4,767 research outputs found
Reassessing agrarian policy and practice in local environmental management: the case of beef cattle
Reassessing agrarian policy and practice in local environmental management: the case of beef cattle
There are policy pressures to make agriculture more environmentally sustainable and to give a more local expression to agri-environmental priorities. This paper considers these moves, with particular reference to the beef sector, and speculates on the further policy responses required to facilitate benign local agri-environmental management. The UK beef sector is characterized by its complexity and diversity but four major systems can be identified operating at varying levels of intensity. Of these, suckler herds and grass-rearing systems have long been associated with high natural value forms of agricultural land management. Many of the cherished habitats and landscapes of the UK are dependent upon grazing for their ecological and amenity value. However a combination of the BSE crisis, the strength of sterling and the recent Foot & Mouth epidemic threatens the sustainability of these high nature value grazing systems. The importance of grazing to fifty selected Sites of Special Scientific Interest is highlighted in the paper. Survey work identified a wide range of systems to be particularly vulnerable to changes in profitability in the beef sector, including: coastal grazing marsh, wet acidic grassland / marshland, upland moor and heath, calcareous grassland and neutral grassland. To maintain these systems requires agricultural policy to be more sensitive to local conditions than appears currently to be the case. There is little policy support for beef farmers in a regional context, still less giving special prominence to those farming within particular biotopes. Nor has there been sufficient policy encouragement to markets for traditional and local beef breeds. The continuing pressure for CAP reform offers further opportunity for policies to be devolved to regions and localities
Merging DNA metabarcoding and ecological network analysis to understand and build resilient terrestrial ecosystems
Summary 1. Significant advances in both mathematical and molecular approaches in ecology offer unprecedented opportunities to describe and understand ecosystem functioning. Ecological networks describe interactions between species, the underlying structure of communities and the function and stability of ecosystems. They provide the ability to assess the robustness of complex ecological communities to species loss, as well as a novel way of guiding restoration. However, empirically quantifying the interactions between entire communities remains a significant challenge. 2. Concomitantly, advances in DNA sequencing technologies are resolving previously intractable questions in functional and taxonomic biodiversity and provide enormous potential to determine hitherto difficult to observe species interactions. Combining DNA metabarcoding approaches with ecological network analysis presents important new opportunities for understanding large-scale ecological and evolutionary processes, as well as providing powerful tools for building ecosystems that are resilient to environmental change. 3. We propose a novel ânested taggingâ metabarcoding approach for the rapid construction of large, phylogenetically structured species-interaction networks. Taking treeâinsectâparasitoid ecological networks as an illustration, we show how measures of network robustness, constructed using DNA metabarcoding, can be used to determine the consequences of tree species loss within forests, and forest habitat loss within wider landscapes. By determining which species and habitats are important to network integrity, we propose new directions for forest management. 4. Merging metabarcoding with ecological network analysis provides a revolutionary opportunity to construct some of the largest, phylogenetically structured species-interaction networks to date, providing new ways to: (i) monitor biodiversity and ecosystem functioning; (ii) assess the robustness of interacting communities to species loss; and (iii) build ecosystems that are more resilient to environmental change
PAGES 2k - Overview of recent products and progress
The goals of the PAGES 2k project include placing recent global change within the context of the past 2000 years (the 2k interval), and identifying the processes most likely to explain those observations. The 2k project is organized into 9 regional working groups and several transregional initiatives. We encourage an inclusive, international, community-driven, interdisciplinary and open source approach driven by workshops, searchable public metadatabases, virtual collaborations and peer reviewed publications. In this contribution, I will review products from Phase 1 (2006-2015) and progress in Phase 2 (2015-2016), including development of temperature, stable isotope and hydroclimate-relevant observational metadatabases; continental-scale surface temperature and regional and global scale sea surface temperature reconstructions and syntheses; comparison of observed and simulated temperatures; and assessment of the timing of the onset of industrial warming. More information is at: http://www.pages-igbp.org/ini/wg/2k-network/intro.</p
Kinematically Cold Populations at Large Radii in the Draco and Ursa Minor Dwarf Spheroidals
We present projected velocity dispersion profiles for the Draco and Ursa
Minor (UMi) dwarf spheroidal galaxies based on 207 and 162 discrete stellar
velocities, respectively. Both profiles show a sharp decline in the velocity
dispersion outside ~30 arcmin (Draco) and ~40 arcmin (UMi). New, deep
photometry of Draco reveals a break in the light profile at ~25 arcmin. These
data imply the existence of a kinematically cold population in the outer parts
of both galaxies. Possible explanations of both the photometric and kinematic
data in terms of both equilibrium and non-equilibrium models are discussed in
detail. We conclude that these data challenge the picture of dSphs as simple,
isolated stellar systems.Comment: 5 pages, accepted for publication in ApJ Letter
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The Earth System Grid Federation: software framework supporting CMIP5 data analysis and dissemination
Three-coordinate iron(II) expanded ring N-heterocyclic carbene complexes
A sterically demanding seven-membered expanded ring N-heterocyclic carbene (NHC) ligand allows access to rare examples of three-coordinate iron(II)-NHC complexes incorporating only halide coligands of the general formula [Fe(NHC)X 2 ] (NHC = 7-DiPP; X = Br (1) Cl (2)). Reducing the steric influence of the ancillary NHC ligand through modulation of the N-aryl substituents leads to either four- or three-coordinate complexes of the general formula [Fe(NHC)Br 2 (THF)] (3) or [Fe(NHC)Br 2 ] (4) (NHC = 7-Mes), dependent upon the solvent of recrystallization. The further reduction of NHC steric influence results in four-coordinate geometries at iron in the form of the dimeric species [Fe(NHC)Br(ÎŒ-Br)] 2 (5) or [Fe(NHC)Br 2 (THF)] (6) (NHC = SDiPP), again dependent upon the solvent of recrystallization. Compounds 1-6 have been analyzed by 1 H NMR spectroscopy, X-ray crystallography, elemental microanalysis, Mössbauer spectroscopy (for 1 and 3-5), and Evans method magnetic susceptibility. In addition to these measurements the three-coordinate species 1 and 4 have been further analyzed by SQUID magnetometry and CASSCF calculations, which show significant magnetic anisotropy that is extremely sensitive to the coordination geometry
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A Pseudoproxy Evaluation of the CCA and RegEM Methods for Reconstructing Climate Fields of the Last Millennium
Canonical correlation analysis (CCA) is evaluated for paleoclimate field reconstructions in the context of pseudoproxy experiments assembled from the millennial integration (850â1999 c.e.) of the National Center for Atmospheric Research Community Climate System Model, version 1.4. A parsimonious method for selecting the order of the CCA model is presented. Results suggest that the method is capable of resolving multiple (3â13) climatic patterns given the estimated proxy observational network and the amount of observational uncertainty. CCA reconstructions are compared to those derived from the regularized expectation maximization method using ridge regression regularization (RegEM-Ridge). CCA and RegEM-Ridge yield similar skill patterns that are characterized by high correlation regions collocated with dense pseudoproxy sampling areas in North America and Europe. Both methods also produce reconstructions characterized by spatially variable warm biases and variance losses, particularly at high pseudoproxy noise levels. RegEM-Ridge in particular is subject to significantly larger variance losses than CCA, even though the spatial correlation patterns of the two methods are comparable. Results collectively indicate the importance of evaluating the field performance of methods that target spatial climate patterns during the last several millennia and indicate that the results of currently available climate field reconstructions should be interpreted carefully
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