11,352 research outputs found

    Butterfly abundance in a warming climate: patterns in space and time are not congruent

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    We present a model of butterfly abundance on transects in England. The model indicates a significant role for climate, but the direction of association is counter to expectation: butterfly population density is higher on sites with a cooler climate. However, the effect is highly heterogeneous, with one in five species displaying a net positive association. We use this model to project the population-level effects of climate warming for the year 2080, using a medium emissions scenario. The results suggest that most populations and species will decline markedly, but that the total number of butterflies will increase as communities become dominated by a few common species. In particular, Maniola jurtina is predicted to make up nearly half of all butterflies on UK Butterfly Monitoring Scheme (UKBMS) transects by 2080. These results contradict the accepted wisdom that most insect populations will grow as the climate becomes warmer. Indeed, our predictions contrast strongly with those derived from inter-annual variation in abundance, emphasizing that we lack a mechanistic understanding about the factors driving butterfly population dynamics over large spatial and temporal scales. Our study underscores the difficulty of predicting future population trends and reveals the naivety of simple space-for-time substitutions, which our projections share with species distribution modelling

    Fifty years of the Biological Records Centre

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    In this special issue of the Biological Journal of the Linnean Society, we celebrate 50 years of the Biological Records Centre (BRC) but, more importantly, we celebrate the pioneers of BRC and the volunteer recording community. It is inspiring to consider the many individuals who have contributed to the rich legacy of biological recording since the 16th Century. The core activity of BRC has remained unchanged since its foundation in 1964: working in partnership with volunteer recording schemes and societies to collate, manage, disseminate, and interpret species observations (biological records). However, innovative technologies and the development of statistical approaches are taking biological recording in new and exciting directions. The large spatial coverage and increasingly fine-scale spatial precision of biological records enable ecologists to examine large-scale processes that would be impossible to address without the contribution of voluntary recorders

    Late Planting Decisions with Crop Insurance: Decision Guidelines for Michigan Farmers in Spring 2011

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    Michigan has had unusually wet planting conditions in 2011, leading to substantial acreage that has not been planted at this late date. Farmers who purchased crop insurance have many options available to them. This paper addresses the major crop insurance decisions that farmers will face during the next 30 days.crop insurance, prevented planting, risk management, farm management, corn returns, soybean returns, Agricultural and Food Policy, Crop Production/Industries, Farm Management, Risk and Uncertainty,

    Competing Magnetic Fluctuations in Iron Pnictide Superconductors: Role of Ferromagnetic Spin Correlations Revealed by NMR

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    In the iron pnictide superconductors, theoretical calculations have consistently shown enhancements of the static magnetic susceptibility at both the stripe-type antiferromagnetic (AFM) and in-plane ferromagnetic (FM) wavevectors. However, the possible existence of FM fluctuations has not yet been examined from a microscopic point of view. Here, using 75^{75}As NMR data, we provide clear evidence for the existence of FM spin correlations in both the hole- and electron-doped BaFe2_2As2_2 families of iron-pnictide superconductors. These FM fluctuations appear to compete with superconductivity and are thus a crucial ingredient to understanding the variability of TcT_{\rm c} and the shape of the superconducting dome in these and other iron-pnictide families.Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev. Let

    What Makes Judicial Elections Unique

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