Arbuscular mycorrhizal fungal community differences among European long-term observatories.

Arbuscular mycorrhizal fungal (AMF) communities have been demonstrated to respond to a variety of biotic and abiotic factors, including various aspects of land management. Numerous studies have specifically addressed the impact of land use on AMF communities, but usually have been confined to one or a few sites. In this study, soil AMF assemblages were described in four different long-term observatories (LTOs) across Europe, each of which included a site-specific high-intensity and a low-intensity land use. AMF communities were characterized on the basis of 454 sequencing of the internal transcribed spacer 2 (ITS2) rDNA region. The primary goals of this study were (i) to determine the main factors that shape AMF communities in differentially managed sites in Europe and (ii) to identify individual AMF taxa or combinations of taxa suitable for use as biomarkers of land use intensification. AMF communities were distinct among LTOs, and we detected significant effects of management type and soil properties within the sites, but not across all sites. Similarly, indicator species were identified for specific LTOs and land use types but not universally for high- or low-intensity land uses. Different subsets of soil properties, including several chemical and physical variables, were found to be able to explain an important fraction of AMF community variation alone or together with other examined factors in most sites. The important factors were different from those for other microorganisms studied in the same sites, highlighting particularities of AMF biology.