Assemblage structure, species richness, abundance, and distribution of fungal fruit bodies in a seven year plot-based survey near Vienna

Almost 900 species were encountered during a seven year survey of fungal fruit bodies in 13 forests and grasslands plots measuring about I ha. The data were comparable to those from a Swiss forest plot monitored for 21 years. Species richness and abundance were almost linearly correlated on a log/log scale. Abundance and yearly frequency of species were tightly correlated. The geographic range of species may also be related to these two parameters. Rare species scored low on abundance, yearly frequency and geographic range. About half of the species were rare, and occurred in only one out of seven years. The two major functional groups of saprotrophic and mycorrhizal species behaved similarly over the years, as in the Swiss study. Annual variation was high for species richness alone and for richness combined with abundances. The log transformed species richness of plots correlated well with parameters that take the abundances or yearly frequencies of species into account. If other mushroom assemblages show similar regularities, it may be possible to omit abundance counts in future surveys. The species composition of the plots varied strongly over the years. Many species did not reach their maximum abundance in the richest year. Species showed their maximum abundances in different plots in the same year more often than expected by chance. Thus the presence and abundance of species depended on factor(s) other than the general productivity of a year, and years showed (a) different aspect(s) than productivity alone. Long-term surveys are important for understanding the structure of mushroom assemblages and their biodiversity.