5,245 results for Lincoln University Research Archive

  • Lineage overwhelms environmental conditions in determining rhizosphere bacterial community structure in a cosmopolitan invasive plant

    Bowen, J. L.; Kearns, P. J.; Byrnes, J. E. K.; Wigginton, S.; Allen, Warwick; Greenwood, M.; Tran, K.; Yu, J.; Cronin, J. T.; Meyerson, L. A.

    Journal article
    Lincoln University

    Plant–microbe interactions play crucial roles in species invasions but are rarely investigated at the intraspecific level. Here, we study these interactions in three lineages of a globally distributed plant, Phragmites australis. We use field surveys and a common garden experiment to analyze bacterial communities in the rhizosphere of P. australis stands from native, introduced, and Gulf lineages to determine lineage-specific controls on rhizosphere bacteria. We show that within-lineage bacterial communities are similar, but are distinct among lineages, which is consistent with our results in a complementary common garden experiment. Introduced P. australis rhizosphere bacterial communities have lower abundances of pathways involved in antimicrobial biosynthesis and degradation, suggesting a lower exposure to enemy attack than native and Gulf lineages. However, lineage and not rhizosphere bacterial communities dictate individual plant growth in the common garden experiment. We conclude that lineage is crucial for determination of both rhizosphere bacterial communities and plant fitness.

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  • Are faecal egg counts approaching their 'sell-by' date?

    Greer, Andrew W.; Sykes, Andrew R.

    Conference Contribution - Published
    Lincoln University

    Historically, the primary determinant for the state of parasitism has been the concentration of nematode eggs in the faeces (FEC). This descriptor has a number of limitations that have implications for the development of drug resistance and hamper the identification of resilient livestock. A major fallacy is that FEC can reliably assess the worm burden, the need for anthelmintic and the efficacy of that treatment. FEC is a ratio, eggs per gram of faeces, not a quantity. Not only is the denominator ignored but interpretation of the numerator requires knowledge of nematode species present and female fecundity which can be affected by infra-population dynamics. By definition, a parasite exists at the expense of its host. As such, the consistent ability of resilient animals to maintain performance, despite a high FEC, strongly suggests that FEC does not provide a reliable indicator of the cost of parasitism. This manuscript reviews the factors that affect FEC and argues for a step change in our approach to the control of nematode parasitism in pastoral systems to one focused on individual treatments based on animal performance utilising radio-frequency electronic identification and automated weighing and drafting systems.

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  • The application of high-resolution atmospheric modelling to weather and climate variability in vineyard regions

    Sturman, A.; Zawar-Reza, P.; Soltanzadeh, I.; Katurji, M.; Bonnardot, V.; Parker, Amber; Trought, Michael C.; Quénol, H.; Le Roux, R.; Gendig, E.; Schulmann, T.

    Journal article
    Lincoln University

    Grapevines are highly sensitive to environmental conditions, with variability in weather and climate (particularly temperature) having a significant influence on wine quality, quantity and style. Improved knowledge of spatial and temporal variations in climate and their impact on grapevine response allows better decision-making to help maintain a sustainable wine industry in the context of medium to long term climate change. This paper describes recent research into the application of mesoscale weather and climate models that aims to improve our understanding of climate variability at high spatial (1 km and less) and temporal (hourly) resolution within vineyard regions of varying terrain complexity. The Weather Research and Forecasting (WRF) model has been used to simulate the weather and climate in the complex terrain of the Marlborough region of New Zealand. The performance of the WRF model in reproducing the temperature variability across vineyard regions is assessed through comparison with automatic weather stations. Coupling the atmospheric model with bioclimatic indices and phenological models (e.g. Huglin, cool nights, Grapevine Flowering Véraison model) also provides useful insights into grapevine response to spatial variability of climate during the growing season, as well as assessment of spatial variability in the optimal climate conditions for specific grape varieties.

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  • Bottom-up governance after a natural disaster: a temporary post-earthquake community garden in central Christchurch, New Zealand

    Montgomery, Roy L.; Wesener, Andreas; Davies, F.

    Journal article
    Lincoln University

    Creative temporary or transitional use of vacant urban open spaces is seldom foreseen in traditional urban planning and has historically been linked to economic or political disturbances. Christchurch, like most cities, has had a relatively small stock of vacant spaces throughout much of its history. This changed dramatically after an earthquake and several damaging aftershocks hit the city in 2010 and 2011; temporary uses emerged on post-earthquake sites that ran parallel to the “official” rebuild discourse and programmes of action. The paper examines a post-earthquake transitional community-initiated open space (CIOS) in central Christchurch. CIOS have been established by local community groups as bottom-up initiatives relying on financial sponsorship, agreements with local landowners who leave their land for temporary projects until they are ready to redevelop, and volunteers who build and maintain the spaces. The paper discusses bottom-up governance approaches in depth in a single temporary post-earthquake community garden project using the concepts of community resilience and social capital. The study analyses and highlights the evolution and actions of the facilitating community organisation (Greening the Rubble) and the impact of this on the project. It discusses key actors’ motivations and values, perceived benefits and challenges, and their current involvement with the garden. The paper concludes with observations and recommendations about the initiation of such projects and the challenges for those wishing to study ephemeral social recovery phenomena.

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  • Loss of functional diversity and network modularity in introduced plant–fungal symbioses

    Dickie, Ian; Cooper, J. A.; Bufford, Jennifer; Hulme, Philip E.; Bates, S. T.

    Journal article
    Lincoln University

    The introduction of alien plants into a new range can result in the loss of co-evolved symbiotic organisms, such as mycorrhizal fungi, that are essential for normal plant physiological functions. Prior studies of mycorrhizal associations in alien plants have tended to focus on individual plant species on a case-by-case basis. This approach limits broad scale understanding of functional shifts and changes in interaction network structure that may occur following introduction. Here we use two extensive datasets of plant–fungal interactions derived from fungal sporocarp observations and recorded plant hosts in two island archipelago nations: New Zealand (NZ) and the United Kingdom (UK). We found that the NZ dataset shows a lower functional diversity of fungal hyphal foraging strategies in mycorrhiza of alien when compared with native trees. Across species this resulted in fungal foraging strategies associated with alien trees being much more variable in functional composition compared with native trees, which had a strikingly similar functional composition. The UK data showed no functional difference in fungal associates of alien and native plant genera. Notwithstanding this, both the NZ and UK data showed a substantial difference in interaction network structure of alien trees compared with native trees. In both cases, fungal associates of native trees showed strong modularity, while fungal associates of alien trees generally integrated into a single large module. The results suggest a lower functional diversity (in one dataset) and a simplification of network structure (in both) as a result of introduction, potentially driven by either limited symbiont co-introductions or disruption of habitat as a driver of specificity due to nursery conditions, planting, or plant edaphic-niche expansion. Recognizing these shifts in function and network structure has important implications for plant invasions and facilitation of secondary invasions via shared mutualist populations

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  • Factors influencing occupancy of modified artificial refuges for monitoring the range-restricted Banks Peninsula tree weta Hemideina ricta (Anostostomatidae)

    Bowie, Michael H.; Allen, Warwick; McCaw, J.; Van Heugten, R.

    Journal article
    Lincoln University

    The use of non-destructive and non-invasive monitoring methods is often necessary for species of high conservation status. Developing monitoring methods to maximise numbers of individuals found is important, given that rare species can be difficult to locate. Artificial refuges called 'weta motels' have been used for monitoring tree weta (Orthoptera: Anostostomatidae) since 1992, but poor occupancy for Hemideina ricta and H. femorata necessitated an improved design and assessment of placement to encourage tree weta use. Modification to a basic design of weta motel was tested on New Zealand's rarest tree weta, H. ricta, on Banks Peninsula, Canterbury, New Zealand. Possible lures such as peanut butter or frass from male and female H. ricta were placed in motels in an attempt to improve occupancy. We recorded high occupancy rates with an improved weta motel design and found that motels containing female frass had significantly higher levels of occupancy than controls, with the former reaching 80% occupation after 6 months. Weta motels were more likely to be used by tree weta in areas with low subcanopy density and patchy or little canopy cover, with H. ricta found to prefer higher altitude sites. Occupation of weta motels was compared with results from a previous hand search survey, finding very similar distributions of tree weta species with the two survey methods. We conclude that this modified refuge is effective for monitoring tree weta, including the range-restricted Banks Peninsula tree weta H. ricta. © New Zealand Ecological Society.

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  • Greater focus needed on alien plant impacts in protected areas

    Hulme, Philip E.; Pyšek, P.; Pergl, J.; Jarošík, V.; Schaffner, U.; Vilà, M.

    Journal article
    Lincoln University

    Alien plants pose significant threats to protected areas worldwide yet many studies only describe the degree to which these areas have become invaded. Research must move toward a better understanding of alien plant impacts since managers urgently require an appropriate evidence base to prioritize control/eradication targets. We analyze a global database of quantitative studies of alien plant impacts to evaluate existing knowledge of alien plant impacts within and outside protected areas. Although protected areas are a significant focus for quantitative impact studies, the biogeographic emphasis of most research effort does not coincide with the global distribution of protected areas nor the plant species or life-forms recognized to have greatest impacts on ecosystems. While impacts were often as significant within protected areas as outside, only a minority of studies provide any subsequent management recommendations. There is therefore considerable scope to improve the evidence base on alien plant management in protected areas.

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  • New pasture plants intensify invasive species risk

    Driscoll, D. A.; Catford, J. A.; Barney, J. N.; Hulme, Philip E.; Inderjit; Martin, T. G.; Pauchard, A.; Pyšek, P.; Richardson, D. M.; Riley, S.; Visser, V.

    Journal article
    Lincoln University

    Agricultural intensification is critical to meet global food demand, but intensification threatens native species and degrades ecosystems. Sustainable intensification (SI) is heralded as a new approach for enabling growth in agriculture while minimizing environmental impacts. However, the SI literature has overlooked a major environmental risk. Using data from eight countries on six continents, we show that few governments regulate conventionally bred pasture taxa to limit threats to natural areas, even though most agribusinesses promote taxa with substantial weed risk. New pasture taxa (including species, subspecies, varieties, cultivars, and plant-endophyte combinations) are bred with characteristics typical of invasive species and environmental weeds. By introducing novel genetic and endophyte variation, pasture taxa are imbued with additional capacity for invasion and environmental impact. New strategies to prevent future problems are urgently needed. We highlight opportunities for researchers, agribusiness, and consumers to reduce environmental risks associated with new pasture taxa. We also emphasize four main approaches that governments could consider as they build new policies to limit weed risks, including (i) national lists of taxa that are prohibited based on environmental risk; (ii) a weed risk assessment for all new taxa; (iii) a program to rapidly detect and control new taxa that invade natural areas; and (iv) the polluter-pays principle, so that if a taxon becomes an environmental weed, industry pays for its management. There is mounting pressure to increase livestock production. With foresight and planning, growth in agriculture can be achieved sustainably provided that the scope of SI expands to encompass environmental weed risks.

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  • Ammonium sorption and ammonia inhibition of nitrite-oxidizing bacteria explain contrasting soil N₂O production

    Venterea, R. T.; Clough, Timothy J.; Coulter, J. A.; Breuillin-Sessoms, F.; Wang, P.; Sadowsky, M. J.

    Journal article
    Lincoln University

    Better understanding of process controls over nitrous oxide (N₂O) production in urine-impacted 'hot spots' and fertilizer bands is needed to improve mitigation strategies and emission models. Following amendment with bovine (Bos taurus) urine (Bu) or urea (Ur), we measured inorganic N, pH, N₂O, and genes associated with nitrification in two soils ('L' and 'W') having similar texture, pH, C, and C/N ratio. Solution-phase ammonia (slNH₃) was also calculated accounting for non-linear ammonium (NH₄⁺) sorption capacities (ASC). Soil W displayed greater nitrification rates and nitrate (NO₃⁻) levels than soil L, but was more resistant to nitrite (NO₂⁻) accumulation and produced two to ten times less N₂O than soil L. Genes associated with NO₂⁻oxidation (nxrA) increased substantially in soil W but remained static in soil L. Soil NO₂⁻was strongly correlated with N₂O production, and cumulative (c-) slNH₃ explained 87% of the variance in c-NO₂⁻. Differences between soils were explained by greater slNH₃ in soil L which inhibited NO₂⁻oxidization leading to greater NO₂⁻ levels and N₂O production. This is the first study to correlate the dynamics of soil slNH₃, NO₂⁻, N₂O and nitrifier genes, and the first to show how ASC can regulate NO₂⁻ levels and N₂O production. © 2015 Macmillan Publishers Limited.

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  • The challenges of regulating diffuse agricultural pollution to improve water quality: a science policy perspective on approaches to setting enforceable catchment load limits in New Zealand

    Duncan, Ronlyn

    Journal article
    Lincoln University

    Worldwide, the cumulative effects of diffuse pollution arising from a range of human activities are diminishing the quality and ecosystem capacity of lakes, rivers, estuaries, and oceans. Devising effective ways to regulate the causes and effects of diffuse pollution is a fraught legal, political, policy, and management challenge given the difficulties in identifying and measuring who is responsible for what, where, and when. In 2011, under its Resource Management Act, 1991, the South Pacific nation of New Zealand introduced national policy to arrest diffuse pollution with a requirement for local government to institute enforceable water quality and quantity limits on all freshwater bodies. The blueprint for these national freshwater policy reforms comes from its South Island region of Canterbury. Canterbury’s regional council has adopted a catchment load approach whereby an overarching limit on nutrient losses from agricultural land is calculated and linked to land use rules to control property-scale agricultural activities. With a focus on the Canterbury region, this case study examines two approaches to establishing a catchment load for diffuse nutrient pollution to link to legal provisions in its regional plan. One is based on a river’s nutrient concentrations and the other relies on predictive modelling. The case study opens important questions about measuring and regulating diffuse pollution and the difficulties faced by policy-makers and regulators in linking numbers to legally binding compliance and enforcement mechanisms, e.g. how to account for lag effects when establishing‘ in-stream’ limits and how to address changes in software when relying on ‘modelled’ limits?

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  • Contouring and earthwork estimation for bordered strip irrigation

    Harrington, G. J.

    Thesis
    Lincoln University

    Computer programmes were developed for processing data from grid, direct, and random stadia field contouring systems. The three systems were evaluated for their use in providing contour plans for bordered strip irrigation design. A computer method of calculating the earthwork volumes associated with bordered strip irrigation was developed which uses terrain data from the above surveying methods or any other convenient source. This method was compared with land grading to form plane or warped paddock surfaces onto which levees may be formed, thus creating bordered strips. With the aid of the bordered strip earthwork calculating programme, the effect of changes of bordered strip paddock layout and slope restraints was investigated. An attempt to correlate estimated earthworks with earthmoving machine times was made.

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  • From decision-support to compliance tool: the social dimensions of Overseer and the implications for farm nutrient management

    Barr, Emma Brittany

    Thesis
    Lincoln University

    An increase of public and scientific pressure resulting in recent reforms of New Zealand’s National Policy Statement for Freshwater Management (NPS-FM) has instigated a reliance on Overseer to regulate nutrient losses from agricultural land. Overseer was previously used as a qualitative tool for farmers to assess fertiliser requirements for the following season, but has now changed to a quantitative, compliance tool in use by a number of regional councils. Understanding farmers’ perceptions of this new approach is vital to its effectiveness as a management technique. This research presents an analysis of fifteen semi-structured interviews of farmers and farm consultants from two locations in the Bay of Plenty: The Rangitāiki Plains, who use Overseer for decision-support, and the Rotorua Lakes, who use Overseer for compliance. This research has found that the role of numbers, power and authority, model credibility, perceived fairness, social identity, and the relationship to data production were significant to farmers’ perceptions of Overseer. The perceptions farmers have of Overseer is a key influence in their acceptance of nutrient regulation and adoption of sustainable nutrient management practices. By taking the focus away from individual’s technical understandings of scientific knowledge, this research has attempted to explore the social identities that characterise public responses to regulations. Trust and credibility emerged as key themes in the development of perceptions to the use of Overseer by farmers, shaped by the working relationships between farmers and council staff, council scientists, private consultants, members of the public, and industry representatives. It was found that when considering Overseer, many farmers focus on contextual factors surrounding its use, rather than the practicalities of the model itself. This shows that continued efforts to improve the scientific accuracy of Overseer will not resolve issues of distrust between farmers and Overseer.

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  • Measuring the economic impact of Whānau Ora programmes: He toki ki te Mahi case study

    Dalziel, Paul C.; Saunders, Caroline M.; Guenther, Meike

    Book
    Lincoln University

    In May 2017, the AERU was contracted by Ihi Research and Development to perform a cost benefit analysis of an initiative funded by Te Pūtahitanga o Te Waipounamu under the Whānau Ora programme. The chosen initiative was He Toki ki te Mahi, which supports participants to obtain and complete apprenticeships in the construction industry. This research report presents the details of the AERU analysis. The net present value as at 30 June 2017 of potential economic benefits from increased capabilities being achieved by the participants in the initiative to date is estimated to be above $5,500,000. The initiative received funding of $250,000 in its first year (including provision for significant set-up costs) and $80,000 in its second year. The analysis allows for a further four years of funding at $80,000 per annum to provide support for the current cohort of participants. These costs are funded from general taxation, and so the analysis makes an allowance for the deadweight loss of taxes, raising the total cost to $780,000. Thus the analysis finds that He Toki ki te Mahi has the potential to return seven times its cost in economic benefits.

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  • Unlocking export prosperity: An introduction to the research programme

    Saunders, Caroline M.; Dalziel, Paul C.; Harker, R.; Reid, J.; Cammock, P.

    Book
    Lincoln University

    On 12 September 2017, the Ministry of Business, Innovation and Employment announced that 27 proposals to the Endeavour Fund for science research programmes had been selected for funding over the next five years. One of the successful proposals is for the research programme Unlocking Export Prosperity from the Agri-food Values of Aotearoa New Zealand. This is the first in a series of Research Reports that will be produced in the programme. It provides a summary of the programme’s research plan for a general audience, recognising that a very wide range of private and public sectors organisations, as well as the general public, are interested in the outputs that will be delivered from the research over the next five years. The research aim is to deliver new knowledge to end users that contributes to building New Zealand’s global profile as a quality country-of-origin for high value agri-food products with distinctive physical, credence and cultural attributes.

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  • A socio-economic research plan for evaluating possible interventions in New Zealand's biosecurity networks

    Dalziel, Paul C.; Hulme, Philip E.

    Book
    Lincoln University

    This report was prepared for the Biological Heritage National Science Challenge. New Zealand has a range of institutional arrangements for responding to a biosecurity incursion, including interventions at points in human-assisted networks such as displaying public notices, distributing information pamphlets, requiring some inspection of vehicles or passengers, or banning the transport of certain animals or commodities. Any intervention along these lines would impose costs as well as benefits. Policy advisors therefore require a robust procedure for ensuring that a possible intervention is found to be justified from a public policy perspective. The purpose of this report is to contribute to better understanding of targeted control efforts by answering the following research question: How can we evaluate the socio-economic costs and benefits, and the distribution of those costs and benefits, resulting from any proposed network intervention in response to a biosecurity incursion?

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  • An investigation of relationship quality and supplier performance in New Zealand red meat supply chains

    Lees, Nicholas Julian

    Thesis
    Lincoln University

    Supplier relationships and performance have become increasingly important in agri-food supply chains. This research aimed to investigate buyer-supplier relationships in the New Zealand red meat industry. Specifically, this meant examining how relationship quality, as well as supplier characteristics and relationship attributes affect supplier performance. The analysis improved the conceptualisation of relationship quality by bringing together constructs from the relationship marketing and social capital literature. This established that relationship quality and social capital were closely related constructs. By combining social capital and relationship quality this created a broader measure of the overall strength of the relationship. The findings show that improving supplier performance requires taking into account both supplier characteristics and relationship attributes. Furthermore, relationship quality played a significant mediating role between all the relationship factors and supplier performance. The implications of this research are that there are specific ways buyers can improve supplier performance. This involves identifying and selecting suppliers who have superior ability, motivation and customer focus. They also need to avoid selecting suppliers with high levels of self-direction. Improving supplier performance also involves influencing relationship attributes and improving the quality of relationships with suppliers. In particular, processors need to ensure that suppliers experience positive value from the supply relationship. Furthermore, they need to manage the interaction between specific assets, dependence and use of coercive power.

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  • Conservation of complete trimethylation of lysine-43 in the rotor ring of c-subunits of metazoan adenosine triphosphate (ATP) synthases

    Walpole, T. B.; Palmer, David N.; Jiang, Huibing; Ding, S.; Fearnley, I. M.; Walker, J. E.

    Journal article
    Lincoln University

    The rotors of ATP synthases turn about 100 times every second. One essential component of the rotor is a ring of hydrophobic c-subunits in the membrane domain of the enzyme. The rotation of these c-rings is driven by a transmembrane proton-motive force, and they turn against a surface provided by another membrane protein, known as subunit a. Together, the rotating c-ring and the static subunit a provide a pathway for protons through the membrane in which the c-ring and subunit a are embedded. Vertebrate and invertebrate c-subunits are well conserved. In the structure of the bovine F₁-ATPase-c-ring subcomplex, the 75 amino acid c-subunit is folded into two transmembrane α-helices linked by a short loop. Each bovine rotor-ring consists of eight c-subunits with the N- and C-terminal α-helices forming concentric inner and outer rings, with the loop regions exposed to the phospholipid head-group region on the matrix side of the inner membrane. Lysine-43 is in the loop region and its ε-amino group is completely trimethylated. The role of this modification is unknown. If the trimethylated lysine-43 plays some important role in the functioning, assembly or degradation of the c-ring, it would be expected to persist throughout vertebrates and possibly invertebrates also. Therefore, we have carried out a proteomic analysis of c-subunits across representative species from different classes of vertebrates and from invertebrate phyla. In the twenty-nine metazoan species that have been examined, the complete methylation of lysine-43 is conserved, and it is likely to be conserved throughout the more than two million extant metazoan species. In unicellular eukaryotes and prokaryotes, when the lysine is conserved it is unmethylated, and the stoichiometries of c-subunits vary from 9-15. One possible role for the trimethylated residue is to provide a site for the specific binding of cardiolipin, an essential component of ATP synthases in mitochondria.

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  • Is there gender bias in reviewer selection and publication success rates for the New Zealand Journal of Ecology?

    Buckley, Hannah L.; Sciligo, A. R.; Adair, K. L.; Case, Bradley S.; Monks, J. M.

    Journal article
    Lincoln University

    Gender bias in the sciences is a prominent issue. Evidence suggests that more equal involvement of women in science, technology, engineering and mathematics fields leads to a diversity of working styles that can contribute to multiple measures of workplace success, such as better student outcomes in university settings and improved managerial approaches. One of the main ways we can combat gender bias is by increasing awareness. Thus, to directly draw attention to this issue for New Zealand ecologists, we performed a gender analysis of the publication process in the New Zealand Journal of Ecology (NZJE) for manuscripts reviewed between 2003 and 2012. First, we compared the frequencies of publication success between female and male authors. Second, we compared the frequencies of female and male reviewers selected by both female and male associate editors on the journal's editorial board from 2010 to 2012. Results show that publication success was not biased by gender, nor was it related to the gender of the editor. However, editors selected more male reviewers and this pattern was slightly more pronounced for male editors, suggesting that there is potential for at least some associate editors to reduce gender bias in their reviewer selections. We believe this will become easier with the development of the new reviewer database and mentoring scheme recently launched by the NZJE. It is important that publication of ecological research in New Zealand is unbiased so that the growing numbers of women in this field are not disadvantaged, and our results show that the NZJE is doing a good job at this. However, it is also important that women's contributions to the field are encouraged and recognised. We believe that reviewer selection is one way to enhance this and we strongly encourage early-career female ecologists to enrol in the NZJE mentoring scheme. © New Zealand Ecological Society.

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  • Effect of plantain (Plantago lanceolata L.) proportion in the diet on nitrogen use, milk production and behaviour of lactating dairy cows

    Nkomboni, Daniel

    Thesis
    Lincoln University

    Expansion and intensification of dairy in pasture based systems whilst economic, creates environmental challenges through nitrate leaching and degradation of water quality. With pressure to reduce nitrate leaching and simultaneously increase pasture productivity and milk production, studies have been carried out to develop management strategies to reduce N surpluses. At the animal level an effective way to reduce the environmental impacts is through nutritional interventions. Inclusion of plantain (Plantago lanceolata L.), in the traditional perennial ryegrass-white clover pastures has shown potential to reduce nitrogen concentration in urine. Most studies including plantain however, grew it in diverse pastures where it is difficult to manage persistence due to different grazing requirements compared with perennial ryegrass. Further its contribution to N loss when sown in a mix with other plant species was not clear. This research evaluated the effect of grazing increasing proportions of spatially planted plantain and perennial ryegrass-white clover pastures species on N excretion, milk production, urinary and feeding behaviour in Canterbury, New Zealand. The experiment was carried out at Lincoln University Research Dairy Farm, Canterbury, New Zealand in April 2016. Forty eight late lactating primi and multi-parous Friesian x Jersey cows were blocked according to pre-experimental average (mean, ± s.e.m) liveweight (499.21 ± 6.44 kg), milk solids (1.41 ± 0.02 kg), milk yield (14.14 ± 0.29 kg) and age (5.42 ± 0.19). Four cows were randomly allocated to 3 replicates of 4 treatments (0% plantain, 15% plantain, 30% plantain, 60% plantain) of proportions of spatially separated perennial ryegrass-white clover and pure plantain. Pre-grazing herbage mass (kg/ha DM ± sem) for pasture and plantain were similar across treatments (3857.9 ± 46.5 and 4973.1 ± 74.5 respectively) whilst the cows grazed the two monocultures to the same post-grazing herbage mass (1504.8 ± 36.1 vs. 1510.5 ± 79.3). Chemical composition was similar between perennial ryegrass-white clover and plantain across treatments. Pre-grazing pasture had similar CP and ME (23.6 ± 0.61%, 12.3 ± 0.03 ME/kg DM and 20.5 ± 0.24% and 12.77 ± 0.04 ME/kg DM for perennial ryegrass-white clover and plantain respectively. Dry matter intake (DMI) estimated from pre- and post-grazing herbage mass was lower (P=0.003) for PL0 than PL15, PL30 and PL60 and similar between PL15, PL30 and PL60 (14.74 vs. 15.96, 16.00, 15.97kg respectively). Milk yield (16.1 L/cow/day ), milk solids (1.6 L/cow/day), protein ( 4.5%) and fat (5.8%) were unaffected by percent proportion increase of plantain in the diet. Urine N concentration and urine N output had 33% lower N (P=0.012) in the PL60 than PL0 (0.30 vs. 0.45 g N/L and 431.3 g N /day vs. 545.4 g N/day respectively). The effect was mainly related to the difference derived from 30% to 60% plantain in the diet with the difference in N concentration and N output between PL0 and PL30 being 13%. Milk, urea and milk urea N declined (P=0.004) by 18% in PL60 compared with PL0. The urine volume (2.3 litres/urination) and patch area (0.34m2) were unaffected by the percent increase of plantain proportions in the diet. Based on urine volume, patch size and N concentration, there was a 40% decline from 316 to 190 kg N/ha in urine patch loading from 0% to 60% proportion of plantain in the diet indicating the key potential of plantain to reduce N loading in pastures. As urine loading is critical for determining N leaching, this is likely to contribute to reduced leaching even if urine frequency is marginally higher. The cows allocated more time (47.3 minutes) to plantain than pasture (43.54 minutes) during the morning grazing, but in the afternoon grazing bout, the reverse was true with more time spent grazing pasture than plantain (62.1 vs. 34.9 minutes/cow respectively). Animal bite rates were similar in the morning and afternoon grazing bouts (46 vs. 39 and 49 vs. 44 bites/minute/cow respectively). This study confirmed that plantain has similar feed value and milk production potential to perennial ryegrass-white clover and when offered as green leafy herbage to dairy cows. However, feeding greater than 30% plantain in the diet resulted in significant reduction in both urine N concentration and urine N excretion. As these are key components of determining N loading of urine patches, the study indicates that plantain may present appealing opportunities to reduce environmental impact of dairy farming.

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  • Big game hunting satisfaction: A test of diminishing marginal satisfaction of harvest

    Kerr, Geoffrey N.

    Report
    Lincoln University

    This paper investigates the hypotheses that marginal utility from killing game animals in New Zealand big game hunts diminishes with number of kills, and that hunt motivations affect marginal satisfaction. In addition to comparison of mean satisfaction scores for hunters experiencing different measures of success, and measures of association based on correlations and analysis of variance, a random parameters ordered-logit model utilises panel data from a large number of hunters to model effects of success on satisfaction. Motivations are important determinants of satisfaction, with harvest-oriented hunters generally less satisfied than were other hunters, unless the harvest-oriented hunters made a kill. Sighting game significantly enhanced satisfaction, which increased more if the hunters killed a game animal. Making a kill had a smaller effect on satisfaction for high-avidity hunters. Results confirm diminishing marginal utility of kills, suggesting potential gains from management responses that spread the game harvest over a larger number of hunters.

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