| 1. |
- Bahr, Adam, et al.
(författare)
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Growth of ectomycorrhizal fungal mycelium along a Norway spruce forest nitrogen deposition gradient and its effect on nitrogen leakage
- 2013
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 59, s. 38-48
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Tidskriftsartikel (refereegranskat)abstract
- Almost all boreal and temperate forest tree species live in symbiosis with ectomycorrhizal fungi (EMF); the trees transfer carbon (C) to the fungi in exchange for nutrients and water. Several studies have shown that experimental application of inorganic nitrogen (N) represses production of EMF extramatrical mycelia (EMM), but studies along N deposition gradients are underrepresented. Other environmental variables than N may influence EMM production and in this study we included 29 thoroughly monitored Norway spruce stands from a large geographical region in Sweden in order to evaluate the importance of N deposition on EMM growth and N leaching in a broader context. It was concluded that N deposition was the most important factor controlling EMM production and that the amounts typically deposited in boreal and boreo-nemoral regions can be sufficient to reduce EMM growth. Other factors, such as phosphorus status and pH, were also correlated with EMM production and should be considered when predicting EMM growth and N leaching. We also showed that EMM production substantially contributed to the C sequestration (320 kg ha(-1) yr(-1)), suggesting that it should be included in C cycle modelling. Furthermore, EMF are probably important for the N retention capacity since high N leaching coincided with low EMM growth. However, it was not possible to differentiate between the effects of EMF and the direct effect of N deposition on N leaching in the present study.
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| 2. |
- Ekblad, Alf, et al.
(författare)
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Production and turnover of ectomycorrhizal extramatrical mycelial biomass and necromass under elevated CO2 and nitrogen fertilization
- 2016
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Ingår i: New Phytologist. - Hoboken, USA : Wiley. - 0028-646X .- 1469-8137. ; 211:3, s. 874-885
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Tidskriftsartikel (refereegranskat)abstract
- Extramatrical mycelia (EMM) of ectomycorrhizal fungi are important in carbon (C) and nitrogen (N) cycling in forests, but poor knowledge about EMM biomass and necromass turnovers makes the quantification of their role problematic. We studied the impacts of elevated CO2 and N fertilization on EMM production and turnover in a Pinus taeda forest. EMM C was determined by the analysis of ergosterol (biomass), chitin (total bio- and necromass) and total organic C (TOC) of sand-filled mycelium in-growth bags. The production and turnover of EMM bio- and necromass and total C were estimated by modelling. N fertilization reduced the standing EMM biomass C to 57% and its production to 51% of the control (from 238 to 122 kg C ha-1 yr-1), whereas elevated CO2 had no detectable effects. Biomass turnover was high (~13 yr-1) and unchanged by the treatments. Necromass turnover was slow and was reduced from 1.5 yr-1 in the control to 0.65 yr-1 in the N-fertilized treatment. However, TOC data did not support an N effect on necromass turnover. An estimated EMM production ranging from 2.5 to 6% of net primary production stresses the importance of its inclusion in C models. A slow EMM necromass turnover indicates an importance in building up forest humus.
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| 3. |
- Mikusinska, Anna, et al.
(författare)
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Quantifying landscape change during the last two centuries in Bialowieza Primeval Forest
- 2013
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Ingår i: Applied Vegetation Science. - 1402-2001 .- 1654-109X. ; 16:2, s. 217-226
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Tidskriftsartikel (refereegranskat)abstract
- QuestionWhat changes in character and extent of land use have occurred during the last 200yr in the Biaowiea Primeval Forest (BPF)? Are the landscape transformations described from the multi-temporal analysis of historical maps coherent with vegetation changes expressed by the previous palynological analyses?LocationBiaowiea Primeval Forest, PolishBelarusian border. MethodsWe used five historical maps (from 1793 to 1936) and one digital land-use map (19992000) to quantify the landscape changes. Land-use types according to historical maps were digitized and georeferenced. The maps were then used for both comparing the extent of cover types in each time step and analysing the nature of change through transition matrices. The sequence of changes concerning the proportion of land-use types was then compared with classes of pollen, which were assumed to represent corresponding vegetation types. ResultsMost of the area (>70%) has been continuously covered with forest. In the period between 1793 and 1830, the forest declined, being the main donor to agricultural land and villages. In the 20th century, the trend was reversed. We found a significant correlation between the percentage of the main vegetation types derived from historical maps and the corresponding vegetation types, as indicated by pollen, with a mean time lag of 20yr. ConclusionThe BPF landscape has been quite stable throughout the last 200yr, mainly due to the high continuity of forest cover. The results obtained from landscape analysis based on maps are coherent with pollen data collected in the same area.
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| 4. |
- Mikusinska, Anna, et al.
(författare)
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Response of ectomycorrhizal extramatrical mycelium production and isotopic composition to in-growth bag size and soil fauna
- 2013
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 66, s. 154-162
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Tidskriftsartikel (refereegranskat)abstract
- In-growth bags are increasingly used to study extramatrical mycelium (EMM) of ectomycorrhizal fungi in forest soils. In this paper we tested whether bag size and presence of soil fauna in bags influence the production, isotopic composition, carbon (C) and nitrogen (N) content of the EMM. Cylindrical in-growth mesh bags (2- or 5-cm-diameter; with or without openings - (1 or 2 mm), allowing faunal colonization or not) were harvested 37, 48, 81 and 283 days after installation in July and the EMM biomass was determined from elemental analyses of the extractable amount of mycelia. The occurrence of openings allowed animals to invade the bags but this did not affect the amount of EMM. We suggest further studies in this matter since the number of animals was low and variable. In the first harvest, mycelial biomass C was three times greater in 2-cm than in 5-cm-bags. After 81 days, mycelial biomass C was 54% greater in the 2-cm (54 kg ha(-1)) than in the 5-cm bags (35 kg ha(-1)). While total mycelial C did not change over winter, N content increased suggesting a role for the EMM in the storage of N from autumn to spring. The delta C-13 and delta N-15 of the EMM changed between the first three harvests. We hypothesize these changes to be mainly driven by changes in plant C and N sinks. The relation between the isotopic composition of sporocarp exploration type, plant roots and EMM is discussed. (C) 2013 Elsevier Ltd. All rights reserved.
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