Temperate forest understorey species performance is altered by local arbuscular mycorrhizal fungal communities from stands of different successional stages

Arbuscular mycorrhizal (AM) fungal communities in plant roots vary in space and time. However, the effect of different fungal communities on plant performance and growth is poorly understood. We test the effect of two AM fungal communities originating from successionally young and old forest stands on eight forest plant species. Two plant species (Geranium pratense, Prunella vulgaris) showed greater positive mycorrhizal growth response to old forest than to young forest inoculum. Hypericum maculatum showed higher positive growth response to old forest inoculum with respect to shoot biomass and Veronica chamaedrys with respect to root biomass. Fragaria vesca, Plantago lanceolata and Primula veris showed no difference in response to old and young forest inoculum, Solidago virgaurea grew better with young forest inoculum. The naturally growing plant individuals of G. pratense and P. vulgaris were also significantly larger in old stands. The effect of AM fungal communities from differently managed forests resulted in different growth of forest plant species; the old growth inoculum exhibited in general a more positive effect than inoculum from young forest. Because land use affects the composition of AM fungal communities, the response of plant communities to forest management intensity may be mediated by mycorrhizal interactions.