1,461 research outputs found

    Improving supplementary feeding in species conservation

    Get PDF
    Supplementary feeding is often a knee-jerk reaction to population declines, and its application is not critically evaluated, leading to polarized views among managers on its usefulness. Here, we advocate a more strategic approach to supplementary feeding so that the choice to use it is clearly justified over, or in combination with, other management actions and the predicted consequences are then critically assessed following implementation. We propose combining methods from a set of specialist disciplines that will allow critical evaluation of the need, benefit, and risks of food supplementation. Through the use of nutritional ecology, population ecology, and structured decision making, conservation managers can make better choices about what and how to feed by estimating consequences on population recovery across a range of possible actions. This structured approach also informs targeted monitoring and more clearly allows supplementary feeding to be integrated in recovery plans and reduces the risk of inefficient decisions. In New Zealand, managers of the endangered Hihi (Notiomystis cincta) often rely on supplementary feeding to support reintroduced populations. On Kapiti island the reintroduced Hihi population has responded well to food supplementation, but the logistics of providing an increasing demand recently outstretched management capacity. To decide whether and how the feeding regime should be revised, managers used a structured decision making approach informed by population responses to alternative feeding regimes. The decision was made to reduce the spatial distribution of feeders and invest saved time in increasing volume of food delivered into a smaller core area. The approach used allowed a transparent and defendable management decision in regard to supplementary feeding, reflecting the multiple objectives of managers and their priorities

    A microcomputer system for use with an EPR spectrometer

    Get PDF

    Body size changes in passerine birds introduced to New Zealand from the UK

    Get PDF
    One feature of global geographic variation in avian body sizes is that they are larger on isolated islands than on continental regions. Therefore, this study aims to assess whether there have been changes in body size following successful establishment for seven passerine bird species (blackbird Turdus merula, song thrush T. philomelos, house sparrow Passer domesticus, chaffinch Fringilla coelebs, greenfinch Chloris chloris, goldfinch Carduelis carduelis, yellowhammer Emberiza citrinella) introduced from the continental islands of the UK to the more isolated oceanic landmass of New Zealand in the middle of the nineteenth century. Measures of tarsus length were taken from individuals from contemporary UK and New Zealand populations of these species, and from historical specimens collected around the time that individuals were translocated from the UK to New Zealand. Analysis of Variance was used to test for size differences between contemporary UK and New Zealand populations, and between historical UK and contemporary UK and New Zealand populations. Historical UK populations have longer tarsi, on average, than 12 (7 UK and 5 New Zealand) of the 14 contemporary populations. Significant decreases in tarsus length relative to the historical populations have occurred in the UK for blackbird, chaffinch and greenfinch, and in the New Zealand blackbird population. Contemporary New Zealand house sparrows have significantly longer tarsi, on average, than both historical and contemporary UK populations. Exposure to novel environments may be expected to lead to changes in the morphology and other traits of exotic species, but changes have also occurred in the native range. In fact, contrary to expectations, the most common differences we found were between contemporary and historical UK populations. Consideration of contemporary populations alone would underestimate the true scale of morphological change in these species over time, which may be due to phenotypic plasticity or genetic adaptation to environmental changes experienced by all populations in the last 150 years

    Effects of paratilling on soil bulk density and infiltration

    Get PDF
    Non-Peer ReviewedParatilling is a form of non-inversion deep tillage sought after by producers for its effectiveness at loosening soil structure without compromising the soil conservation practices that are already employed on the farm. An experiment was set up to evaluate the tillage effects of paratilling. Looking at changes to the soil physical properties, bulk density and infiltration, and crop yield. Initially, paraplowing reduced bulk density and soil strength but with over time these effects were eroded. At the Vertisolic site the effects were lost before the end of the first growing season, which may be a result of natural processes and the unusually wet spring. Infiltration increased as a result of paratilling. Soil loosening did not increase yield suggesting that soil structure is not limiting plant growth at these sites. Paratilling is only feasible if a yield response is observed

    Is there a link between agricultural land-use management and flooding?

    No full text
    International audienceOver the past fifty years, significant changes in UK land use and management practices have occurred, driven by UK and EU agricultural policies. There is substantial evidence that modern land-use management practices have enhanced surface runoff generation at the local scale, frequently creating impacts through "muddy floods". Such local impacts can be avoided or mitigated through the adoption of better land management practices and/or small scale surface runoff control measures. There is little evidence that local scale changes in runoff generation propagate downstream to create impacts at the larger catchment scale. This does not imply that impacts do not exist, but the very few studies in which evidence has been sought have not produced any conclusive findings. Multiscale catchment experimentation, linked to new developments in modelling, is needed which can lead to a better understanding of how small scale changes to runoff generation propagate to larger catchment scales. To facilitate the tracking of changes from the local to the catchment scale, a new modelling approach is demonstrated which allows a downstream flood hydrograph to be mapped back onto its source areas, thus presenting impact information to users in a useful and comprehensible form

    Interpacket diffusion in SAMP model for water and solute movement in unsaturated soil

    No full text
    International audienceSAMP (subsystems and moving packets) is a recently developed method for modelling preferential flow and solute movement in porous media, and for determining the fate of "new" and "old" water and solute when the new enters a region containing the old. In a SAMP model, the modelled region (e.g. the unsaturated zone) is divided into cells, and the pore space within each cell is divided into many (often 100 or more) subsystems. Packets of water, containing solute, move within and between the cells, from subsystem to subsystem, thus simulating the bulk movement of water and solute. A theory is developed here for representing molecular diffusion in the liquid phase of porewater as interpacket diffusion, and this theory is implemented in the SAMP I one-dimensional vertical-column model. The model is found to exhibit appropriate sensitivity to its parameters, and is successfully calibrated against existing laboratory breakthrough data for tritium movement in Glendale silty clay loam. The quality of fit achieved to the laboratory data is found to be significantly better when interpacket diffusion is simulated than when it is not. The main parameters for the model are those for the matric potential and unsaturated hydraulic conductivity functions, and the only parameter requiring calibration is the internal scale, which affects both interpacket diffusion and the way packets move within the soil. Theoretical and numerical comparisons show there are similarities between the internal scale and the coefficient for solute exchange between the dynamic region and dead-space in the two-region (mobile-immobile) model of van Genuchten and Wierenga (1976)

    Do mothers bias offspring sex ratios in carotenoid-rich environments?

    Get PDF
    If environmental or maternal factors favor the fitness of one sex over the other, theory predicts that mothers should produce more offspring of the sex most likely to benefit from prevailing conditions. For species where males depend on carotenoid-based colorful ornaments to secure territory or attract mates, carotenoid availability in the environment could be one such component: mothers experiencing high availability of carotenoids should produce more sons. Here, we test this hypothesis by providing carotenoids to a wild population of a sexually dimorphic passerine, the hihi (stitch bird: Notiomystis cincta). Access to carotenoids during early life influences the color of male hihi plumage, which improves territory acquisition as adults. Therefore, carotenoid availability when young may influence male fitness. However, we found no evidence of sex ratio bias in treated or untreated groups, either before or after hatching. First-laid eggs, where carotenoid concentrations are usually highest, were also unbiased. For hihi, access to carotenoids during egg laying does not appear to encourage mothers to alter sex ratios of offspring. Alternatively, the fitness of daughters may also benefit from increased carotenoids during development. Disentangling these alternatives requires further work

    Electronic Spectroscopy of He@C60+ for Astrochemical Consideration

    Get PDF
    The electronic spectrum of the endohedral fullerene He@C+60 observed by messenger spectroscopy in a cryogenic ion trap is presented. The role played by the messanger tag in the adopted experimental method is evaluated by recording spectra of He@C+60 − Hen with n = 1−4. The results indicate a linear shift of ∼ 0.7 Å in the wavelengths allowing accurate gas phase values to be reported. The presence of the helium inside the cage shifts the absorption bands by 2−3 Å toward shorter wavelengths compared to C+60. The magnitude of this displacement will enable searches for the spectral signatures of this fullerene analogue in interstellar environments by absorption spectroscopy. The implications for potential astronomical detection are discussed

    When a patient\u27s ethnicity is declared, medical students\u27 decision-making processes are affected

    Get PDF
    Background: Disparity in health status and healthcare outcomes is widespread and well known. This holds true for Indigenous peoples in many settings including Australia and Hawaii. While multi-factorial, there is increasing evidence of health practitioner contribution to this disparity. This research explored senior medical students’ clinical decision-making processes. Methods: A qualitative study was conducted in 2014 with 30 final year medical students from The University of Melbourne, Australia, and The John Burns Medical School, Hawaii, USA. Each student responded to questions about a paper-based case, first in writing and elaborated further in an interview. Half the students were given a case of a patient whose ethnicity was not declared; the other half considered the patient who was Native Hawaiian or Australian Aboriginal. A systematic thematic analysis of the interview transcripts was conducted. Results: The study detected subtle biases in students’ ways of talking about the Indigenous person and their anticipation of interacting with her as a patient. Four main themes emerged from the interview transcripts: the patient as a person; constructions of the person as patient; patient–student/doctor interactions; and the value of various education settings. There was a strong commitment to the patient’s agenda and to the element of trust in the doctor–patient interaction. Conclusion: These findings will help to advance medical curricula so that institutions graduate physicians who are increasingly able to contribute to equitable outcomes for all patients in their care. The study also draws attention to subtle biases based on ethnicity that may be currently at play in physicians’ practices

    Advanced oxygen-hydrocarbon rocket engine study

    Get PDF
    The program consists of parametric analysis and design to provide a consistent engine system data base for defining advantages and disadvantages, system performance and operating limits, engine parametric data, and technology requirements for candidate high pressure LO2/Hydrocarbon engine systems. The parametric chamber and nozzle cooling analysis was completed for the four potential coolants: RP-1, LCH4, LO2, and LH2. A summary of the cooling capability of each propellant is presented
    • …
    corecore