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Sökning: WFRF:(Williams Alwyn)

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1.
  • Albizua, Amaia, et al. (författare)
  • Crop rotations including ley and manure can promote ecosystem services in conventional farming systems
  • 2015
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 95, s. 54-61
  • Tidskriftsartikel (refereegranskat)abstract
    • Agricultural intensification has contributed substantially to the increase in food production, but has come at the expense of soil degradation and environmental problems. Management of soil based ecosystem services need to be considered in agricultural management since intensive management implies not only costs to the farmer but also to society. In this study we used data from four long-term (55 years) agricultural experiments in southern Sweden to assess the effects of two arable farming systems on a range of indicators of soil ecosystem services. One farming system used only annual commodity crops (ACC system) while the other integrated one year of ley (ley system) into the crop rotation. Nitrogen (N) fertiliser was applied annually in both farming systems at two rates (0 and 150 kg N ha(-1)). The ley farming system had an addition of farmyard manure (FYM) once every fourth year. Soil organic carbon, total N, phosphorous, potassium, pH and water holding capacity were used as indicators of regulating services; bacterial and fungal biomass were used as indicators of supporting services; grain yield and protein content were used as indicators of provisioning services. We analysed each of the indicators separately, to identify effects of the farming systems, using linear mixed effects models. In addition, we used principal components analysis to bundle the individual indicators together to create latent variables representing categories of ecosystem services. Yields of wheat were greatest in the plots that received N fertiliser, irrespective of farming system, while mycorrhizal fungal biomass was greatest in the ley system with no inorganic N fertiliser. The rest of the indicators were similar in both farming systems although the lowest values of all ecosystem service indicators were found in the ACC system with no N fertiliser. When bundling the indicators, no trade-offs were found between regulating, supporting and provisioning services. Regulating and supporting services were positively correlated, as were regulating and provisioning services. The ley system with N fertiliser had significantly greater values of regulating and provisioning services relative to the other treatments. The results indicate that different farming systems can have large effects on ecosystem service flows, and that integrating leys into arable rotations can enhance the delivery of soil ecosystem services. (C) 2015 Elsevier B.V. All rights reserved.
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2.
  • Birkhofer, Klaus, et al. (författare)
  • A framework to identify indicator species for ecosystem services in agricultural landscapes
  • 2018
  • Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 91, s. 278-286
  • Tidskriftsartikel (refereegranskat)abstract
    • Improving our understanding of the relationships between biodiversity and the delivery of ecosystem services is crucial for the development of sustainable agriculture. We introduce a novel framework that is based on the identification of indicator species for single or multiple ecosystem services across taxonomic groups based on indicator species analyses. We utilize multi-species community data (unlike previous single species approaches) without giving up information about the identity of species in our framework (unlike previous species richness approaches). We compiled a comprehensive community dataset including abundances of 683 invertebrate, vertebrate and plant species to identify indicator species that were either positively or negatively related to biological control, diversity of red-listed species or crop yield in agricultural landscapes in southern Sweden. Our results demonstrate that some taxonomic groups include significantly higher percentages of indicator species for these ecosystem services. Spider communities for example included a higher percentage of significant positive indicator species for biological control than ground or rove beetle communities. Bundles of indicator species for the analysed ecosystem service potentials usually included species that could be linked to the respective ecosystem service based on their functional role in local communities. Several of these species are conspicuous enough to be monitored by trained amateurs and could be used in bundles that are either crucial for the provision of individual ecosystem services or indicate agricultural landscapes with high value for red-listed species or crop yields. The use of bundles of characteristic indicator species for the simultaneous assessment of ecosystem services may reduce the amount of labour, time and cost in future assessments. In addition, future analysis using our framework in other ecosystems or with other subsets of ecosystem services and taxonomic groups will improve our understanding of service-providing species in local communities. In any case, expert knowledge is needed to select species from the identified subsets of significant indicator species and these species should be validated by existing data or additional sampling prior to being used for ecosystem service monitoring.
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3.
  • Birkhofer, Klaus, et al. (författare)
  • Relationships between multiple biodiversity components and ecosystem services along a landscape complexity gradient
  • 2018
  • Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207 .- 1873-2917. ; 218, s. 247-253
  • Tidskriftsartikel (refereegranskat)abstract
    • The assessment of effects of anthropogenic disturbance on biodiversity (BD) and ecosystem services (ES) and their relationships are key priorities of the Intergovernmental Panel for Biodiversity and Ecosystem Services. Agricultural landscapes and their associated BD provide multiple ES and it is crucial to understand how relationships between ES and BD components change along gradients of landscape complexity. In this study, we related eight ES potentials to the species richness of five invertebrate, vertebrate and plant taxonomic groups in cereal farming systems. The landscape complexity gradient ranged from areas dominated by annually tilled arable land to areas with high proportions of unfertilized, non-rotational pastures and uncultivated field borders. We show that after accounting for landscape complexity relationships between yield and bird richness or biological control became more positive, but relationships between bird richness and biological control became less positive. The relationship between bird and plant richness turned from positive to negative. Multidiversity (overall biodiversity), was positively related to landscape complexity, whereas multifunctionality (overall ES provision), was not significantly related to either one of these. Our results suggest that multidiversity can be promoted by increasing landscape complexity; however; we found no support for a simultaneous increase of several individual ES, BD components or multifunctionality. These results challenge the assumption that bio-diversity-friendly landscape management will always simultaneously promote multiple ES in agricultural landscapes. Future studies need to verify this pattern by using multi-year data, larger sets of ES and BD components and a study design that is appropriate to address larger spatial scales and relationships in several regions.
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4.
  • Holmer, Lars E., et al. (författare)
  • A stem group brachiopod from the Lower Cambrian - support for a Micrina (Halkieriid) ancestry.
  • 2002
  • Ingår i: Palaeontology. - : Wiley. - 0031-0239 .- 1475-4983. ; 45:5, s. 875-882
  • Tidskriftsartikel (refereegranskat)abstract
    • The shell structure of the Lower Cambrian Mickwitzia, a bilaterally symmetrical bivalve hitherto doubtfully assigned to the Brachiopoda, confirms that the genus shares characters with linguliform brachiopods. The columnar lamination of its organophosphatic shell is homologous with that characterizing acrotretides. The shell, however, is also pervaded by striated apatitic tubes indistinguishable from those permeating the sclerites of the problematic organophosphatic, laminar–shelled Micrina which is close to Halkieria. No crown group brachiopods have such tubes that are presumed to have contained setae. The presence of both these features in the Mickwitzia shell suggests that the stock is a stem group brachiopod with a halkieriid ancestry.
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5.
  • Manoharan, Lokeshwaran, et al. (författare)
  • Agricultural management practices influence AMF diversity and community composition with cascading effects on plant productivity
  • 2017
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 115, s. 53-59
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding the effects of different agricultural practices on the mycorrhizal symbiosis is important for agricultural production and the sustainable use of soil. We investigated the composition and diversity of arbuscular mycorrhizal fungi (AMF) in soils from fields under different agricultural practices (conventional and organic cereal fields, leys and permanent pastures) in southern Sweden. The diversity of AMF was found to be greatest in permanent pastures, corroborating evidence that agricultural practices such as tillage impair AMF diversity. Neither geographical location nor soil type nor any of the major soil characteristics we measured impacted AMF diversity or community composition. AMF community composition was significantly affected by the different agricultural practices, particularly conventional management, which reduced AMF diversity. Of the cereal fields sampled, those under organic management held the greatest AMF diversity, and in a glasshouse experiment this greater diversity was positively related to barley phosphorus uptake and grain biomass production. Our results demonstrate the impact of different agricultural practices on AMF communities. In particular, we demonstrate the ability of organic farming to sustain greater AMF diversity relative to conventional farming, and the potential importance of this increased diversity for sustainable cereal production.
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6.
  • McCaddon, Andrew, et al. (författare)
  • Transcobalamin polymorphism and serum holo-transcobalamin in relation to Alzheimer's disease
  • 2004
  • Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 17:3, s. 215-221
  • Tidskriftsartikel (refereegranskat)abstract
    • Isoforms of the vitamin B<sub>12</sub> carrier protein transcobalamin (TC) might influence its cellular availability and contribute to the association between disrupted single-carbon metabolism and Alzheimer’s disease (AD). We therefore investigated the relationships between the TC 776C>G (Pro259Arg) genetic polymorphism, total serum cobalamin and holo-TC levels, and disease onset in 70 patients with clinically diagnosed AD and 74 healthy elderly controls. TC 776C>G polymorphism was also determined for 94 histopathologically confirmed AD patients and 107 controls. Serum holo-TC levels were significantly higher in TC 776C homozygotes (p = 0.04). Kaplan-Meier survival functions differed between homozygous genotypes (Cox’s F-Test F(42, 46) = 2.1; p = 0.008) and between 776C homozygotes and heterozygotes (Cox’s F test F(46, 108) = 1.7; p = 0.02). Proportionately fewer TC 776C homozygotes appear to develop AD at any given age, but this will require confirmation in a longitudinal study.
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7.
  • Williams, Alwyn, et al. (författare)
  • Above- and below-ground interactions with agricultural management: Effects of soil microbial communities on barley and aphids
  • 2014
  • Ingår i: Pedobiologia. - : Elsevier BV. - 1873-1511 .- 0031-4056. ; 57:2, s. 67-74
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent research has shown that agricultural management affects microbial biomass and community composition. We investigated the functional implications of such effects in terms of barley biomass production and nutrient acquisition, and whether changes in barley nutrient status affected aphid fecundity. Soils were collected from conventional, ley and organic arable fields and used as inocula in a glasshouse experiment. We determined microbial biomass and community composition using PLFA. We investigated barley growth and nutrient responses to the different soil inoculums, and the impact of excluding arbuscular mycorrhizal fungi (AMF). Aphids were applied to plants within clip cages and numbers of offspring counted. Microbial biomass and community composition were unaffected by agricultural management. The microbial communities altered root and shoot biomass and nutrient allocation, but had no effect on grain yield. Exclusion of AMF significantly increased shoot biomass but reduced grain yield. Aphid fecundity was not significantly affected by the microbial community or shoot nitrogen. We conclude that agricultural intensification does not necessarily have negative consequences for above- and below-ground interactions, and microbial communities from conventionally managed soils may offer equal benefit to crop productivity and nutrition as those from organically managed soils. (C) 2014 Elsevier GmbH. All rights reserved.
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8.
  • Williams, Alwyn, et al. (författare)
  • Different arbuscular mycorrhizae and competition with an exotic grass affect the growth of Podocarpus cunninghamii Colenso cuttings
  • 2013
  • Ingår i: New Forests. - : Springer Science and Business Media LLC. - 0169-4286 .- 1573-5095. ; 44, s. 183-195
  • Tidskriftsartikel (refereegranskat)abstract
    • There is growing interest in the use of arbuscular mycorrhizal fungi (AMF) for ecological restoration. Numerous commercial AMF products are now available and are often used in preference to collecting indigenous AMF in treating restoration plants. Commercial AMF products are typically based on AMF strains exotic to the plant species and locations where they are used. We treated rooted cuttings of an endemic New Zealand tree species (Podocarpus cunninghamii) and an exotic and invasive grass (Agrostis capillaris) with an indigenous, pot-cultured AMF (Acaulospora laevis) and an exotic commercial AMF product (Glomus spp.). P. cunninghamii was grown in monoculture and together with A. capillaris, the latter to simulate field competition that often occurs in restoration plantings. In monoculture, the indigenous AMF resulted in significant increases in P. cunninghamii growth rates and tissue concentrations of both nitrogen and phosphorus. The commercial AMF had either no effect or a negative effect on P. cunninghamii growth and nutrient levels. A. capillaris growth and nutrient status were unaffected by the different AMF treatments. Competition eliminated any AMF benefit for P. cunninghamii. The results show that, for our chosen indigenous woody plant species, the commercially available AMF did not improve its early growth and nutrient acquisition in monoculture while, over the same period, the indigenous AMF induced positive growth and nutrient responses. These results have potential implications for forest restoration, particularly for nursery production of indigenous woody species.
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9.
  • Williams, Alwyn, et al. (författare)
  • Different arbuscular mycorrhizal inoculants affect the growth and survival of Podocarpus cunninghamii restoration plantings in the Mackenzie Basin, New Zealand
  • 2012
  • Ingår i: New Zealand Journal of Botany. - 0028-825X. ; 50:4, s. 473-479
  • Tidskriftsartikel (refereegranskat)abstract
    • There is increasing interest in the use of arbuscular mycorrhizal fungi (AMF) for ecological restoration, as AMF can improve plant nutrition and growth. However, some AMF can have negative effects on plant growth. It is therefore critical that restoration strategies incorporate appropriate AMF. This research investigated differences in growth and survival of Podocarpus cunninghamii (mountain tōtara) cuttings with six different AMF inoculums, with the aim of choosing the most appropriate mycorrhizal species for restoration success. Cuttings of P. cunninghamii were inoculated with AMF ranging from indigenous to exotic, including commercially available AMF and AMF isolated from remnant P. cunninghamii forest and ex-agricultural grassland. Plant growth and survival was compared after two seasons at a high country restoration site in the Mackenzie Basin. Plants treated with forest and indigenous AMF had significantly greater survival than those treated with commercial AMF. Forest AMF also resulted in significantly greater P. cunninghamii growth than all the other treatments. This has potentially important implications for restoration, as improved growth and survival of native woody species can improve restoration success by increasing establishment success and reducing management costs.
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10.
  • Williams, Alwyn, et al. (författare)
  • Indicators and trade-offs of ecosystem services in agricultural soils along a landscape heterogeneity gradient
  • 2014
  • Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393. ; 77, s. 1-8
  • Tidskriftsartikel (refereegranskat)abstract
    • Soil functions can be classified as supporting (nutrient cycling) and provisioning (crop production) ecosystem services (ES). These services consist of multiple and dynamic functions and are typically assessed using indicators, e.g. microbial biomass as an indicator of supporting services. Agricultural intensification negatively affects indicators of soil functions and is therefore considered to deplete soil ES. It has been suggested that incorporating leys into crop rotations can enhance soil ES. We examined this by comparing indicators of supporting soil services - organic carbon, nitrogen, water holding capacity and available phosphorous (carbon storage and nutrient retention); net nitrogen mineralisation rate and microbial biomass (nutrient cycling and retention) - in barley fields, leys and permanent pastures along a landscape heterogeneity gradient (100, 500 and 1000 m radii). In addition, barley yields (provisioning service) were analysed against these indicators to identify trade-offs among soil services. Levels of most indicators did not differ between barley and ley fields and were consistently lower than in permanent pastures. Leys supported greater microbial biomass than barley fields. Landscape heterogeneity had no effect on the indicators or microbial community composition. However, landscape heterogeneity correlated negatively with yield and soil pH, suggesting that soils in heterogeneous landscapes are less fertile and therefore have lower yields. No trade-offs were found between increasing barley yield and the soil indicators. The results suggest that soil ES are determined at the field level, with little influence from the surrounding landscape, and that greater crop yields do not necessarily come at the expense of supporting soil services. (C) 2014 Elsevier B.V. All rights reserved.
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