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Aim Fungi are drivers of wood decay in forested ecosystem, while bryophytes use dead wood as a platform for their autotrophic lifestyle. We tested the hypothesis that fungal communities on beech logs are mainly structured by substrate quality, while bryophyte communities are structured by climatic gradients. In addition, we tested whether community structure in both organism groups is altered along a gradient from nearly pristine forest to forests heavily affected by management and human disturbance in the past. Location Europe. Methods We surveyed 1207 fallen beech logs in 26 of the best‐preserved forest stands across six European countries, representing a gradient in overall naturalness of the forest landscape. Recorded species were classified into ecological guilds. Indirect ordination and variation partitioning was used to analyse the relationship between species composition and environmental variables, recorded at log or site level. Results In total, 10,367 bryophyte and 15,575 fungal records were made, representing 157 and 272 species, respectively. Fungal communities were more clearly structured by substrate quality than were bryophyte communities. In both groups a distinct turnover in species composition was evident along a longitudinal gradient from Central to Western Europe. Fungi specialized in trunk rot and specialized epixylic bryophytes were scarcely represented in Atlantic regions, and partly replaced by species belonging to less specialized guilds. Variables related to climate and forest conditions were confounded along this main geographical gradient in community composition. Main conclusions We found that bryophyte and fungal communities co‐occurring on fallen beech logs in European beech forest reserves differed in their responses to biogeographical drivers and local‐scale habitat filters. Both groups responded to major gradients in climate and forest conditions, but the loss of specialist guilds in degraded forest landscapes points to a functionally important effect of forest landscape degradation at the European continental scale.

Bryophyte and fungal communities were investigated on fallen trees representing seven deciduous tree species in a mixed near natural nemoral forest. Bryophytes were represented by 41 taxa, including several very frequent species. Of the 296 fungal species, most were recorded with very low frequency and the share of high frequent species was much lower than among the bryophytes. Species turnover was bigger in the fungal communities, compared to the bryophyte communities, and related to a higher extent to measured differences in environmental conditions. Tree species diversity was found to be an important factor for fungal species composition, while only small differences in bryophyte species composition were found between the different tree species. On the other hand bryophyte species richness showed distinct relations to tree species and microclimatic variables, a tendency which was not evident for fungal diversity. It is concluded that the two organism groups to some extent differ in their conservation demands. Thus, conservation of wood-inhabiting bryophytes requires prioritising of large, coherent forest stands in which a stable humid microclimate and a reasonable supply of dead wood is secured. Successful conservation of fungi requires that substantial amounts of dead wood are left for natural decay in a variety of natural forest environments representing different tree species, so that heterogeneity in dead wood types is secured.

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Aude, E. and Ejrnaes, R. 2005. Bryophyte colonisation in experimental microcosms: the role of nutrients, defoliation and vascular vegetation. Á/ Oikos 109: 323 Á/330.A three-year multi-factorial microcosm experiment simulating fertilisation, defoliation and the composition of vascular vegetation in a dry grassland succession was used to test four hypotheses concerning the establishment and survival of bryophytes in grassland vegetation. H 1 : bryophyte cover may be used to predict bryophyte species richness. H 2 : bryophyte richness is suppressed at high nutrient levels and promoted by defoliation of vascular plants. H 3 : species richness of bryophytes is influenced by the species composition of the vascular vegetation. H 4 : bryophyte species richness is negatively correlated with vascular plant biomass.The relationship between bryophyte richness and bryophyte cover was found to follow the classical species-area richness curve. Bryophyte species richness responded positively to defoliation and negatively to fertilisation. The species composition of vascular vegetation had no significant effect on bryophyte richness. Bryophyte species richness was lower at high vascular plant biomass and vascular plant dry weight above 400 g m (2 appeared fatal to bryophytes. At high nutrient levels, defoliation increased bryophyte richness, but defoliation did not fully compensate for the negative effect of fertilisation. The study reinforces the concern for short lived shuttle bryophytes in the agricultural landscape.