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Bryophytes are a dominant and functionally important component of the forest floor vegetation in boreal forests, yet little is known about the fungal diversity associated with these abundant plants. Using molecular identification, we document an ecologically and phylogenetically diverse array of fungi associated with the living parts of three widespread and abundant boreal forest bryophytes, i.e., Hylocomium splendens (Hedw.) Schimp. in B.S.G., Pleurozium schreberi (Brid.) Mitt., and Polytrichum commune Hedw. From 376 cloned ITS sequences, 158 operational taxonomic units (OTUs), roughly corresponding to the number of species, were defined based on sequence similarity searches (Fasta) and phylogenetic analyses. A main portion (62.8%) of the OTUs belonged to Ascomycota, 32.0% to Basidiomycota, 3.9% to Chytridiomycota, and 1.3% to Glomeromycota. The most common orders were Helotiales (18.6%), Agaricales (11.5%), Chaetothyriales (9.6%), and Tremellales (9.0%). Frequently detected OTUs of potentially high ecologic importance included two with high sequence similarity (>99%) to the agaric Entoloma conferendum (Britzelm.) Noordel and the endophyte Lophodermium piceae (Fckl.) Hoehn., and various OTUs with affinity to the Helotian genus Hyphodiscus. Several ectomycorrhiza-forming basidiomycetes were also detected. Most OTUs (77.2%) were only detected once and a very small overlap in composition of OTUs was observed among the three bryophytes, indicating the occurrence of an immense fungal diversity associated with boreal forest bryophytes that deserves further study. Key words: bryophytes, boreal forest, endophytes, environmental sampling, rRNA ITS sequence, moss. Les bryophytes constituent une part importante dominante et fonctionnelle de la vegetation des parterres forestiers en foret boreale, pourtant on connait peu de choses sur la diversite fongique associee a ces plantes abondantes. A l'aide de l'identification moleculaire, les auteurs ont etudie un ensemble ecologiquement et phylogenetiquement diversifie de champignons associes aux parties vivantes de trois bryophytes abondantes et largement distribuees dans la foret boreale, soient les Hylocomium splendens (Hedw.) Schimp. in B.S.G., Pleurozium schreberi (Brid.) Mitt. et Polytrichum commune Hedw. A partir de 376 sequences ITS clonees et en appliquant des recherches de similarite de sequences (Fasta) et des analyses phylogenetiques, les auteurs ont defini 158 unites taxonomiques operationnelles (OTU's) correspondant en gros au nombre d'especes. La majorite (62,8%) des OTU's appartiennent aux Ascomycota, 32,0% aux Basidiomycota, 3,9% aux Chytridiomycota et 1,3% aux Glomeromycota. Les Helotiales (18,6%, les Agaricales (11,5%), les Chaetothyriales (9,6%) et les Tremellales, constituent les principaux ordres. Parmi les OTU's de grande importance ecologique frequemment reperes on en retrouve deux avec forte ressemblance de sequences (>99%) avec l'agaric Entoloma conferendum (Britzelm.) Noordel et l'endophyte Lophodermium piceae (Fckl.) Hoehn., ainsi que divers OTU's ayant des affinites avec les Helotiales du genre Hyphodiscus. On retrouve egalement plusieurs basidiomycetes mycorhiziens. La plupart des OTU's n'apparaissent qu'une seule fois (72,2%) et on observe un tres faible recouvrement des OTU's pour l'ensemble des trois bryophytes, ce qui indique le besoin de poursuivre les etudes sur l'immense diversite fongique associee aux bryophytes de la foret boreale. Mots-cles : bryophytes, foret boreale, endophytes, echantillon environnemental, sequence rARN ITS, mousse., Introduction Bryophytes are dominating constituents of the forest floor vegetation in boreal forests, which make up the world's second largest terrestrial biome covering ca. 1.4 x [10.sup.7] [km.sup.2] of the [...]

Abstract: We investigated soil microbial community structure by phospholipid fatty acid (PLFA) analysis in a mature boreal spruce forest landscape in southern Norway, with low diversity of vascular plants. We [...]

Swamp forests in the boreal part of Sweden are dominated by Norway spruce (Picea abies). These forests typically grow on peat deposits with a water table that is often situated [...]

European beech Fagus sylvatica and Norway spruce Picea abies are economically and ecologically important forest trees in large parts of Europe. Today, the beech forest reaches its northern distribution limit in south-eastern Norway and it is expected to expand northwards due to climate warming. This expansion will likely result in fundamental ecosystem changes. To increase our knowledge about the competitive balance between spruce and beech, we have investigated how beech and spruce litter affect spruce seedling emergence, growth and uptake of C and N. We did this in a seed-sowing experiment that included litter layer removal as well as reciprocal transplantations of litter layers between spruce and beech forests. Our results show that spruce seedling emergence was significantly impaired by both litter layer types, and especially so by the beech litter layer in the beech forest. The low seedling emergence in beech forests is concurrent with their lower light availability. [ABSTRACT FROM AUTHOR]

European beech and Norway spruce are late successional tree species that have become rapidly dominant in northern Europe in late-Holocene. The northern distribution limit for natural beech forests is in SE Norway, where beech forests and boreal spruce forests meet. Here we have estimated the size, composition and age of the macroscopic charcoal pool to infer past fire history and the establishment of neighbouring Norwegian beech- and spruce forests. To encompass landscape level scales of variations in the charcoal pool, we have analysed the charcoal record in 100 soil cores that were collected using a restricted random procedure. The sizes of the soil charcoal pools ranged from 2 to 1214 g m−2, and they were significantly more spatially variable in the beech forest landscape than in the spruce forest landscape. We show that today’s beech forests took over the dominance from Norway spruce in the landscape about 300 years ago, and that fire disturbances on the landscape level preceded the establishment of beech in the former spruce forest landscape. Interestingly, large-scale fire disturbances have not occurred ever since beech gained dominance. Conversely, we show that today’s spruce forests took over the dominance from Scots pine in the landscape, and that also the establishment of spruce was preceded by fire disturbances on the landscape level. [ABSTRACT FROM AUTHOR]

European beech and Norway spruce are late successional and competitive species meeting each other in southern Norway. Beech is predicted to expand northwards with increased temperature, implying increased competition between the two tree species. Seed survival is a key process in this competition and here we estimate detection times and predation rates of beech and spruce seeds in adjacent beech and spruce forests by combining quantitative and qualitative approaches based on reciprocal seed predation experiments and video surveillance. These experiments were repeated over two growing seasons, and by using a video-surveillance technique, we were able to precisely reveal seed detection times and high seed predation rates, up to 15 seeds min−1, with bank vole and chaffinch as main predators. Moreover, the two main predators were different in their seed preferences, that is, beech seeds were exclusively removed or predated by the vole, while the finch consumed spruce seeds only. As we show high predation rates, even small variations in seed predator population densities would impact the regeneration success of beech and spruce. Because the highest predation rates were recorded for spruce seeds, it is likely that this will alter the competitive balance between the two tree species in favour of beech. [ABSTRACT FROM PUBLISHER]

The production of pyrogenic carbon (PyC; a continuum of organic carbon (C) ranging from partially charred biomass and charcoal to soot) is a widely acknowledged C sink, with the latest estimates indicating that ~50% of the PyC produced by vegetation fires potentially sequesters C over centuries. Nevertheless, the quantitative importance of PyC in the global C balance remains contentious, and therefore, PyC is rarely considered in global C cycle and climate studies. Here we examine the robustness of existing evidence and identify the main research gaps in the production, fluxes and fate of PyC from vegetation fires. Much of the previous work on PyC production has focused on selected components of total PyC generated in vegetation fires, likely leading to underestimates. We suggest that global PyC production could be in the range of 116-385 Tg C yr-1, that is ~0.2-0.6% of the annual terrestrial net primary production. According to our estimations, atmospheric emissions of soot/black C might be a smaller fraction of total PyC (<2%) than previously reported. Research on the fate of PyC in the environment has mainly focused on its degradation pathways, and its accumulation and resilience either in situ (surface soils) or in ultimate sinks (marine sediments). Off-site transport, transformation and PyC storage in intermediate pools are often overlooked, which could explain the fate of a substantial fraction of the PyC mobilized annually. We propose new research directions addressing gaps in the global PyC cycle to fully understand the importance of the products of burning in global C cycle dynamics. [ABSTRACT FROM AUTHOR]