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Stipitate hydnoid fungi are considered to be rare in the United Kingdom based on infrequent and localised observations of fruit bodies. Here, we investigate whether the production of stipitate hydnoid fruit bodies is related to weather conditions using a 14 year standardised survey of 11 species associated with Scots pine. Fruit body production was highly variable over time and asynchronous between species. Relationships with climatic predictors were variable between species, however both overall abundance and species richness of stipitate hydnoid fruit bodies were related to rainfall. These results suggest that climatic conditions in the preceding months can influence the likelihood of observing stipitate hydnoid fruit bodies, but that a large part of variation in fruiting of these taxa remains unexplained. [ABSTRACT FROM AUTHOR]

Moss-sedge heath, an important habitat of oceanic alpine regions, is under threat from elevated nitrogen (N) deposition and rising temperatures increasing decomposition rates and fragmentation of the extensive, thick moss mats of Racomitrium lanuginosum which characterise this habitat. Here, we examine the potential effects of N deposition and temperature on fungal communities associated with R. lanuginosum mats. Fungal community composition in both green moss shoots and underlying soil were significantly influenced by mat temperatures and green moss shoot N contents. Total OTU, Ascomycota, Basidiomycota and saprotrophic fungal richness in shoots were all positively related to temperature, while in soil, the richness of all groups, except Basidiomycota, was positively related to moss tissue N. The observed community changes suggest that increased N loading and increasing temperatures are ameliorating growing conditions for fungi associated with moss-sedge heath. Further study is required to determine if the observed changes in fungal communities contribute to accelerated decomposition of moss mats and degradation of the habitat. • Alpine moss-sedge heath degradation is linked to N deposition and climate change. • Moss-sedge heath fungal communities are species rich and structured by N deposition and temperature. • Nitrogen enrichment and temperature appear to ameliorate conditions for fungi. • Further studies are required to test possible links between habitat loss and increased fungal species richness. [ABSTRACT FROM AUTHOR]

Ectomycorrhizas (ECM) are dual organs formed between the terminal feeder roots of many plant species and certain soil fungi. The species richness and taxonomic diversity of ECM symbionts is impressive: ca. 7-10,000 fungal and ca. 8,000 plant species may be capable of forming ECM. The latter are the dominant components of forest and woodland ecosystems over much of the earth''s surface. The obligate nature of the symbiosis for ECM fungi has been brought into question by reports that some species produce sporocarps under field conditions in the absence of a host plant. We suggest that there is no unequivocal evidence to support this. The spread of tree roots is often underestimated and small, overlooked hosts such as dwarf Salix spp or sedges may explain the appearance of ECM sporocarps in vegetation apparently devoid of ECM hosts. Compared to plant material, the sporocarps of ECM fungi contain high concentrations of N and P. We show that it would take between 3 and 14 million mycorrhizal tips, or 1800 km of hyphae, to supply the N in one sporocarp of Boletus edulis. The mantle formed by the fungus over the root tip is the likely site of storage for the N and P required for sporocarp production, and we discuss the chemical and structural mechanisms developed on mantles by ECM fungi to defend this resource against fungivory. [Copyright &y& Elsevier]

Two willow clones, Salix viminalis L. and S. dasyclados Wimm., growing in separate blocks in mineral soil in one short-rotation forestry (SRF) plantation in Estonia, were analysed to compare the frequency, structure and species composition of ectomycorrhizal (EM) colonisation on their fine roots. Salix dasyclados had significantly greater EM colonisation on root tips (94%) than S. viminalis (75%). The development of EM and associated fungal structures in fine roots (Hartig net, mantle, Hartig net and mantle combined, surface hyphae, endophyte) was similar for both Salix clones. Nine groups of ectomycorrhizal tips were distinguished on the basis of morphological characterisation. Due to high variability among samples, no significant differences between the Salix clones could be found with respect to the abundance of these morphological groups. In total, nine fungal taxa were identified as fungal associates of the two Salix clones. Identification was based upon amplifying and sequencing the rDNA-ITS region of the fungal associates of the root tips. Phialophora finlandia was the most common fungal associate. Morphological groups with well-defined features (e.g., Tomentella sp.) showed limited taxonomic variation, while groups with ill-defined features contained wider taxonomic variation, including unrelated species (e.g., Laccaria sp., Hebeloma helodes). EM fungal diversity was low and largely comprised species considered as pioneer or early stage fungi. A tendency towards higher EM levels with higher N and organic matter concentrations, and low pH, P and K concentrations were observed when the mean levels of EM colonisation were compared with soil variables. It is suggested that EM colonisation level may be primarily determined by the tree species but that local soil nutrient status also influences colonisation. The quality of root litter produced by the Salix clones is known to differ and this may have a role in determining EM colonisation. [Copyright &y& Elsevier]