Ecological studies of ectomycorrhizal fungi: an analysis of survey methods

Abstract

In this paper, by reviewing ecological studies of ectomycorrhizal fungi where both fruiting bodies and mycorrhizal root tips were simultaneously surveyed, we investigate whether the diversity data obtained by the two methods leads to similar conclusions about the underlying ecological processes of interest. Despite discrepancies in identifying species, we found that both survey methods identified similar responses by ectomycorrhizal fungal communities to experimental manipulations, successional changes and environmental disturbances (exceptions are short-term or low-level disturbances). By analysing the results of the reviewed studies, we found a positive relationship to exist between fungal species richness and (i) the host plant age and (ii) the number of putative host plant species, independently of the applied survey method. Of the methodological variables, only the number of soil samples (for the below-ground approach) and the duration of the study (for the above-ground approach) have a significant effect on the EMF species richness, with species richness increasing with both. Our investigation also shows that in 73% of the reviewed studies (27 out of 37) a greater species richness was found by fruiting body surveys than by methods based on sampling of the root tips. Based on these findings, we argue for the continuation of fruiting body surveys in order to gain rapid and still valuable information on ecosystems over a wide spatial and temporal range and strongly recommend their use in long-term ecosystem monitoring projects.