22 research outputs found

    Surface structure on abandoned upland blanket peatland tracks

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    Temporary permissions are often granted for track use on peatlands. However, even when peatland track designs attempt to minimise environmental impacts via use of mesh systems, such linear disturbances may have persistent impacts. We evaluated the surface peatland structure of five abandoned tracks (four with a mesh surface, one unsurfaced) with varying past usage frequencies, at an upland site in northern England. Simplification of the surface nanotopography was found on all tracks compared to surrounding control areas, with increased micro-erosion patterns in rutted areas, and invasive species on some treatments. The frequency of previous usage was not found to be a significant factor controlling nano-topographic loss. Edge effects and hillslope position were influential in places, but these effects were not consistent across treatments. Nano-topographic recovery was found to be inhibited when track usage commenced within a short time frame after track construction. Mesh tracks appear to create a spatial constraint leading to poor development of plants and a reduced ability to form characteristic structures which are integral to mire function

    Blanket bogs exhibit significant alterations to physical properties as a result of temporary track removal or abandonment

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    Temporarily consented tracks made from high-density polyethylene (HDPE) mesh have been used to mitigate both the physical and ecological impacts on peatlands from low-frequency vehicle usage. However, the impacts of mesh track removal or abandonment at the end of the consented period remain poorly understood. Over a 2-year period, we studied replicate sections of abandoned mesh track which, at the start of the experiment, had been unused for approximately 5 years, on a UK blanket bog. Some sections were removed (using two treatment methods – vegetation mown and unprepared), whereas others were left in situ. Metrics were compared both between treatments and to undisturbed reference areas. Significant differences in surface soil moisture were found between abandoned and removed tracks depending on season. Control areas had higher volumetric soil moisture than track locations. Compaction was significantly higher across all track locations in comparison to controls (p < 0.001), but rarefaction was not recorded post-removal, suggesting long-term deformation. Overland flow events were recorded in rut sections for a mean of 16% of the time, compared to <1% in control areas. Sediment traps on the tracks collected 0.406 kg compared to 0.0048 kg from the control traps, equating to a per trap value of 7.3 g from track samplers and 0.17 g from control samplers. Erosion and desiccation features occurred on both removed and abandoned track sections. Both abandonment and removal of mesh tracks have a wide range of impacts on the physical properties of peatlands, suggesting that only where access is a necessity should such a track be installed

    Removal of mesh track on an upland blanket peatland leads to changes in vegetation composition and structure

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    Mesh tracks on peatlands are often granted permits on a temporary basis under the presumption that the tracks are either removed at the end of their permitted use or remain unused in situ. However, the fragility of peatland habitats and poor resilience of the specialist plant communities within them, mean that these linear disturbances may persist post-abandonment or post-removal. We removed sections of mesh track, abandoned five years earlier, from a blanket peatland using two different removal treatment methods (mown and unprepared) and studied a third treatment with sections left in place over a period of 19 months. On abandoned tracks, invasive species including Campylopus introflexus and Deschampsia flexulosa had established, while track removal led to extensive loss of Sphagnum species. Loss of surficial nanotopographic vegetation structures during track removal was extensive, and micro-erosion features were prevalent in both removal treatments. Abandoned sections of track performed comparably better across all metrics than removed sections. However, similarity between the vegetation assemblage of the abandoned track and the controls was <40% at the study outset, with NMDS (Non-metric Multidimensional Scaling) highlighting divergences. There was a mean species loss of 5 per quadrat for the removed sections. Bare peat was present in 52% of all track quadrats by the finish of the study. Our findings suggest that mesh tracks left in situ and track removal both present significant barriers to recovery and additional conservation interventions may be required after peatland tracks are abandoned

    Surface structure on abandoned upland blanket peatland tracks

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    Temporary permissions are often granted for track use on peatlands. However, even when peatland track designs attempt to minimise environmental impacts via use of mesh systems, such linear disturbances may have persistent impacts. We evaluated the surface peatland structure of five abandoned tracks (four with a mesh surface, one unsurfaced) with varying past usage frequencies, at an upland site in northern England. Simplification of the surface nanotopography was found on all tracks compared to surrounding control areas, with increased micro-erosion patterns in rutted areas, and invasive species on some treatments. The frequency of previous usage was not found to be a significant factor controlling nano-topographic loss. Edge effects and hillslope position were influential in places, but these effects were not consistent across treatments. Nano-topographic recovery was found to be inhibited when track usage commenced within a short time frame after track construction. Mesh tracks appear to create a spatial constraint leading to poor development of plants and a reduced ability to form characteristic structures which are integral to mire function

    Blanket bogs exhibit significant alterations to physical properties as a result of temporary track removal or abandonment

    Get PDF
    Temporarily consented tracks made from high-density polyethylene (HDPE) mesh have been used to mitigate both the physical and ecological impacts on peatlands from low-frequency vehicle usage. However, the impacts of mesh track removal or abandonment at the end of the consented period remain poorly understood. Over a 2-year period, we studied replicate sections of abandoned mesh track which, at the start of the experiment, had been unused for approximately 5 years, on a UK blanket bog. Some sections were removed (using two treatment methods – vegetation mown and unprepared), whereas others were left in situ. Metrics were compared both between treatments and to undisturbed reference areas. Significant differences in surface soil moisture were found between abandoned and removed tracks depending on season. Control areas had higher volumetric soil moisture than track locations. Compaction was significantly higher across all track locations in comparison to controls (p < 0.001), but rarefaction was not recorded post-removal, suggesting long-term deformation. Overland flow events were recorded in rut sections for a mean of 16% of the time, compared to <1% in control areas. Sediment traps on the tracks collected 0.406 kg compared to 0.0048 kg from the control traps, equating to a per trap value of 7.3 g from track samplers and 0.17 g from control samplers. Erosion and desiccation features occurred on both removed and abandoned track sections. Both abandonment and removal of mesh tracks have a wide range of impacts on the physical properties of peatlands, suggesting that only where access is a necessity should such a track be installed

    Trade-offs between antibacterial resistance and fitness cost in the production of metallo-b-lactamases by enteric bacteria manifest as sporadic emergence of carbapenem resistance in a clinical setting

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    Meropenem is a clinically important antibacterial reserved for treatment of multiresistant infections. In meropenem-resistant bacteria of the family Enterobacterales, NDM-1 is considerably more common than IMP-1, despite both metallo-β-lactamases (MBLs) hydrolyzing meropenem with almost identical kinetics. We show that bla(NDM-1) consistently confers meropenem resistance in wild-type Enterobacterales, but bla(IMP-1) does not. The reason is higher bla(NDM-1) expression because of its stronger promoter. However, the cost of meropenem resistance is reduced fitness of bla(NDM-1)-positive Enterobacterales. In parallel, from a clinical case, we identified multiple Enterobacter spp. isolates carrying a plasmid-encoded bla(NDM-1) having a modified promoter region. This modification lowered MBL production to a level associated with zero fitness cost, but, consequently, the isolates were not meropenem resistant. However, we identified a Klebsiella pneumoniae isolate from this same clinical case carrying the same bla(NDM-1) plasmid. This isolate was meropenem resistant despite low-level NDM-1 production because of a ramR mutation reducing envelope permeability. Overall, therefore, we show how the resistance/fitness trade-off for MBL carriage can be resolved. The result is sporadic emergence of meropenem resistance in a clinical setting

    The Winchcombe meteorite, a unique and pristine witness from the outer solar system.

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    Direct links between carbonaceous chondrites and their parent bodies in the solar system are rare. The Winchcombe meteorite is the most accurately recorded carbonaceous chondrite fall. Its pre-atmospheric orbit and cosmic-ray exposure age confirm that it arrived on Earth shortly after ejection from a primitive asteroid. Recovered only hours after falling, the composition of the Winchcombe meteorite is largely unmodified by the terrestrial environment. It contains abundant hydrated silicates formed during fluid-rock reactions, and carbon- and nitrogen-bearing organic matter including soluble protein amino acids. The near-pristine hydrogen isotopic composition of the Winchcombe meteorite is comparable to the terrestrial hydrosphere, providing further evidence that volatile-rich carbonaceous asteroids played an important role in the origin of Earth's water

    A review of the effects of vehicular access roads on peatland ecohydrological processes

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    An increasing demand for resources, coupled with technological advances which make remote exploration possible and economically viable, have led to a human push into previously inaccessible areas, including peatlands. In spite of the unsuitable nature of peat as a substrate for engineering projects there has been a growth of vehicular access networks on peatlands. However, there is a lack of understanding about how such networks impact peatland functioning. We found that research trends on peatland access track studies have changed from a concern largely with the physical properties of peat and its suitability as a substrate for building, to study of vegetation recovery, microbiological functioning and carbon cycling processes. Some recent research has examined vehicular access route impacts on peat ecohydrological processes showing that biogeochemical processes are affected, and that vegetation recovery is significantly impeded in post abandonment periods. Sizeable knowledge gaps which could form the focus of future research include the effects of roads on tropical peatlands, influence of plastic, erosion and pipe formation processes, the hydrological effects of seismic trails, ecotoxicological effects of plastic tracks and chemical pollutants on peatlands resulting from vehicular access, the ecohydrological recovery process after temporary roads are removed from peatlands

    Limping and Lameness on the Early Modern Stage

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    Performing Disability in Early Modern English Drama investigates the cultural work done by early modern theatrical performances of disability
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