the interplay between intra-population heterogeneity in foraging behaviour, life-history traits, and demographic processes.

Evaluating the impact of handling and logger attachment on foraging parameters and physiology in southern rockhopper penguins.

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Katrin Ludynia

Full Text Available Logger technology has revolutionised our knowledge of the behaviour and physiology of free-living animals but handling and logger attachments may have negative effects on the behaviour of the animals and their welfare. We studied southern rockhopper penguin (Eudyptes chrysocome females during the guard stage in three consecutive breeding seasons (2008/09-2010/11 to evaluate the effects of handling and logger attachment on foraging trip duration, dive behaviour and physiological parameters. Smaller dive loggers (TDRs were used in 2010/11 for comparison to larger GPS data loggers used in all three seasons and we included two categories of control birds: handled controls and PIT control birds that were previously marked with passive integrative transponders (PITs, but which had not been handled during this study. Increased foraging trip duration was only observed in GPS birds during 2010/11, the breeding season in which we also found GPS birds foraging further away from the colony and travelling longer distances. Compared to previous breeding seasons, 2010/11 may have been a period with less favourable environmental conditions, which would enhance the impact of logger attachments. A comparison between GPS and TDR birds showed a significant difference in dive depth frequencies with birds carrying larger GPS data loggers diving shallower. Mean and maximum dive depths were similar between GPS and TDR birds. We measured little impact of logger attachments on physiological parameters (corticosterone, protein, triglyceride levels and leucocyte counts. Overall, handling and short-term logger attachments (1-3 days showed limited impact on the behaviour and physiology of the birds but care must be taken with the size of data loggers on diving seabirds. Increased drag may alter their diving behaviour substantially, thus constraining them in their ability to catch prey. Results obtained in this study indicate that data recorded may also not represent their

A Decade of Carbon Flux Measurements with Annual and Perennial Crop Rotations on the Canadian Prairies

Science.gov (United States)

Amiro, B. D.; Tenuta, M.; Gao, X.; Gervais, M.

2016-12-01

The Fluxnet database has over 100 cropland sites, some of which have long-term (over a decade) measurements. Carbon neutrality is one goal of sustainable agriculture, although measurements over many annual cropping systems have indicated that soil carbon is often lost. Croplands are complex systems because the CO2 exchange depends on the type of crop, soil, weather, and management decisions such as planting date, nutrient fertilization and pest management strategy. Crop rotations are often used to decrease pest pressure, and can range from a simple 2-crop system, to have 4 or more crops in series. Carbon dioxide exchange has been measured using the flux-gradient technique since 2006 in agricultural systems in Manitoba, Canada. Two cropping systems are being followed: one that is a rotation of annual crops (corn, faba bean, spring wheat, rapeseed, barley, spring wheat, corn, soybean, spring wheat, soybean); and the other with a perennial phase of alfalfa/grass in years 3 to 6. Net ecosystem production ranged from a gain of 330 g C m-2 y-1 in corn to a loss of 75 g C m-2 y-1 in a poor spring-wheat crop. Over a decade, net ecosystem production for the annual cropping system was not significantly different from zero (carbon neutral), but the addition of the perennial phase increased the sink to 130 g C m-2 y-1. Once harvest removals were included, there was a net loss of carbon ranging from 77 g C m-2 y-1 in the annual system to 52 g C m-2 y-1 in the annual-perennial system; but neither of these were significantly different from zero. Termination of the perennial phase of the rotation only caused short-term increases in respiration. We conclude that both these systems were close to carbon-neutral over a decade even though they were tilled with a short growing season (90 to 130 days). We discuss the need for more datasets on agricultural systems to inform management options to increase the soil carbon sink.

Evaluating poverty grass (Danthonia spicata L.) for use in tees, fairways, or rough areas in golf courses in the midwest

Science.gov (United States)

Nadia E. Navarrete-Tindall; Brad Fresenburg; J.W. Van Sambeek

2007-01-01

Poverty grass (Danthonia spicata L.), a native, cool-season perennial bunchgrass with wide distribution in the United States, is being evaluated for its suitability for use on golf courses. The goal is to identify practices to improve seed germination and successfully establish field plots as monocultures or with other native species to mimic natural...

Root Zone Cooling and Exogenous Spermidine Root-Pretreatment Promoting Lactuca sativa L. Growth and Photosynthesis in the High-Temperature Season

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Jin eSun

2016-03-01

Full Text Available Root zone high-temperature stress is a major factor limiting hydroponic plant growth during the high-temperature season. The effects of root zone cooling (RZC; at 25°C and exogenous spermidine (Spd root-pretreatment (SRP, 0.1 mM on growth, leaf photosynthetic traits, and chlorophyll fluorescence characteristics of hydroponic Lactuca sativa L. grown in a high-temperature season (average temperature > 30°C were examined. Both treatments significantly promoted plant growth and photosynthesis in the high-temperature season, but the mechanisms of photosynthesis improvement in the hydroponic grown lettuce plants were different between the RZC and SRP treatments. The former improved plant photosynthesis by increasing stoma conductance (Gs to enhance CO2 supply, thus promoting photosynthetic electron transport activity and phosphorylation, which improved the level of the photochemical efficiency of photosystem II (PSII, rather than enhancing CO2 assimilation efficiency. The latter improved plant photosynthesis by enhancing CO2 assimilation efficiency, rather than stomatal regulation. Combination of RZC and SRP significantly improved PN of lettuce plants in a high-temperature season by both improvement of Gs to enhance CO2 supply and enhancement of CO2 assimilation. The enhancement of photosynthetic efficiency in both treatments was independent of altering light-harvesting or excessive energy dissipation.

Root Zone Cooling and Exogenous Spermidine Root-Pretreatment Promoting Lactuca sativa L. Growth and Photosynthesis in the High-temperature Season.

Science.gov (United States)

Sun, Jin; Lu, Na; Xu, Hongjia; Maruo, Toru; Guo, Shirong

2016-01-01

Root zone high-temperature stress is a major factor limiting hydroponic plant growth during the high-temperature season. The effects of root zone cooling (RZC; at 25°C) and exogenous spermidine (Spd) root-pretreatment (SRP, 0.1 mM) on growth, leaf photosynthetic traits, and chlorophyll fluorescence characteristics of hydroponic Lactuca sativa L. grown in a high-temperature season (average temperature > 30°C) were examined. Both treatments significantly promoted plant growth and photosynthesis in the high-temperature season, but the mechanisms of photosynthesis improvement in the hydroponic grown lettuce plants were different between the RZC and SRP treatments. The former improved plant photosynthesis by increasing stoma conductance (G s) to enhance CO2 supply, thus promoting photosynthetic electron transport activity and phosphorylation, which improved the level of the photochemical efficiency of photosystem II (PSII), rather than enhancing CO2 assimilation efficiency. The latter improved plant photosynthesis by enhancing CO2 assimilation efficiency, rather than stomatal regulation. Combination of RZC and SRP significantly improved P N of lettuce plants in a high-temperature season by both improvement of G s to enhance CO2 supply and enhancement of CO2 assimilation. The enhancement of photosynthetic efficiency in both treatments was independent of altering light-harvesting or excessive energy dissipation.

Economic and conservation implications of converting exotic forages to native warm-season grass

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Adrian P. Monroe

2017-07-01

Full Text Available Intensive agriculture can have negative environmental consequences such as nonpoint source pollution and the simplification of biotic communities, and land sharing posits that conservation can be enhanced by integrating agricultural productivity and biodiversity on the same land. In the Southeastern United States, native warm-season grasses (NWSG may be a land sharing alternative to exotic forages currently in production because of greater livestock gains with lower fertilizer inputs, and habitat for grassland birds. However, uncertainty regarding costs and risk poses an important barrier to incorporating NWSG in livestock operations. We evaluated the economic and conservation implications of NWSG conversion among small, operational-scale pastures (6.8–10.5 ha during 2011–2012 at the Prairie Research Unit in Monroe Co., Mississippi (USA. We used partial budgets to compare the marginal rate of return (MRRe from converting exotic grass pastures to either a NWSG monoculture of Indiangrass (Sorghastrum nutans or a NWSG mix of Indiangrass, little bluestem (Schizachyrium scoparium, and big bluestem (Andropogon gerardii. We similarly compared changes in productivity of dickcissels (Spiza americana, a grassland bird specializing in tall structure. Average daily gain (ADG of steers and revenue were consistently higher for NWSG treatments than exotic grass pasture, but ADG declined between years. Indiangrass pastures yielded consistently positive MRRe, indicating producers would receive 16–24% return on investment. Marginal rate of return was lower for mixed NWSG (−12 to 3%, driven by slightly lower livestock ADG and higher establishment costs than for Indiangrass. Sensitivity analyses indicated that MRRe also was influenced by cattle selling price. Conversely, mixed NWSG increased dickcissel productivity by a greater degree than Indiangrass per amount invested in NWSG conversion, suggesting a tradeoff between livestock and dickcissel production

Effect of forage quality in faeces from different ruminant species fed high and low quality forage

DEFF Research Database (Denmark)

Jalali, A R; Nørgaard, P; Nielsen, M O

2010-01-01

Effect of forage quality in faeces from different ruminant species fed high and low quality forage......Effect of forage quality in faeces from different ruminant species fed high and low quality forage...

Does greed help a forager survive?

Science.gov (United States)

Bhat, U.; Redner, S.; Bénichou, O.

2017-06-01

We investigate the role of greed on the lifetime of a random-walking forager on an initially resource-rich lattice. Whenever the forager lands on a food-containing site, all the food there is eaten and the forager can hop S more steps without food before starving. Upon reaching an empty site, the forager comes one time unit closer to starvation. The forager is also greedy—given a choice to move to an empty or to a food-containing site in its local neighborhood, the forager moves preferentially toward food. Surprisingly, the forager lifetime varies nonmonotonically with greed, with different senses of the nonmonotonicity in one and two dimensions. Also unexpectedly, the forager lifetime in one dimension has a huge peak for very negative greed where the forager is food averse.

Yield and environmental effects of organic and inorganic fertilizer applications on mixed-season perennial forages

Science.gov (United States)

Although primarily a research project, this study included a training component whereby undergraduate research assistants gained practical knowledge in plant, soil and soil-water sampling and analysis, and learned about the environmental impact of nutrient loading in ground and surface waters. The ...

Comparison of common lignin methods and modifications on forage and lignocellulosic biomass materials.

Science.gov (United States)

Goff, Ben M; Murphy, Patrick T; Moore, Kenneth J

2012-03-15

A variety of methods have been developed for estimating lignin concentration within plant materials. The objective of this study was to compare the lignin concentrations produced by six methods on a diverse population of forage and biomass materials and to examine the relationship between these concentrations and the portions of these materials that are available for utilisation by livestock or for ethanol conversion. Several methods produced lignin concentrations that were highly correlated with the digestibility of the forages, but there were few relationships between these methods and the available carbohydrate of the biomass materials. The use of Na₂SO₃ during preparation of residues for hydrolysis resulted in reduced lignin concentrations and decreased correlation with digestibility of forage materials, particularly the warm-season grasses. There were several methods that were well suited for predicting the digestible portion of forage materials, with the acid detergent lignin and Klason lignin method giving the highest correlation across the three types of forage. The continued use of Na₂SO₃ during preparation of Van Soest fibres needs to be evaluated owing to its ability to reduce lignin concentrations and effectiveness in predicting the utilisation of feedstuffs and feedstocks. Because there was little correlation between the lignin concentration and the biomass materials, there is a need to examine alternative or develop new methods to estimate lignin concentrations that may be used to predict the availability of carbohydrates for ethanol conversion. Copyright © 2011 Society of Chemical Industry.

Foraging behavior, environmental parameters and nests development of Melipona colimana Ayala (Hymenoptera: Meliponini) in temperate climate of Jalisco, México.

Science.gov (United States)

Macías-Macías, J O; Tapia-Gonzalez, J M; Contreras-Escareño, F

2017-01-01

Melipona colimana Ayala is an endemic species inhabiting temperate forests of pine and oak of south of Jalisco in Mexico. During a year, it was recorded every 15 days foraging activity, environmental parameters and the development of colonies of M. colimana in its wild habitat. For five minutes every hour from 7:00 to 21:00, the bees that entered and left the hive and bringing pollen and resin were registered. Every hour the relative humidity, temperature, wind speed and light intensity was recorded and related to foraging activity. Additionally, the weight of the colonies recently transferred to wooden boxes, the number of brood combs, honey pots and pollen were registered. The time of beginning and ending of the foraging activity differs from the reports of stingless bees of tropical weather and the same happens with the pollen collection. The environmental parameters that affect other tropical stingless bees in the foraging activity also affect M. colimana in temperate climate. It was determined that the major activity season and the presence of more pollen pots in the colony is from November through February, for what it could be the best time of the year for the division and obtainance of new colonies, while the critical period of minor activity and pollen flow was during rainy season. These data may be useful for the future sustainable use of this species in temperate climate.

The potential of perennial cave ice in isotope palaeoclimatology

International Nuclear Information System (INIS)

Yonge, Charles J.; MacDonald, William D.

1999-01-01

Perennial ice from caves on and to the east of the Canadian Great Divide yield delta O 18 and delta D values which are usually high measurements where compared with the average precipitation for the region. Furthermore, these ice data fall below and along lines of lower slope than the Global Meteoric Water Line. To explain the observed relationships, we propose the following process. a vapour-ice isotopic fractionation mechanism operates on warm season vapour when it precipitates as hoar ice on entering the caves. The subsequent fall of hoar to the cave floor through mechanical overloading along with ice derived from ground-water seepage (with a mean annual isotopic composition), results in massive ice formation of a mixed composition. This mixed composition is what is observed in the characteristic relationships found here. Such findings suggest that a warm versus cold climate interpretation for ancient cave ice may be the opposite of that found in the more familiar polar and glacial ice caves. (Author) 3 figs., 1 tab., 12 refs

Agroecology of Novel Annual and Perennial Crops for Biomass Production

DEFF Research Database (Denmark)

Manevski, Kiril; Jørgensen, Uffe; Lærke, Poul Erik

The agroecological potential of many crops under sustainable intensification has not been investigated. This study investigates such potential for novel annual and perennial crops grown for biomass production.......The agroecological potential of many crops under sustainable intensification has not been investigated. This study investigates such potential for novel annual and perennial crops grown for biomass production....

Possible causes of decreasing migratory ungulate populations in an East African savannah after restrictions in their seasonal movements

NARCIS (Netherlands)

Voeten, Margje M.; van de Vijver, Claudius A. D. M.; Olff, Han; van Langevelde, Frank

In many areas in Africa, seasonal movements of migratory ungulates are restricted and their population numbers decline, for example in the Tarangire region, Tanzania. Here, agriculture restricts migration of ungulates to their wet season ranges. We investigated whether low forage quality or supply

Hooded seal Cystophora cristata foraging areas in the Northeast Atlantic Ocean-Investigated using three complementary methods.

Directory of Open Access Journals (Sweden)

Jade Vacquie-Garcia

Full Text Available Identifying environmental characteristics that define the ecological niche of a species is essential to understanding how changes in physical conditions might affect its distribution and other aspects of its ecology. The present study used satellite relay data loggers (SRDLs to study habitat use by Northeast Atlantic hooded seals (N = 20; 9 adult females, 3 adult males, and 8 juveniles. Three different methods were used in combination to achieve maximum insight regarding key foraging areas for hooded seals in this region, which have decline by 85% in recent decades: 1 first passage time (FPT; 2 vertical transit rate and; 3 change in dive drift rate. Generalized additive mixed models (GAMM were applied to each method to determine whether specific habitat characteristics were associated with foraging. Separate models were run for the post-molting and the post-breeding seasons; sex and age classes were included in the GAMMs. All three methods highlighted a few common geographic areas as being important foraging zones; however, there were also some different areas identified by the different methods, which highlights the importance of using multiple indexes when analyzing tracking and diving data to study foraging behavior. Foraging occurred most commonly in relatively shallow areas with high Sea Surface Temperatures (SST, corresponding to continental shelf areas with Atlantic Water masses. All age and sex classes overlapped spatially to some extent, but the different age and sex groups showed differences in the bathymetry of their foraging areas as well as in their vertical use of the water column. When foraging, pups dove in the upper part of the water column in relatively deep areas. Adult females foraged relatively shallowly in deep water areas too, though in shallower areas than pups. Adult males foraged close to the bottom in shallower areas.

Wetland selection by breeding and foraging black terns in the Prairie Pothole Region of the United States

Science.gov (United States)

Steen, Valerie A.; Powell, Abby N.

2012-01-01

We examined wetland selection by the Black Tern (Chlidonias niger), a species that breeds primarily in the prairie pothole region, has experienced population declines, and is difficult to manage because of low site fidelity. To characterize its selection of wetlands in this region, we surveyed 589 wetlands throughout North and South Dakota. We documented breeding at 5% and foraging at 17% of wetlands. We created predictive habitat models with a machine-learning algorithm, Random Forests, to explore the relative role of local wetland characteristics and those of the surrounding landscape and to evaluate which characteristics were important to predicting breeding versus foraging. We also examined area-dependent wetland selection while addressing the passive sampling bias by replacing occurrence of terns in the models with an index of density. Local wetland variables were more important than landscape variables in predictions of occurrence of breeding and foraging. Wetland size was more important to prediction of foraging than of breeding locations, while floating matted vegetation was more important to prediction of breeding than of foraging locations. The amount of seasonal wetland in the landscape was the only landscape variable important to prediction of both foraging and breeding. Models based on a density index indicated that wetland selection by foraging terns may be more area dependent than that by breeding terns. Our study provides some of the first evidence for differential breeding and foraging wetland selection by Black Terns and for a more limited role of landscape effects and area sensitivity than has been previously shown.

Control of perennial weeds by mechanical methods and anaerobic soil disinfection

NARCIS (Netherlands)

Huiting, H.F.; Bleeker, P.O.; Riemens, M.M.

2011-01-01

Perennial weeds are difficult to control and ask for a specific approach. During the most recent years it has even become a great challenge to control these weeds in conventional farming systems, although in comparison effective perennial weed control in organic farming systems remains more

Seasonal forecasts: communicating current climate variability in southern Africa

CSIR Research Space (South Africa)

Landman, WA

2011-11-01

Full Text Available seasonal time scale. Seasonal climate forecasts are defined as probabilistic predictions of how much rain is expected during the season and how warm or cool it will be, based primarily on the principle that the ocean (sea-surface temperatures) influences...

Predicting seed yield in perennial ryegrass using repeated canopy reflectance measurements and PLSR

DEFF Research Database (Denmark)

Gislum, René; Deleuran, Lise Christina; Boelt, Birte

2009-01-01

with first year seed crops using three sowing rates and three spring nitrogen (N) application rates. PLSR models were developed for each year and showed correlation coefficients of 0.71, 0.76, and 0.92, respectively. Regression coefficients showed in these experiments that the optimum time for canopy...... reflectance measurements was from approximately 600 cumulative growing degree-days (CGDD) to approximately 900 CGDD. This is the period just before and at heading of the seed crop. Furthermore, regression coefficients showed that information about N and water is important. The results support the development......Repeated canopy reflectance measurements together with partial least-squares regression (PLSR) were used to predict seed yield in perennial ryegrass (Lolium perenne L.). The measurements were performed during the spring and summer growing seasons of 2001 to 2003 in three field experiments...

Cool-season precipitation in the southwestern USA since AD 1000: comparison of linear and nonlinear techniques for reconstruction

Science.gov (United States)

Ni, Fenbiao; Cavazos, Tereza; Hughes, Malcolm K.; Comrie, Andrew C.; Funkhouser, Gary

2002-11-01

A 1000 year reconstruction of cool-season (November-April) precipitation was developed for each climate division in Arizona and New Mexico from a network of 19 tree-ring chronologies in the southwestern USA. Linear regression (LR) and artificial neural network (NN) models were used to identify the cool-season precipitation signal in tree rings. Using 1931-88 records, the stepwise LR model was cross-validated with a leave-one-out procedure and the NN was validated with a bootstrap technique. The final models were also independently validated using the 1896-1930 precipitation data. In most of the climate divisions, both techniques can successfully reconstruct dry and normal years, and the NN seems to capture large precipitation events and more variability better than the LR. In the 1000 year reconstructions the NN also produces more distinctive wet events and more variability, whereas the LR produces more distinctive dry events. The 1000 year reconstructed precipitation from the two models shows several sustained dry and wet periods comparable to the 1950s drought (e.g. 16th century mega drought) and to the post-1976 wet period (e.g. 1330s, 1610s). The impact of extreme periods on the environment may be stronger during sudden reversals from dry to wet, which were not uncommon throughout the millennium, such as the 1610s wet interval that followed the 16th century mega drought. The instrumental records suggest that strong dry to wet precipitation reversals in the past 1000 years might be linked to strong shifts from cold to warm El Niño-southern oscillation events and from a negative to positive Pacific decadal oscillation.

Seasonal habitat selection by African buffalo Syncerus caffer in the Savuti–Mababe–Linyanti ecosystem of northern Botswana

Directory of Open Access Journals (Sweden)

Keoikantse Sianga

2017-05-01

Full Text Available This study aimed to establish seasonal movement and habitat selection patterns of African buffalo Syncerus caffer in relation to a detailed habitat map and according to seasonal changes in forage quality and quantity in the Savuti–Mababe–Linyanti ecosystem (Botswana. Two buffalo were collared in November 2011 and another in October 2012. All three buffalo had greater activities in the mopane–sandveld woodland mosaic during the wet season, which provided high-quality leafy grasses and ephemeral water for drinking, but moved to permanent water and reliable forage of various wetlands (swamps and floodplains and riverine woodlands during the dry season. Wetlands had higher grass greenness, height and biomass than woodlands during the dry season. Buffalo had similar wet season concentration areas in the 2011–2012 and 2012–2013 wet seasons and similar dry season concentration areas over the 2012 and 2013 dry seasons. However, their dry season location of collaring in 2011 differed dramatically from their 2012 and 2013 dry season concentration areas, possibly because of the exceptionally high flood levels in 2011, which reduced accessibility to their usual dry season concentration areas. The study demonstrates that extremely large and heterogeneous landscapes are needed to conserve buffalo in sandy, dystrophic ecosystems with variable rainfall. Conservation implications: This study emphasises the importance of large spatial scale available for movement, which enables adaptation to changing conditions between years and seasons.

Saving energy in ventilation cooling towers. Optimization by control; Energieeinsparung bei Ventilatorkuehltuermen. Optimierung durch Regelung

Energy Technology Data Exchange (ETDEWEB)

Schnell, Wolf-Dieter [Ingenieurbuero fuer Energietechnik, Langenargen/Bodensee (Germany)

2009-07-01

Industrial-scale users of cooling water use bigger and higher natural-draught cooling towers to improve recirculation cooling. Smaller and medium-sized consumers as a rule use ventilation cooling towers.The market offers a wide choice of efficient products. At the same time, competition enforces savings so that often these ventilation cooling towers have no control option. However, optimum operation in the winter season necessitates variable air supply which is also a cost factor that can help to compensate the higher cost incurred in other seasons. (orig.)

Quitting time: When do honey bee foragers decide to stop foraging on natural resources?

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Michael eRivera

2015-05-01

Full Text Available Honey bee foragers may use both personal and social information when making decisions about when to visit resources. In particular, foragers may stop foraging at resources when their own experience indicates declining resource quality, or when social information, namely the delay to being able to unload nectar to receiver bees, indicates that the colony has little need for the particular resource being collected. Here we test the relative importance of these two factors in a natural setting, where colonies are using many dynamically changing resources. We recorded detailed foraging histories of individually marked bees, and identified when they appeared to abandon any resources (such as flower patches that they had previously been collecting from consistently. As in previous studies, we recorded duration of trophallaxis events (unloading nectar to receiver bees as a proxy for resource quality and the delays before returning foragers started trophallaxis as a proxy for social need for the resource. If these proxy measures accurately reflect changes in resource quality and social need, they should predict whether bees continue foraging or not. However, neither factor predicted when individuals stopped foraging on a particular resource, nor did they explain changes in colony-level foraging activity. This may indicate that other, as yet unstudied processes also affect individual decisions to abandon particular resources.

Nitrogen fertilization strategies for xaraes and tifton 85 grasses irrigated in the dry season

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Domingos Sávio Queiroz

2012-08-01

Full Text Available An experiment was carried out to assess rates and nitrogen fertilization strategies on the forage yield using irrigation to supply the water deficit during the dry season. The grasses Cynodon spp cv. tifton 85 and Brachiaria brizantha cv. Xaraés were cultivated with nitrogen (N at levels of 200 and 400 kg/ha according to strategies: 1 half dose applied during the rainy season (RS and half during the dry season (DS; 2 1/3 during the RS and 2/3 during the DS; 3 2/3 during the RS and 1/3 during the DS; 4 all doses applied during the DS. In each season the dose was divided in three applications. Eleven harvests were conducted: six in the RS and five in the DS. When 2/3 of N was applied in the DS, forage yield in this period was statistically equivalent to those obtained in the RS in three of the five harvests for both 200 and 400 kg/ha of N. With 100% of N applied in the DS, the yield of four of five cuts of forage was similar to that obtained in the RS for both rates of N. The strategy of applying more N in the DS rather than in the RS was effective, keeping the yield steadily throughout the year. The application of 100% of the dose of 200 kg/ha N and 2/3 of the dose of 400 kg/ha N both in the dry period, under irrigation, promote uniform productions per harvest throughout the year.

Competition and facilitation between a native and a domestic herbivore: trade-offs between forage quantity and quality.

Science.gov (United States)

Augustine, David J; Springer, Tim L

2013-06-01

Potential competition between native and domestic herbivores is a major consideration influencing the management and conservation of native herbivores in rangeland ecosystems. In grasslands of the North American Great Plains, black-tailed prairie dogs (Cynomys ludovicianus) are widely viewed as competitors with cattle but are also important for biodiversity conservation due to their role in creating habitat for other native species. We examined spatiotemporal variation in prairie dog effects on growing-season forage quality and quantity using measurements from three colony complexes in Colorado and South Dakota and from a previous study of a fourth complex in Montana. At two complexes experiencing below-average precipitation, forage availability both on and off colonies was so low (12-54 g/m2) that daily forage intake rates of cattle were likely constrained by instantaneous intake rates and daily foraging time. Under these dry conditions, prairie dogs (1) substantially reduced forage availability, thus further limiting cattle daily intake rates, and (2) had either no or a small positive effect on forage digestibility. Under such conditions, prairie dogs are likely to compete with cattle in direct proportion to their abundance. For two complexes experiencing above-average precipitation, forage quantity on and off colonies (77-208 g/m2) was sufficient for daily forage intake of cattle to be limited by digestion rather than instantaneous forage intake. At one complex where prairie dogs enhanced forage digestibility and [N] while having no effect on forage quantity, prairie dogs are predicted to facilitate cattle mass gains regardless of prairie dog abundance. At the second complex where prairie dogs enhanced digestibility and [N] but reduced forage quantity, effects on cattle can vary from competition to facilitation depending on prairie dog abundance. Our findings show that the high spatiotemporal variation in vegetation dynamics characteristic of semiarid grasslands

Consumer sensory evaluation and chemical composition of beef gluteus medius and triceps brachii steaks from cattle finished on forage or concentrate diets.

Science.gov (United States)

Chail, A; Legako, J F; Pitcher, L R; Ward, R E; Martini, S; MacAdam, J W

2017-04-01

The objective of this study was to assess the impact of cattle finishing diet and muscle type on meat quality. Consumer sensory response, proximate composition, Warner-Bratzler shear force (WBSF), fatty acid composition, and volatile compounds were assessed from the gluteus medius (GM) and triceps brachii (TB) muscles of cattle ( = 6 per diet) which were grain-finished (USUGrain) on conventional feedlot or 2 forage diets, a perennial legume, birdsfoot trefoil-finished (USUBFT; ), and grass-finished (USUGrass; ). Diet had an interacting effect with muscle for all sensory attributes ( ≤ 0.002), except aroma and flavor ( ≥ 0.078). In forage-finished beef, tenderness, fattiness, overall liking, and WBSF tenderness of GM was greater ( 0.05) but the juiciness of TB was more liked than USUGrain GM ( 0.05) between GM and TB. Lower ( 0.05) to both USUGrass and USUGrain beef. However, IMF percent was not impacted by muscle type ( = 0.092). The ratio of -6:-3 fatty acids was affected by muscle dependent on diet ( = 0.016). The ratio of -6:-3 fatty acids was affected by the interaction of muscle × diet ( = 0.016). Between forage diets (USUGrass and USUBFT), -6:-3 ratios were similar ( > 0.05) between GM and TB, whereas within USUGrain, the GM was greater ( 0.05). Strecker aldehydes, ketones, pyrazines, and methional were affected ( ≤ 0.036) by muscle and found to have a greater concentration in GM compared with TB. Overall, consumers determined that USUGrain GM and TB had similar ( > 0.05) quality ratings. However, within forage-finished beef, the GM was perceived more frequently ( consumer group grilled GM and TB steaks, grain-finished beef provided more uniform quality and eating experience compared with forage-finished beef.

Spatial and Temporal Variations in the Occurrence and Foraging Activity of Coastal Dolphins in Menai Bay, Zanzibar, Tanzania.

Directory of Open Access Journals (Sweden)

Andrew J Temple

Full Text Available Understanding temporal patterns in distribution, occurrence and behaviour is vital for the effective conservation of cetaceans. This study used cetacean click detectors (C-PODs to investigate spatial and temporal variation in occurrence and foraging activity of the Indo-Pacific bottlenose (Tursiops aduncus and Indian Ocean humpback (Sousa plumbea dolphins resident in the Menai Bay Conservation Area (MBCA, Zanzibar, Tanzania. Occurrence was measured using detection positive minutes. Inter-click intervals were used to identify terminal buzz vocalisations, allowing for analysis of foraging activity. Data were analysed in relation to spatial (location and temporal (monsoon season, diel phase and tidal phase variables. Results showed significantly increased occurrence and foraging activity of dolphins in southern areas and during hours of darkness. Higher occurrence at night was not explained by diel variation in echolocation rate and so were considered representative of occurrence patterns. Both tidal phase and monsoon season influenced occurrence but results varied among sites, with no general patterns found. Foraging activity was greatest during hours of darkness, High water and Flood tidal phases. Comparisons of echolocation data among sites suggested differences in the broadband click spectra of MBCA dolphins, possibly indicative of species differences. These dolphin populations are threatened by unsustainable fisheries bycatch and tourism activities. The spatial and temporal patterns identified in this study have implications for future conservation and management actions with regards to these two threats. Further, the results indicate future potential for using passive acoustics to identify and monitor the occurrence of these two species in areas where they co-exist.

A quantification of predation rates, indirect positive effects on plants, and foraging variation of the giant tropical ant, Paraponera clavata

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Lee A. Dyer

2002-09-01

Full Text Available While a clear consensus is emerging that predators can play a major role in shaping terrestrial communities, basic natural history observations and simple quantifications of predation rates in complex terrestrial systems are lacking. The potential indirect effect of a large predatory ant, Paraponera clavata Fabricius (Formicidae: Ponerinae, on herbivores was determined on rainforest trees at La Selva Biological Station in Costa Rica and Barro Colorado Island in Panama. Prey and other food brought back to nests by 75 colonies of P. clavata were quantified, taking into account temporal, seasonal, and microhabitat variation for both foraging activity and composition of foraging booty. The dispersion and density of ant colonies and combined density with the mean amounts of prey retrieval were used to calculate rates of predation per hectare in the two forests. In addition, herbivory was measured on trees containing P. clavata and on trees where the ants were not foraging. Colonies at La Selva brought back significantly more nectar plus prey than those at Barro Colorado Island, but foraging patterns were similar in the two forests. At both forests, the ants were more active at night, and there was no significant seasonal or colonial variation in consumption of nectar, composition of foraging booty, and overall activity of the colonies. At La Selva, trees containing P. clavata colonies had the same levels of folivory as nearest neighbor trees without P. clavata but had significantly lower folivory than randomly selected trees. Predation by this ant was high in both forests, despite its omnivorous diet. This insect predator is part of potentially important top-down controls in these wet and moist forests.

A Remote Sensing Based Forage Biomass Yield Inversion Model of Alpine-cold Meadow during Grass-withering Period in Sanjiangyuan Area

International Nuclear Information System (INIS)

Song, Weize; Jia, Haifeng; Liang, Shidong; Wang, Zheng; Liu, Shujie; Hao, Lizhuang; Chai, Shatuo

2014-01-01

Estimating forage biomass yield remotely from space is still challenging nowadays. Field experiments were conducted and ground measurements correlated to remote sensing data to estimate the forage biomass yield of Alpine-cold meadow grassland during the grass and grass-withering period in Sanjiangyuan area in Yushu county. Both Shapiro-Wilk and Kolmogorov-Smirnov two-tailed tests showed that the field training samples are normally distributed, the Spearman coefficient indicated that the parametric correlation analysis had significant differences. The optimal regression models were developed based on the Landsat Thematic Mapper Normalized Difference Vegetation Index (TM-NDVI) and the forage biomass field data during the grass and the grass-withering periods, respectively. Then an integration model was used to predict forage biomass yield of alpine-cold meadow in the grass-withering period. The model showed good prediction accuracy and reliability. It was found that this approach can not only estimate forage yield in large scale efficiently but also overcome the seasonal limitation of remote sensing inversion. This technique can provides valuable guidance to animal husbandry to resource more efficiently in winter

Swimming strategy and body plan of the world’s largest fish: implications for foraging efficiency and thermoregulation

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Mark eMeekan

2015-09-01

Full Text Available The largest animals in the oceans eat prey that are orders of magnitude smaller than themselves, implying strong selection for cost-effective foraging to meet their energy demands. Whale sharks (Rhincodon typus may be especially challenged by warm seas that elevate their metabolism and contain sparse prey resources. Using a combination of biologging and satellite tagging, we show that whale sharks use four strategies to save energy and improve foraging efficiency: 1 fixed, low power swimming, 2 constant low speed swimming, 3 gliding and 4 asymmetrical diving. These strategies increase foraging efficiency by 22 – 32% relative to swimming horizontally and resolve the energy-budget paradox of whale sharks. However, sharks in the open ocean must access food resources that reside in relatively cold waters (up to 20oC cooler than the surface at depths of 250-500 m during the daytime, where long, slow gliding descents, continuous ram ventilation of the gills and filter-feeding could rapidly cool the circulating blood and body tissues. We suggest that whale sharks may overcome this problem through their large size and a specialized body plan that isolates highly vascularized red muscle on the dorsal surface, allowing heat to be retained near the centre of the body within a massive core of white muscle. This could allow a warm-adapted species to maintain enhanced function of organs and sensory systems while exploiting food resources in deep, cool water.

Hybrid value foraging: How the value of targets shapes human foraging behavior.

Science.gov (United States)

Wolfe, Jeremy M; Cain, Matthew S; Alaoui-Soce, Abla

2018-04-01

In hybrid foraging, observers search visual displays for multiple instances of multiple target types. In previous hybrid foraging experiments, although there were multiple types of target, all instances of all targets had the same value. Under such conditions, behavior was well described by the marginal value theorem (MVT). Foragers left the current "patch" for the next patch when the instantaneous rate of collection dropped below their average rate of collection. An observer's specific target selections were shaped by previous target selections. Observers were biased toward picking another instance of the same target. In the present work, observers forage for instances of four target types whose value and prevalence can vary. If value is kept constant and prevalence manipulated, participants consistently show a preference for the most common targets. Patch-leaving behavior follows MVT. When value is manipulated, observers favor more valuable targets, though individual foraging strategies become more diverse, with some observers favoring the most valuable target types very strongly, sometimes moving to the next patch without collecting any of the less valuable targets.

Specific immunotherapy has long-term preventive effect of seasonal and perennial asthma

DEFF Research Database (Denmark)

Jacobsen, L; Niggemann, B; Dreborg, S

2007-01-01

BACKGROUND: 3-year subcutaneous specific immunotherapy (SIT) in children with seasonal allergic rhinoconjunctivitis reduced the risk of developing asthma during treatment and 2 years after discontinuation of SIT (5-year follow-up) indicating long-term preventive effect of SIT. OBJECTIVE: We......: Specific immunotherapy has long-term clinical effects and the potential of preventing development of asthma in children with allergic rhino conjunctivitis up to 7 years after treatment termination....

Supporting Agricultural Ecosystem Services through the Integration of Perennial Polycultures into Crop Rotations

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Peter Weißhuhn

2017-12-01

Full Text Available This review analyzes the potential role and long-term effects of field perennial polycultures (mixtures in agricultural systems, with the aim of reducing the trade-offs between provisioning and regulating ecosystem services. First, crop rotations are identified as a suitable tool for the assessment of the long-term effects of perennial polycultures on ecosystem services, which are not visible at the single-crop level. Second, the ability of perennial polycultures to support ecosystem services when used in crop rotations is quantified through eight agricultural ecosystem services. Legume–grass mixtures and wildflower mixtures are used as examples of perennial polycultures, and compared with silage maize as a typical crop for biomass production. Perennial polycultures enhance soil fertility, soil protection, climate regulation, pollination, pest and weed control, and landscape aesthetics compared with maize. They also score lower for biomass production compared with maize, which confirms the trade-off between provisioning and regulating ecosystem services. However, the additional positive factors provided by perennial polycultures, such as reduced costs for mineral fertilizer, pesticides, and soil tillage, and a significant preceding crop effect that increases the yields of subsequent crops, should be taken into account. However, a full assessment of agricultural ecosystem services requires a more holistic analysis that is beyond the capabilities of current frameworks.

Starvation dynamics of a greedy forager

Science.gov (United States)

Bhat, U.; Redner, S.; Bénichou, O.

2017-07-01

We investigate the dynamics of a greedy forager that moves by random walking in an environment where each site initially contains one unit of food. Upon encountering a food-containing site, the forager eats all the food there and can subsequently hop an additional S steps without food before starving to death. Upon encountering an empty site, the forager goes hungry and comes one time unit closer to starvation. We investigate the new feature of forager greed; if the forager has a choice between hopping to an empty site or to a food-containing site in its nearest neighborhood, it hops preferentially towards food. If the neighboring sites all contain food or are all empty, the forager hops equiprobably to one of these neighbors. Paradoxically, the lifetime of the forager can depend non-monotonically on greed, and the sense of the non-monotonicity is opposite in one and two dimensions. Even more unexpectedly, the forager lifetime in one dimension is substantially enhanced when the greed is negative; here the forager tends to avoid food in its local neighborhood. We also determine the average amount of food consumed at the instant when the forager starves. We present analytic, heuristic, and numerical results to elucidate these intriguing phenomena.

Honey bee workers that are pollen stressed as larvae become poor foragers and waggle dancers as adults.

Directory of Open Access Journals (Sweden)

Hailey N Scofield

Full Text Available The negative effects on adult behavior of juvenile undernourishment are well documented in vertebrates, but relatively poorly understood in invertebrates. We examined the effects of larval nutritional stress on the foraging and recruitment behavior of an economically important model invertebrate, the honey bee (Apis mellifera. Pollen, which supplies essential nutrients to developing workers, can become limited in colonies because of seasonal dearths, loss of foraging habitat, or intensive management. However, the functional consequences of being reared by pollen-stressed nestmates remain unclear, despite growing concern that poor nutrition interacts with other stressors to exacerbate colony decline. We manipulated nurse bees' access to pollen and then assessed differences in weight, longevity, foraging activity, and waggle-dance behavior of the workers that they reared (who were co-fostered as adults. Pollen stress during larval development had far-reaching physical and behavioral effects on adult workers. Workers reared in pollen-stressed colonies were lighter and shorter lived than nestmates reared with adequate access to pollen. Proportionally fewer stressed workers were observed foraging and those who did forage started foraging sooner, foraged for fewer days, and were more likely to die after only a single day of foraging. Pollen-stressed workers were also less likely to waggle dance than their unstressed counterparts and, if they danced, the information they conveyed about the location of food was less precise. These performance deficits may escalate if long-term pollen limitation prevents stressed foragers from providing sufficiently for developing workers. Furthermore, the effects of brief pollen shortages reported here mirror the effects of other environmental stressors that limit worker access to nutrients, suggesting the likelihood of their synergistic interaction. Honey bees often experience the level of stress that we created, thus

Genetic options for improving fodder yield and quality in forage sorghum

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C. Aruna

2015-01-01

Full Text Available Improving yield and quality of fodder from forage sorghum is important, especially in the semi-arid tropics, where sorghum is a major source of fodder. The aim of this work was to understand the genetic basis of fodder yield and quality traits, and character associations, and to estimate combining ability of the parents. The experiment was carried out during 2 successive rainy seasons using 10 parents crossed in a half-diallel design. Significant differences among the genotypes for fodder yield, quality and cell wall constituents were observed. Important quality traits, crude protein and digestibility (IVOMD, were not correlated with fodder yield, indicating the potential to improve yield and quality simultaneously in forage sorghum. General combining ability and specific combining ability variances showed that, for almost all characters, both additive and non-additive gene effects were important, with a predominance of non-additive effects. Parental lines SEVS4, HC308 and UPMC503 were good general combiners for yield and quality. The brown midrib lines, EC582508 and EC582510, were good general combiners for low lignin and high IVOMD. Strategies for improving forage sorghum to suit animal and biofuel industries are discussed.Keywords: Digestibility, crude protein, ADL, diallel analysis, gene effects.DOI: 10.17138/TGFT(349-58

New Developments in Forage Varieties

Science.gov (United States)

Forage crops harvested for hay or haylage or grazed support dairy, beef, sheep and horse production. Additional livestock production from reduced forage acreage supports the need for forage variety improvement. The Consortium for Alfalfa Improvement is a partnership model of government, private no...

Exploring the Factors Driving Seasonal Farmland Abandonment: A Case Study at the Regional Level in Hunan Province, Central China

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Zhonglei Yu

2017-01-01

Full Text Available Farmland abandonment, including perennial and seasonal abandonment, is an important process of land use change that matters most to food security. Although there is a great deal of studies on farmland abandonment, seasonal abandonment, which is as serious as perennial abandonment, has attracted little academic attention. This paper takes Hunan Province in central China as its study area and uses a spatial regression model to examine the driving factors of seasonal farmland abandonment at the county level. Our results show that farmland abandonment has striking spatial relativity, and there are two clustering zones with a high index of farmland abandonment (IFA in the Dongting plain and the basin in south-central Hunan, while a clustering zone of low IFA can be found in the mountains of southwest Hunan. Farmland abandonment at the regional level is negatively affected by the land productive potentialities, proportion of mechanized planting, ratio of effective irrigation, and distance to provincial capital, while it is positively associated with the variables mountainous terrain, per capita farmland area, and labor shortage. Additionally, farmland abandonment is also affected by adjacent areas through its spatial dependence. In short, seasonal farmland abandonment is also driven integratedly by the socioeconomic and environmental dimensions and spatial interaction of farm abandonment.

Totally impermeable film (TIF reduces emissions in perennial crop fumigation

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Suduan Gao

2013-10-01

Full Text Available Many perennial nursery fields and replanted orchards and vineyards in California are treated with preplant soil fumigants to control soilborne pests. In annual crops, such as strawberry, covering fumigated fields with totally impermeable film (TIF has shown promise in controlling emissions and improving fumigant distribution in soil. The objective of this research was to optimize the use of TIF for perennial crops via three field trials. TIF reduced peak emission flux and cumulative emissions by > 90% relative to polyethylene tarp during a 2-week covering period. After the TIF was cut, emissions were greatly reduced compared to when tarps were cut after 6 days. TIF maintained higher fumigant concentrations under tarp and in the soil than polyethylene film. The results indicate that TIF can increase fumigation efficiency for perennial crop growers.

Foraging behavior, environmental parameters and nests development of Melipona colimana Ayala (Hymenoptera: Meliponini in temperate climate of Jalisco, México

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J. O. Macías-Macías

Full Text Available Abstract Melipona colimana Ayala is an endemic species inhabiting temperate forests of pine and oak of south of Jalisco in Mexico. During a year, it was recorded every 15 days foraging activity, environmental parameters and the development of colonies of M. colimana in its wild habitat. For five minutes every hour from 7:00 to 21:00, the bees that entered and left the hive and bringing pollen and resin were registered. Every hour the relative humidity, temperature, wind speed and light intensity was recorded and related to foraging activity. Additionally, the weight of the colonies recently transferred to wooden boxes, the number of brood combs, honey pots and pollen were registered. The time of beginning and ending of the foraging activity differs from the reports of stingless bees of tropical weather and the same happens with the pollen collection. The environmental parameters that affect other tropical stingless bees in the foraging activity also affect M. colimana in temperate climate. It was determined that the major activity season and the presence of more pollen pots in the colony is from November through February, for what it could be the best time of the year for the division and obtainance of new colonies, while the critical period of minor activity and pollen flow was during rainy season. These data may be useful for the future sustainable use of this species in temperate climate.

Estabelecimento de gramíneas forrageiras tropicais perenes simultaneamente com as culturas de milho e soja no Norte do RS Perennial tropical forage grasses establishment simultaneously with soybean and maize in northern of RS state, Brazil

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Franciele Mariani

2012-08-01

ça' single pasture was higher than the others, with average accumulation of 6.515 and 5.778kg ha-1, respectively. Intercropped with maize the average accumulation of dry matter was 2.380kg ha-1, without significant differences between species, but with the greatest accumulation occurred in soybeans for 'Marandu' (3.040kg ha-1. There was no decrease in soybean and maize yield in presence of forages, but for mechanical harvesting of soybean further investigation will be required. The intercropping between maize and tropical perennial forages is a viable alternative to the northern of RS.

Contrasting Patterns of Gene Flow for Amazonian Snakes That Actively Forage and Those That Wait in Ambush.

Science.gov (United States)

de Fraga, Rafael; Lima, Albertina P; Magnusson, William E; Ferrão, Miquéias; Stow, Adam J

2017-07-01

Knowledge of genetic structure, geographic distance and environmental heterogeneity can be used to identify environmental features and natural history traits that influence dispersal and gene flow. Foraging mode is a trait that might predict dispersal capacity in snakes, because actively foragers typically have greater movement rates than ambush predators. Here, we test the hypothesis that 2 actively foraging snakes have higher levels of gene flow than 2 ambush predators. We evaluated these 4 co-distributed species of snakes in the Brazilian Amazon. Snakes were sampled along an 880 km transect from the central to the southwest of the Amazon basin, which covered a mosaic of vegetation types and seasonal differences in climate. We analyzed thousands of single nucleotide polymorphisms to compare patterns of neutral gene flow based on isolation by geographic distance (IBD) and environmental resistance (IBR). We show that IBD and IBR were only evident in ambush predators, implying lower levels of dispersal than the active foragers. Therefore, gene flow was high enough in the active foragers analyzed here to prevent any build-up of spatial genotypic structure with respect to geographic distance and environmental heterogeneity. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Nocturnal Foraging by Red-Legged Kittiwakes, a Surface Feeding Seabird That Relies on Deep Water Prey During Reproduction.

Science.gov (United States)

Kokubun, Nobuo; Yamamoto, Takashi; Kikuchi, Dale M; Kitaysky, Alexander; Takahashi, Akinori

2015-01-01

Narrow foraging specialization may increase the vulnerability of marine predators to climate change. The red-legged kittiwake (Rissa brevirostris) is endemic to the Bering Sea and has experienced drastic population fluctuations in recent decades, presumably due to climate-driven changes in food resources. Red-legged kittiwakes are presumed to be a nocturnal surface-foraging seabird that feed almost entirely on deep water Myctophidae fishes. However, there is little empirical evidence confirming their nocturnal foraging activity during the breeding season. This study investigated the foraging behavior of red-legged kittiwakes by combining GPS tracking, accelerometry, and dietary analyses at the world's largest breeding colony of red-legged kittiwakes on St. George I. GPS tracking of 5 individuals revealed that 82.5% of non-flight behavior (including foraging and resting) occurred over the ocean basin (bottom depth >1,000 m). Acceleration data from 4 birds showed three types of behaviors during foraging trips: (1) flight, characterized by regular wing flapping, (2) resting on water, characterized by non-active behavior, and (3) foraging, when wing flapping was irregular. The proportions of both foraging and resting behaviors were higher at night (14.1 ± 7.1% and 20.8 ± 14.3%) compared to those during the day (6.5 ± 3.0% and 1.7 ± 2.7%). The mean duration of foraging (2.4 ± 2.9 min) was shorter than that of flight between prey patches (24.2 ± 53.1 min). Dietary analyses confirmed myctophids as the dominant prey (100% by occurrence and 98.4 ± 2.4% by wet-weight). Although the sample size was limited, these results suggest that breeding red-legged kittiwakes concentrated their foraging on myctophids available at the surface during nighttime in deep water regions. We propose that the diel patterns and ephemeral nature of their foraging activity reflected the availability of myctophids. Such foraging specialization may exacerbate the vulnerability of red

Nocturnal Foraging by Red-Legged Kittiwakes, a Surface Feeding Seabird That Relies on Deep Water Prey During Reproduction.

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Nobuo Kokubun

Full Text Available Narrow foraging specialization may increase the vulnerability of marine predators to climate change. The red-legged kittiwake (Rissa brevirostris is endemic to the Bering Sea and has experienced drastic population fluctuations in recent decades, presumably due to climate-driven changes in food resources. Red-legged kittiwakes are presumed to be a nocturnal surface-foraging seabird that feed almost entirely on deep water Myctophidae fishes. However, there is little empirical evidence confirming their nocturnal foraging activity during the breeding season. This study investigated the foraging behavior of red-legged kittiwakes by combining GPS tracking, accelerometry, and dietary analyses at the world's largest breeding colony of red-legged kittiwakes on St. George I. GPS tracking of 5 individuals revealed that 82.5% of non-flight behavior (including foraging and resting occurred over the ocean basin (bottom depth >1,000 m. Acceleration data from 4 birds showed three types of behaviors during foraging trips: (1 flight, characterized by regular wing flapping, (2 resting on water, characterized by non-active behavior, and (3 foraging, when wing flapping was irregular. The proportions of both foraging and resting behaviors were higher at night (14.1 ± 7.1% and 20.8 ± 14.3% compared to those during the day (6.5 ± 3.0% and 1.7 ± 2.7%. The mean duration of foraging (2.4 ± 2.9 min was shorter than that of flight between prey patches (24.2 ± 53.1 min. Dietary analyses confirmed myctophids as the dominant prey (100% by occurrence and 98.4 ± 2.4% by wet-weight. Although the sample size was limited, these results suggest that breeding red-legged kittiwakes concentrated their foraging on myctophids available at the surface during nighttime in deep water regions. We propose that the diel patterns and ephemeral nature of their foraging activity reflected the availability of myctophids. Such foraging specialization may exacerbate the vulnerability of red

Cooling ponds and small rivers in north central United States

International Nuclear Information System (INIS)

Howe, P.H.

1987-01-01

An attempt is made to review those Commonwealth Edison (Ceco) programs related directly or indirectly to compensation and stock manipulation in fish populations. The direct stocking of sport fish fingerlings for mitigation is one method of stock manipulation. There are, however, two other, less common manipulative approaches to enhancing local fish stocks. First is the use of cooling ponds as off-stream nursery areas for forage and sport species. Second is the use of waste heat to modify habitat temperatures and permit or improve overwintering survival of select species such as gizzard or threadfin shad in north-temperate waters that are naturally too cold to sustain strong populations. This, in turn, will increase the abundance of these species as forage in subsequent years. There are four different Ceco projects which are discussed. These are: Fish releases in Pool 14 of the Mississippi River; Studies of endemic and stock fishes at the Collins and Dresden Cooling Ponds; Fish and water quality monitoring of the Des Plaines and Upper Illinois Rivers; and Proposed walleye, muskellunge and striped bass x white bass hybrid stocking in the Rock River. 7 references

Basin wildrye (Leymus cinereus) pooled tetraploid accessions for U.S. Intermountain rangeland reclamation

Science.gov (United States)

Stanford A. Young; Jason Vernon; Nancy Shaw

2013-01-01

Basin wildrye (Leymus cinereus [Scribn. & Merr.] A. Love) is an important perennial, hardy, long-lived, cool season C3 native grass of rangeland plant communities throughout much of western United States and Canada. All classes of livestock and wildlife, including large and small birds and mammals, utilise the grass year round for food and protection due to its 2-3...

Plant-water relationships and growth of black walnut in a walnut-forage multicropping regime

Science.gov (United States)

Daniel C. Dey; M. R. Conway; H. E. Garrett; T. S. Hinckley; G. S. Cox

1987-01-01

Eastern black walnut seedlings were planted on a 1.5 ? 1.5m spacing in the spring of 1976 and irrigated throughout the growing season. During the spring of 1977, forage plots consisting of Kentucky 31 tall fescue, orchard grass, or Kobe lespedeza measuring 1 m wide and 10.2 m long and centered on a row of trees, were established with and without irrigation. Soil-water...

Adaptive management of perennial pepperweed for endangered specias and tidal marsh recovery

Science.gov (United States)

Perennial pepperweed has invaded a wide range of habitat types in the far west. In the San Francisco Estuary, dense infestations have impacted sensitive tidal wetlands and compromised endangered species recovery efforts. An adaptive management effort to reduce perennial pepperweed was initiated by...

Knowledge of the Yucatec Maya in seasonal tropical forest management: the forage plants El conocimiento de los mayas yucatecos en el manejo del bosque tropical estacional: las plantas forrajeras

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José Salvador Flores

2012-06-01

Full Text Available Indigenous knowledge and the millenary experience in management of natural vegetation on karstic landscapes are important aspects that should be considered in animal production in seasonal tropical environments. The aim of the present work was to make an inventory of native plants associated to soilscapes from seasonal tropical forests from the Yucatán Peninsula that are used as forage by Mayan people. The work was carried out in 27 Mayan communities on karst landscapes in the Yucatán Peninsula as a part of the "Ethnoflora Yucatanense" project of the Universidad Autónoma de Yucatán. Samples were taken of forage plants together with corresponding floristic and ethnobotanical information. Data were processed in EXCEL dynamic tables, grouped by plant family, geoforms and soils, life form and animal consumers. Results indicate that Mayan communities use 196 plant species as forage: 139 herbaceous, 17 shrubs, 35 trees and 2 palms. These plants are fed to cows, pigs, horses, lambs, turkeys, chickens, ducks and pigeons. The use of native forage plants may be an agricultural option both for rural communities and for intensive animal production on silvopastoral systems on karstic tropical landscapes from the Yucatán Peninsula.El conocimiento indígena y la experiencia de milenios de años en el manejo de la vegetación natural en ambientes kársticos tropicales son aspectos importantes que deben ser considerados en la producción animal. El objetivo de este trabajo fue hacer un inventario de las plantas forrajeras nativas de los bosques tropicales estacionales de la península de Yucatán que son utilizadas por los mayas, incluyendo los paisajes edáficos en los que se encuentran las plantas, información que servirá de base para la planeación de las actividades agropecuarias. El trabajo se llevó al cabo en 27 comunidades indígenas mayas, como parte del proyecto "Etnoflora Yucatanense" de la Universidad Autónoma de Yucatán. Las muestras de

A mechanistic assessment of seasonal microhabitat selection by drift-feeding rainbow trout Oncorhynchus mykiss in a southwestern headwater stream

Science.gov (United States)

Kalb, Bradley W.; Huntsman, Brock M.; Caldwell, Colleen A.; Bozek, Michael A.

2018-01-01

The positioning of fishes within a riverscape is dependent on the proximity of complementary habitats. In this study, foraging and non-foraging habitat were quantified monthly over an entire year for a rainbow trout (Oncorhynchus mykiss) population in an isolated, headwater stream in southcentral New Mexico. The stream follows a seasonal thermal and hydrologic pattern typical for a Southwestern stream and was deemed suitable for re-introduction of the native and close relative, Rio Grande cutthroat trout (O. clarkii virginalis). However, uncertainty associated with limited habitat needed to be resolved if repatriation of the native fish was to be successful. Habitat was evaluated using resource selection functions with a mechanistic drift-foraging model to explain trout distributions. Macroinvertebrate drift was strongly season- and temperature-dependent (lower in winter and spring, higher in summer and fall). Models identified stream depth as the most limiting factor for habitat selection across seasons and size-classes. Additionally, positions closer to cover were selected during the winter by smaller size-classes (0, 1, 2), while net energy intake was important during the spring for most size-classes (0, 1, 2, 3). Drift-foraging models identified that 81% of observed trout selected positions that could meet maintenance levels throughout the year. Moreover, 40% of selected habitats could sustain maximum growth. Stream positions occupied by rainbow trout were more energetically profitable than random sites regardless of season or size-class. Larger size-classes (3, 4+) were energetically more limited throughout the year than were smaller size-classes. This research suggests that habitat in the form of deep pools is of paramount importance for rainbow trout or native cutthroat trout.

Cool-season annual pastures with clovers to supplement wintering beef cows nursing calves

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Gunter Stacey A

2012-07-01

Full Text Available Abstract In December of 3 years, 87 beef cows with nursing calves (594 ± 9.8 kg; calving season, September to November at side were stratified by body condition score, body weight, cow age, and calf gender and divided randomly into 6 groups assigned to 1 of 6 cool-season annual pastures (0.45 ha/cow that had been interseeded into a dormant common bermudagrass (Cynodon dactylon [L.] Pers./bahiagrass (Paspalum notatum Flugge sod. Pastures contained 1 of the following 3 seeding mixtures (2 pastures/mixture: 1 wheat (Triticum aestivum L. and ryegrass (Lolium multiflorum Lam., WRG, 2 wheat and ryegrass plus red clover (Trifolium pretense L., WRR, or 3 wheat and ryegrass plus white (Trifolium repens L. and crimson clovers (Trifolium incarnatum L., WRW. All groups had ad libitum access to grass hay (12% crude protein; 58% total digestible nutrients. The second week in December, cow estrous cycles were synchronized and artificially inseminated. In late December, a bull was placed with each group for 60-d. Data were analyzed with an analysis of variance using a mixed model containing treatment as the fixed effect and year as the random effect. Body weight and condition scores did not differ (P ≥ 0.27 among cows between February and June. Calf birth weights or average daily gain did not differ (P ≥ 0.17 among treatments; however, calves grazing pastures with clovers did tend (P = 0.06 to weigh more than calves grazing grass only. Weaning weight per cow exposed to a bull was greater (P = 0.02 for WRR and WRW than WRG. Cows grazing winter-annual pastures containing clovers tended to wean more calf body weight per cow exposed to a bull than cows grazing the grass only pastures.

Seasonal Variation of Harbor Seal's Diet from the Wadden Sea in Relation to Prey Availability.

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Camille de la Vega

Full Text Available The Wadden Sea has an important role for marine mammals in terms of resting, nursing and foraging. Harbor seal is the most abundant marine mammal species in this area. The use of the food resources of the Wadden Sea by seals is not clear, and previous studies showed that this species can travel kilometers away from their haul-outs to forage in the North Sea. In this study, we analyzed the stable isotopes of vibrissae from 23 dead harbor seals found on the island of Sylt to investigate their diet. The predator´s carbon and nitrogen isotope compositions were compared to the compositions of different potential prey items from the Sylt-Rømø Bight and from the North Sea in order to study seasonal pattern in the diet and in the foraging location. In parallel, seasonal variation of abundance and biomass of the potential prey items from the Sylt-Rømø Bight were studied and compare to their contribution to the seal´s diet. The results revealed a change in the seal´s diet from pelagic sources in spring to a benthic based diet in summer, and an increasing use of the North Sea resources in fall and winter in accordance with the seasonal variation of the availability of prey in the Sylt-Rømø Bight.

Foraging and metabolic consequences of semi-anadromy for an endangered estuarine fish.

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Bruce G Hammock

Full Text Available Diadromy affords fish access to productive ecosystems, increasing growth and ultimately fitness, but it is unclear whether these advantages persist for species migrating within highly altered habitat. Here, we compared the foraging success of wild Delta Smelt-an endangered, zooplanktivorous, annual, semi-anadromous fish that is endemic to the highly altered San Francisco Estuary (SFE-collected from freshwater (<0.55 psu and brackish habitat (≥0.55 psu. Stomach fullness, averaged across three generations of wild Delta Smelt sampled from juvenile through adult life stages (n = 1,318, was 1.5-fold higher in brackish than in freshwater habitat. However, salinity and season interacted, with higher fullness (1.7-fold in freshwater than in brackish habitat in summer, but far higher fullness in brackish than freshwater habitat during fall/winter and winter/spring (1.8 and 2.0-fold, respectively. To examine potential causes of this interaction we compared mesozooplankton abundance, collected concurrently with the Delta Smelt, in freshwater and brackish habitat during summer and fall/winter, and the metabolic rate of sub-adult Delta Smelt acclimated to salinities of 0.4, 2.0, and 12.0 psu in a laboratory experiment. A seasonal peak in mesozooplankton density coincided with the summer peak in Delta Smelt foraging success in freshwater, and a pronounced decline in freshwater mesozooplankton abundance in the fall coincided with declining stomach fullness, which persisted for the remainder of the year (fall, winter and spring. In brackish habitat, greater foraging 'efficiency' (prey items in stomachs/mesozooplankton abundance led to more prey items per fish and generally higher stomach fullness (i.e., a higher proportion of mesozooplankton detected in concurrent trawls were eaten by fish in brackish habitat. Delta Smelt exhibited no difference in metabolic rate across the three salinities, indicating that metabolic responses to salinity are unlikely to have

Forage quantity and quality

Science.gov (United States)

Jorgenson, Janet C.; Udevitz, Mark S.; Felix, Nancy A.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

2002-01-01

The Porcupine caribou herd has traditionally used the coastal plain of the Arctic National Wildlife Refuge, Alaska, for calving. Availability of nutritious forage has been hypothesized as one of the reasons the Porcupine caribou herd migrates hundreds of kilometers to reach the coastal plain for calving (Kuropat and Bryant 1980, Russell et al. 1993).Forage quantity and quality and the chronology of snowmelt (which determines availability and phenological stages of forage) have been suggested as important habitat attributes that lead calving caribou to select one area over another (Lent 1980, White and Trudell 1980, Eastland et al. 1989). A major question when considering the impact of petroleum development is whether potential displacement of the caribou from the 1002 Area to alternate calving habitat will limit access to high quantity and quality forage.Our study had the following objectives: 1) quantify snowmelt patterns by area; 2) quantify relationships among phenology, biomass, and nutrient content of principal forage species by vegetation type; and 3) determine if traditional concentrated calving areas differ from adjacent areas with lower calving densities in terms of vegetation characteristics.

Density and climate influence seasonal population dynamics in an Arctic ungulate

DEFF Research Database (Denmark)

Mortensen, Lars O.; Moshøj, Charlotte; Forchhammer, Mads C.

2016-01-01

The locally migratory behavior of the high arctic muskox (Ovibos muschatus) is a central component of the breeding and winter survival strategies applied to cope with the highly seasonal arctic climate. However, altered climate regimes affecting plant growth are likely to affect local migration...... cover), forage availability (length of growth season), and the number of adult females available per male (operational sex ratio) influence changes in the seasonal density dependence, abundance, and immigration rate of muskoxen into the valley. The results suggested summer temperature as the major...... controlling factor in the seasonal, local-scale migration of muskoxen at Zackenberg. Specifically, higher summer temperatures, defined as the cumulative average daily positive degrees in June, July, and August, resulted in decreased density dependence and, consequently, increase in the seasonal abundance...

Bacterial endophytes of perennial crops for management of plant disease

OpenAIRE

Melnick, Rachel L.; Bailey, B.A.; Backman, Paul A.

2013-01-01

Metadata only record Bacterial endophytes, microorganisms which inhabit the internal tissues of plants, can suppress disease and are often used as a biological control in annual crops. Less research, however, has been applied to the use of bacterial endophytes to prevent disease in perennial crops, which presents a more complex challenge. However, exploration of their potential as a biological control in perennial crops has been limited. This chapter assembles current knowledge on the subj...

Optimal Foraging in Semantic Memory

Science.gov (United States)

Hills, Thomas T.; Jones, Michael N.; Todd, Peter M.

2012-01-01

Do humans search in memory using dynamic local-to-global search strategies similar to those that animals use to forage between patches in space? If so, do their dynamic memory search policies correspond to optimal foraging strategies seen for spatial foraging? Results from a number of fields suggest these possibilities, including the shared…

Foraging plasticity of breeding Northern Rockhopper Penguins, Eudyptes moseleyi, in response to changing energy requirements

KAUST Repository

Booth, Jenny Marie

2018-04-02

During the breeding season, seabirds must balance the changing demands of self- and off-spring provisioning with the constraints imposed by central-place foraging. Recently, it was shown that Northern Rockhopper Penguins at Tristan da Cunha in the South Atlantic Ocean switch diet from lower to higher trophic level prey throughout their breeding cycle. Here, we investigated if this switch is reflected in their foraging behaviour, using time-depth recorders to study the diving behaviour of 27 guard and 10 crèche birds during the breeding season 2010 at Tristan da Cunha and obtaining complementary stomach contents of 20 birds. While no significant effects of breeding stage were detected on any foraging trip or dive parameters, stage/prey had a significant effect on feeding dive parameters, with dive duration, bottom time, and maximum depth explaining the majority of the dissimilarity amongst categories. We verified the previously shown dietary shift from zooplankton and cephalopods during the guard stage to a higher-energy fish-based diet during the crèche stage, which was reflected in a change in dive behaviour from shorter, shallower to longer, deeper dives. This prey switching behaviour may reflect preferential selection to account for the increased physiological needs of chicks or simply mirror changes in local prey abundance. Nonetheless, we show that Northern Rockhopper Penguins demonstrate behavioural plasticity as a response to their changing energy requirements, which is a critical trait when living in a spatio-temporally heterogeneous environment. This ability is likely to be particularly important under extrinsic constraints such as long-term environmental change.

Guanaco’s diet and forage preferences in Nothofagus forest environments of Tierra del Fuego, Argentina

Energy Technology Data Exchange (ETDEWEB)

Quinteros, C.P.; Bava, J.; Gobbi, M.E.; Defossé, G.E.

2017-11-01

Aim of study: Guanaco (Lama guanicoe Müller), is a South American native ungulate widely distributed in Patagonia, which in the island of Tierra del Fuego (TF), extends its habitat into Nothofagus spp. forests. Within these forests, guanacos consume lenga (Nothofagus pumilio) leaves and twigs, and other understory species. The aim of this work was to determine: 1) the spring and summer diet of free ranging guanacos, and 2) which plants, grown in the forest understory, guanacos do prefer, or avoid, in these seasons of great forage abundance. Area of study: Tierra del Fuego (Argentina), on three representative areas which combined Nothofagus forests and adjacent meadows (vegas). Material and Methods: uanacos’ diet was determined by comparing epidermal and non-epidermal plant fragments with micro-histological analyses of feces. The analysis was made from composite samples of fresh feces, collected at the seasons of maximum forage productivity (spring and summer). Main results: During spring, 48% of guanacos’ diet was composed of lenga leaves, 30% of grass-like species, 15% of grasses, and less than 7% of herbs, shrubs, and lichens. In summer, 40% of the diet was composed of grasses, 30% of lenga leaves, 25% of grass-like species and the rest corresponded to herbs, shrubs, and lichens. Within the forest understory, guanaco selected lenga leaves and twigs, grass species were consumed according to their availability (or sometimes rejected), while other herbs were not consumed at all. Research highlights: Guanacos’ consumption preference for lenga, even considering the high availability of other forages, could adversely affect forest regeneration.

Guanaco’s diet and forage preferences in Nothofagus forest environments of Tierra del Fuego, Argentina

International Nuclear Information System (INIS)

Quinteros, C.P.; Bava, J.; Gobbi, M.E.; Defossé, G.E.

2017-01-01

Aim of study: Guanaco (Lama guanicoe Müller), is a South American native ungulate widely distributed in Patagonia, which in the island of Tierra del Fuego (TF), extends its habitat into Nothofagus spp. forests. Within these forests, guanacos consume lenga (Nothofagus pumilio) leaves and twigs, and other understory species. The aim of this work was to determine: 1) the spring and summer diet of free ranging guanacos, and 2) which plants, grown in the forest understory, guanacos do prefer, or avoid, in these seasons of great forage abundance. Area of study: Tierra del Fuego (Argentina), on three representative areas which combined Nothofagus forests and adjacent meadows (vegas). Material and Methods: uanacos’ diet was determined by comparing epidermal and non-epidermal plant fragments with micro-histological analyses of feces. The analysis was made from composite samples of fresh feces, collected at the seasons of maximum forage productivity (spring and summer). Main results: During spring, 48% of guanacos’ diet was composed of lenga leaves, 30% of grass-like species, 15% of grasses, and less than 7% of herbs, shrubs, and lichens. In summer, 40% of the diet was composed of grasses, 30% of lenga leaves, 25% of grass-like species and the rest corresponded to herbs, shrubs, and lichens. Within the forest understory, guanaco selected lenga leaves and twigs, grass species were consumed according to their availability (or sometimes rejected), while other herbs were not consumed at all. Research highlights: Guanacos’ consumption preference for lenga, even considering the high availability of other forages, could adversely affect forest regeneration.

Foraging ecology as related to the distribution of planktivorous auklets in the Bering Sea

Science.gov (United States)

Hunt, George L.; Harrison, Nancy M.; Piatt, John F.

1993-01-01

We review recent accounts of the foraging ecologies of  five species of small auklets found in the Bering Sea. These birds eat a wide variety of zooplankton and micronekton. Least Auklets Aethia pusilla and Whiskered Auklets A. pygmaea, as far as is known, primarily eat copepods, whereas Created Auklets A. cristatella appear to specialize on euphausiids, at least during the breeding season. The diet of Parakeet Auklets Cyclorrhynchus psittacula is much broader than that of most other Aethia species, and includes many gelatinous species and their commensals. Little is known of the diet of Cassin's Auklet Ptychoramphus aleuticus in the Bering Sea, although elsewhere they take large copepods, euphausiids, and larval fish.There are considerable differences in the at-sea distributions and foraging behaviors of these five species of auklet. Least Auklets in the norhtern Bering Sea concentrate their foraging activities over strongly stratified water and near fronts where pycnoclines may approach the surface. In the Aleutian Islands, Least Auklets forage where oceanic and tidal currents strike the shelf between the islands and rise toward the surface carrying plankton. Least Auklets and Crested Auklets are often found in large flocks, whereas Parakeet Auklets are rarely found in groups of more than three birds and are usually widely dispersed. The few at-sea observations of Whiskered Auklets have been of small flocks in turbulent waters of island passes. We relate prey types taken, foraging dispersion, and the use of hydrographic features by these auklet species.

GPS-tracking and colony observations reveal variation in offshore habitat use and foraging ecology of breeding Sandwich Terns

Science.gov (United States)

Fijn, R. C.; de Jong, J.; Courtens, W.; Verstraete, H.; Stienen, E. W. M.; Poot, M. J. M.

2017-09-01

Breeding success of seabirds critically depends on their foraging success offshore. However, studies combining at-sea tracking and visual provisioning observations are scarce, especially for smaller species of seabirds. This study is the first in which breeding Sandwich Terns were tracked with GPS-loggers to collect detailed data on foraging habitat use in four breeding seasons. The maximum home range of individual Sandwich Terns comprised approximately 1900 km2 and the average foraging range was 27 km. Trip durations were on average 135 min with average trip lengths of 67 km. Actual foraging behaviour comprised 35% of the time budget of a foraging trip. Substantial year-to-year variation was found in habitat use and trip variables, yet with the exception of 2012, home range size remained similar between years. Food availability, chick age and environmental conditions are proposed as the main driving factors between inter- and intra-annual variations in trip variables. Our multi-method approach also provided geo-referenced information on prey presence and we conclude that future combining of colony observations and GPS-loggers deployments can potentially provide a near complete insight into the feeding ecology of breeding Sandwich Terns, including the behaviour of birds at sea.

Inter-simple sequence repeat (ISSR) loci mapping in the genome of perennial ryegrass

DEFF Research Database (Denmark)

Pivorienė, O; Pašakinskienė, I; Brazauskas, G

2008-01-01

The aim of this study was to identify and characterize new ISSR markers and their loci in the genome of perennial ryegrass. A subsample of the VrnA F2 mapping family of perennial ryegrass comprising 92 individuals was used to develop a linkage map including inter-simple sequence repeat markers...... demonstrated a 70% similarity to the Hordeum vulgare germin gene GerA. Inter-SSR mapping will provide useful information for gene targeting, quantitative trait loci mapping and marker-assisted selection in perennial ryegrass....

Forage production in mixed grazing systems of elephant grass with arrowleaf clover or forage peanut

Directory of Open Access Journals (Sweden)

Daiane Cristine Seibt

Full Text Available ABSTRACT Most dairy production systems are pasture-based, usually consisting of sole grass species. This system facilitates pasture management, but results in high production costs, mainly because of nitrogen fertilizers. An alternative to making forage systems more sustainable is to introduce legumes into the pasture. Mixed pastures allow better forage distribution over time and reduce fertilization costs. Thus, the objective of this study was to evaluate, throughout the year, three forage systems (FS: FS1 (control - elephant grass (EG, ryegrass (RG, and spontaneous species (SS; FS2 - EG + RG + SS + arrowleaf clover; and FS3 - EG + RG + SS + forage peanut. Elephant grass was planted in rows spaced 4 m apart. Ryegrass was sown between the EG lines, in the winter. Arrowleaf clover was sown according to the respective treatments and forage peanut was preserved. Evaluation was carried out using Holstein cows. The experiment was arranged in a completely randomized design, with three treatments (FS, and three repetitions (paddocks with repeated measurements (grazing cycles. Forage mass achieved 3.46, 3.80, and 3.91 t ha-1 for the treatments FS1, FS2 and FS3, respectively. The forage systems intercropped with legumes produced the best results.

Honeybee Foraging, Nectar Secretion, and Honey Potential of Wild Jujube Trees, Ziziphus nummularia.

Science.gov (United States)

Alqarni, A S

2015-06-01

Ziziphus trees are of economic importance due to their aggregated value (source of fruits and timber) and are the most important melliferous plants in the Arabian Peninsula. Interaction between honeybees and Ziziphus nummularia was investigated by assessing foraging, flower phenology, nectar secretion, and honey potential. It is demonstrate that both the native Apis mellifera jemenitica Ruttner and the exotic Apis mellifera carnica Pollmann foraged on Z. nummularia flowers. Bee foraging for nectar and pollen was low (2 ± 0.7 workers/200 flowers/3 min) during early morning and increased to a peak in the afternoon (100 ± 15 workers/200 flowers/3 min). Remarkable foraging activity was recorded during high temperature (35°C) and low humidity (20%) conditions. Foraging for nectar collection was more distinct than that for pollen. The flowering of Z. nummularia was gradual, and was characterized by some flowers that opened and secreted nectar early before sunrise, whereas other flowers remained opened until sunrise. The flowers lasted 2 days, with 83% of nectar secreted in the first day. The peak of nectar secretion was recorded at noon under hot and dry conditions. The lowest amount of nectar was secreted during sunrise under mild temperature (24°C) and humidity (31%) conditions. Under optimum conditions, it is assumed that the average sugar mass was 0.321 ± 0.03 mg TSS/flower, while the total sugar mass was 27.65 ± 11 g/tree. The average honey production potential of tested Z. nummularia was approximately 2.998 kg/tree and 749.475 kg/ha in the main flowering season.

Sympatric cattle grazing and desert bighorn sheep foraging

Science.gov (United States)

Garrison, Kyle R.; Cain, James W.; Rominger, Eric M.; Goldstein, Elise J.

2015-01-01

Foraging behavior affects animal fitness and is largely dictated by the resources available to an animal. Understanding factors that affect forage resources is important for conservation and management of wildlife. Cattle sympatry is proposed to limit desert bighorn population performance, but few studies have quantified the effect of cattle foraging on bighorn forage resources or foraging behavior by desert bighorn. We estimated forage biomass for desert bighorn sheep in 2 mountain ranges: the cattle-grazed Caballo Mountains and the ungrazed San Andres Mountains, New Mexico. We recorded foraging bout efficiency of adult females by recording feeding time/step while foraging, and activity budgets of 3 age-sex classes (i.e., adult males, adult females, yearlings). We also estimated forage biomass at sites where bighorn were observed foraging. We expected lower forage biomass in the cattle-grazed Caballo range than in the ungrazed San Andres range and lower biomass at cattle-accessible versus inaccessible areas within the Caballo range. We predicted bighorn would be less efficient foragers in the Caballo range. Groundcover forage biomass was low in both ranges throughout the study (Jun 2012–Nov 2013). Browse biomass, however, was 4.7 times lower in the Caballo range versus the San Andres range. Bighorn in the Caballo range exhibited greater overall daily travel time, presumably to locate areas of higher forage abundance. By selecting areas with greater forage abundance, adult females in the Caballo range exhibited foraging bout efficiency similar to their San Andres counterparts but lower overall daily browsing time. We did not find a significant reduction in forage biomass at cattle-accessible areas in the Caballo range. Only the most rugged areas in the Caballo range had abundant forage, potentially a result of intensive historical livestock use in less rugged areas. Forage conditions in the Caballo range apparently force bighorn to increase foraging effort by

Project CONVERGE: Impacts of local oceanographic processes on Adélie penguin foraging ecology

Science.gov (United States)

Kohut, J. T.; Bernard, K. S.; Fraser, W.; Oliver, M. J.; Statscewich, H.; Patterson-Fraser, D.; Winsor, P.; Cimino, M. A.; Miles, T. N.

2016-02-01

During the austral summer of 2014-2015, project CONVERGE deployed a multi-platform network to sample the Adélie penguin foraging hotspot associated with Palmer Deep Canyon along the Western Antarctic Peninsula. The focus of CONVERGE was to assess the impact of prey-concentrating ocean circulation dynamics on Adélie penguin foraging behavior. Food web links between phytoplankton and zooplankton abundance and penguin behavior were examined to better understand the within-season variability in Adélie foraging ecology. Since the High Frequency Radar (HFR) network installation in November 2014, the radial component current data from each of the three sites were combined to provide a high resolution (0.5 km) surface velocity maps. These hourly maps have revealed an incredibly dynamic system with strong fronts and frequent eddies extending across the Palmer Deep foraging area. A coordinated fleet of underwater gliders were used in concert with the HFR fields to sample the hydrography and phytoplankton distributions associated with convergent and divergent features. Three gliders mapped the along and across canyon variability of the hydrography, chlorophyll fluorescence and acoustic backscatter in the context of the observed surface currents and simultaneous penguin tracks. This presentation will highlight these synchronized measures of the food web in the context of the observed HFR fronts and eddies. The location and persistence of these features coupled with ecological sampling through the food web offer an unprecedented view of the Palmer Deep ecosystem. Specific examples will highlight how the vertical structure of the water column beneath the surface features stack the primary and secondary producers relative to observed penguin foraging behavior. The coupling from the physics through the food web as observed by our multi-platform network gives strong evidence for the critical role that distribution patterns of lower trophic levels have on Adélie foraging.

Spring nitrogen fertilization of ryegrass-bermudagrass for phytoremediation of phosphorus-enriched soils

Science.gov (United States)

Nitrogen fertilization of forage grasses is critical for optimizing biomass and utilization of manure soil nutrients. Field studies were conducted in 2007-09 to determine the effects of spring N fertilization on amelioration of high soil P when cool-season, annual ryegrass (Lolium multiflorum L.) is...

Perennial Pepperweed Patches - San Francisco Estuary [ds295

Data.gov (United States)

California Natural Resource Agency — This layer contains polygon data for the perennial pepperweed (Lepidium latifolium) database. This database represents distribution data collected within the areas...

Soil water status under perennial and annual pastures on an acid duplex soil

International Nuclear Information System (INIS)

Heng, L.K.; White, R.E.; Chen, D.

2000-01-01

A comprehensive field study of soil water balance, nitrogen (N) cycling, pasture management and animal production was carried out on an acid duplex soil at Book Book near Wagga Wagga in southern New South Wales. The experiment, carried out over a 3-year period, tested the hypothesis that sown perennial grass pastures improve the sustainability of a grazing system through better use of water and N. The treatments were: annual pastures without lime (AP-), annual pastures with lime (AP+), perennial pastures without lime (PP-) and perennial pastures with lime (PP+). Soil water measurement was made using a neutron probe on one set of the treatments comprising four adjacent paddocks. Over three winter and spring periods, the results showed that perennial grass pastures, especially PP+, consistently extracted about 40 mm more soil water each year than did the annual grass pastures. As a result, surface runoff, sub-surface flow and deep drainage (percolation below 180 cm depth) were about 40 mm less from the perennial pastures. The soil water status of the four pasture treatments was simulated reasonably well using a simple soil water model. Together with the long-term simulation of deep drainage, using past meteorological records, it is shown that proper management of perennial pastures can reduce recharge to groundwater and make pastoral systems more sustainable in the high rainfall zone. However, to completely reduce recharge, more-deeply rooted plants or trees are needed. (author)

Evaporite deposition in a shallow perennial lake, Qaidam basin, western China

Energy Technology Data Exchange (ETDEWEB)

Schubel, K.A.; Lowenstein, T.K. (SUNY, Binghampton, NY (United States)); Spencer, R.J. (Univ. of Calgary, Alberta (Canada)); Pengxi, Z. (Institute of Salt Lakes, Xining (China))

1991-03-01

Evaporites accumulate in ephemeral saline-pans, shallow perennial lakes or lagoons, and deep perennial systems. Continuous brine trench exposures of Holocene evaporites from the Qaidam basin provide criteria for the recognition of shallow perennial lake sediments. Based on Landsat photographs, lateral extent of beds (at least 7 km), and sequence thicknesses (maximum 2.5 m), the paleolake is interpreted to have been less than 2.5 m deep and at least 120 km{sup 2} in area. Sediments consist of laminated siliciclastic mud overlain by mud-halite couplets (mm- to cm-scale layers), which represent one vertical shallowing- and concentrating-upwards sequence. The basal laminite marks the onset of deposition in this shallow perennial paleolake. Syndepositional halite textures and fabrics in the overlying mud-halite couplets include cumulates, rafts, and chevrons, draped by mud laminae, and halite layers truncated by horizontal dissolution surfaces (increasing in frequency upwards). Paleolake brines, determined from fluid inclusion melting temperatures, are Na-Mg-Cl-rich and evolve from 0.84 m Mg{sup 2} to 1.52 m Mg{sup 2+} (near the surface). Combinations of the following criteria may be used for the recognition of shallow, nonstratified, perennial lake sediments: lateral continuity of layers; muds undisrupted by subaerial exposure; vertical bottom-growth of halite; halite layers conformably overlain by mud; halite layers truncated by nonuniformly spaced horizontal dissolution surfaces; erosional scours and channels filled with cross-laminated gypsum, halite, and siliciclastic sand and mud; and salinity fluctuations over small stratigraphic intervals within an overall concentrating-upwards sequence.

Effect of nocturnal grazing and supplementation on diet selection, eating time, forage intake and weight changes of cattle

NARCIS (Netherlands)

Ayantunde, A.A.; Fernandez-Rivera, S.; Hiernaux, P.H.Y.; Keulen, van H.; Udo, H.M.J.; Chanono, M.

2000-01-01

Sixty-four Azawak male calves were used to study the effect of nocturnal grazing (NG) and supplementation (S) in the dry season on forage and water intake, faecal output, eating time and weight changes of cattle in the Sahel. Treatments were factorial combinations of four levels of NG (0, 2, 4 and 6

Age-related variation in foraging behaviour in the wandering albatross at South Georgia: no evidence for senescence.

Directory of Open Access Journals (Sweden)

Hannah Froy

Full Text Available Age-related variation in demographic rates is now widely documented in wild vertebrate systems, and has significant consequences for population and evolutionary dynamics. However, the mechanisms underpinning such variation, particularly in later life, are less well understood. Foraging efficiency is a key determinant of fitness, with implications for individual life history trade-offs. A variety of faculties known to decline in old age, such as muscular function and visual acuity, are likely to influence foraging performance. We examine age-related variation in the foraging behaviour of a long-lived, wide-ranging oceanic seabird, the wandering albatross Diomedea exulans. Using miniaturised tracking technologies, we compared foraging trip characteristics of birds breeding at Bird Island, South Georgia. Based on movement and immersion data collected during the incubation phase of a single breeding season, and from extensive tracking data collected in previous years from different stages of the breeding cycle, we found limited evidence for age-related variation in commonly reported trip parameters, and failed to detect signs of senescent decline. Our results contrast with the limited number of past studies that have examined foraging behaviour in later life, since these have documented changes in performance consistent with senescence. This highlights the importance of studies across different wild animal populations to gain a broader perspective on the processes driving variation in ageing rates.

Variability in the Foraging Distribution and Diet of Cape Gannets between the Guard and Post-guard Phases of the Breeding Cycle

Directory of Open Access Journals (Sweden)

Jonathan A. Botha

2018-02-01

Full Text Available During breeding, seabirds are central place foragers and are sensitive to changes in local prey availability. As the breeding season progresses, foraging behavior and distribution is expected to change in response to possible changes in local prey availability. In addition, adult gender, and the increasing nutritional demands of a growing chick may also influence the foraging behavior of individuals. At present, relatively few studies have assessed the foraging behavior of adult birds during the late post-guard stages of chick rearing. Through a combination of GPS tracking and diet sampling we investigated the foraging distances, spatial distribution, and prey composition of adult Cape gannets (Morus capensis during the guard and post-guard stages of chick rearing. We found no clear evidence for consistent sex-specific differences in foraging distances and spatial distribution during the guard stage, although marginal differences in the location of core foraging areas during the post-guard stage were apparent. Results, however, revealed a clear increase in foraging range from the early guard to the late post-guard stage of chick rearing. During December the diet was comprised almost exclusively of anchovy (Engraulis encrasicolus, the proportion of which had decreased significantly in the diet by January. This was mirrored by a substantial increase in the proportion of saury (Scomberesox saurus. These results suggest that Cape gannets show flexibility in the foraging behavior and diet, which may be related to changes in the abundance and distribution of prey or may reflect changes in the energetic requirements of the growing offspring. This study provides the first assessment of Cape gannet foraging behavior and spatial distribution during the post-guard stage of chick rearing. The importance of considering intra-annual variability in foraging distribution when using seabird tracking data in trophic and marine spatial planning studies are

Dietary variation and stress among prehistoric Jomon foragers from Japan.

Science.gov (United States)

Temple, Daniel H

2007-08-01

Current archaeological evidence indicates that greater dietary reliance on marine resources is recorded among the eastern Jomon, while plant dependence prevailed in western/inland Japan. The hypothesis that the dietary choices of the western/inland Jomon will be associated with greater systemic stress is tested by comparing carious tooth and enamel hypoplasia frequencies between the eastern and western/inland Jomon. Demographic collapse coincides with climate change during the Middle to Late Jomon period, suggesting dwindling resource availability. It is hypothesized that this change was associated with greater systemic stress and/or dietary change among the Middle to Late Jomon. This hypothesis is tested by comparing enamel hypoplasia and carious tooth frequencies between Middle to Late and Late to Final Jomon foragers. Enamel hypoplasia was significantly more prevalent among the western/inland Jomon. Such findings are consistent with archaeological studies that argue for greater plant consumption and stresses associated with seasonal resource depletion among the western/inland Jomon. Approximately equivalent enamel hypoplasia frequencies between Middle to Late and Late to Final Jomon foragers argues against a demographic collapse in association with diminished nutritional returns. Significant differences in carious tooth frequencies are, however, observed between Middle to Late and Late to Final Jomon foragers. These results suggest a subsistence shift during the Middle to Late Jomon period, perhaps in response to a changed climate. The overall patterns of stress documented by this study indicate wide-spread environmentally directed biological variation among the prehistoric Jomon. (c) 2007 Wiley-Liss, Inc.

Root proliferation in native perennial grasses of arid Patagonia, Argentina

Institute of Scientific and Technical Information of China (English)

Yanina A. TORRES; Mara M. MUJICA; Sandra S. BAIONI; Jos ENTO; Mara N. FIORETTI; Guillermo TUCAT; Carlos A. BUSSO; Oscar A. MONTENEGRO; Leticia ITHURRART; Hugo D. GIORGETTI; Gustavo RODRGUEZ; Diego BENTIVEGNA; Roberto E. BREVEDAN; Osvaldo A. FERNNDEZ

2014-01-01

Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that (1) defoliation reduce net primary productivity, and root length density and weight in the native species, and (2) root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species (i.e., Aristida spegazzinii, A. subulata and Sporobolus cryptandrus). Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season (2008-2009), cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid-and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length den-sity and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.

Stable isotopes (δ13C, δ15N combined with conventional dietary approaches reveal plasticity in central-place foraging behaviour of little penguins (Eudyptula minor

Directory of Open Access Journals (Sweden)

Andre eChiaradia

2016-01-01

Full Text Available Marine top and meso predators like seabirds are limited by the need to breed on land but forage on limited or patchily distributed resources at sea. Constraints imposed by such central-place foraging behaviour change during breeding or even disappear outside the breeding period when there is no immediate pressure to return to a central place. However, central place foraging is usually factored as an unchanging condition in life history studies. Here we used little penguin Eudyptula minor, a resident bird with one of the smallest foraging range among seabirds, to examine the different degree of pressure/constraints of being a central-place forager. We combined data on isotopic composition (δ13C and δ15N, conventional stomach contents and body mass of little penguins breeding at Phillip Island, Australia over nine years (2003-11. We explored relationships between diet and body mass in each stage of the breeding season (pre-laying, incubation, guard, and post-guard in years of high and low reproductive success. Values of δ13C and δ15N as well as isotopic niche width had similar patterns among years, with less variability later in the season when little penguins shorten their foraging range at the expected peak of their central-place foraging limitation. Body mass peaked before laying and hatching in preparation for the energetically demanding periods of egg production and chick provisioning. An increase of anchovy and barracouta in the diet, two major prey for little penguins, occurred at the critical stage of chick rearing. These intra-annual trends could be a response to imposed foraging constraints as reproduction progresses, while inter-annual trends could reflect their ability to match or mismatch the high energy demanding chick rearing period with the peak in availability of high-quality prey such as anchovy. Our findings underline the key advantages of using a stable isotope approach combined with conventional dietary reconstruction to

System performance and economic analysis of solar-assisted cooling/heating system

KAUST Repository

Huang, B.J.

2011-11-01

The long-term system simulation and economic analysis of solar-assisted cooling/heating system (SACH-2) was carried out in order to find an economical design. The solar heat driven ejector cooling system (ECS) is used to provide part of the cooling load to reduce the energy consumption of the air conditioner installed as the base-load cooler. A standard SACH-2 system for cooling load 3.5. kW (1. RT) and daily cooling time 10 h is used for case study. The cooling performance is assumed only in summer seasons from May to October. In winter season from November to April, only heat is supplied. Two installation locations (Taipei and Tainan) were examined.It was found from the cooling performance simulation that in order to save 50% energy of the air conditioner, the required solar collector area is 40m2 in Taipei and 31m2 in Tainan, for COPj=0.2. If the solar collector area is designed as 20m2, the solar ejector cooling system will supply about 17-26% cooling load in Taipei in summer season and about 21-27% cooling load in Tainan. Simulation for long-term performance including cooling in summer (May-October) and hot water supply in winter (November-April) was carried out to determine the monthly-average energy savings. The corresponding daily hot water supply (with 40°C temperature rise of water) for 20m2 solar collector area is 616-858L/day in Tainan and 304-533L/day in Taipei.The economic analysis shows that the payback time of SACH-2 decreases with increasing cooling capacity. The payback time is 4.8. years in Tainan and 6.2. years in Taipei when the cooling capacity >10. RT. If the ECS is treated as an additional device used as a protective equipment to avoid overheating of solar collectors and to convert the excess solar heat in summer into cooling to reduce the energy consumption of air conditioner, the payback time is less than 3 years for cooling capacity larger than 3. RT. © 2011 Elsevier Ltd.

Perennial wheat lines have highly admixed population structure and elevated rates of outcrossing.

Science.gov (United States)

Perennial wheat has been proposed to alleviate long standing issues with soil erosion in annual cropping systems, while supporting rural communities and providing grain farmers with a marketable climate-resilient crop. The Washington State University perennial wheat breeding program has created sev...

Perennial ryegrass for dairy cows: effects of cultivar on herbage intake during grazing

NARCIS (Netherlands)

Smit, H.J.

2005-01-01

Keywords:Perennial ryegrass, Lolium perenne , sward morphology, sward cutting, n-alkanes, herbage intake, selection, preference.Perennial ryegrass ( Lolium perenne L.) is the most important species for feeding dairy cows. The majority of the farmers in the Netherlands graze their

Seasonally dynamic diel vertical migrations of Mysis diluviana, coregonine fishes, and siscowet lake trout in the pelagia of western Lake Superior

Science.gov (United States)

Ahrenstorff, Tyler D.; Hrabik, Thomas R.; Stockwell, Jason D.; Yule, Daniel L.; Sass, Greg G.

2011-01-01

Diel vertical migrations are common among many aquatic species and are often associated with changing light levels. The underlying mechanisms are generally attributed to optimizing foraging efficiency or growth rates and avoiding predation risk (μ). The objectives of this study were to (1) assess seasonal and interannual changes in vertical migration patterns of three trophic levels in the Lake Superior pelagic food web and (2) examine the mechanisms underlying the observed variability by using models of foraging, growth, and μ. Our results suggest that the opossum shrimp Mysis diluviana, kiyi Coregonus kiyi, and siscowet lake trout Salvelinus namaycush migrate concurrently during each season, but spring migrations are less extensive than summer and fall migrations. In comparison with M. diluviana, kiyis, and siscowets, the migrations by ciscoes C. artedi were not as deep in the water column during the day, regardless of season. Foraging potential and μ probably drive the movement patterns of M. diluviana, while our modeling results indicate that movements by kiyis and ciscoes are related to foraging opportunity and growth potential and receive a lesser influence from μ. The siscowet is an abundant apex predator in the pelagia of Lake Superior and probably undertakes vertical migrations in the water column to optimize foraging efficiency and growth. The concurrent vertical movement patterns of most species are likely to facilitate nutrient transport in this exceedingly oligotrophic ecosystem, and they demonstrate strong linkages between predators and prey. Fishery management strategies should use an ecosystem approach and should consider how altering the densities of long-lived top predators produces cascading effects on the nutrient cycling and energy flow in lower trophic levels.

Geothermal heat can cool, too

International Nuclear Information System (INIS)

Wellstein, J.

2008-01-01

This article takes a look at how geothermal energy can not only be used to supply heating energy, but also be used to provide cooling too. The article reports on a conference on heating and cooling with geothermal energy that was held in Duebendorf, Switzerland, in March 2008. The influence of climate change on needs for heating and cooling and the need for additional knowledge and data on deeper rock layers is noted. The seasonal use of geothermal systems to provide heating in winter and cooling in summer is discussed. The planning of geothermal probe fields and their simulation is addressed. As an example, the geothermal installations under the recently renewed and extended 'Dolder Grand' luxury hotel in Zurich are quoted. The new SIA 384/6 norm on geothermal probes issued by the Swiss Association of Architects SIA is briefly reviewed.

Seasonal variations in the diet and foraging behaviour of dunlins Calidris alpina in a south European estuary: improved feeding conditions for northward migrants.

Directory of Open Access Journals (Sweden)

Ricardo C Martins

Full Text Available During the annual cycle, migratory waders may face strikingly different feeding conditions as they move between breeding areas and wintering grounds. Thus, it is of crucial importance that they rapidly adjust their behaviour and diet to benefit from peaks of prey abundance, in particular during migration, when they need to accumulate energy at a fast pace. In this study, we compared foraging behaviour and diet of wintering and northward migrating dunlins in the Tagus estuary, Portugal, by video-recording foraging birds and analysing their droppings. We also estimated energy intake rates and analysed variations in prey availability, including those that were active at the sediment surface. Wintering and northward migrating dunlins showed clearly different foraging behaviour and diet. In winter, birds predominantly adopted a tactile foraging technique (probing, mainly used to search for small buried bivalves, with some visual surface pecking to collect gastropods and crop bivalve siphons. Contrastingly, in spring dunlins generally used a visual foraging strategy, mostly to consume worms, but also bivalve siphons and shrimps. From winter to spring, we found a marked increase both in the biomass of invertebrate prey in the sediment and in the surface activity of worms and siphons. The combination of these two factors, together with the availability of shrimps in spring, most likely explains the changes in the diet and foraging behaviour of dunlins. Northward migrating birds took advantage from the improved feeding conditions in spring, achieving 65% higher energy intake rates as compared with wintering birds. Building on these results and on known daily activity budgets for this species, our results suggest that Tagus estuary provides high-quality feeding conditions for birds during their stopovers, enabling high fattening rates. These findings show that this large wetland plays a key role as a stopover site for migratory waders within the East

A Systematic Review of Perennial Staple Crops Literature Using Topic Modeling and Bibliometric Analysis

Science.gov (United States)

2016-01-01

Research on perennial staple crops has increased in the past ten years due to their potential to improve ecosystem services in agricultural systems. However, multiple past breeding efforts as well as research on traditional ratoon systems mean there is already a broad body of literature on perennial crops. In this review, we compare the development of research on perennial staple crops, including wheat, rice, rye, sorghum, and pigeon pea. We utilized the advanced search capabilities of Web of Science, Scopus, ScienceDirect, and Agricola to gather a library of 914 articles published from 1930 to the present. We analyzed the metadata in the entire library and in collections of literature on each crop to understand trends in research and publishing. In addition, we applied topic modeling to the article abstracts, a type of text analysis that identifies frequently co-occurring terms and latent topics. We found: 1.) Research on perennials is increasing overall, but individual crops have each seen periods of heightened interest and research activity; 2.) Specialist journals play an important role in supporting early research efforts. Research often begins within communities of specialists or breeders for the individual crop before transitioning to a more general scientific audience; 3.) Existing perennial agricultural systems and their domesticated crop material, such as ratoon rice systems, can provide a useful foundation for breeding efforts, accelerating the development of truly perennial crops and farming systems; 4.) Primary research is lacking for crops that are produced on a smaller scale globally, such as pigeon pea and sorghum, and on the ecosystem service benefits of perennial agricultural systems. PMID:27213283

Utilization of 15N in the sequence of mineral fertilizer - forage - animal - slurry - forage

International Nuclear Information System (INIS)

Peschke, H.

1981-01-01

After systematic application of 15 N-ammonium nitrate, the change of the dinuclidic composition and 15 N quantity was studied by isotope analysis of several open systems in the sequence mineral fertilizer - (soil) - forage - (animal) - slurry - (soil) - forage. The relative 15 N isotope frequency of 50 atom% in the mineral fertilizer declined to 12.2 to 21.4 atom% in the forage (beet, oats, hay) and went down to 3.15 atom% in the slurry of a dairy cow fed on this forage. Silage maize manured with the slurry of the dairy cow only showed 1.98 atom %, green oats grown after the silage maize on the same area was found to have 0.45 atom%. The 15 N quantity of 104.5 g N in the fertilizer gradually decreased to 41.6 g N in the forage, 30.5 g N in the slurry and 22.6 g N in the silage maize. The causes discussed are 15 N isotope dilution as qualitative factor and productive and unproductive N losses as quantitative factors. (author)

Germination of tropical forage seeds stored for six years in ambient and controlled temperature and humidity conditions in Thailand

Directory of Open Access Journals (Sweden)

Michael D. Hare

2018-01-01

Full Text Available The germination performances of fresh seed lots were determined for 5 tropical forage species: Mulato II hybrid brachiaria [Urochloa ruziziensis (syn. Brachiaria ruziziensis x U. decumbens (syn. B. decumbens x U. brizantha (syn. B. brizantha], Mombasa guinea [Megathyrsus maximus (syn. Panicum maximum], Tanzania guinea [M. maximus (syn. P. maximum], Ubon paspalum (Paspalum atratum and Ubon stylo (Stylosanthes guianensis, stored under ambient conditions in Thailand (mean monthly temperatures 23‒34 ºC; mean monthly relative humidity 40‒92% or in a cool room (18‒20 ºC and 50% relative humidity for up to 6 years. The first paper of this study showed all seeds, except unscarified Ubon stylo seed, were dead after a single year of storage in ambient conditions. This second paper shows that cool-room storage extended seed viability, but performance varied considerably between species. Germination percentage under laboratory conditions declined to below 50%, after 3 years storage for Mombasa guinea seed and Tanzania guinea seed, 4 years for Ubon paspalum seed and 4‒5 years for Mulato II seed. Ubon stylo seed maintained high germination for 5 years, in both cool-room storage (96% and ambient-room storage (84%. Apparent embryo dormancy in acid-scarified Mulato II seed steadily increased with time in cool-storage and this seed had to be acid-scarified again each year at the time of germination testing to overcome dormancy. Physical dormancy of Mulato II seeds, imposed by the tightly bound lemma and palea in unscarified seed, was not overcome by length of time in cool-storage and these seeds had to be acid-scarified to induce germination. Hardseeded percentage in Ubon stylo seed remained high throughout the study and could be overcome only by acid-scarification. The difficulties of maintaining acceptable seed germination percentages when storing forage seeds in the humid tropics are discussed.

The Performance of Early-Generation Perennial Winter Cereals at 21 Sites across Four Continents

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Richard C. Hayes

2018-04-01

Full Text Available A network of 21 experiments was established across nine countries on four continents and spanning both hemispheres, to evaluate the relative performance of early generation perennial cereal material derived from wheat, rye, and barley and to inform future breeding strategies. The experimental lines were grown in replicated single rows, and first year production and phenology characteristics as well as yield and persistence for up to three years were monitored. The study showed that the existing experimental material is all relatively short-lived (≤3 years, with environments that are milder in summer and winter generally conferring greater longevity. No pedigree was superior across this diverse network of sites although better performing lines at the higher latitude sites were generally derived from Thinopyrum intermedium. By contrast, at lower latitudes the superior lines were generally derived from Th. ponticum and Th. elongatum parentage. The study observed a poor relationship between year 1 performance and productivity in later years, highlighting the need for perennial cereal material with greater longevity to underpin future experimental evaluation, and the importance for breeding programs to emphasize post-year 1 performance in their selections. Hybrid lines derived from the tetraploid durum wheat generally showed greater longevity than derivatives of hexaploid wheat, highlighting potential for greater use of Triticum turgidum in perennial wheat breeding. We advocate a model in future breeding initiatives that develops perennial cereal genotypes for specific target environments rather than a generic product for one global market. These products may include a diversity of cultivars derived from locally adapted annual and perennial parents. In this scenario the breeding program may have access to only a limited range of adapted perennial grass parents. In other situations, such as at very high latitude environments, perennial crops derived

Moisture Concentration Variation of Silages Produced on Commercial Farms in the South-Central USA

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K. J. Han

2014-10-01

Full Text Available Preservation of forage crops as silage offers opportunity to avoid the high risk of rain-damaged hay in the humid south-central USA. Recent developments with baled silage or baleage make silage a less expensive option than typical chopped silage. Silage has been important in the region primarily for dairy production, but baleage has become an option for the more extensive beef cattle industry in the region. Silage samples submitted to the Louisiana State University Agricultural Center Forage Quality Lab from 2006 through 2013 were assessed for dry matter (DM and forage nutritive characteristics of chopped silage and baleage of the different forage types from commercial farms primarily in Louisiana and Mississippi. Of the 1,308 silage samples submitted, 1,065 were annual ryegrass (AR with small grains (SG, the warm-season annual (WA grasses, sorghums and pearl millet, and the warm-season perennial (WP grasses, bermudagrass and bahiagrass, providing the remaining samples. Concentration of DM was used to indicate an effective ensiling opportunity, and AR silage was more frequently within the target DM range than was the WA forage group. The AR samples also indicated a high-quality forage with average crude protein (CP of 130 g/kg and total digestible nutrient (TDN near 600 g/kg. The cooler winter weather at harvest apparently complicated harvest of SG silage with chopped SG silage lower in both CP and TDN (104 and 553 g/kg, respectively than either AR silage or baleage of SG (137 and 624 g/kg for CP and TDN, respectively. The hot, humid summer weather along with large stems and large forage quantities of the WA grasses and the inherently higher fiber concentration of WP grasses at harvest stage indicate that preservation of these forage types as silage will be challenging, although successful commercial silage samples of each forage type and preservation approach were included among samples of silages produced in the region.

Evaluation of Rgb-Based Vegetation Indices from Uav Imagery to Estimate Forage Yield in Grassland

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Lussem, U.; Bolten, A.; Gnyp, M. L.; Jasper, J.; Bareth, G.

2018-04-01

Monitoring forage yield throughout the growing season is of key importance to support management decisions on grasslands/pastures. Especially on intensely managed grasslands, where nitrogen fertilizer and/or manure are applied regularly, precision agriculture applications are beneficial to support sustainable, site-specific management decisions on fertilizer treatment, grazing management and yield forecasting to mitigate potential negative impacts. To support these management decisions, timely and accurate information is needed on plant parameters (e.g. forage yield) with a high spatial and temporal resolution. However, in highly heterogeneous plant communities such as grasslands, assessing their in-field variability non-destructively to determine e.g. adequate fertilizer application still remains challenging. Especially biomass/yield estimation, as an important parameter in assessing grassland quality and quantity, is rather laborious. Forage yield (dry or fresh matter) is mostly measured manually with rising plate meters (RPM) or ultrasonic sensors (handheld or mounted on vehicles). Thus the in-field variability cannot be assessed for the entire field or only with potential disturbances. Using unmanned aerial vehicles (UAV) equipped with consumer grade RGB cameras in-field variability can be assessed by computing RGB-based vegetation indices. In this contribution we want to test and evaluate the robustness of RGB-based vegetation indices to estimate dry matter forage yield on a recently established experimental grassland site in Germany. Furthermore, the RGB-based VIs are compared to indices computed from the Yara N-Sensor. The results show a good correlation of forage yield with RGB-based VIs such as the NGRDI with R2 values of 0.62.

Adaptive Bacterial Foraging Optimization

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Hanning Chen

2011-01-01

Full Text Available Bacterial Foraging Optimization (BFO is a recently developed nature-inspired optimization algorithm, which is based on the foraging behavior of E. coli bacteria. Up to now, BFO has been applied successfully to some engineering problems due to its simplicity and ease of implementation. However, BFO possesses a poor convergence behavior over complex optimization problems as compared to other nature-inspired optimization techniques. This paper first analyzes how the run-length unit parameter of BFO controls the exploration of the whole search space and the exploitation of the promising areas. Then it presents a variation on the original BFO, called the adaptive bacterial foraging optimization (ABFO, employing the adaptive foraging strategies to improve the performance of the original BFO. This improvement is achieved by enabling the bacterial foraging algorithm to adjust the run-length unit parameter dynamically during algorithm execution in order to balance the exploration/exploitation tradeoff. The experiments compare the performance of two versions of ABFO with the original BFO, the standard particle swarm optimization (PSO and a real-coded genetic algorithm (GA on four widely-used benchmark functions. The proposed ABFO shows a marked improvement in performance over the original BFO and appears to be comparable with the PSO and GA.

A transcriptome map of perennial ryegrass (Lolium perenne L.

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Studer Bruno

2012-04-01

Full Text Available Abstract Background Single nucleotide polymorphisms (SNPs are increasingly becoming the DNA marker system of choice due to their prevalence in the genome and their ability to be used in highly multiplexed genotyping assays. Although needed in high numbers for genome-wide marker profiles and genomics-assisted breeding, a surprisingly low number of validated SNPs are currently available for perennial ryegrass. Results A perennial ryegrass unigene set representing 9,399 genes was used as a reference for the assembly of 802,156 high quality reads generated by 454 transcriptome sequencing and for in silico SNP discovery. Out of more than 15,433 SNPs in 1,778 unigenes fulfilling highly stringent assembly and detection parameters, a total of 768 SNP markers were selected for GoldenGate genotyping in 184 individuals of the perennial ryegrass mapping population VrnA, a population being previously evaluated for important agronomic traits. A total of 592 (77% of the SNPs tested were successfully called with a cluster separation above 0.9. Of these, 509 (86% genic SNP markers segregated in the VrnA mapping population, out of which 495 were assigned to map positions. The genetic linkage map presented here comprises a total of 838 DNA markers (767 gene-derived markers and spans 750 centi Mogan (cM with an average marker interval distance of less than 0.9 cM. Moreover, it locates 732 expressed genes involved in a broad range of molecular functions of different biological processes in the perennial ryegrass genome. Conclusions Here, we present an efficient approach of using next generation sequencing (NGS data for SNP discovery, and the successful design of a 768-plex Illumina GoldenGate genotyping assay in a complex genome. The ryegrass SNPs along with the corresponding transcribed sequences represent a milestone in the establishment of genetic and genomics resources available for this species and constitute a further step towards molecular breeding

Linking extreme interannual changes in prey availability to foraging behaviour and breeding investment in a marine predator, the macaroni penguin.

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Cat Horswill

Full Text Available Understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. We documented the behavioural responses and breeding investment of macaroni penguins Eudyptes chrysolophus across five breeding seasons where local prey density changed by five-fold; from very low to highly abundant. When prey availability was low, foraging trips were significantly longer and extended overnight. Birds also foraged farther from the colony, potentially in order to reach more distant foraging grounds and allow for increased search times. These extended foraging trips were also linked to a marked decrease in fledgling weights, most likely associated with reduced rates of provisioning. Furthermore, by comparing our results with previous work on this population, it appears that lowered first-year survival rates associated, at least partially, with fledging masses were also evident for this cohort. This study integrates a unique set of prey density, predator behaviour and predator breeding investment data to highlight a possible behavioural mechanism linking perturbations in prey availability to population demography.

Linking extreme interannual changes in prey availability to foraging behaviour and breeding investment in a marine predator, the macaroni penguin.

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Horswill, Cat; Trathan, Philip N; Ratcliffe, Norman

2017-01-01

Understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. We documented the behavioural responses and breeding investment of macaroni penguins Eudyptes chrysolophus across five breeding seasons where local prey density changed by five-fold; from very low to highly abundant. When prey availability was low, foraging trips were significantly longer and extended overnight. Birds also foraged farther from the colony, potentially in order to reach more distant foraging grounds and allow for increased search times. These extended foraging trips were also linked to a marked decrease in fledgling weights, most likely associated with reduced rates of provisioning. Furthermore, by comparing our results with previous work on this population, it appears that lowered first-year survival rates associated, at least partially, with fledging masses were also evident for this cohort. This study integrates a unique set of prey density, predator behaviour and predator breeding investment data to highlight a possible behavioural mechanism linking perturbations in prey availability to population demography.

Direct control of perennial weeds between crops - Implication for organic farming

DEFF Research Database (Denmark)

Melander, Bo; Holst, Niels; Rasmussen, Ilse Ankjær

2012-01-01

and ending the strategy with mouldboard ploughing in the succeeding spring. Grain yields did not differ among the treatments in the two experiments as a result of the generally high effectiveness exerted by the control strategies. Especially post-harvest control strategies based on rotating weed devices...... and mouldboard ploughing appear to be effective solutions against mixed stands of perennials on sandy soils but they do not comply with optimal nutrient management in organic cropping. Therefore, intensive autumn cultivation is only relevant where a perennial weed problem is uncontrollable by other means.......Perennial weeds can be a major constraint to organic crop production and direct control actions applied between crops can then be necessary to reduce the problems. We conducted two experiments, one on a sandy loam and one on a sandy soil in Denmark, with the aim of studying the efficacy...

Activity time budget during foraging trips of emperor penguins.

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Shinichi Watanabe

Full Text Available We developed an automated method using depth and one axis of body acceleration data recorded by animal-borne data loggers to identify activities of penguins over long-term deployments. Using this technique, we evaluated the activity time budget of emperor penguins (n = 10 both in water and on sea ice during foraging trips in chick-rearing season. During the foraging trips, emperor penguins alternated dive bouts (4.8 ± 4.5 h and rest periods on sea ice (2.5 ± 2.3 h. After recorder deployment and release near the colony, the birds spent 17.9 ± 8.4% of their time traveling until they reached the ice edge. Once at the ice edge, they stayed there more than 4 hours before the first dive. After the first dive, the mean proportions of time spent on the ice and in water were 30.8 ± 7.4% and 69.2 ± 7.4%, respectively. When in the water, they spent 67.9 ± 3.1% of time making dives deeper than 5 m. Dive activity had no typical diurnal pattern for individual birds. While in the water between dives, the birds had short resting periods (1.2 ± 1.7 min and periods of swimming at depths shallower than 5 m (0.25 ± 0.38 min. When the birds were on the ice, they primarily used time for resting (90.3 ± 4.1% of time and spent only 9.7 ± 4.1% of time traveling. Thus, it appears that, during foraging trips at sea, emperor penguins traveled during dives >5 m depth, and that sea ice was primarily used for resting. Sea ice probably provides refuge from natural predators such as leopard seals. We also suggest that 24 hours of sunlight and the cycling of dive bouts with short rest periods on sea ice allow emperor penguins to dive continuously throughout the day during foraging trips to sea.

Introduced cool-season grasses in diversified systems of forage and feedstock production

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Interest in producing biomass feedstock for biorefineries has increased in the southern Great Plains, though research has largely focused on the potential function of biorefineries. This study examined feedstock production from the producers’ viewpoint, and how this activity might function within di...

Energy balance and cost-benefit analysis of biogas production from perennial energy crops pretreated by wet oxidation

DEFF Research Database (Denmark)

Uellendahl, Hinrich; Wang, Guangtao; Møller, Henrik B.

2008-01-01

Perennial crops need far less energy to plant, require less fertilizer and pesticides, and show a lower negative environmental impact compared with annual crops like for example corn. This makes the cultivation of perennial crops as energy crops more sustainable than the use of annual crops....... The conversion into biogas in anaerobic digestion plants shows however much lower specific methane yields for the raw perennial crops like miscanthus and willow due to their lignocellulosic structure. Without pretreatment the net energy gain is therefore lower for the perennials than for corn. When applying wet...... oxidation to the perennial crops, however, the specific methane yield increases significantly and the ratio of energy output to input and of costs to benefit for the whole chain of biomass supply and conversion into biogas becomes higher than for corn. This will make the use of perennial crops as energy...

Prescribed burning effects on summer elk forage availability in the subalpine zone, Banff National Park, Canada.

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Sachro, L L; Strong, W L; Gates, C C

2005-11-01

The effects of prescribed burning on forage abundance and suitability for elk (Cervus elaphus) during the snow-free season was evaluated in east-central Banff National Park, Canada. Six coniferous forest and mixed shrub-herb plant communities (n=144 plots), and 5223ha of burned (n=131) vegetation Burning coniferous forest stands reduced woody biomass, and increased herbaceous forage from 146 to 790 kg/ha. Increases commonly occurred in the percent cover of hairy wild rye (Leymus innovatus (Beal) Pigler) and fireweed (Chamerion angustifolium (L.) Holub.). The herbaceous components of mixed shrub-herb communities increased from 336-747 kg/ha to 517-1104 kg/ha in response to burning (Por=220% (Pburned vegetation-types were assessed as low and moderate, respectively. Potential summer carrying capacity, based on forage availability, increased from eight to 28 elk/100 km2 within burned areas, whereas spring grazing potential rose from 13 to 45 elk/100 km2. Most of the increase (73%) was attributable to changes within burned Engelmann Spruce stands, which composed 58% of the burned area.

Evidence of trapline foraging in honeybees.

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Buatois, Alexis; Lihoreau, Mathieu

2016-08-15

Central-place foragers exploiting floral resources often use multi-destination routes (traplines) to maximise their foraging efficiency. Recent studies on bumblebees have showed how solitary foragers can learn traplines, minimising travel costs between multiple replenishing feeding locations. Here we demonstrate a similar routing strategy in the honeybee (Apis mellifera), a major pollinator known to recruit nestmates to discovered food resources. Individual honeybees trained to collect sucrose solution from four artificial flowers arranged within 10 m of the hive location developed repeatable visitation sequences both in the laboratory and in the field. A 10-fold increase of between-flower distances considerably intensified this routing behaviour, with bees establishing more stable and more efficient routes at larger spatial scales. In these advanced social insects, trapline foraging may complement cooperative foraging for exploiting food resources near the hive (where dance recruitment is not used) or when resources are not large enough to sustain multiple foragers at once. © 2016. Published by The Company of Biologists Ltd.

Water Use and Water-Use Efficiency of Three Perennial Bioenergy Grass Crops in Florida

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Jerry M. Bennett

2012-10-01

Full Text Available Over two-thirds of human water withdrawals are estimated to be used for agricultural production, which is expected to increase as demand for renewable liquid fuels from agricultural crops intensifies. Despite the potential implications of bioenergy crop production on water resources, few data are available on water use of perennial bioenergy grass crops. Therefore, the objective of this study was to compare dry matter yield, water use, and water-use efficiency (WUE of elephantgrass, energycane, and giant reed, grown under field conditions for two growing seasons in North Central Florida. Using scaled sap flow sensor data, water use ranged from about 850 to 1150 mm during the growing season, and was generally greater for giant reed and less for elephantgrass. Despite similar or greater water use by giant reed, dry biomass yields of 35 to 40 Mg ha−1 were significantly greater for energycane and elephantgrass, resulting in greater WUE. Overall, water use by the bioenergy crops was greater than the rainfall received during the study, indicating that irrigation will be needed in the region to achieve optimal yields. Species differ in water use and WUE and species selection can play an important role with regard to potential consequences for water resources.

Boa constrictor (Boa constrictor): foraging behavior

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Sorrell, G.G.; Boback, M.S.; Reed, R.N.; Green, S.; Montgomery, Chad E.; DeSouza, L.S.; Chiaraviglio, M.

2011-01-01

Boa constrictor is often referred to as a sit-and-wait or ambush forager that chooses locations to maximize the likelihood of prey encounters (Greene 1983. In Janzen [ed.], Costa Rica Natural History, pp. 380-382. Univ. Chicago Press, Illinois). However, as more is learned about the natural history of snakes in general, the dichotomy between active versus ambush foraging is becoming blurred. Herein, we describe an instance of diurnal active foraging by a B. constrictor, illustrating that this species exhibits a range of foraging behaviors.

Visual Foraging With Fingers and Eye Gaze

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Ómar I. Jóhannesson

2016-03-01

Full Text Available A popular model of the function of selective visual attention involves search where a single target is to be found among distractors. For many scenarios, a more realistic model involves search for multiple targets of various types, since natural tasks typically do not involve a single target. Here we present results from a novel multiple-target foraging paradigm. We compare finger foraging where observers cancel a set of predesignated targets by tapping them, to gaze foraging where observers cancel items by fixating them for 100 ms. During finger foraging, for most observers, there was a large difference between foraging based on a single feature, where observers switch easily between target types, and foraging based on a conjunction of features where observers tended to stick to one target type. The pattern was notably different during gaze foraging where these condition differences were smaller. Two conclusions follow: (a The fact that a sizeable number of observers (in particular during gaze foraging had little trouble switching between different target types raises challenges for many prominent theoretical accounts of visual attention and working memory. (b While caveats must be noted for the comparison of gaze and finger foraging, the results suggest that selection mechanisms for gaze and pointing have different operational constraints.

Habitat-specific foraging strategies in Australasian gannets

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Melanie R. Wells

2016-07-01

Full Text Available Knowledge of top predator foraging adaptability is imperative for predicting their biological response to environmental variability. While seabirds have developed highly specialised techniques to locate prey, little is known about intraspecific variation in foraging strategies with many studies deriving information from uniform oceanic environments. Australasian gannets (Morus serrator typically forage in continental shelf regions on small schooling prey. The present study used GPS and video data loggers to compare habitat-specific foraging strategies at two sites of contrasting oceanographic regimes (deep water near the continental shelf edge, n=23; shallow inshore embayment, n=26, in south-eastern Australia. Individuals from the continental shelf site exhibited pelagic foraging behaviours typical of gannet species, using local enhancement to locate and feed on small schooling fish; in contrast only 50% of the individuals from the inshore site foraged offshore, displaying the typical pelagic foraging strategy. The remainder adopted a strategy of searching sand banks in shallow inshore waters in the absence of conspecifics and other predators for large, single prey items. Furthermore, of the individuals foraging inshore, 93% were male, indicating that the inshore strategy may be sex-specific. Large inter-colony differences in Australasian gannets suggest strong plasticity in foraging behaviours, essential for adapting to environmental change.

Growth and nutritional evaluation of napier grass hybrids as forage for ruminants

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Brian Turano

2016-09-01

Full Text Available Napier grass is a perennial, tropical C-4 grass that can produce large amounts of forage. However, low temperatures and drought stress limit its productivity and nutritive value as a forage. To overcome these limitations, pearl millet × napier grass hybrids (PMN were developed. It was hypothesized that PMN hybrids were more drought-tolerant, produced higher yields, and had higher nutritive value than napier grass varieties. The yield and nutritive value of 4 napier grass varieties (Bana grass, Mott, MB4 and N51 and 4 PMN hybrids (PMN2, PMN3, 5344 and 4604 were determined with or without irrigation in a strip plot design in Hawaii. Hybrid PMN3 outperformed napier grass varieties and the other hybrids for yield, while 5344 showed higher nutritional content and digestibility than most other grasses. Dry matter yields during the 110-day study period ranged from 10.3 to 32.1 t/ha without irrigation and 19.6 to 55.8 t/ha with irrigation, indicating that moisture stress was limiting performance in raingrown pastures. Only hybrids PMN3 and PMN2 and variety MB4 showed significant growth responses to irrigation. Further work is needed to evaluate the hybrids in a range of environments over much longer periods to determine if these preliminary results can be reproduced over the long term. Similarly, feeding studies with animals are needed to determine if the in vitro data for digestibility are reflected in superior performance for the promising hybrids.Keywords: Biomass, cattle, in vitro digestion, nutrient content, Pennisetum, tropical grasses.DOI: 10.17138/TGFT(4168-178

Seasonal diet and prey preference of the African lion in a waterhole-driven semi-arid savanna.

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Zeke Davidson

Full Text Available Large carnivores inhabiting ecosystems with heterogeneously distributed environmental resources with strong seasonal variations frequently employ opportunistic foraging strategies, often typified by seasonal switches in diet. In semi-arid ecosystems, herbivore distribution is generally more homogeneous in the wet season, when surface water is abundant, than in the dry season when only permanent sources remain. Here, we investigate the seasonal contribution of the different herbivore species, prey preference and distribution of kills (i.e. feeding locations of African lions in Hwange National Park, Zimbabwe, a semi-arid African savanna structured by artificial waterholes. We used data from 245 kills and 74 faecal samples. Buffalo consistently emerged as the most frequently utilised prey in all seasons by both male (56% and female (33% lions, contributing the most to lion dietary biomass. Jacobs' index also revealed that buffalo was the most intensively selected species throughout the year. For female lions, kudu and to a lesser extent the group "medium Bovidae" are the most important secondary prey. This study revealed seasonal patterns in secondary prey consumption by female lions partly based on prey ecology with browsers, such as giraffe and kudu, mainly consumed in the early dry season, and grazers, such as zebra and suids, contributing more to female diet in the late dry season. Further, it revealed the opportunistic hunting behaviour of lions for prey as diverse as elephants and mice, with elephants taken mostly as juveniles at the end of the dry season during droughts. Jacobs' index finally revealed a very strong preference for kills within 2 km from a waterhole for all prey species, except small antelopes, in all seasons. This suggested that surface-water resources form passive traps and contribute to the structuring of lion foraging behaviour.

Seasonal diet and prey preference of the African lion in a waterhole-driven semi-arid savanna.

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Davidson, Zeke; Valeix, Marion; Van Kesteren, Freya; Loveridge, Andrew J; Hunt, Jane E; Murindagomo, Felix; Macdonald, David W

2013-01-01

Large carnivores inhabiting ecosystems with heterogeneously distributed environmental resources with strong seasonal variations frequently employ opportunistic foraging strategies, often typified by seasonal switches in diet. In semi-arid ecosystems, herbivore distribution is generally more homogeneous in the wet season, when surface water is abundant, than in the dry season when only permanent sources remain. Here, we investigate the seasonal contribution of the different herbivore species, prey preference and distribution of kills (i.e. feeding locations) of African lions in Hwange National Park, Zimbabwe, a semi-arid African savanna structured by artificial waterholes. We used data from 245 kills and 74 faecal samples. Buffalo consistently emerged as the most frequently utilised prey in all seasons by both male (56%) and female (33%) lions, contributing the most to lion dietary biomass. Jacobs' index also revealed that buffalo was the most intensively selected species throughout the year. For female lions, kudu and to a lesser extent the group "medium Bovidae" are the most important secondary prey. This study revealed seasonal patterns in secondary prey consumption by female lions partly based on prey ecology with browsers, such as giraffe and kudu, mainly consumed in the early dry season, and grazers, such as zebra and suids, contributing more to female diet in the late dry season. Further, it revealed the opportunistic hunting behaviour of lions for prey as diverse as elephants and mice, with elephants taken mostly as juveniles at the end of the dry season during droughts. Jacobs' index finally revealed a very strong preference for kills within 2 km from a waterhole for all prey species, except small antelopes, in all seasons. This suggested that surface-water resources form passive traps and contribute to the structuring of lion foraging behaviour.

Foraging modality and plasticity in foraging traits determine the strength of competitive interactions among carnivorous plants, spiders and toads.

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Jennings, David E; Krupa, James J; Rohr, Jason R

2016-07-01

Foraging modalities (e.g. passive, sit-and-wait, active) and traits are plastic in some species, but the extent to which this plasticity affects interspecific competition remains unclear. Using a long-term laboratory mesocosm experiment, we quantified competition strength and the plasticity of foraging traits in a guild of generalist predators of arthropods with a range of foraging modalities. Each mesocosm contained eight passively foraging pink sundews, and we employed an experimental design where treatments were the presence or absence of a sit-and-wait foraging spider and actively foraging toad crossed with five levels of prey abundance. We hypothesized that actively foraging toads would outcompete the other species at low prey abundance, but that spiders and sundews would exhibit plasticity in foraging traits to compensate for strong competition when prey were limited. Results generally supported our hypotheses. Toads had a greater effect on sundews at low prey abundances, and toad presence caused spiders to locate webs higher above the ground. Additionally, the closer large spider webs were to the ground, the greater the trichome densities produced by sundews. Also, spider webs were larger with than without toads and as sundew numbers increased, and these effects were more prominent as resources became limited. Finally, spiders negatively affected toad growth only at low prey abundance. These findings highlight the long-term importance of foraging modality and plasticity of foraging traits in determining the strength of competition within and across taxonomic kingdoms. Future research should assess whether plasticity in foraging traits helps to maintain coexistence within this guild and whether foraging modality can be used as a trait to reliably predict the strength of competitive interactions. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

A generic model for estimating biomass accumulation and greenhouse gas emissions from perennial crops

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Ledo, Alicia; Heathcote, Richard; Hastings, Astley; Smith, Pete; Hillier, Jonathan

2017-04-01

Agriculture is essential to maintain humankind but is, at the same time, a substantial emitter of greenhouse gas (GHG) emissions. With a rising global population, the need for agriculture to provide secure food and energy supply is one of the main human challenges. At the same time, it is the only sector which has significant potential for negative emissions through the sequestration of carbon and offsetting via supply of feedstock for energy production. Perennial crops accumulate carbon during their lifetime and enhance organic soil carbon increase via root senescence and decomposition. However, inconsistency in accounting for this stored biomass undermines efforts to assess the benefits of such cropping systems when applied at scale. A consequence of this exclusion is that efforts to manage this important carbon stock are neglected. Detailed information on carbon balance is crucial to identify the main processes responsible for greenhouse gas emissions in order to develop strategic mitigation programs. Perennial crops systems represent 30% in area of total global crop systems, a considerable amount to be ignored. Furthermore, they have a major standing both in the bioenergy and global food industries. In this study, we first present a generic model to calculate the carbon balance and GHGs emissions from perennial crops, covering both food and bioenergy crops. The model is composed of two simple process-based sub-models, to cover perennial grasses and other perennial woody plants. The first is a generic individual based sub-model (IBM) covering crops in which the yield is the fruit and the plant biomass is an unharvested residue. Trees, shrubs and climbers fall into this category. The second model is a generic area based sub-model (ABM) covering perennial grasses, in which the harvested part includes some of the plant parts in which the carbon storage is accounted. Most second generation perennial bioenergy crops fall into this category. Both generic sub

A Bayesian modelling method for post-processing daily sub-seasonal to seasonal rainfall forecasts from global climate models and evaluation for 12 Australian catchments

Science.gov (United States)

Schepen, Andrew; Zhao, Tongtiegang; Wang, Quan J.; Robertson, David E.

2018-03-01

Rainfall forecasts are an integral part of hydrological forecasting systems at sub-seasonal to seasonal timescales. In seasonal forecasting, global climate models (GCMs) are now the go-to source for rainfall forecasts. For hydrological applications however, GCM forecasts are often biased and unreliable in uncertainty spread, and calibration is therefore required before use. There are sophisticated statistical techniques for calibrating monthly and seasonal aggregations of the forecasts. However, calibration of seasonal forecasts at the daily time step typically uses very simple statistical methods or climate analogue methods. These methods generally lack the sophistication to achieve unbiased, reliable and coherent forecasts of daily amounts and seasonal accumulated totals. In this study, we propose and evaluate a Rainfall Post-Processing method for Seasonal forecasts (RPP-S), which is based on the Bayesian joint probability modelling approach for calibrating daily forecasts and the Schaake Shuffle for connecting the daily ensemble members of different lead times. We apply the method to post-process ACCESS-S forecasts for 12 perennial and ephemeral catchments across Australia and for 12 initialisation dates. RPP-S significantly reduces bias in raw forecasts and improves both skill and reliability. RPP-S forecasts are also more skilful and reliable than forecasts derived from ACCESS-S forecasts that have been post-processed using quantile mapping, especially for monthly and seasonal accumulations. Several opportunities to improve the robustness and skill of RPP-S are identified. The new RPP-S post-processed forecasts will be used in ensemble sub-seasonal to seasonal streamflow applications.

Potential phytoextraction and phytostabilization of perennial peanut on copper-contaminated vineyard soils and copper mining waste.

Science.gov (United States)

Andreazza, Robson; Bortolon, Leandro; Pieniz, Simone; Giacometti, Marcelo; Roehrs, Dione D; Lambais, Mácio R; Camargo, Flávio A O

2011-12-01

This study sought to evaluate the potential of perennial peanut (Arachis pintoi) for copper phytoremediation in vineyard soils (Inceptisol and Mollisol) contaminated with copper and copper mining waste. Our results showed high phytomass production of perennial peanut in both vineyard soils. Macronutrient uptakes were not negatively affected by perennial peanut cultivated in all contaminated soils. Plants cultivated in Mollisol showed high copper concentrations in the roots and shoots of 475 and 52 mg kg(-1), respectively. Perennial peanut plants showed low translocation factor values for Cu, although these plants showed high bioaccumulation factor (BCF) for both vineyard soils, Inceptisol and Mollisol, with BCF values of 3.83 and 3.24, respectively, being characterized as a copper hyperaccumulator plant in these soils. Copper phytoextraction from Inceptisol soil was the highest for both roots and entire plant biomass, with more than 800 mg kg(-1) of copper in whole plant. The highest potential copper phytoextraction by perennial peanut was in Inceptisol soil with copper removal of 2,500 g ha(-1). Also, perennial peanut showed high potential for copper phytoremoval in copper mining waste and Mollisol with 1,700 and 1,500 g of copper per hectare, respectively. In addition, perennial peanuts characterized high potential for phytoextraction and phytostabilization of copper in vineyard soils and copper mining waste.

By the Light of the Moon: North Pacific Dolphins Optimize Foraging with the Lunar Cycle

Science.gov (United States)

Simonis, Anne Elizabeth

The influence of the lunar cycle on dolphin foraging behavior was investigated in the productive, southern California Current Ecosystem and the oligotrophic Hawaiian Archipelago. Passive acoustic recordings from 2009 to 2015 were analyzed to document the presence of echolocation from four dolphin species that demonstrate distinct foraging preferences and diving abilities. Visual observations of dolphins, cloud coverage, commercial landings of market squid (Doryteuthis opalescens) and acoustic backscatter of fish were also considered in the Southern California Bight. The temporal variability of echolocation is described from daily to annual timescales, with emphasis on the lunar cycle as an established behavioral driver for potential dolphin prey. For dolphins that foraged at night, the presence of echolocation was reduced during nights of the full moon and during times of night that the moon was present in the night sky. In the Southern California Bight, echolocation activity was reduced for both shallow- diving common dolphins (Delphinus delphis) and deeper-diving Risso's dolphins (Grampus griseus) during times of increased illumination. Seasonal differences in acoustic behavior for both species suggest a geographic shift in dolphin populations, shoaling scattering layers or prey switching behavior during warm months, whereby dolphins target prey that do not vertically migrate. In the Hawaiian Archipelago, deep-diving short-finned pilot whales (Globicephala macrorhynchus) and shallow-diving false killer whales (Pseudorca crassidens) also showed reduced echolocation behavior during periods of increased lunar illumination. In contrast to nocturnal foraging in the northwestern Hawaiian Islands, false killer whales in the main Hawaiian Islands mainly foraged during the day and the lunar cycle showed little influence on their nocturnal acoustic behavior. Different temporal patterns in false killer whale acoustic behavior between the main and northwestern Hawaiian

Interactions Increase Forager Availability and Activity in Harvester Ants.

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Evlyn Pless

Full Text Available Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the 'entrance chamber'. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated.

Forage-based dairying in a water-limited future: use of models to investigate farming system adaptation in southern Australia.

Science.gov (United States)

Chapman, D F; Dassanayake, K; Hill, J O; Cullen, B R; Lane, N

2012-07-01

The irrigated dairy industry in southern Australia has experienced significant restrictions in irrigation water allocations since 2005, consistent with climate change impact predictions for the region. Simulation models of pasture growth (DairyMod), crop yield (Agricultural Production Systems Simulator, APSIM), and dairy system management and production (UDDER) were used in combination to investigate a range of forage options that may be capable of sustaining dairy business profitability under restricted water-allocation scenarios in northern Victoria, Australia. A total of 23 scenarios were simulated and compared with a base farm system (100% of historical water allocations, grazed perennial ryegrass pasture with supplements; estimated operating surplus $A2,615/ha at a milk price of $A4.14/kg of milk solids). Nine simulations explored the response of the base farm to changes in stocking rate or the implementation of a double cropping rotation on 30% of farm area, or both. Five simulations explored the extreme scenario of dairying without any irrigation water. Two general responses to water restrictions were investigated in a further 9 simulations. Annual ryegrass grazed pasture, complemented by a double cropping rotation (maize grown in summer for silage, followed by either brassica forage crop and annual ryegrass for silage in winter and spring) on 30% of farm area, led to an estimated operating surplus of $A1746/ha at the same stocking rate as the base farm when calving was moved to autumn (instead of late winter, as in the base system). Estimated total irrigation water use was 2.7ML/ha compared with 5.4ML/ha for the base system. Summer-dormant perennial grass plus double cropping (30% of farm area) lifted operating surplus by a further $A100/ha if associated with autumn calving (estimated total irrigation water use 3.1ML/ha). Large shifts in the forage base of dairy farms could sustain profitability in the face of lower, and fluctuating, water allocations

Utilization of /sup 15/N in the sequence of mineral fertilizer - forage - animal - slurry - forage

Energy Technology Data Exchange (ETDEWEB)

Peschke, H [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Pflanzenproduktion

1981-12-01

After systematic application of /sup 15/N-ammonium nitrate, the change of the dinuclidic composition and /sup 15/N quantity was studied by isotope analysis of several open systems in the sequence mineral fertilizer - (soil) - forage - (animal) - slurry - (soil) - forage. The relative /sup 15/N isotope frequency of 50 atom% in the mineral fertilizer declined to 12.2 to 21.4 atom% in the forage (beet, oats, hay) and went down to 3.15 atom% in the slurry of a dairy cow fed on this forage. Silage maize manured with the slurry of the dairy cow only showed 1.98 atom %, green oats grown after the silage maize on the same area was found to have 0.45 atom%. The /sup 15/N quantity of 104.5 g N in the fertilizer gradually decreased to 41.6 g N in the forage, 30.5 g N in the slurry and 22.6 g N in the silage maize. The causes discussed are /sup 15/N isotope dilution as qualitative factor and productive and unproductive N losses as quantitative factors.

Mapping the temporary and perennial character of whole river networks

Science.gov (United States)

González-Ferreras, A. M.; Barquín, J.

2017-08-01

Knowledge of the spatial distribution of temporary and perennial river channels in a whole catchment is important for effective integrated basin management and river biodiversity conservation. However, this information is usually not available or is incomplete. In this study, we present a statistically based methodology to classify river segments from a whole river network (Deva-Cares catchment, Northern Spain) as temporary or perennial. This method is based on an a priori classification of a subset of river segments as temporary or perennial, using field surveys and aerial images, and then running Random Forest models to predict classification membership for the rest of the river network. The independent variables and the river network were derived following a computer-based geospatial simulation of riverine landscapes. The model results show high values of overall accuracy, sensitivity, and specificity for the evaluation of the fitted model to the training and testing data set (≥0.9). The most important independent variables were catchment area, area occupied by broadleaf forest, minimum monthly precipitation in August, and average catchment elevation. The final map shows 7525 temporary river segments (1012.5 km) and 3731 perennial river segments (662.5 km). A subsequent validation of the mapping results using River Habitat Survey data and expert knowledge supported the validity of the proposed maps. We conclude that the proposed methodology is a valid method for mapping the limits of flow permanence that could substantially increase our understanding of the spatial links between terrestrial and aquatic interfaces, improving the research, management, and conservation of river biodiversity and functioning.

Dynamics of initial colonization of nonconserved perennial ryegrass by anaerobic fungi in the bovine rumen.

Science.gov (United States)

Edwards, Joan E; Kingston-Smith, Alison H; Jimenez, Hugo R; Huws, Sharon A; Skøt, Kirsten P; Griffith, Gareth W; McEwan, Neil R; Theodorou, Michael K

2008-12-01

Anaerobic fungi (Neocallimastigales) are active degraders of fibrous plant material in the rumen. However, only limited information is available relating to how quickly they colonize ingested feed particles. The aim of this study was to determine the dynamics of initial colonization of forage by anaerobic fungi in the rumen and the impact of different postsampling wash procedures used to remove loosely associated microorganisms. Neocallimastigales-specific molecular techniques were optimized to ensure maximal coverage before application to assess the population size (quantitative PCR) and composition (automated ribosomal intergenic spacer analysis) of the colonizing anaerobic fungi. Colonization of perennial ryegrass (PRG) was evident within 5 min, with no consistent effect of time or wash procedure on fungal population composition. Wash procedure had no effect on population size unlike time, which had a significant effect. Colonizing fungal population size continued to increase over the incubation period after an initial lag of c. 4 min. This dynamic differs from that reported previously for rumen bacteria, where substantial colonization of PRG occurred within 5 min. The observed delay in colonization of plant material by anaerobic fungi is suggested to be primarily mediated by the time taken for fungal zoospores to locate, attach and encyst on plant material.

A Bayesian modelling method for post-processing daily sub-seasonal to seasonal rainfall forecasts from global climate models and evaluation for 12 Australian catchments

Directory of Open Access Journals (Sweden)

A. Schepen

2018-03-01

Full Text Available Rainfall forecasts are an integral part of hydrological forecasting systems at sub-seasonal to seasonal timescales. In seasonal forecasting, global climate models (GCMs are now the go-to source for rainfall forecasts. For hydrological applications however, GCM forecasts are often biased and unreliable in uncertainty spread, and calibration is therefore required before use. There are sophisticated statistical techniques for calibrating monthly and seasonal aggregations of the forecasts. However, calibration of seasonal forecasts at the daily time step typically uses very simple statistical methods or climate analogue methods. These methods generally lack the sophistication to achieve unbiased, reliable and coherent forecasts of daily amounts and seasonal accumulated totals. In this study, we propose and evaluate a Rainfall Post-Processing method for Seasonal forecasts (RPP-S, which is based on the Bayesian joint probability modelling approach for calibrating daily forecasts and the Schaake Shuffle for connecting the daily ensemble members of different lead times. We apply the method to post-process ACCESS-S forecasts for 12 perennial and ephemeral catchments across Australia and for 12 initialisation dates. RPP-S significantly reduces bias in raw forecasts and improves both skill and reliability. RPP-S forecasts are also more skilful and reliable than forecasts derived from ACCESS-S forecasts that have been post-processed using quantile mapping, especially for monthly and seasonal accumulations. Several opportunities to improve the robustness and skill of RPP-S are identified. The new RPP-S post-processed forecasts will be used in ensemble sub-seasonal to seasonal streamflow applications.

Energy-conserving perennial agriculture for marginal land in southern Appalachia. Final technical report

Energy Technology Data Exchange (ETDEWEB)

Williams, G.

1982-01-30

USDA economists predict the end of surplus farm production in the US within this decade. More and more marginal land will be cropped to provide feed for the growing world population and to produce energy. Much of this potential cropland in Southern Appalachia is poorly suited to annual crops, such as corn. Perennial crops are much better suited to steep, rocky, and wet sites. Research was undertaken on the theoretical potentials of perennial species with high predicted yields of protein, carbohydrates, or oils. Several candidate staple perennial crops for marginal land in Southern Appalachia were identified, and estimates were made of their yields, energy input requirements, and general suitabilities. Cropping systems incorporating honeylocust, persimmon, mulberry, jujube, and beech were compared with corn cropping systems. It appears that these candidate staple perennials show distinct advantages for energy conservation and environmental preservation. Detailed economic analyses must await actual demonstration trials, but preliminary indications for ethanol conversion systems with honeylocust are encouraging. It is suggested that short-term loans to farmers undertaking this new type of agriculture would be appropriate to solve cash-flow problems.

Forage production and growing goats’ response under silvopastoral systems based on Guazuma ulmifolia, Leucaena leucocephala and Crescentia cujete

OpenAIRE

Gustavo Rodríguez Fernández; Belisario Roncallo Fandiño

2013-01-01

Grass monoculture, besides being unnatural to goat’s natural eating habits, exhibits low forage production during the dry season, with negative impacts on animal productivity. This research aimed to determine the productive advantages of silvopastoral system arrangements in goat production. A completely randomized design with repeated measurements through time was used. Six treatments were evaluated: kikuyina grass monoculture (Bothriochloa per...

The Forecasting of Adaptation Potential of Herbaceous Perennials

Directory of Open Access Journals (Sweden)

Belykh, O. A.

2013-04-01

Full Text Available This work investigates the problem of the ecobiomorph productive features formation of perennial herbs Ranunculaceae family forecasting on the basis of quantitative connections of species parameters with the leading geomorphological factors of South Siberia environment.

Produção de forragem em pastagens consorciadas com diferentes leguminosas sob pastejo rotacionado = Forage production in pasture-based systems mixed with different legumes under rotational grazing

Directory of Open Access Journals (Sweden)

Edilene Steinwandter

2009-04-01

Full Text Available O objetivo desta pesquisa foi avaliar dois sistemas forrageiros, constituídos por capim-elefante, azevém, trevo branco ou amendoim forrageiro e espécies de crescimento espontâneo, quanto às taxas de acúmulo e de desaparecimento de MS. Para avaliação utilizaram-se quatro piquetes, com 0,25 ha cada um, com capim-elefante estabelecido em linhas afastadas a cada 4 m. No período hibernal, entre as linhas do capim-elefante, fez-se o estabelecimento do azevém; em dois piquetes foi semeado o trevo branco e nos demais se preservou o amendoim forrageiro. O delineamento experimental utilizado foi inteiramente casualizado. Para a determinação das taxas de acúmulo e de desaparecimento de MS, avaliaram-se as massas de forragem de pré e pós-pastejo. Foram avaliadas a composição botânica e estrutural da pastagem e a lotação. Na média, as taxas de acúmulo e dedesaparecimento da MS e a lotação foram de 47,29 kg de MS ha-1 dia-1; 3,24% e 3,01 UA ha-1 e de 53,16 kg de MS ha-1 dia-1; 3,45% e 3,48 UA ha-1 para os sistemas constituídos por trevo branco e por amendoim forrageiro, respectivamente. Considerando-se a taxa de acúmulo deMS, a MS desaparecida e a lotação, os resultados demonstram melhores resultados para o sistema forrageiro constituído pelo amendoim forrageiro.The objective of this research was to evaluate two pasture-based systems, with elephantgrass, ryegrass, white clover or forage peanut and spontaneous growth species about the accumulation rate and of disappearance of forage mass. The elephantgrass was established in rows with a distance of 4 m between rows. In the cool season, ryegrass was planted between rows of elephantgrass; white clover wassowed,in two paddocks, and in the other two the forage peanut was preserved. The experimental design was completely randomized. In order to stipulate the accumulation rate and of disappearance of forage mass, the pre- and post-graze forage mass were evaluated.The botanical and

Effects of tidal cycles on shorebird distribution and foraging behaviour in a coastal tropical wetland: Insights for carrying capacity assessment

Science.gov (United States)

Fonseca, Juanita; Basso, Enzo; Serrano, David; Navedo, Juan G.

2017-11-01

Wetland loss has driven negative effects on biodiversity by a reduction in potential available habitats, directly impacting wetland-dependent species such as migratory shorebirds. At coastal areas where tidal cycles can restrict food access, the degree to which density of foraging birds is mediated by conspecific abundance or by the available areas is crucial to understanding patterns of bird distribution and wetland carrying capacity. We used the bathymetry of two sectors modeled with two numerical matrices to determine the availability of intertidal foraging areas in relation to tidal level (spring and neap tides), and this information was used to estimate shorebird density and foraging activity throughout the low-tide cycle in a tropical coastal lagoon in northwestern Mexico. Relative to spring tides, an 80% reduction in available foraging areas occurred during neap tides. Overall shorebird abundance was significantly reduced during neap tide periods, with differences between species. Densities of shorebirds increased during neap tides, particularly in one sector, and remained similar throughout the low-tide period (i.e. 4 h) either during spring or neap tides. Time spent foraging was consistently lower during neap-tides relative to spring-tides, especially for Long-billed curlew (44% reduction), Willet (37% reduction) and Black-necked stilt (29% reduction). These decreases in foraging activity when available habitats became reduced can hamper the opportunities of migratory shorebirds to reach their daily energy requirements to survive during the non-breeding season. This study shows that when intertidal habitats are severely reduced an important fraction of shorebird populations would probably be forced to find alternative areas to forage or increase foraging time during the night. Serving an essential function as top-predators, these results can have important implications on carrying capacity assessment for shorebirds at coastal wetlands.

Environmental DNA (eDNA) Detection Probability Is Influenced by Seasonal Activity of Organisms.

Science.gov (United States)

de Souza, Lesley S; Godwin, James C; Renshaw, Mark A; Larson, Eric

2016-01-01

Environmental DNA (eDNA) holds great promise for conservation applications like the monitoring of invasive or imperiled species, yet this emerging technique requires ongoing testing in order to determine the contexts over which it is effective. For example, little research to date has evaluated how seasonality of organism behavior or activity may influence detection probability of eDNA. We applied eDNA to survey for two highly imperiled species endemic to the upper Black Warrior River basin in Alabama, US: the Black Warrior Waterdog (Necturus alabamensis) and the Flattened Musk Turtle (Sternotherus depressus). Importantly, these species have contrasting patterns of seasonal activity, with N. alabamensis more active in the cool season (October-April) and S. depressus more active in the warm season (May-September). We surveyed sites historically occupied by these species across cool and warm seasons over two years with replicated eDNA water samples, which were analyzed in the laboratory using species-specific quantitative PCR (qPCR) assays. We then used occupancy estimation with detection probability modeling to evaluate both the effects of landscape attributes on organism presence and season of sampling on detection probability of eDNA. Importantly, we found that season strongly affected eDNA detection probability for both species, with N. alabamensis having higher eDNA detection probabilities during the cool season and S. depressus have higher eDNA detection probabilities during the warm season. These results illustrate the influence of organismal behavior or activity on eDNA detection in the environment and identify an important role for basic natural history in designing eDNA monitoring programs.

Individual lifetime pollen and nectar foraging preferences in bumble bees

Science.gov (United States)

Hagbery, Jessica; Nieh, James C.

2012-10-01

Foraging specialization plays an important role in the ability of social insects to efficiently allocate labor. However, relatively little is known about the degree to which individual bumble bees specialize on collecting nectar or pollen, when such preferences manifest, and if individuals can alter their foraging preferences in response to changes in the colony workforce. Using Bombus impatiens, we monitored all foraging visits made by every bee in multiple colonies and showed that individual foragers exhibit consistent lifetime foraging preferences. Based upon the distribution of foraging preferences, we defined three forager types (pollen specialists, nectar specialists, and generalists). In unmanipulated colonies, 16-36 % of individuals specialized (≥90 % of visits) on nectar or pollen only. On its first day of foraging, an individual's foraging choices (nectar only, pollen only, or nectar and pollen) significantly predicted its lifetime foraging preferences. Foragers that only collected pollen on their first day of foraging made 1.61- to 1.67-fold more lifetime pollen foraging visits (as a proportion of total trips) than foragers that only collected nectar on their first foraging day. Foragers were significantly larger than bees that stayed only in the nest. We also determined the effect of removing pollen specialists at early (brood present) or later (brood absent) stages in colony life. These results suggest that generalists can alter their foraging preferences in response to the loss of a small subset of foragers. Thus, bumble bees exhibit individual lifetime foraging preferences that are established early in life, but generalists may be able to adapt to colony needs.

Optimal design and application of a compound cold storage system combining seasonal ice storage and chilled water storage

NARCIS (Netherlands)

Yan, C.; Shi, W.; Li, X.; Zhao, Y.

2016-01-01

Seasonal cold storage using natural cold sources for cooling is a sustainable cooling technique. However, this technique suffers from limitations such as large storage space and poor reliability. Combining seasonal storage with short-term storage might be a promising solution while it is not

Can reduced stocking rates and natural forage utilization produce market sized catfish from fingerlings in one growing season

Science.gov (United States)

The purpose of this study was to determine the feasibility of growing marketable channel catfish Ictalurus punctatus from pond-run fingerlings (15.9 g/fish) using low stocking densities (7,413 or 14,826 fish/ha) and electrified bug lights to enhance natural forage available to fish. Even at low sto...

Agronomic and forage characteristics of Guazuma ulmifolia Lam.

OpenAIRE

Manríquez-Mendoza, Leonor Yalid; López-Ortíz, Silvia; Pérez-Hernández, Ponciano; Ortega- Jiménez, Eusebio; López-Tecpoyotl, Zenón Gerardo; Villarruel-Fuentes, Manuel

2011-01-01

Native trees are an important source of forage for livestock, particularly in regions having prolonged dry periods. Some tree species have fast growth rates, good nutritional quality, and the ability to produce forage during dry periods when the need for forage is greater. Guazuma ulmifolia Lam. is a tree native to tropical America that has a high forage potential. This species is mentioned in a number of studies assessing the forage potential of trees in a diverse array of environments and v...

Effect of Nitrogen Rate on Quantitative and Qualitative Forage Yield of Maize, Pearl Millet and Sorghum in Double Cropping System

Directory of Open Access Journals (Sweden)

sh Khalesro

2012-02-01

Full Text Available Abstract In order to compare three summer forage grasses including sorghum (Sorghum bicolor cv. Speedfeed, corn (Zea mayz S.C. 704 and pearl millet (Pennisetum americanum cv. Nutrifeed for green chop forage production in double cropping system, a field experiment was conducted at research field of Tarbiat Modares University on 2006 growing season. Treatments were arranged in a split- plot design based on randomized complete blocks with four replications. In this research three forage crops as main factor and nitrogen rates (100, 200 and 300 kg N. ha-1 from the urea source as the sub- plot were studied. Results showed the positive response of crops to nitrogen increment, in such a manner that millet with 300 kg N ha-1 produced 85.8 t ha-1 fresh forage (%20.3 more than sorghum and %30.9 more than corn. Regarding to the sustainable agriculture objects, millet and sorghum with 200 kg N ha-1could be suggested. Forage yield advantages of millet and sorghum to corn was %10 and %12 respectively. They produce 72.4 and 73.5 t ha-1 fresh forage under this treatment. Finally regarding to general advantages of sorghum and millet to corn, especially in unsuitable condition like as drought and poor soil fertility, it seems that changing the corn with sorghum or pearl millet could be an appropriate option. Also decision making for recommending one of sorghum and millet need to more information like qualitative attributes in details and determining animal feeding indices (voluntary intake using in vivo methods. Keywords: Sorghum, Pearl millet, Corn, Nitrogen, Forage, Organic matter, Crud protein

Tracking Changes in Dissolved Organic Matter Patterns in Perennial Headwater Streams Throughout a Hydrologic Year Using In-situ Sensors and Optical Properties

Science.gov (United States)

Armstrong, A.; Epting, S.; Hosen, J. D.; Palmer, M.

2015-12-01

Dissolved organic matter (DOM) plays a central role in freshwater streams but key questions remain unanswered about temporal patterns in its quantity and composition. DOM in perennial streams in the temperate zone is a complex mixture reflecting a variety of sources such as leached plant material, organic matter from surrounding soils, and microbial processes in the streams themselves. Headwater perennial streams in the Tuckahoe Creek watershed of the Atlantic coastal plain (Maryland, USA) drain a mosaic of land cover types including row crops, forests, and both forested and marshy small depressional wetlands. Wetland-stream surface hydrologic connections generally occur between mid-fall and late spring, coinciding with peak wetland hydrologic expression (i.e. highest groundwater levels and surface inundation extent). When inundated, these wetlands contain high DOM concentrations, and surface connections may serve as conduits for downstream export. We hypothesized that changes in wetland-stream surface hydrologic connectivity would affect patterns of DOM concentration and composition in these streams. We deployed 6 sondes equipped with fluorescent DOM sensors in 4 perennial streams, 1 forested wetland, and the larger downstream channel draining all study sites for the 2015 water year. The 4 headwater streams drain areas containing forested wetlands and have documented temporary channel connections. Combined with baseflow and stormflow sampling, the sondes provided 15 minute estimates of dissolved organic carbon (DOC) concentrations. This resolution provided insights into patterns of DOC concentration across temporal scales from daily rhythms to seasonal changes, during both baseflow and storm conditions. Discrete measurements of absorbance and fluorescence provided information about DOM composition throughout the study. Together these measurements give a detailed record of DOM dynamics in multiple perennial headwater streams for an entire year. This information

Effects of chicory/perennial ryegrass swards compared with perennial ryegrass swards on the performance and carcass quality of grazing beef steers.

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Christina L Marley

Full Text Available An experiment investigated whether the inclusion of chicory (Cichorium intybus in swards grazed by beef steers altered their performance, carcass characteristics or parasitism when compared to steers grazing perennial ryegrass (Lolium perenne. Triplicate 2-ha plots were established with a chicory/ryegrass mix or ryegrass control. Forty-eight Belgian Blue-cross steers were used in the first grazing season and a core group (n = 36 were retained for finishing in the second grazing season. The experiment comprised of a standardisation and measurement period. During standardisation, steers grazed a ryegrass/white clover pasture as one group. Animals were allocated to treatment on the basis of liveweight, body condition and faecal egg counts (FEC determined 7 days prior to the measurement period. The measurement period ran from 25 May until 28 September 2010 and 12 April until 11 October 2011 in the first and second grazing year. Steers were weighed every 14 days at pasture or 28 days during housing. In the first grazing year, faecal samples were collected for FEC and parasite cultures. At the end of the first grazing year, individual blood samples were taken to determine O. ostertagi antibody and plasma pepsinogen levels. During winter, animals were housed as one group and fed silage. In the second grazing year, steers were slaughtered when deemed to reach fat class 3. Data on steer performance showed no differences in daily live-weight gain which averaged 1.04 kg/day. The conformation, fat grade and killing out proportion of beef steers grazing chicory/ryegrass or ryegrass were not found to differ. No differences in FEC, O. ostertagi antibody or plasma pepsinogen levels of beef steers grazing either chicory/ryegrass or ryegrass were observed. Overall, there were no detrimental effects of including chicory in swards grazed by beef cattle on their performance, carcass characteristics or helminth parasitism, when compared with steers grazing ryegrass.

Seasonal cycles of pelagic production and consumption

Science.gov (United States)

Longhurst, Alan

Comprehensive seasonal cycles of production and consumption in the pelagial require the ocean to be partitioned. This can be done rationally at two levels: into four primary ecological domains (three oceanic and one coastal), or about fifty biogeochemical provinces. The domains differ in their characteristic seasonal cycles of stability, nutrient supply and illumination, while provinces are defined by ocean currents, fronts, topography and recurrent features in the sea surface chlorophyll field. For each of these compartments, seasonal cycles of photic depth, primary production and accumulation (or loss) of algal biomass were obtained from the climatological CZCS chlorophyll field and other data and these, together with mixed layer depths, rendered characteristic seasonal cycles of production and consumption, which can be grouped into eight models: i - polar irradiance-mediated production peak; ii - nutrient-limited spring production peak; iii - winter-spring production with nutrient limitation; iv - small amplitude response to trade wind seasonality; v - large amplitude response to monsoon reversal; vi - canonical spring-fall blooms of mid-latitude continental shelves; vii - topography-forced summer production; viii - intermittent production at coastal divergences. For higher latitudes, these models suggest that the observed late-summer ‘blooms’ result not from a renewal of primary production rate, but from a relaxation of grazing pressure; in mid-latitudes, the observed ‘winter’ bloom represents chlorophyll accumulation at a season when loss terms are apparently smaller than during the period of peak primary production rate which occurs later, in spring. Where an episodic seasonal increase in rate of primary production occurs, as in the Arabian Sea, algal biomass accumulation may brief, lasting only until consumption is fully re-established. Only in the low latitude oligotrophic ocean are production and consumption perennially and closely coupled.

Ionomics: Genes and QTLs controlling heavy metal uptake in perennial grasses grown on phytoxic soil

Science.gov (United States)

Perennial grasses occupy diverse soils throughout the world, including many sites contaminated with heavy metals. Uncovering the genetic architecture of QTLs controlling mineral homoeostasis is critical for understanding the biochemical pathways that determine the elemental profiles of perennial pl...

Simulated Optimum Sowing Date for Forage Pearl Millet Cultivars in Multilocation Trials in Brazilian Semi-Arid Region.

Science.gov (United States)

Santos, Rafael D; Boote, Kenneth J; Sollenberger, Lynn E; Neves, Andre L A; Pereira, Luiz G R; Scherer, Carolina B; Gonçalves, Lucio C

2017-01-01

Forage production is primarily limited by weather conditions under dryland production systems in Brazilian semi-arid regions, therefore sowing at the appropriate time is critical. The objectives of this study were to evaluate the CSM-CERES-Pearl Millet model from the DSSAT software suite for its ability to simulate growth, development, and forage accumulation of pearl millet [ Pennisetum glaucum (L.) R.] at three Brazilian semi-arid locations, and to use the model to study the impact of different sowing dates on pearl millet performance for forage. Four pearl millet cultivars were grown during the 2011 rainy season in field experiments conducted at three Brazilian semi-arid locations, under rainfed conditions. The genetic coefficients of the four pearl millet cultivars were calibrated for the model, and the model performance was evaluated with experimental data. The model was run for 14 sowing dates using long-term historical weather data from three locations, to determine the optimum sowing window. Results showed that performance of the model was satisfactory as indicated by accurate simulation of crop phenology and forage accumulation against measured data. The optimum sowing window varied among locations depending on rainfall patterns, although showing the same trend for cultivars within the site. The best sowing windows were from 15 April to 15 May for the Bom Conselho location; 12 April to 02 May for Nossa Senhora da Gloria; and 17 April to 25 May for Sao Bento do Una. The model can be used as a tool to evaluate the effect of sowing date on forage pearl millet performance in Brazilian semi-arid conditions.

Transgenic perennial biofuel feedstocks and strategies for bioconfinement

Science.gov (United States)

The use of transgenic tools for the improvement of plant feedstocks will be required to realize the full economic and environmental benefits of cellulosic and other biofuels, particularly from perennial plants. Traits that are targets for improvement of biofuels crops include he...

BEE FORAGE MAPPING BASED ON MULTISPECTRAL IMAGES LANDSAT

Directory of Open Access Journals (Sweden)

A. Moskalenko

2016-10-01

Full Text Available Possibilities of bee forage identification and mapping based on multispectral images have been shown in the research. Spectral brightness of bee forage has been determined with the use of satellite images. The effectiveness of some methods of image classification for mapping of bee forage is shown. Keywords: bee forage, mapping, multispectral images, image classification.