Fungal diversity and community composition are mainly related to soil and vegetation factors. However, the relative contribution of the different drivers remains largely unexplored, especially in subtropical forest ecosystems. We studied the fungal diversity and community composition of soils sampled from 12 comparative study plots representing three forest age classes (Young: 10–40 yrs; Medium: 40–80 yrs; Old: > 80 yrs) in Gutianshan National Nature Reserve in South-eastern China. Soil fungal communities were assessed employing ITS rDNA pyrotag sequencing. Members of Basidiomycota and Ascomycota dominated the fungal community, with 22 putative ectomycorrhizal fungal families, where Russulaceae and Thelephoraceae were the most abundant taxa. Analysis of similarity showed that the fungal community composition significantly differed among the three forest age classes. Forest age class, elevation of the study plots, and soil organic carbon (SOC) were the most important factors shaping the fungal community composition. We found a significant correlation between plant and fungal communities at different taxonomic and functional group levels, including a strong relationship between ectomycorrhizal fungal and non-ectomycorrhizal plant communities. Our results suggest that in subtropical forests, plant species community composition is the main driver of the soil fungal diversity and community composition.

A subset of 12 CSPs were selected according to an successional age and a diversity gradient; based on the original age classifications : young (CSPs 16,17,25,26), medium (CSPs 1,5,8,9) and old (CSPs 2,4,12,13). At each CSP, samples were originally taken by SP6 at 5 cm intervals down to 50 cm, and we analysed the pooled samples taken from 9 subplots representing the first 10 cm.

The Gutianshan National Nature Reserve (NNR) is located in the western part of Zhejiang Province (29º8'18" – 29º17'29" N, 118º2'14" – 118º11'12" E, Fig. 1). The Gutianshan NNR has an area of approximately 81 km2 and was initially established as a National Forest Reserve in 1975 and became a National Nature Reserve in 2001. The NNR comprises a large portion of broad-leaved forests of advanced successional stages (Hu & Yu 2008), which have not been managed since the beginning of the 1990ies, as well as young successional stages and conifer plantations, mainly of Cunninghamia lanceolata and Pinus massoniana. --- The vegetation is composed of different types of subtropical evergreen and mixed broad-leaved forests (Yu et al. 2001). Most of the stands are secondary forests, evidenced by maximum tree ages of 180 years, by agricultural terraces in almost all plots and by the presence of charcoal in almost all soil profiles. Around the Gutianshan NRR extensive deforestation has occurred during the Great Leap Forward in the 1950s, as in most parts of Southeast China. However, due to prevailing steep slopes, the Gutianshan area was only marginally usable for agricultural activities, and thus an exceptionally intact forest cover has been preserved. --- The climate at Gutianshan NNR is warm and temperate with a short dry season in November and December and with warm summers (Fig. 2). The climatic conditions are characteristic for the subtropics with an annual average temperature of 15.1°C, January minimum temperatures of -6.8°C, July maximum temperatures of 38.1°C and an accumulated temperature sum (≥ 5°C) of 5221.5 degree days.

Samples were taken in August and September 2008 from the CSPs, taken to Germany, and analyzed in the laboratory afterward (over the next several months).

Fungal communities based on fungal IST rDNA pyrosequencing.

This data was from the PhD thesis of Yuting Wu in the group of Tesfaye Wubet.

Fungal diversity was analysed based on pyrotag sequencing of the fungal ITS rDNA using the primer pair ITS1F and ITS4. Sequences were quality filtered and clustered at a 97% sequence similarity criteria to obtain species level operational taxonomic units. Representative sequences were then used to assigned a taxonomic affiliation of the fungal OTUs (operational taxonimic units) using reference datsets. We used the relative abundance of the dominant fungal OTUs to assess the relationship between fungal and plant community composition and assess the environmental variables affecting the changes in the fungal community composition. We used R to carry out different multivariate tests.