Ordination of the community composition of fungal fruiting species based on constrained correspondence analysis (CCA). Abundance data were square-root transformed. We used year, canopy openness, size, local dead-wood amount and local dead-wood heterogeneity as constraint environmental variables. Displayed are the two main drivers of the community composition, namely host species and canopy openness. Size had a minor effect (see Table 2). Note that most of our environmental variables are factorial treatments, which cannot be easily displayed as arrows within the CCA. Angiosperm tree image by Michele M. Tobias (phylopic.org).
Independent effects of host and environment on the diversity of wood-inhabiting fungi
FS Krah, S Seibold, R Brandl, P Baldrian, J Müller, C Bässler
Dead wood is a habitat for numerous fungal species,many of which are important agents of decomposition. Previous studies suggested that wood-inhabiting fungal communities are affected by climate, availability of dead wood in the surrounding landscape and characteristics of the colonized dead-wood object (e.g. host tree species). These findings indicate that different filters structure fungal communi- ties at different scales, but how these factors individually drive fungal fruiting di- versity on dead-wood objects is unknown. 2. We conducted an orthogonal experiment comprising 180 plots (0.1 ha) in a ran- dom block design and measured fungal fruit body richness and community com- position on 720 dead-wood objects over the first 4 years of succession. The experiment allowed us to disentangle the effects of the host (beech and fir; logs and branches) and the environment (microclimate: sunny and shady plots; local dead wood: amount and heterogeneity of dead wood added to plot). 3. Variance partitioning revealed that the host was more important than the envi- ronment for the diversity of wood-inhabiting fungi. A more detailed model re- vealed that host tree species had the highest independent effect on richness and community composition of fruiting species of fungi. Host size had significant but low independent effects on richness and community composition of fruiting spe- cies. Canopy openness significantly affected the community composition of fruit- ing species. By contrast, neither local amount nor heterogeneity of dead wood significantly affected the fungal diversity measures. 4. Synthesis. Our study identified host tree species as a more important driver of the diversity of wood-inhabiting fungi than the environment, which suggests a host- centred filter of this diversity in the early phase of the decomposition process. For the conservation of wood-inhabiting fungi, a high variety of host species in various microclimates is more important than the availability of dead wood at the stand level.