| 1. |
- Volchko, Yevheniya, 1979, et al.
(författare)
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Assessing costs and benefits of improved soil quality management in remediation projects : A study of an urban site contaminated with PAH and metals
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 707
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Tidskriftsartikel (refereegranskat)abstract
- Contaminants in the soil may threaten soil functions (SFs) and, in turn, hinder the delivery of ecosystem services (ES). A framework for ecological risk assessments (ERAs) within the APPLICERA - APPLICable site-specific Environmental Risk Assessment research project promotes assessments that consider other soil quality parameters than only contaminant concentrations. The developed framework is: (i) able to differentiate the effects of contamination on SFs from the effects of other soil qualities essential for soil biota; and (ii) provides a robust basis for improved soil quality management in remediation projects. This study evaluates the socio-economic consequences of remediation alternatives stemming from a Tier 1 ERA that focusses on total contaminant concentrations and soil quality standards and a detailed, site-specific Tier 3 Triad approach that is based on the APPLICERA framework. The present study demonstrates how Tier 1 and Tier 3 ERAs differ in terms of the socio-economic consequences of their remediation actions, as well as presents a novel method for the semi-quantitative assessment of on-site ES. Although the presented Tier 3 ERA is more expensive and time-consuming than the more traditional Tier 1 ERA approach, it has the potential to lower the costs of remediation actions, decrease greenhouse gas emissions, reduce other environmental impacts, and minimise socio-economic losses. Furthermore, the remediation actions stemming from the Tier 3 ERA were predicted to exert far less negative ES effects than the actions proposed based on the results of the Tier 1 ERA.
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| 2. |
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| 3. |
- Auffret, Alistair, et al.
(författare)
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Can field botany be effectively taught as a distance course? Experiences and reflections from the COVID-19 pandemic
- 2022
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Ingår i: AoB PLANTS. - : Oxford University Press (OUP). - 2041-2851. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The COVID-19 pandemic that started in 2020 forced a rapid change in university teaching, with large numbers of courses switching to distance learning with very little time for preparation. Courses involving many practical elements and field excursions required particular care if students were to fulfil planned learning outcomes. Here, we present our experiences in teaching field botany in 2020 and 2021. Using a range of methods and tools to introduce students to the subject, promote self-learning and reflection and give rapid and regular feedback, we were able to produce a course that allowed students to achieve the intended learning outcomes and that obtained similarly positive student evaluations to previous years. The course and its outcomes were further improved in 2021. We describe how we structured field botany as a distance course in order that we could give the best possible learning experience for the students. Finally, we reflect on how digital tools can aid teaching such subjects in the future, in a world where public knowledge of natural history is declining.In an era of large-scale biodiversity change and reductions in basic knowledge of natural history, it is important that practical courses in subjects like field botany continue to be taught effectively. Forced by the COVID-19 pandemic to teach plant identification with no direct contact with students, we used a range of methods and tools to promote self-learning and reflection in students, and to facilitate rapid feedback by teachers. Here, we present our method for producing a course that allowed students to achieve the intended learning outcomes and that obtained positive student evaluations.
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| 4. |
- Barrios Latorre, Sergio Alejandro, et al.
(författare)
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Exploring the benefits of intermediate crops : Is it possible to offset soil organic carbon losses caused by crop residue removal?
- 2024
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Ingår i: Agricultural Systems. - 0308-521X .- 1873-2267. ; 215
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Agriculture plays a central role as a feedstock provider for the bioeconomy. However, utilization competing with food production and associated land use change have previously been a matter of debate. Nonetheless, strengthening the productivity of agroecosystems through sustainable intensification can prevent the depletion of natural resources, enhance food security, and facilitate adaptation to and mitigation of climate change. OBJECTIVE: This study explores the effects of combining crop residue removal for use as biomass feedstock with the establishment of intermediate crops to compensate for organic carbon depletion in arable land in Sweden. METHODS: The analysis relied on Swedish national agricultural statistics at the highest available spatial resolution (yield survey district). Crop residue calculations factored in crop:residue ratios, and harvestable and recoverable potentials. A model was devised to estimate land availability for cultivating intermediate crops based on generalized crop rotation sequences, and a spatial interpolation was employed to determine oilseed radish yields as a model intermediate crop. Estimates of long-term soil carbon inputs hinged on biomass carbon content and humification coefficients dependent on soil clay content. RESULTS AND CONCLUSION: The total annual residual biomass availability in the country stands at approximately 2139 kt per year. The potential harvestable biomass production from intermediate crops was estimated at 383 kt per year. However, spatial differences were evident in total biomass production and effects on soil organic carbon inputs. For the majority of districts, the inclusion of intermediate crops could offset the negative effect of a complete removal of crop residues on soil organic carbon inputs. In other cases, establishing intermediate crops could not compensate for these negative effects, but some differences were observed when comparing the harvesting and the incorporation of the intermediate crops' biomass. Spatial disparities originated from variations in soil texture, intermediate crop yield, and rotation sequences. SIGNIFICANCE: This research is an attempt to address the challenge of maintaining and increasing the soil carbon stocks under the context of a growing biomass demand in a developing biobased economy. It highlights the divergent effects of combining crop residue removal with the inclusion of intermediate crops under distinct agroecological conditions in the Northern European context. By giving estimates on biomass availability and effects on soil organic carbon inputs, we provide information that can support decision making for bioeconomy planning and sustainable resource utilization. This also has long-term implications for preservation of soil fertility, agricultural productivity and climate change mitigation.
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| 5. |
- Björsell, Pia, et al.
(författare)
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Interactions between some plant-parasitic nematodes and Rhizoctonia solani in potato fields
- 2017
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 113, s. 151-154
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Tidskriftsartikel (refereegranskat)abstract
- The pathogenic fungus Rhizoctonia solani causes major economic losses for potato producers in Sweden. Producers, as well as extension officers, have reported possible increases in severity of R. solani when free-living plant-parasitic nematodes are present and active. The aim of this study was to investigate possible interactions and spatial correlations between root-lesion nematodes (Pratylenchus spp.), stubby-root nematodes (Trichodoridae) and the severity of stem canker caused by the fungus R. solani under field conditions. Nematodes in the genus' Globodera were also included after finding high numbers of these potato cyst nematode juveniles in the samples. Soil samples were taken in eight potato fields, located in the middle part of Sweden, with observed outbreaks of soil-borne stem canker caused by R. solani. Grading of stem canker and soil collections for nematode extraction were performed along transects starting from the centre of field patches with observed stem canker. There was no difference in the number of nematodes within the patches for any of the investigated nematode taxa, but the severity of stem canker was higher on plants graded in the centre of the patches compared to those graded in the margins. In addition, there was a spatial correlation between R. solani and stubby-root nematodes as well as potato cyst nematodes, but not for root-lesion nematodes. These results show that there is an interaction between plant-parasitic nematodes and R. solani in the field and this knowledge is of importance for future decisions of appropriate management methods. (C) 2017 The Authors. Published by Elsevier B.V.
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| 6. |
- Borgström, Pernilla, et al.
(författare)
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Above- and belowground insect herbivores mediate the impact of nitrogen eutrophication on the soil food web in a grassland ecosystem
- 2018
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Ingår i: Oikos. - : Wiley. - 0030-1299 .- 1600-0706. ; 127, s. 1272-1279
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Tidskriftsartikel (refereegranskat)abstract
- Insect herbivores are important drivers of ecosystem processes in grasslands, and can mediate the grassland's response to environmental change. For example, recent evidence shows that above- and belowground herbivory, individually and in combination, can modify how a plant community responds to nitrogen (N) eutrophication, an important driver of global change. However, knowledge about how such effects extend to the associated soil food web is lacking. In a mesocosm experiment, we investigated how communities of soil nematodes - an abundant and functionally important group of soil organisms - responded to above- and belowground insect herbivory at contrasting N levels. We found that the strongest influence of above- and belowground herbivory on the nematode community appeared at elevated N. The abundance of root-feeding nematodes increased when either above- or belowground insect herbivores were present at elevated N, but when applied together the two herbivore types cancelled out one another's effect. Additionally, at elevated N aboveground herbivory increased the abundance of fungal-feeders relative to bacterial-feeders, which indicates changes in decomposition pathways induced by N and herbivory. Belowground herbivory increased the abundance of omnivorous nematodes. The shifts in both the herbivorous and detrital parts of the soil food web demonstrate that above- and belowground herbivory does not only mediate the response of the plant community to N eutrophication, but in extension also the soil food web sustained by the plant community. We conclude that feedbacks between effects of above- and belowground herbivory mediate the response of the grassland ecosystem to N eutrophication.
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| 7. |
- Borgström, Pernilla, et al.
(författare)
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Above- and belowground insect herbivory modifies the response of a grassland plant community to nitrogen eutrophication
- 2017
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 98, s. 545-554
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the role that species interactions play in determining the rate and direction of ecosystem change due to nitrogen (N) eutrophication is important for predicting the consequences of global change. Insects might play a major role in this context. They consume substantial amounts of plant biomass and can alter competitive interactions among plants, indirectly shaping plant community composition. Nitrogen eutrophication affects plant communities globally, but there is limited experimental evidence of how insect herbivory modifies plant community response to raised N levels. Even less is known about the roles of above- and below-ground herbivory in shaping plant communities, and how the interaction between the two might modify a plant community's response to N eutrophication. We conducted a 3-yr field experiment where grassland plant communities were subjected to above- and belowground insect herbivory with and without N addition, in a full-factorial design. We found that herbivory modified plant community responses to N addition. Aboveground herbivory decreased aboveground plant community biomass by 21%, but only at elevated N. When combined, above- and belowground herbivory had a stronger negative effect on plant community biomass at ambient N (11% decrease) than at elevated N (4% decrease). In addition, herbivory shifted the functional composition of the plant community, and the magnitude of the shifts depended on the N level. The N and herbivory treatments synergistically conferred a competitive advantage to forbs, which benefited when both herbivory types were present at elevated N. Evenness among the plant species groups increased when aboveground herbivory was present, but N addition attenuated this increase. Our results demonstrate that a deeper understanding of how plant-herbivore interactions above and below ground shape the composition of a plant community is crucial for making reliable predictions about the ecological consequences of global change.
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| 8. |
- Borgström, Pernilla, et al.
(författare)
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Aboveground insect herbivory increases plant competitive asymmetry, while belowground herbivory mitigates the effect
- 2016
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- Insect herbivores can shift the composition of a plant community, but the mechanism underlying such shifts remains largely unexplored. A possibility is that insects alter the competitive symmetry between plant species. The effect of herbivory on competition likely depends on whether the plants are subjected to aboveground or belowground herbivory or both, and also depends on soil nitrogen levels. It is unclear how these biotic and abiotic factors interactively affect competition. Ina greenhouse experiment, we measured competition between two coexisting grass species that respond differently to nitrogen deposition: Dactylis glomerata L., which is competitively favoured by nitrogen addition, and Festuca rubra L., which is competitively favoured on nitrogen-poor soils. We predicted: (1) that aboveground herbivory would reduce competitive asymmetry at high soil nitrogen by reducing the competitive advantage of D. glomerata; and (2), that belowground herbivory would relax competition at low soil nitrogen, by reducing the competitive advantage of F. rubra. Aboveground herbivory caused a 46 A) decrease in the competitive ability of F. rubra, and a 23% increase in that of D. glomerata, thus increasing competitive asymmetry, independently of soil nitrogen level. Belowground herbivory did not affect competitive symmetry, but the combined influence of above and belowground herbivory was weaker than predicted from their individual effects. Belowground herbivory thus mitigated the increased competitive asymmetry caused by aboveground herbivory. D. glomerata remained competitively dominant after the cessation of aboveground herbivory, showing that the influence of herbivory continued beyond the feeding period. We showed that insect herbivory can strongly influence plant competitive interactions. In our experimental plant community, aboveground insect herbivory increased the risk of competitive exclusion of F. rubra. Belowground herbivory appeared to mitigate the influence of aboveground herbivory, and this mechanism may play a role for plant species coexistence.
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| 9. |
- Borgström, Pernilla, et al.
(författare)
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Below‑ground herbivory mitigates biomass loss from above‑ground herbivory of nitrogen fertilized plants
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Herbivorous insects can infuence grassland ecosystem functions in several ways, notably by alteringprimary production and nutrient turnover. Interactions between above- and belowground herbivorycould afect these functions; an efect that might be modifed by nitrogen (N) addition, an importantglobal change driver. To explore this, we added above- (grasshoppers) and belowground (wireworms)insect herbivores and N into enclosed, equally composed, grassland plant communities in a fullyfactorial feld experiment. N addition substantially altered the impact of above- and belowgroundherbivory on ecosystem functioning. Herbivory and N interacted such that biomass was reduced underabove ground herbivory and high N input, while plant biomass remained stable under simultaneousabove- and belowground herbivory. Aboveground herbivory lowered nutrient turnover rate in thesoil, while belowground herbivory mitigated the efect of aboveground herbivory. Soil decompositionpotential and N mineralization rate were faster under belowground herbivory at ambient N, butat elevated N this efect was only observed when aboveground herbivores were also present. Wefound that N addition does not only infuence productivity directly (repeatedly shown by others), butalso appears to infuence productivity by herbivory mediated efects on nutrient dynamics, whichhighlights the importance of a better understanding of complex biotic interactions.
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| 10. |
- Bötzl, Fabian, et al.
(författare)
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Undersowing oats with clovers supports pollinators and suppresses arable weeds without reducing yields
- 2023
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 60, s. 614-623
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Tidskriftsartikel (refereegranskat)abstract
- Sustainable food production requires agriculture to conserve biodiversity and facilitate ecosystem services to maintain productivity levels while reducing inputs detrimental to ecosystem functioning. Increasing within-field vegetation diversity by legume intercropping seems promising to facilitate cropping system multi-functionality. Effects of intercropping with legumes on biodiversity-mediated ecosystem services such as pollination or natural pest control are, however, not sufficiently understood. Using 26 observation plots in a paired field design, we studied the effects of undersowing oats with a mixture of three annual clovers across different aspects of cropping system multi-functionality. We investigated 16 below- and above-ground ecosystem service indicators related to soil mineral nitrogen, arable weed control, pollination, disease and pest pressures, natural pest control and crop yield. We found lower arable weed cover, higher flower cover and pollinator densities as well as decreased root-feeding nematode densities in intercropped observation plots compared with the non-intercropped controls. However, intercropping decreased spider activity densities and oat yield nitrogen content. Root diseases, pest damages, natural pest control and crop yield were not affected by intercropping. The biomass of undersown clovers was positively related with the differences in flower cover and pollinator densities, and negatively related with the differences in arable weed cover between the intercropped and the control treatment. Synthesis and applications: We demonstrate that undersowing annual clovers suppresses arable weeds and simultaneously support pollinators without reducing crop yields or taking land out of arable production. Undersown plant mixtures should, however, be tailored to support a wider spectrum of pollinators and benefit natural pest control to support a higher level of overall cropping system multi-functionality.
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| 11. |
- Edin, Eva, et al.
(författare)
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Free-Living Plant-Parasitic Nematodes do not Affect the Efficiency of Seed Tuber Fungicide Treatment against Rhizoctonia solani
- 2017
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Ingår i: American Journal of Potato Research. - : Springer Science and Business Media LLC. - 1099-209X .- 1874-9380. ; 94, s. 258-265
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Tidskriftsartikel (refereegranskat)abstract
- Stem canker on germinating potato sprouts is often caused by seed-borne inoculum of the fungus Rhizoctonia solani. However, high amounts of freeliving plant-parasitic nematodes have been found in field patches of potato plants with stem canker. Fungicide treatment of the seed tubers can be used to avoid stem canker caused by seed-borne inoculum but it is unknown if nematodes can affect this. To investigate whether free-living plant-parasitic nematodes, the root-lesion nematode Pratylenchus penetrans or a combination of several plant-parasitic nematode genera in a full nematode community, may have a negative effect on the fungicide seed treatment, a pot experiment with seed tubers inoculated with R. solani, half of which were treated with fungicides, was performed. The seed-borne inoculum caused severe damage to the plants, while no fungal damages were observed on the fungicide treated plants. This shows that the nematodes did not affect the fungicide treatment. The probability of black scurf decreased in treatments with a full nematode community, which may be due to the action of fungal-feeding nematodes.
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| 12. |
- Edin, Eva, et al.
(författare)
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Temporal Interactions between Root-Lesion Nematodes and the Fungus Rhizoctonia Solani Lead to Reduced Potato Yield
- 2019
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Ingår i: Agronomy. - : MDPI AG. - 2073-4395. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Soil microorganisms and soil fauna may have a large impact on the tuber yield of potato crops. The interaction between root-lesion nematodes and the pathogenic fungus Rhizoctonia solani Kuhn was studied on potato plants grown in pots under controlled conditions. In two similar experiments, different combinations of nematodes and fungal mycelium were added to the pots at three occasions; at planting, after 14 days, and after 28 days. The nematodes reduced root biomass and the combination of nematodes and R. solani resulted in reduced tuber yield in both experiments, but the interaction was not synergistic. In contrast, the number of stem canker lesions decreased in the presence of nematodes compared to treatments with R. solani only. The time of inoculation influenced the severity of both fungal and nematode damage. The nematode damage on tubers was less severe if the nematodes were added at 28 days, while the number of severe stem canker lesions increased if the fungus was added at 28 days. However, the time of nematode inoculation did not affect the incidence of fungal damage, hence the nematodes did not assist R. solani to infect the plant. Our results highlight the underestimated importance of root-lesion nematodes, not resulting in obvious above ground symptoms or misshaped tubers yet affecting the performance of other pathogens.
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| 13. |
- Faber, Jack H., et al.
(författare)
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Stocktaking for Agricultural Soil Quality and Ecosystem Services Indicators and their Reference Values : EJP SOIL Internal Project SIREN Deliverable 2
- 2022
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The SIREN project has made an inventory of indicator systems for assessing soil quality and ecosystem services derived from agricultural soils, as currently used by Member States associated in the EJP SOIL program and beyond. The project aimed to identify and review the national approaches to make use of soil data in the assessment of soil-related ecosystem services, and has surveyed the knowledge gaps and needs for development hindering policy implementation as experienced in the 20 countries participating in the SIREN consortium. A comprehensive conceptual framework linking soil quality to ecosystem services has been collated from earlier proposals in the scientific literature, unifying various concepts associated with soil quality and ecosystem services, and providing a glossary of consistent terminology. SIREN has also taken stock of evaluation criteria for indicators of soil quality as implemented in national soil monitoring schemes. Based on reviews of literature, international policy, international stakeholder views, wide application in national soil monitoring and application in EU projects contributing to agricultural soil quality assessment, a synthesis was produced of policy-relevant soil quality indicators with high potential for harmonised application in national and European monitoring. A tiered approach is proposed for implementation of such a minimum dataset.
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| 14. |
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| 15. |
- Iqbal, Mudassir, et al.
(författare)
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Comparative evolutionary histories of fungal proteases reveal gene gains in the mycoparasitic and nematode-parasitic fungus Clonostachys rosea
- 2018
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Ingår i: BMC Evolutionary Biology. - : Springer Science and Business Media LLC. - 1471-2148. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Background: The ascomycete fungus Clonostachys rosea (order Hypocreales) can control several important plant diseases caused by plant pathogenic fungi and nematodes. Subtilisin-like serine proteases are considered to play an important role in pathogenesis in entomopathogenic, mycoparasitic, and nematophagous fungi used for biological control. In this study, we analysed the evolutionary histories of protease gene families, and investigated sequence divergence and regulation of serine protease genes in C. rosea.Results: Proteases of selected hypocrealean fungal species were classified into families based on the MEROPS peptidase database. The highest number of protease genes (590) was found in Fusarium solani, followed by C. rosea with 576 genes. Analysis of gene family evolution identified non-random changes in gene copy numbers in the five serine protease gene families S1A, S8A, S9X, S12 and S33. Four families, S1A, S8A, S9X, and S33, displayed gene gains in C. rosea. A gene-tree / species-tree reconciliation analysis of the S8A family revealed that the gene copy number increase in C. rosea was primarily associated with the S08.054 (proteinase K) subgroup. In addition, regulatory and predicted structural differences, including twelve sites evolving under positive selection, among eighteen C. rosea S8A serine protease paralog genes were also observed. The C. rosea S8A serine protease gene prs6 was induced during interaction with the plant pathogenic species F. graminearum.Conclusions: Non-random increases in S8A, S9X and S33 serine protease gene numbers in the mycoparasitic species C. rosea, Trichoderma atroviride and T. virens suggests an involvement in fungal-fungal interactions. Regulatory and predicted structural differences between C. rosea S8A paralogs indicate that functional diversification is driving the observed increase in gene copy numbers. The induction of prs6 expression in C. rosea during confrontation with F. graminearum suggests an involvement of the corresponding protease in fungal-fungal interactions. The results pinpoint the importance of serine proteases for ecological niche adaptation in C. rosea, including a potential role in the mycoparasitic attack on fungal prey.
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| 16. |
- Iqbal, Mudassir, et al.
(författare)
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Deletion of the Nonribosomal Peptide Synthetase Gene nps1 in the Fungus Clonostachys rosea Attenuates Antagonism and Biocontrol of Plant Pathogenic Fusarium and Nematodes
- 2019
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Ingår i: Phytopathology. - 0031-949X .- 1943-7684. ; 109, s. 1698-1709
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Tidskriftsartikel (refereegranskat)abstract
- Secondary metabolites produced by biological control agents may influence the outcome of their interactions with plant pathogenic microorganisms and plants. In the present study, we investigated the role of the nonribosomal peptide synthetase gene nps1 expressed by the biocontrol fungus Clonostachys rosea. A gene expression analysis showed that nps1 was induced during confrontations with the plant pathogenic fungus Botrytis cinerea. Gene deletion strains of nps1 displayed increased growth rates and conidiation. However, the nematicidal activity of culture filtrates from C. rosea Delta nps1 strains was significantly weaker than that from wild-type filtrates (P <= 0.001); after 24 h of incubation with culture filtrates from nps1 deletion strains, only 13 to 33% of a mixed community of nematodes were dead compared with 42% of nematodes incubated with wild-type culture filtrates. The Delta nps1 strains also showed reduced biocontrol efficacy during pot experiments, thus failing to protect wheat seedlings from foot rot disease caused by the plant pathogenic fungus Fusarium graminearum. Furthermore, C. rosea Delta nps1 strains were not able to reduce populations of plant-parasitic nematodes in soil or in roots of wheat as efficiently as the wild-type strain. Both C. rosea wild-type and Delta nps1 strains increased the dry shoot weight and shoot length of wheat by 20 and 13%, respectively. We showed that NPS1, a putative nonribosomal peptide synthetase encoded by nps1, is a biocontrol factor, presumably by producing a hitherto unknown nonribosomal peptide compound with antifungal and nematicidal properties that contributes to the biocontrol properties of C. rosea.
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| 17. |
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| 18. |
- Iqbal, Mudassir, et al.
(författare)
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Evaluation of Clonostachys rosea for Control of Plant- Parasitic Nematodes in Soil and in Roots of Carrot and Wheat
- 2018
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Ingår i: Phytopathology. - 0031-949X .- 1943-7684. ; 108, s. 52-59
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Tidskriftsartikel (refereegranskat)abstract
- Biological control is a promising approach to reduce plant diseases caused by nematodes. We tested the effect of the fungus Clonostachys rosea strain IK726 inoculation on nematode community composition in a naturally nematode infested soil in a pot experiment, and the effect of C. rosea on plant health. The numbers of plant- parasitic nematode genera extracted from soil and plant roots decreased by 40 to 73% when C. rosea was applied, while genera of nonparasitic nematodes were not affected. Soil inoculation of C. rosea increased fresh shoot weight and shoot length of wheat plants by 20 and 24%, respectively, while only shoot dry weight increased by 48% in carrots. Light microscopy of in vitro C. rosea-nematode interactions did not reveal evidence of direct parasitism. However, culture filtrates of C. rosea growing in potato dextrose broth, malt extract broth and synthetic nutrient broth exhibited toxicity toward nematodes and immobilized 57, 62, and 100% of the nematodes, respectively, within 48 h. This study demonstrates that C. rosea can control plant- parasitic nematodes and thereby improve plant growth. The most likely mechanism responsible for the antagonism is antibiosis through production of nematicidal compounds, rather than direct parasitism.
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| 19. |
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| 20. |
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| 21. |
- Iqbal, Mudassir, et al.
(författare)
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Natural variation of root lesion nematode antagonism in the biocontrol fungus Clonostachys rosea and identification of biocontrol factors through genome-wide association mapping
- 2020
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Ingår i: Evolutionary applications. - : Wiley. - 1752-4571. ; 13, s. 2264-2283
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Tidskriftsartikel (refereegranskat)abstract
- Biological control is a promising approach to reduce plant diseases caused by nematodes to ensure high productivity in agricultural production. Large-scale analyses of genetic variation in fungal species used for biocontrol can generate knowledge regarding interaction mechanisms that can improve efficacy of biocontrol applications. In this study, we performed a genome-wide association study (GWAS) for in vitro antagonism against the root lesion nematode Pratylenchus penetrans in 53 previously genome re-sequenced strains of the biocontrol fungus Clonostachys rosea. Nematode mortality in C. rosea potato dextrose broth (PDB) culture filtrates was highly variable and showed continuous variation (p < .001) between strains, indicating a polygenic inheritance. Twenty-one strains produced culture filtrates with higher (p <= .05) nematode mortality compared with the PDB control treatment, while ten strains lowered (p <= .05) the mortality. The difference in in vitro antagonism against P. penetrans correlated with antagonism against the soybean cyst nematode Heterodera glycines, indicating lack of host specificity in C. rosea. An empirical Bayesian multiple hypothesis testing approach identified 279 single nucleotide polymorphism markers significantly (local false sign rate < 10(-10)) associated with the trait. Genes present in the genomic regions associated with nematicidal activity included several membrane transporters, a chitinase and genes encoding proteins predicted to biosynthesize secondary metabolites. Gene deletion strains of the predicted nonribosomal peptide synthetase genes nps4 and nps5 were generated and showed increased (p <= .001) fungal growth and conidiation rates compared to the wild type. Deletion strains also exhibited reduced (p < .001) nematicidal activity and reduced (p <= .05) biocontrol efficacy against nematode root disease and against fusarium foot rot on wheat. In summary, we show that the GWAS approach can be used to identify biocontrol factors in C. rosea, specifically the putative nonribosomal peptide synthetases NPS4 and NPS5.
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| 22. |
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| 23. |
- Kardol, Paul, et al.
(författare)
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A test of the hierarchical model of litter decomposition
- 2017
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Ingår i: Nature ecology & evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 1, s. 1836-
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Tidskriftsartikel (refereegranskat)abstract
- Our basic understanding of plant litter decomposition informs the assumptions underlying widely applied soil biogeochemical models, including those embedded in Earth system models. Confidence in projected carbon cycle-climate feedbacks therefore depends on accurate knowledge about the controls regulating the rate at which plant biomass is decomposed into products such as CO2. Here we test underlying assumptions of the dominant conceptual model of litter decomposition. The model posits that a primary control on the rate of decomposition at regional to global scales is climate (temperature and moisture), with the controlling effects of decomposers negligible at such broad spatial scales. Using a regional-scale litter decomposition experiment at six sites spanning from northern Sweden to southern France-and capturing both within and among site variation in putative controls-we find that contrary to predictions from the hierarchical model, decomposer (microbial) biomass strongly regulates decomposition at regional scales. Furthermore, the size of the microbial biomass dictates the absolute change in decomposition rates with changing climate variables. Our findings suggest the need for revision of the hierarchical model, with decomposers acting as both local-and broad-scale controls on litter decomposition rates, necessitating their explicit consideration in global biogeochemical models.
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| 24. |
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| 25. |
- Pérez-Izquierdo, Leticia, et al.
(författare)
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Fire severity as a key determinant of aboveground and belowground biological community recovery in managed even-aged boreal forests
- 2023
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 13:5
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Tidskriftsartikel (refereegranskat)abstract
- Changes in fire regime of boreal forests in response to climate warming are expected to impact postfire recovery. However, quantitative data on how managed forests sustain and recover from recent fire disturbance are limited.Two years after a large wildfire in managed even-aged boreal forests in Sweden, we investigated how recovery of aboveground and belowground communities, that is, understory vegetation and soil microbial and faunal communities, responded to variation in the severity of soil (i.e., consumption of soil organic matter) and canopy fires (i.e., tree mortality).While fire overall enhanced diversity of understory vegetation through colonization of fire adapted plant species, it reduced the abundance and diversity of soil biota. We observed contrasting effects of tree- and soil-related fire severity on survival and recovery of understory vegetation and soil biological communities. Severe fires that killed overstory Pinus sylvestris promoted a successional stage dominated by the mosses Ceratodon purpureus and Polytrichum juniperinum, but reduced regeneration of tree seedlings and disfavored the ericaceous dwarf-shrub Vaccinium vitis-idaea and the grass Deschampsia flexuosa. Moreover, high tree mortality from fire reduced fungal biomass and changed fungal community composition, in particular that of ectomycorrhizal fungi, and reduced the fungivorous soil Oribatida. In contrast, soil-related fire severity had little impact on vegetation composition, fungal communities, and soil animals. Bacterial communities responded to both tree- and soil-related fire severity.Synthesis: Our results 2 years postfire suggest that a change in fire regime from a historically low-severity ground fire regime, with fires that mainly burns into the soil organic layer, to a stand-replacing fire regime with a high degree of tree mortality, as may be expected with climate change, is likely to impact the short-term recovery of stand structure and above- and belowground species composition of even-aged P. sylvestris boreal forests.
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| 26. |
- Ranheim Sveen, Tord, et al.
(författare)
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Core taxa underpin soil microbial community turnover during secondary succession
- 2024
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Ingår i: Environmental Microbiology. - 1462-2912 .- 1462-2920. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the processes that underpin the community assembly of bacteria is a key challenge in microbial ecology. We studied soil bacterial communities across a large-scale successional gradient of managed and abandoned grasslands paired with mature forest sites to disentangle drivers of community turnover and assembly. Diversity partitioning and phylogenetic null-modelling showed that bacterial communities in grasslands remain compositionally stable following abandonment and secondary succession but they differ markedly from fully afforested sites. Zeta diversity analyses revealed the persistence of core microbial taxa that both reflected and differed from whole-scale community turnover patterns. Differences in soil pH and C:N were the main drivers of community turnover between paired grassland and forest sites and the variability of pH within successional stages was a key factor related to the relative dominance of deterministic assembly processes. Our results indicate that grassland microbiomes could be compositionally resilient to abandonment and secondary succession and that the major changes in microbial communities between grasslands and forests occur fairly late in the succession when trees have established as the dominant vegetation. We also show that core taxa may show contrasting responses to management and abandonment in grasslands.Soil microbial communities are compositionally stable across grasslands under secondary succession but differ from paired forest reference sites. Core taxa underpin whole-community turnover patterns, with the underlying assembly processes driven by site-variation in soil pH.image
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| 27. |
- Ranheim Sveen, Tord, et al.
(författare)
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Plant-microbe interactions in response to grassland herbivory and nitrogen eutrophication
- 2021
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Ingår i: Soil Biology & Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 156
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Tidskriftsartikel (refereegranskat)abstract
- Plant-soil feedback is increasingly recognized as a vital framework to analyze multi-trophic interactions involving herbivores, plants and microbes, but research is still lacking on understanding such feedback in the context of global change. In grasslands, patterns of herbivory are expected to be affected by global change, further modifying existing plant-soil feedbacks. We tested this by evaluating the individual and combined impacts of aboveground herbivory by a generalist leaf-chewer and nitrogen (N) eutrophication, simulating elevated N deposition, on soil microbial communities and root colonization of arbuscular mycorrhizal fungi and related these to existing data on plant functional types and community composition. We found that colonization of arbuscular mycorrhizal fungi in the plant roots responded differently to treatments depending on host plant species in patterns consistent with the changes in the plant community composition and biomass. Further, the effect of aboveground herbivory on plant-soil interactions was comparable and even exceeded that of N-eutrophication, with the additive effects of herbivory and N-eutrophication on the soil microbiome being stronger than each factor separately. Our results suggest that plant-soil feedback in response to N-eutrophication is contingent on biotic variables such as herbivory and plant species, and that biotic and abiotic disturbances may have additive effects on the soil microbiome structure.
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| 28. |
- Rijk, Ingrid, 1985-, et al.
(författare)
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Effects of copper contamination on N cycling microbial guilds and plant performance in two contrasting grassland soils
- 2023
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Ingår i: Soil Biology and Biochemistry. - : Elsevier. - 0038-0717 .- 1879-3428. ; 180
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Tidskriftsartikel (refereegranskat)abstract
- Heavy metal pollution has important effects on ecosystem nitrogen (N) cycling, but factors driving differences between the direction, onset and intensity of responses are poorly understood. We used two contrasting grassland soils to examine the effects of copper (Cu) on the abundance and activity of N cycling microbial guilds and plant responses, including plant delta 15N as an integrator of the N cycle. A low pH sandy soil and a high pH sandy loam soil were aged two years in outdoor mesocosms with copper (Cu) treatments of background, 200, 400 or 1000 mg kg-1 Cu. After two years, increased Cu treatments resulted in significantly lower abundances of ammonia oxidizing archaea, Nitrospira nitrite oxidizing bacteria (NOB), potential ammonia oxidation rates and plant biomass in both soils. Plants possessed significantly increased N content and enriched shoot delta 15N in with higher Cu in both soils. While abundances of ammonia oxidizing bacteria were unaffected by Cu, the response among Nitrobacter NOB and denitrifiers and plant delta 13C differed between the two soils. In contrast to plants, differences in the intensity and direction of microbial guild responses were not explained by increasing soluble Cu but rather shaped by soil type. This indicates that the two soils differed in metal bioavailability to plants, as well as harbored microbial communities with inherent differences in metal sensitivity. Furthermore, effects of increasing Cu on microbial N-cycling guilds became more apparent with longer incubation time, emphasizing the importance of long-term studies to assess important ecosystem effects of Cu contamination. Taken together, we conclude that a combination of plant and microbial responses can give better insights on how Cu is affecting the N cycle in polluted soils.
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| 29. |
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| 30. |
- Stenberg, Johan A, et al.
(författare)
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When is it biological control? A framework of definitions, mechanisms, and classifications
- 2021
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Ingår i: Journal of Pest Science. - : Springer Science and Business Media LLC. - 1612-4758 .- 1612-4766. ; 94, s. 665-676
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Forskningsöversikt (refereegranskat)abstract
- Biological control, or biocontrol, is the exploitation of living agents (incl. viruses) to combat pestilential organisms (incl. pathogens, pests, and weeds) for diverse purposes to provide human benefits. Thus, during the last century the practices and concepts involved have evolved in separate streams associated with distinct scientific and taxonomic disciplines. In parallel developments, there have been increasing references to biological control in industrial contexts and legislation, resulting in conceptual and terminological disintegration. The aim of this paper is to provide a global conceptual and terminological platform that facilitates future development of the field. We review use of previously suggested terms in key fields (e.g., phytopathology, entomology, and weed science), eliminate redundant terminology, identify three principles that should underpin the concept, and then present a new framework for biological control, rooted in seminal publications. The three principles establish that (1) only living agents can mediate biological control, (2) biological control always targets a pest, directly or indirectly, and (3) all biocontrol methods can be classified in four main categories depending on whether resident agents are utilized, with or without targeted human intervention (conservation biological control and natural biological control, respectively) or agents are added for permanent or temporary establishment (classical biological control and augmentative biological control, respectively). Correct identification of what is, and is not, biological control can help efforts to understand and optimize biological pest control for human and environmental benefits. The new conceptual framework may contribute to more uniform and appropriate regulatory approaches to biological control, and more efficient authorization and application of biocontrol products.
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| 31. |
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| 32. |
- Torppa, Kaisa A., et al.
(författare)
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Soil moisture and fertility drive earthworm diversity in north temperate semi-natural grasslands
- 2024
-
Ingår i: Agriculture, Ecosystems & Environment. - 0167-8809 .- 1873-2305. ; 362
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Tidskriftsartikel (refereegranskat)abstract
- Intensive management of arable land reduces earthworm density and diversity. This may impair earthworm-mediated soil functions, such as nutrient mineralization and soil structure formation. To sustain earthworm source populations for re-colonization of cultivated soils, it is therefore important to preserve habitats with high earthworm diversity. Semi-natural grasslands, with a long continuity without soil disturbance, could serve as such earthworm diversity reservoirs. This is particularly important in mixed agricultural landscapes with elements of multiple land uses. Nonetheless, earthworm density and diversity vary greatly among grasslands. To preserve and optimally manage the most suitable grasslands, knowledge about which grassland characteristics best explain earthworm diversity is needed. Additionally, we have a limited picture of earthworm diversity in general, because previous studies have neglected juvenile earthworms and cryptic species. The juvenile fraction commonly comprises the main part of earthworm samples, whereas morphologically inseparable cryptic species account for an unknown fraction. This fraction is of particular importance, as juveniles reflect the local reproductive and regeneration potential of earthworm populations and communities. To determine the full species composition of earthworm communities, we sampled earthworms from 28 semi-natural grasslands in south-central Sweden and identified them to species by DNA barcoding. To test how grassland characteristics explain earthworm density, diversity, and community composition, we measured several characteristics of soils, vegetation, and management of the grasslands, and descriptors of the surrounding landscape. DNA barcoding revealed nearly twice as many species as were identified morphologically. Earthworm densities were higher in grasslands with higher Ellenberg moisture indicator values and lower soil C:N ratios. The diversity and occurrence of many earthworm species was also higher in grasslands with higher soil moisture indicator values and lower C:N ratios, and further increased with habitat heterogeneity. Certain species occurred more likely in grasslands with higher grazing intensity. Epigeic earthworms, which live in and feed on surface litter, were more common in grasslands with higher moisture indicator values and SOM content. Thus, dry and relatively unproductive semi-natural grasslands, which are common in Sweden, are unlikely to sustain high earthworm diversity – a pattern contrasting to previously reported plant diversity responses. Instead, earthworm diversity seems concentrated to more productive grazed grasslands, with large within-grassland heterogeneity. Therefore, we highlight the importance of considering soil animals in conservation policies for semi-natural grasslands.
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| 33. |
- Torppa, Kaisa, et al.
(författare)
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Soil compaction effects on arbuscular mycorrhizal symbiosis in wheat depend on host plant variety
- 2023
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Ingår i: Plant and Soil. - 0032-079X .- 1573-5036. ; 493, s. 555-571
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Tidskriftsartikel (refereegranskat)abstract
- Background and aim sSupporting arbuscular mycorrhizal (AM) nutrient acquisition in crops may reduce the need for fertilizer inputs, leading to more cost effective and sustainable crop production. In wheat, AM fungal responsiveness and benefits of symbiosis vary among varieties. This study explored the role of soil compaction in this variation.Methods We examined in a field experiment how soil compaction affects AM fungal colonization and biomass in five spring wheat varieties, and how these varieties differ in their AM-mediated phosphorus (P) uptake. We also studied soil properties, and AM fungal community composition in roots and soil.Results Soil compaction increased AM fungal colonization in the variety Alderon, characterized by root traits that indicate inefficient P uptake. Wheat P concentration and P:N ratio in Alderon and Diskett increased with increased root AM fungal colonization and biomass. In Diskett, which is the most cultivated spring wheat variety in Sweden and has intermediate root traits, total P content per m2 also increased with root AM fungal colonization and biomass.Conclusions Some wheat varieties, potentially those characterized by P inefficient root traits, such as Alderon, may depend more on AM-mediated P uptake in compacted than in non-compacted soil. Increased P uptake with increased AM fungal colonization in Diskett suggests that efficient root and AM-mediated nutrient uptake can occur simultaneously in a modern variety. Breeding varieties that use roots and AM symbiosis as complementary strategies for nutrient uptake could improve nutrient uptake efficiency and help farmers achieve stable yields in varying conditions.
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| 34. |
- Viketoft, Maria, et al.
(författare)
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Additive effect of the root-lesion nematode Pratylenchus penetransand the fungus Rhizoctonia solanion potato yield and damage
- 2020
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Ingår i: Journal of Plant Diseases and Protection. - : Springer Science and Business Media LLC. - 1861-3829 .- 1861-3837. ; 127, s. 821-829
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Tidskriftsartikel (refereegranskat)abstract
- The significance of nematodes for disease development caused by other soil-borne pathogens has been demonstrated in many crops throughout the world and specifically prevalent are interactions between plant-parasitic nematodes and species of plant pathogenic fungi. Here, the interaction between the fungusRhizoctonia solani(AG2) and the migratory endoparasitic root-lesion nematodePratylenchus penetranswas investigated on potato. The hypotheses were that the combination ofR. solaniandP. penetranswould result in more severe canker lesions, reduced quality of the tubers and lower tuber yield, and we also expected higher nematode levels to render more nematode damage. To test this, potato plants were grown in pots in two replicate experiments and the presence and/or abundance of the two pathogens were controlled. The first three hypotheses were rejected as (1) the tuber yield decreased when the fungus and nematode occurred together but not more than the sum of their separate effects, i.e. additive, (2) there was no effect of presence of nematodes on the incidence of stem canker, and (3) the quality of tubers was actually partly improved as the presence of the nematodes reduced the likelihood of elephant hide on the tubers in one of the experiments. As expected, there were more visible nematode damages with addition of more nematodes, but beyond that the different nematode levels rendered in most cases similar responses. To have knowledge about interactions between pathogens, as the one showed here, is essential for disease control through appropriate management methods.
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| 35. |
- Viketoft, Maria, et al.
(författare)
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Cultivar Effects on the Interaction between Free-Living Plant-Parasitic Nematodes and the Fungal Pathogen Rhizoctonia solani in Potato
- 2017
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Ingår i: American Journal of Potato Research. - : Springer Science and Business Media LLC. - 1099-209X .- 1874-9380. ; 94, s. 314-322
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Tidskriftsartikel (refereegranskat)abstract
- Crop damage is associated with infection by plant pathogens but can also arise through abiotic factors. However, the plant pathogens are involved in biotic interactions with other plant pathogens, and these interactions may differ depending of the cultivar of the crop. Here, the interaction between the fungus Rhizoctonia solani (AG3) and free-living plant-parasitic nematodes was investigated in a pot experiment with different potato cultivars. No synergistic interaction between R. solani and plant-parasitic nematodes was found, instead there was an effect of treatment with lower tuber yield when nematodes occurred alone. There were differences among the cultivars regarding incidence of black scurf, dry weight of stems and tubers, and there was interactive effects between treatment and cultivar regarding dry weight of stolons and roots. Therefore, results concerning incidence and damage of R. solani and/or plant-parasitic nematodes found for one cultivar may not be applicable to other cultivars.
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| 36. |
- Viketoft, Maria
(författare)
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Determinants of small-scale spatial patterns: Importance of space, plants and abiotics for soil nematodes
- 2013
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 62, s. 92-98
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Tidskriftsartikel (refereegranskat)abstract
- Belowground communities support a great diversity of organisms, but the factors that maintain and regulate this diversity are poorly understood. Both abiotic and biotic factors affect the abundance, diversity and distribution of soil organisms, and the spatial heterogeneity in these factors is a key in explaining belowground biodiversity. However, a combined approach estimating the relative importance of spatial and environmental factors in small-scale structuring of soil communities is yet missing. Here, a semi-natural grassland in south-central Sweden with high diversity of plants was sampled at two spatial scales (10 and 60 cm intervals) with the aim to examine the relative roles of plant identity, abiotic environmental factors and spatial factors for the small-scale spatial patterns of nematodes. The data were analysed by variance partitioning with redundancy analysis. Space, vegetation and abiotics were of similar importance for variation in nematode community composition. However, the contribution of the different sets of variables differed between the different nematode feeding groups: plant-feeding nematodes were influenced more by spatial variables, fungal-feeding nematodes and omnivores/predators more by plants and bacterial-feeding nematodes more by abiotic variables. The ranges of spatial dependence for the different feeding groups were all of the same magnitude, around 1 m. The results add to the understanding of the factors that contribute to soil biodiversity, and they show that combining plant and abiotic variables into one set of environmental variables hide important information about the drivers for belowground community assembly. (C) 2013 Elsevier Ltd. All rights reserved.
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| 37. |
- Viketoft, Maria
(författare)
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Development of Loop-Mediated Isothermal Amplification Assay for Rapid Detection and Analysis of the Root-Knot Nematode Meloidogyne hapla in Soil
- 2022
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Ingår i: Horticulturae. - : MDPI AG. - 2311-7524. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Soil analysis is crucial for estimating the risk of crop damage by the root-knot nematode Meloidogyne hapla. Here, we developed an analysis assay based on Loop-mediated Isothermal Amplification (LAMP). The LAMP primers were verified for specificity against 10 different nematode species. A manual soil DNA extraction, referred to as SKMM, was developed and compared with a FastDNA kit followed by DNA purification. DNA was extracted with both methods from artificially inoculated soils as well as from naturally infested soil collected from farm fields. The primers exclusively amplified DNA from M. hapla with both colorimetric and real-time LAMP. The detection limit was 193 gene copies and 0.0016 juveniles (12 pg mu L-1) per reaction. DNA concentrations and purity (A(260)/A(230)) were significantly higher using the SKMM procedure compared with the kit. From the field samples collected in 2019, DNA was amplified from 16% of samples extracted with SKMM and from 11% of samples using the kit. Occurrence of M. hapla DNA was confirmed in soil samples from two out of six field soils in 2020 using both real-time LAMP and qPCR. In conclusion, the developed real-time LAMP is a fast and specific assay for detection and quantification of M. hapla DNA in soil.
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| 38. |
- Viketoft, Maria
(författare)
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Effects of plant species and plant diversity on soil nematodes - a field experiment on grassland run for seven years
- 2011
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Ingår i: Nematology. - 1388-5545 .- 1568-5411. ; 13, s. 115-131
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Tidskriftsartikel (refereegranskat)abstract
- Plant species identity and diversity may greatly influence the composition of the nematode fauna. In this study the development of the nematode fauna was followed in a field experiment on arable soil with monocultures and mixtures of several plant species. Experimental plots were sown with one, four or 12 species of grass, legumes and forbs and were sampled four times in 7 years. Nematode diversity was little influenced by plant diversity. Due to a pronounced increase of Paratylenchus project us populations, the Shannon diversity index decreased in several treatments towards the end of the experiment. Differences in nematode faunal composition among treatments increased with time. In spite of the rather long duration of the experiment, the faunal composition did not stabilise but changed continuously. The obligate plant feeders Tylenchorhynchus dubius, T maximus and Pratylenchus spp. occurred in higher numbers in monocultures than in mixtures of several plant species. Among the microbivores, the abundance of some bacterial- and fungal-feeding nematode taxa seemed to be directly influenced by the plant species identity. In the plots with Trifolium spp. there was an increase of rapidly growing bacterial feeders belonging to Rhabditidae and Panagrolaimidae already after the first growing season. The abundances of some bacterial-feeding nematodes were correlated to total plant production. The numbers of the omnivorous Mesodorylaimus sp. appeared to be influenced by the degree of plant coverage. The abundance of several nematode taxa appeared to be little influenced by the composition of the vegetation. The plant feeder P. projectus and the bacterial feeder Prismatolaimus sp. reacted rather slowly and a distinct increase in numbers was only seen after 7 years, when P projectus strongly dominated the fauna in several treatments. Among the bacterial feeders, some species with moderate growth rate belonging to Cephalobidae decreased with time in several treatments.
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| 39. |
- Viketoft, Maria, et al.
(författare)
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Frilevande nematoder kan förvärra angrepp av groddbränna
- 2016
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Ingår i: Viola Potatis. - 2002-0309. ; , s. 28-29
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Betydelsen av frilevande nematoder i potatisodling är troligtvis underskattad. De kan ge skördesänkningar utan några iögonfallande ovanjordiska symtom eller missformade knölar. Dessutom kan de förvärra angrepp av andra skadeorganismer.
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| 40. |
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| 41. |
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| 42. |
- Viketoft, Maria, et al.
(författare)
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Helminths associated with terrestrial slugs in Swedish agricultural fields
- 2023
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Ingår i: Journal of Helminthology. - 0022-149X .- 1475-2697. ; 97
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Tidskriftsartikel (refereegranskat)abstract
- Slugs are important agricultural pests causing yearly yield losses. However, parasitizing helminths potentially could affect the size of the slug population. Here, a survey of terrestrial slug-parasitic helminths (nematodes and trematodes) was conducted for the first time in Sweden. In total, 268 terrestrial slugs were collected from 27 agricultural field edges in three seasons over 2020 and 2021 and dissected for presence of helminth parasites. Slugs belonging to the genus Arion were molecularly identified by mitochondrial DNA cytochrome c oxidase subunit I (COI) while parasites were identified using ribosomal RNA (18S). Overall, 13% of the collected slugs had helminth parasites and the likelihood of a slug being parasitized was highest in autumn. Slugs identified as Arion vulgaris were more likely to be parasitized than native slug species. The prevalence of nematodes and trematodes were similar; the dominant species found were Alloionema appendiculatum and Brachylaima thompsoni, respectively. This is the first record of the presence of these two species in Sweden.
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| 43. |
- Viketoft, Maria, et al.
(författare)
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Long-term effects of plant diversity and composition on soil nematode communities in model grasslands
- 2009
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 90, s. 90-99
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Tidskriftsartikel (refereegranskat)abstract
- An important component of plant-soil feedbacks is how plant species identity and diversity influence soil organism communities. We examine the effects of grassland plant species growing alone and together up to a richness of 12 species on nematode diversity and feeding group composition, eight years after the establishment of experimental grassland plots at the BIODEPTH site in northern Sweden. This is a substantially longer time than most other experimental studies of plant effects on soil fauna. We address the hypotheses that (1a) higher species or functional diversity of plants increases nematode diversity, as well as influences nematode community composition. Alternatively, (1b) individual plant species traits are most important for nematode diversity and community composition. (2) Plant effects on soil organisms will decrease with increasing number of trophic links between plants and soil fauna.Plant species identity was often more important than plant diversity for nematode community composition, supporting hypothesis 1b. There was a weak positive relation between plant and nematode richness, which could be attributed to the presence of the legume Trifolium pratense, but also to some other plant species, suggesting a selection or sampling effect. Several plant species in different functional groups affected nematode community composition. For example, we found that legumes increased bacterial-feeding nematodes, most notably r-selected Rhabditida, while fungal-feeding nematodes were enhanced by forbs. Other bacterial feeders and obligate root feeders were positively related to grasses. Plant effects were usually stronger on plant-, bacterial- and fungal-feeding nematodes than on omnivores/predators, which supports hypothesis 2.Our study suggests that plant identity has stronger effects than plant diversity on nematode community composition, but when comparing our results with similar previous studies the effects of particular plant species appear to vary. We also found that more productive plant species affected bacterial- feeding nematodes more than fungal feeders. Moreover, we observed stronger effects the fewer the number of trophic links there were between a nematode feeding group and plants. Although we found clear effects of plants on soil nematodes, these were probably not large enough to result in strong and persistent plant- soil-organism-plant feedback loops.
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| 44. |
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| 45. |
- Viketoft, Maria, et al.
(författare)
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Odla för nyttodjur : En praktisk handbok om pollen- och nektarproducerande växter som gynnar nyttoinsekter
- 2022
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Rapport (populärvet., debatt m.m.)abstract
- Det övergripande syftet med denna handbok är att öka kunskapen om nyttodjur som pollinerar grödor eller begränsar skadegörare i svensk växtodling genom att samla information som hjälper till att välja vilka växtarter som kan odlas i blomremsor för att effektivt främja och stödja nyttodjurens populationer. Vi har samlat vetenskapliga belägg om effekter på nyttodjur för 40 växtarter. Vi sammanfattar praktiska erfarenheter av att odla dessa växtarter och ger en översikt över både generella och artspecifika odlingsanvisningar.Sammanställningen innefattar också möjliga problem med att odla vissa arter. I arbetet med att ta fram denna handbok genomförde vi ett fältförsök där vi testade tio växtarters potential att bli ogräs i nästa års gröda. Försöket visade att risken för att de tio arterna ska bli ogräs i efterföljande sockerbetsodling är liten.Handboken är tänkt att användas som uppslagsverk för lantbrukare och rådgivare som vill välja arter till sin blomremsa. Beroende på syftet med blomremsan kan man välja olika artsammansättning. Vill man gynna pollinerande humlor är det bra att välja blommor som ger gott om pollen och nektar i ganska djupa blommor från vår till höst. För att gynna naturliga fiender till skadegörare kan det vara bättre att fokusera på grundare blommor vars pollen och nektar är mer lättillgängligt. Vi sammanfattar de vetenskapliga beläggen för hur bra 40 olika växtarter är för att främja olika typer av nyttodjur. Vi har också samlat information om dessa växtarter uppförökar skadeinsekter eller sjukdomar. Sist, men inte minst, har vi sammanställt lantbrukares praktiska erfarenheter av att odla de 40 växtarterna.
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| 46. |
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| 47. |
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| 48. |
- Viketoft, Maria, et al.
(författare)
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Skadegörare och växtskydd i rot- och knölgrödor
- 2019
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Rapport (populärvet., debatt m.m.)abstract
- Det finns ett stort antal rot- och knölgrödor och många av dessa odlas på en liten areal i Sverige. Några håller på att introduceras (t.ex. sötpotatis) och kanske kan odlingen bli mer omfattande i framtiden. De flesta radodlade rot och knölgrödor har under en period i utvecklingen en stor yta av obeväxt mark som gynnar utvecklingen av ogräs och flera markbundna patogener/skadegörare, både svampar och skadedjur kan angripa flera av dessa grödor. Denna litteraturöversikt har arbetats fram inom ett fokusgrupp-projekt inom Plattform Växtskydd vid SLU 2017–2019.För att få en rimlig avgränsning valde vi att fokusera på de för närvarande större grödorna potatis, sockerbetor, lök och morot.Rapporten är indelad i tre delar som behandlar:• Insekter, virus och nematoder• Svampar, svampliknande organismer och bakterier• OgräsSyftet med fokusgruppen var att i samverkan mellan forskare, rådgivare och näring beskriva de viktigaste växtskyddsproblemen i rot- och knölgrödor samt att bidra till och försöka hitta vägar till att öka finansieringen till forskning för att underlätta innovation och genomförande av ett hållbart växtskydd i dessa grödor. Vi har lagt ett särskilt fokus på potatis, lök, morötter och sockerbetor.Några generella slutsatser om prioriterade forskningsområden:• Behovet av forskning utifrån ett odlingssystemperspektiv (växtföljd, odlingsåtgärder etc) där man kan undersöka flera skadegörare samtidigt. Att försöka få till fler projekt med deltagardriven forskning där odlare involveras och där odlarexperiment ingår.• Sjukdomar orsakade av svampen Rhizoctonia solani är generellt viktiga och skördeförlusterna orsakade av angrepp är dåligt kända i många fall och behöver utredas noggrannare. Svampen har ett brett spektrum av värdväxter, särskilt rot och knölgrödor och det finns interaktioner med flera andra skadegörare, t.ex. nematoder som är viktiga att studera vidare.• Viktigt att utreda konsekvenser och ta fram alternativa metoder till bekämpningsmedel som riskerar att försvinna och en förmodad framtida generellt minskad tillgång till effektiva kemiska medel.• Osäkerheten vad gäller ett framtida förbud för användning av glyfosat gör att utvecklingen av alternativa ogrässtrategier måste ges hög prioritet.• Stort behov av utveckling av alternativa bekämpningsmetoder och utveckling av appliceringsteknik anpassad till dessa.• Behov av teknisk utveckling kring prognosmodeller, sensor- och robotteknik för tidig detektion av olika skadegörare.• Behov av studier av skadegörares spridningsbiologi (vind-vektorer-maskin-utsäde).• Behov av bättre och säkrare diagnostikDet finns stort behov av ökad finansiering till den tillämpningsnära växtskyddsforskningen i samverkan med rådgivning och näring.
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| 49. |
- Viketoft, Maria
(författare)
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Soil and Freshwater and Marine Sediment Food Webs: Their Structure and Function
- 2013
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Ingår i: Bioscience. - : Oxford University Press (OUP). - 0006-3568 .- 1525-3244. ; 63, s. 35-42
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Tidskriftsartikel (refereegranskat)abstract
- The food webs of terrestrial soils and of freshwater and marine sediments depend on adjacent aboveground or pelagic ecosystems for organic matter input that provides nutrients and energy. There are important similarities in the flow of organic matter through these food webs and how this flow feeds back to primary production. In both soils and sediments, trophic interactions occur in a cycle in which consumers stimulate nutrient cycling such that mineralized resources are made available to the primary producers. However, aquatic sediments and terrestrial soils differ greatly in the connectivity between the production and the consumption of organic matter. Terrestrial soils and shallow aquatic sediments can receive organic matter within hours of photosynthesis when roots leak carbon, whereas deep oceanic sediments receive organic matter possibly months after carbon assimilation by phytoplankton. This comparison has implications for the capacity of soils and sediments to affect the global carbon balance.
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| 50. |
- Viketoft, Maria
(författare)
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Soil nematode populations in a grassland plant diversity experiment run for seven years
- 2011
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 48, s. 174-184
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Tidskriftsartikel (refereegranskat)abstract
- Plant species identity and diversity may greatly influence the composition of the nematode fauna. The abundance of various nematode populations was investigated in a field experiment on plant diversity. 58 plots in an arable field planted with plant species growing alone or together up to a richness of 12 species were sampled after seven years for analysis of composition of the nematode fauna. Two additional control plots without vegetation were also sampled. Plant species identity was generally more important than plant diversity for the composition of the nematode fauna. Only the omnivorous Aporcelaimidae was positively related to plant species richness, and the fungal-feeding Aphelenchus and the bacterial-feeding Prismatolaimus were affected by functional diversity. Some nematode populations were strongly influenced by plant species composition, e.g. the plant-feeder Tylenchorhynchus maxim us was clearly coupled to the grass Phleum pratense. Nematode species within a feeding group sometimes had a rather specific abundance patterns under various plant species and plant species combinations. This was especially the case with the plant-feeding nematodes some of which obviously were directly influenced by the host suitability of specific plant species. Other nematode species were probably more influenced by indirect effects of plants on edaphic and nutrient conditions including biotic interactions from other components in the soil organism community. Yet other nematode species were little influenced by the kind of vegetation in the different plots. Our results show that to fully understand plant community effects on the nematode fauna there is a need to go further than just a division into nematode feeding groups. (C) 2011 Elsevier B.V. All rights reserved.
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