575 research outputs found

    Ecosystem service provision by road verges

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    1. Roads form a vast, rapidly growing global network that has diverse, detrimental ecological impacts. However, the habitats that border roads (‘road verges’) form a parallel network that might help mitigate these impacts and provide additional benefits (ecosystem services; ES). 2. We evaluate the capacity of road verges to provide ES by reviewing existing research and considering their relevant characteristics: area, connectivity, shape, and contextual ES supply and demand. We consider the present situation, and how this is likely to change based on future projections for growth in road extent, traffic densities and urban populations. 3. Road verges not only provide a wide range of ES, including biodiversity provision, regulating services (e.g. air and water filtration) and cultural services (e.g. health and aesthetic benefits by providing access to nature) but also displace other habitats and provide ecosystem disservices (e.g. plant allergens and damage to infrastructure). Globally, road verges may currently cover 270,000 km2 and store 0.015 Gt C/year, which will further increase with 70% projected growth in the global road network. 4. Road verges are well placed to mitigate traffic pollution and address demand for ES in surrounding ES‐impoverished landscapes, thereby improving human health and well‐being in urban areas, and improving agricultural production and sustainability in farmland. Demand for ES provided by road verges will likely increase due to projected growth in traffic densities and urban populations, though traffic pollution will be reduced by technological advances (e.g. electric vehicles). Road verges form a highly connected network, which may enhance ES provision but facilitate the dispersal of invasive species and increase vehicle–wildlife collisions. 5. Synthesis and applications. Road verges offer a significant opportunity to mitigate the negative ecological effects of roads and to address demand for ecosystem services (ES) in urban and agricultural landscapes. Their capacity to provide ES might be enhanced considerably if they were strategically designed and managed for environmental outcomes, namely by optimizing the selection, position and management of plant species and habitats. Specific opportunities include reducing mowing frequencies and planting trees in large verges. Road verge management for ES must consider safety guidelines, financial costs and ecosystem disservices, but is likely to provide long‐term financial returns if environmental benefits are considered

    High-pressure investigations of CaTiO3 up to 60 GPa using X-ray diffraction and Raman spectroscopy

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    In this work, we investigate calcium titanate (CaTiO3 - CTO) using X-ray diffraction and Raman spectroscopy up to 60 and 55 GPa respectively. Both experiments show that the orthorhombic Pnma structure remains stable up to the highest pressures measured, in contradiction to ab-initio predictions. A fit of the compression data with a second-order Birch-Murnaghan equation of state yields a bulk modulus K0 of 181.0(6) GPa. The orthorhombic distortion is found to increase slightly with pressure, in agreement with previous experiments at lower pressures and the general rules for the evolution of perovskites under pressure. High-pressure polarized Raman spectra also enable us to clarify the Raman mode assignment of CTO and identify the modes corresponding to rigid rotation of the octahedra, A-cation shifts and Ti-O bond stretching. The Raman signature is then discussed in terms of compression mechanisms.Comment: 11 pages, 6 figures, 4 table

    Road verges support pollinators in agricultural landscapes, but are diminished by heavy traffic and summer cutting

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    1. Supporting pollinators in agricultural landscapes is important for reversing their global decline. Road verges and hedges are used by pollinators for feeding and reproduction, but few studies consider entire pollinator communities, and it remains unclear how they are distributed across adjacent verges, hedges and fields, or how they are affected by traffic and verge cutting. 2. We surveyed flowers and pollinators, using transect counts and pan traps, to explore the role of road verges and their associated hedges in supporting pollinators in an agricultural landscape in southwest England, and the impacts of traffic and verge cutting. At 19 sites, we surveyed the road verge (verge edge and verge centre), the verge hedge (both sides), a field hedge and the field interior. 3. Road verges and hedges had a much greater flower abundance, flower species richness and pollinator abundance than field interiors. Verge hedges had far less woody cover than field hedges, but greater flower species richness. 4. There were fewer pollinators along verge edges (next to roads) than along verge centres (2–11 m from roads) and fewer pollinators in road verges next to busier roads. 5. Road verges were generally cut once (in summer), and cuttings were never removed. There were substantially fewer flowers and pollinators in road verges that had been cut, even though surveys often took place many weeks after cutting. 6. Synthesis and applications. Road verges and their associated hedges can provide hotspots of resources for pollinators in agricultural landscapes, but their capacity to do so is reduced by heavy traffic and summer verge cutting. We recommend that beneficial management for pollinators should prioritize wider road verges (at least 2 m wide), roads with less traffic, and areas away from the immediate vicinity of the road. Where possible, verge cutting should not be carried out during peak flowering times

    Spatial extent of road pollution: a national analysis

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    Roads form vast, pervasive and growing networks across the Earth, causing negative environmental impacts that spill out into a ‘road-effect zone’. Previous research has estimated the regional and global extent of these zones using arbitrary distances, ignoring the spatial distribution and distance-dependent attenuation of different forms of road environmental impact. With Great Britain as a study area, we used mapping of roads and realistic estimates of how pollution levels decay with distance to project the spatial distribution of road pollution. We found that 25% of land was less than 79 m from a road, 50% of land was less than 216 m and 75% of land was less than 527 m. Roadless areas were scarce, and confined almost exclusively to the uplands (mean elevation 391 m), with only ca 12% of land in Great Britain more than 1 km from roads and 70% of the land area. Potentially less than 6% of land escapes any impact, resulting in nearly ubiquitously elevated pollution levels. Generalising from this, we find that, whilst the greatest levels of road pollution are relatively localised around the busiest roads, low levels of road pollution (which may be ecologically significant) are pervasive. Our findings demonstrate the importance of incorporating greater realism into road-effect zones and considering the ubiquity of road pollution in global environmental issues. We used Great Britain as a study area, but the findings likely apply to other densely populated regions at present, and to many additional regions in the future due to the predicted rapid expansion of the global road network

    Enhancing road verges to aid pollinator conservation: A review

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    Road verges provide habitats that have considerable potential as a tool for pollinator conservation, especially given the significant area of land that they collectively cover. Growing societal interest in managing road verges for pollinators suggests an immediate need for evidence-based management guidance. We used a formal, global literature review to assess evidence for the benefits of road verges for pollinators (as habitats and corridors), the potential negative impacts of roads on pollinators (vehicle-pollinator collisions, pollution, barriers to movement) and how to enhance road verges for pollinators through management. We identified, reviewed and synthesised 140 relevant studies. Overall, the literature review demonstrated that: (i) road verges are often hotspots of flowers and pollinators (well established), (ii) traffic and road pollution can cause mortality and other negative impacts on pollinators (well established), but available evidence suggests that the benefits of road verges to pollinators far outweigh the costs (established but incomplete), and (iii) road verges can be enhanced for pollinators through strategic management (well established). Future research should address the lack of holistic and large-scale understanding of the net effects of road verges on pollinators. We provide management recommendations for enhancing both individual road verges for pollinators (e.g. optimised mowing regimes) and entire road networks (e.g. prioritising enhancement of verges with the greatest capacity to benefit pollinators), and highlight three of the most strongly supported recommendations: (i) creating high quality habitats on new and existing road verges, (ii) reducing mowing frequency to 0–2 cuts/year and (iii) reducing impacts of street lighting

    Road verge extent and habitat composition across Great Britain

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    There is growing societal and scientific interest in enhancing road verges for nature and the environment. This is partly because they are estimated to cover large areas in some regions. Yet, to our knowledge, there has been no quantitative assessment of national road verge extent, or of the habitats they encompass. We present a novel method for characterising and classifying road verges remotely. We use this to evaluate the extent and habitat composition of road verges across Great Britain, and to identify opportunities for improving verges for nature and the environment. We use stratified random sampling of freely-available road maps combined with satellite (Google Earth) and ground-level imagery (Google Street View). Overall, we estimate that there are 2,579 km2 (2,149-3,010 km2) of road verges across Great Britain, equivalent to 1.2% of land area, of which 707 km2 (27.47%) is short, frequently-mown grassland, 1,062 km2 (40.87%) is regular grassland, 480 km2 (18.73%) is woodland, and 272 km2 (10.66%) is scrub. By comparison, we estimate that there are 3,694 km2 of hard road surfaces across Great Britain, equivalent to 1.8% of land. Only 27% of frequently-mown grassland verges contained trees, indicating potential for planting trees and shrubs to provide environmental benefits. Our findings suggest that there are significant opportunities to enhance (i) verges along major roads, because these constitute a disproportionately large area of road verge and have the widest verges, and (ii) frequently-mown grassland verges for example by, where appropriate, reducing mowing frequencies and/or planting trees. Our method can be used, adapted and further developed by others, for example to assess road verges across other regions, and to assess verge habitat composition in greater detail

    Breath Formate Is a Marker of Airway S-Nitrosothiol Depletion in Severe Asthma

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    -nitrosothiols (SNOs), a class of endogenous airway smooth muscle relaxants. This deficiency results from increased activity of an enzyme that both reduces SNOs to ammonia and oxidizes formaldehyde to formic acid, a volatile carboxylic acid that is more easily detected in exhaled breath condensate (EBC) than SNOs. We therefore hypothesize that depletion of airway SNOs is related to asthma pathology, and breath formate concentration may be a proxy measure of SNO catabolism. (r = −0.39, p = 0.002, asthmatics only), and positively correlated with the NO-derived ion nitrite (r = 0.46, p<0.0001) as well as with total serum IgE (r = 0.28, p = 0.016, asthmatics only). Furthermore, formate was not significantly correlated with other volatile organic acids nor with inhaled corticosteroid dose.-nitrosothiols

    HSD3B1 genotype identifies glucocorticoid responsiveness in severe asthma

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    Asthma resistance to glucocorticoid treatment is a major health problem with unclear etiology. Glucocorticoids inhibit adrenal androgen production. However, androgens have potential benefits in asthma. HSD3B1 encodes for 3ÎČ-hydroxysteroid dehydrogenase-1 (3ÎČ-HSD1), which catalyzes peripheral conversion from adrenal dehydroepiandrosterone (DHEA) to potent androgens and has a germline missense-encoding polymorphism. The adrenal restrictive HSD3B1(1245A) allele limits conversion, whereas the adrenal permissive HSD3B1(1245C) allele increases DHEA metabolism to potent androgens. In the Severe Asthma Research Program (SARP) III cohort, we determined the association between DHEA-sulfate and percentage predicted forced expiratory volume in 1 s (FEV1PP). HSD3B1(1245) genotypes were assessed, and association between adrenal restrictive and adrenal permissive alleles and FEV1PP in patients with (GC) and without (noGC) daily oral glucocorticoid treatment was determined (n = 318). Validation was performed in a second cohort (SARP I&II; n = 184). DHEA-sulfate is associated with FEV1PP and is suppressed with GC treatment. GC patients homozygous for the adrenal restrictive genotype have lower FEV1PP compared with noGC patients (54.3% vs. 75.1%; P < 0.001). In patients with the homozygous adrenal permissive genotype, there was no FEV1PP difference in GC vs. noGC patients (73.4% vs. 78.9%; P = 0.39). Results were independently confirmed: FEV1PP for homozygous adrenal restrictive genotype in GC vs. noGC is 49.8 vs. 63.4 (P < 0.001), and for homozygous adrenal permissive genotype, it is 66.7 vs. 67.7 (P = 0.92). The adrenal restrictive HSD3B1(1245) genotype is associated with GC resistance. This effect appears to be driven by GC suppression of 3ÎČ-HSD1 substrate. Our results suggest opportunities for prediction of GC resistance and pharmacologic intervention

    d-Cystine di(m)ethyl ester reverses the deleterious effects of morphine on ventilation and arterial blood gas chemistry while promoting antinociception

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    We have identified thiolesters that reverse the negative effects of opioids on breathing without compromising antinociception. Here we report the effects of d-cystine diethyl ester (d-cystine diEE) or d-cystine dimethyl ester (d-cystine diME) on morphine-induced changes in ventilation, arterial-blood gas chemistry, A-a gradient (index of gas-exchange in the lungs) and antinociception in freely moving rats. Injection of morphine (10 mg/kg, IV) elicited negative effects on breathing (e.g., depression of tidal volume, minute ventilation, peak inspiratory flow, and inspiratory drive). Subsequent injection of d-cystine diEE (500 ÎŒmol/kg, IV) elicited an immediate and sustained reversal of these effects of morphine. Injection of morphine (10 mg/kg, IV) also elicited pronounced decreases in arterial blood pH, pO2 and sO2 accompanied by pronounced increases in pCO2 (all indicative of a decrease in ventilatory drive) and A-a gradient (mismatch in ventilation-perfusion in the lungs). These effects of morphine were reversed in an immediate and sustained fashion by d-cystine diME (500 ÎŒmol/kg, IV). Finally, the duration of morphine (5 and 10 mg/kg, IV) antinociception was augmented by d-cystine diEE. d-cystine diEE and d-cystine diME may be clinically useful agents that can effectively reverse the negative effects of morphine on breathing and gas-exchange in the lungs while promoting antinociception. Our study suggests that the d-cystine thiolesters are able to differentially modulate the intracellular signaling cascades that mediate morphine-induced ventilatory depression as opposed to those that mediate morphine-induced antinociception and sedation

    Developing policy-relevant biodiversity indicators : lessons learnt from case studies in Africa

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    There is an increasing need for monitoring schemes that help understand the evolution of the global biodiversity crisis and propose solutions for the future. Indicators, including temporal baselines, are crucial to measure the change in biodiversity over time, to evaluate progress towards its conservation and sustainable use and to set conservation priorities. They help design and monitor national and regional policies on biodiversity; they also feed into national reporting on international agreements such as the Convention on Biological Diversity and the Sustainable Development Goals. We analyse the methodological approach of five small African projects resulting from a call to promote indicator development, improve monitoring capacity and strengthen the science-policy interface in the field of biodiversity. We compared their approach to existing guidance provided by the international community, specifically the Biodiversity Indicators Partnership. To this end, we assess whether internationally recommended steps are effectively applied to national/local biodiversity monitoring in selected developing countries. We also present lessons learnt from workshop interactions between partners involved in these projects. Through our pilot projects we identified data availability and data accessibility, together with the involvement of stakeholders, as critical steps in indicator development. Moreover, there is a need for a better awareness and a wider application of the indicator concept itself. Hence, training of key actors both in the policy and science spheres is needed to operationalize indicators and ensure their continuity and sustainability. We hope that these case studies and lessons learnt can stimulate and support countries in the Global South to formulate policy-relevant biodiversity indicators.Peer reviewe
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