Wood-inhabiting Fungal Communities Research Articles

Species associations during the succession of wood-inhabiting fungal communities

We studied fungal succession in decaying wood by compiling time-series data of fruit body observations. We tested the hypothesis that the presence of a primary species affects the probability of a succeeding species occurring later on the same log. Significant associations were detected for 15 species pairs; these were consistent with earlier findings on cooccurrence patterns in single time surveys. We used enrichment analysis to test if species with particular life-history attributes were more often associated with the occurrence of a succeeding species, or vice versa. White rot fungi and fungi abundant as mycelia were more often associated with the occurrence of succeeding species, compared to brown rot fungi and species with low mycelial abundance. Our results indicate that certain primary species cause priority effects and non-random co-occurrence patterns in the field. These successional patterns are likely to be connected both with substrate modification and species interactions.

Loss of diversity in wood-inhabiting fungal communities affects decomposition activity in Norway spruce wood

Hundreds of wood-inhabiting fungal species are now threatened, principally due to a lack of dead wood in intensively managed forests, but the consequences of reduced fungal diversity on ecosystem functioning are not known. Several experiments have shown that primary productivity is negatively affected by a loss of species, but the effects of microbial diversity on decomposition are less studied. We studied the relationship between fungal diversity and the in vitro decomposition rate of slightly, moderately and heavily decayed Picea abies wood with indigenous fungal communities that were diluted to examine the influence of diversity. Respiration rate, wood-degrading hydrolytic enzymes and fungal community structure were assessed during a 16-week incubation. The number of observed OTUs in DGGE was used as a measure of fungal diversity. Respiration rate increased between early- and late-decay stages. Reduced fungal diversity was associated with lower respiration rates during intermediate stages of decay, but no effects were detected at later stages. The activity of hydrolytic enzymes varied among decay stages and fungal dilutions. Our results suggest that functioning of highly diverse communities of the late-decay stage were more resistant to the loss of diversity than less diverse communities of early decomposers. This indicates the accumulation of functional redundancy during the succession of the fungal community in decomposing substrates.

Fungi ahoy! Diversity on marine wooden substrata in the high North

Marine fungi are severely understudied in the polar regions. We used molecularly identified cultures to study fungi inhabiting 50 intertidal and sea-floor logs along the North Norwegian coast. The aim was to explore the taxonomic and ecological diversity and to examine factors shaping the marine wood-inhabiting fungal communities. The 577 pure cultures analyzed clustered into 147 operational taxonomic units (OTUs) based on 97 % ITS sequence similarity. Ascomycota dominated, but OTUs belonging to Basidiomycota, Mucoromycotina and Chytridiomycota were also isolated. Nine OTUs could not be assigned to any fungal phylum. Almost half of the OTUs were considered non-marine. The western and eastern part of the Norwegian Barents Sea coast hosted different communities. Geography, substratum and site level variables contributed to shaping these communities. We characterized a previously overlooked fungal community in a poorly studied area, discovered high diversity and report many taxa for the first time from the marine environment.

Response of wood-inhabiting fungal community to fragmentation in a beech forest landscape

Fragmentation of natural habitats has become one of the main causes of the loss of biodiversity. To assess the effects of forest fragmentation on wood-inhabiting fungal community in a beech-dominated landscape, 15 differently shaped beech forest fragments were examined in northern Spain. This work covers all the wood-inhabiting macromycetes, including Basidiomycota and Ascomycota. A modelling approach was used to examine the predictability of the fungal community in a fragmented beech forest landscape. In the beech forest patches, a large proportion of edge, low tree densities and low levels of variety of woody debris caused a decrease of wood-inhabiting fungal richness. The fungal community composition proved complex to model due to its specific traits: it is made up of many species, most of which are rare, and each fungal group responds differently to environmental variables. Nevertheless, the dead wood availability and the exposure to light significantly affected the fungal community composition.

Linking forest history and conservation efforts: Long-term impact of low-intensity timber harvest on forest structure and wood-inhabiting fungi in northern Sweden

Throughout the northern hemisphere old forests with high abundance of dead wood are rare features in most landscapes today, and the loss of dead wood constitutes a serious threat to the existence of many species. This study, using field surveys and dendrochronology, examines the relationship between wood-inhabiting fungi and past forest utilisation along a gradient of early logging activity. Data were collected in three late-successional Scots pine forests in northern Sweden. Nonmetric Multidimensional Scaling (NMS) was then used to assess differences in species composition among the forests. Our results show that minor forest logging (22–26 cut stumps ha −1) carried out a century ago may have continuing effects on forest characteristics, including dead wood dynamics and the wood-inhabiting fungal community – especially the abundance of red-listed species. The most important effects are lower numbers of logs in early and intermediate stages of decomposition. Additionally, numbers of species (including red-listed species) can be high in forests that have been subject to low levels of logging. Overall, the high species numbers recorded in this study ( n = 60–87) show that old, low-productivity pine forests harbour a considerable fraction of the total diversity of Basidiomycetes in northern Fennoscandian boreal forests. We conclude that the formation of a framework linking forest history and environmental data is vital for understanding the ecology and formulating goals for future management of these forests.

Species diversity of polyporoid and corticioid fungi in northern hardwood forests with differing management histories

Effects of forest management on fungal diversity were investigated by sampling fruit bodies of polyporoid and corticioid fungi in forest stands that have different management histories. Fruit bodies were sampled in 15 northern hardwood stands in northern Wisconsin and the upper peninsula of Michigan. Sampling was conducted in five old-growth stands, five uneven-age stands, three even-age un-thinned stands and two even-age thinned stands. Plots 100 m × 60 m were established and 3000 m2 within each plot was sampled during the summers of 1996 and 1997. A total of 255 polyporoid and corticioid morphological species were identified, 46 (≈18%) of which could not be assigned to a described species. Species accumulation curves for sites and management classes differed from straight lines, although variability from year to year suggests that more than 2 y of sampling are needed to characterize annual variation. Mean species richness and diversity index values did not vary significantly by management class, although mean richness on large diameter wood (≥ 15 cm diam) varied with moderate significance. Richness values on small diameter debris varied significantly by year, indicating that a large part of year-to-year variability in total species richness is due to small diameter debris. Ten species had abundance levels that varied by management class. Two of these species, Cystostereum murraii and Rigidoporus crocatus, were most abundant in old-growth and might be good indicators of stands with old-growth characteristics. Oxyporus populinus, an important pathogen of Acer spp., was most abundant in even-age stands. Regression analyses indicated that substrate quality (diameter and species), quantity and management history of the stand were important in predicting the number of occurrences of the five most-abundant species. Changes in the diversity and species composition of the wood-inhabiting fungal community could have significant implications for the diversity, health and productivity of forest ecosystems.

Species diversity of polyporoid and corticioid fungi in northern hardwood forests with differing management histories

Effects of forest management on fungal diversity were investigated by sampling fruit bodies of polyporoid and corticioid fungi in forest stands that have different management histories. Fruit bodies were sampled in 15 northern hardwood stands in northern Wisconsin and the upper peninsula of Michigan. Sampling was conducted in five old-growth stands, five uneven-age stands, three even-age unthinned stands and two even-age thinned stands. Plots 100 m x 60 m were established and 3000 m2 within each plot was sampled during the summers of 1996 and 1997. A total of 255 polyporoid and corticioid morphological species were identified, 46 (18%) of which could not be assigned to a described species. Species accumulation curves for sites and management classes differed from straight lines, although variability from year to year suggests that more than 2 y of sampling are needed to characterize annual variation. Mean species richness and diversity index values did not vary significantly by management class, although mean richness on large diameter wood (> or = 15 cm diam) varied with moderate significance. Richness values on small diameter debris varied significantly by year, indicating that a large part of year-to-year variability in total species richness is due to small diameter debris. Ten species had abundance levels that varied by management class. Two of these species. Changes in the diversity and species composition of the wood-inhabiting fungal community could have significant implications for the diversity, health and productivity of forest ecosystems.

Wood-inhabiting fungal communities in woody debris of Norway spruce (Picea abies (L.) Karst.), as reflected by sporocarps, mycelial isolations and T-RFLP identification

Wood-inhabiting fungi play a key role in forest ecosystems and constitute an essential part of forest biodiversity. We therefore examined the composition and abundance of wood-inhabiting fungi by three methods: sporocarp counts, mycelial culturing and direct amplification of internal transcribed spacer terminal restriction fragment length polymorphism from wood combined with sequencing of reference rDNA. Seven-year-old slash piles left after a thinning were analyzed in a 50-year-old Norway spruce plantation. Fifty-eight fungal species were detected from the piled branches and treetops. More species were revealed by sporocarp counts and cultured mycelia than by direct amplification from wood. In principle, sporocarp monitoring may reveal all fruiting taxa, but it poorly reflects their relative abundance in the wood. In contrast, terminal restriction fragment length polymorphism will record the most frequent fungal taxa in the wood, but it may overlook uncommon taxa. Culturing mycelia from wood gives a bias towards species favoured by the cultural medium. The results demonstrate the advantage and the limitations of these methods to be considered in analyses of fungal communities in wood.

Comparison of macrofungi communities anti examination of macrofungi-plant interactions in forest stands in North Hungary

Parallel phyto- and mycocoenological investigations have been made since 2001 in all characteristic forest types in Borzsony Mts., North Hungary. The main aim of this work was the examination of similarities between plant and fungal communities, as well as the plant—fungi connections within certain habitats. Among the total 381 macrofungi species documented, 330 occurred in the investigated 7 forest stands. Wood-inhabiting fungal communities of coniferous stands can be separated unambiguously from those of deciduous stands. Communities of deciduous stands can be divided into two subgroups: those fructifying in wet and in semidry stands. The main factors which influence the composition of wood inhabiting fungal communities seem to be, in decreasing order: (1) crown layer composition; and (2) soil properties (probably only humidity). Wood-inhabiting fungal communities do not show any relation with the underwood layer of particular plant associations. Amongst soil inhabiting fungal communities, three groups can be separated: (1) those of coniferous stands and alderwood; (2) those of the two climax stands; and (3) those of the two edaphic deciduous stands. Classification of these communities is similar to classification of plants of underwood layers. Probably both are dependent upon soil properties (humidity and pH) of particular habitats, but the range of mycorrhizal partners is also decisive for macrofungi communities. All investigated stands are under forestry management, with low quantity of dead and infected wood, so forestry management type may have a great influence in composition of both wood and soil saprotrophic fungal communities.