Soil properties and soil microbial communities can greatly affect plant communities, especially in disturbed ecosystems. However, their relative contribution to the final effect on plants has rarely been assessed.
We manipulated the soil microbial community in microcosms by inoculating sterilized soils originating from preserved species-rich meadow and a restored meadow with a high and low diversity of microbial inoculum (manipulated by the dilution of microbial community extract) from those soils in full factorial manner, yielding eight treatments (2 soil origins x 2 inoculum sources x 2 levels of inoculum diversity). In general, the biomass of plant meadow specialists (Filipendula vulgaris, Phleum phleoides, and Prunella grandiflora) was greater with the preserved meadow inoculum than with the restored meadow inoculum but tended to be greater in the restored meadow soil than in the preserved meadow soil.
Two meadow generalists (Festuca rubra and Centaurea jacea) were not significantly affected by soil origin, inoculum source, or inoculum diversity, but the third generalist Plantago media produced greater biomass in the preserved meadow soil than in the restored meadow soil. Total above-ground biomass was not affected by the treatments, but total below-ground biomass was greater with microbial inoculum from the preserved meadow than from the restored meadow, and this increase was greater in the restored meadow soil than in the preserved meadow soil.
Our results indicate strong responses of the preserved meadow specialists to the soil microbial community, which may explain why they are rare in the meadows that were restored following agricultural use. Read the free Plain Language Summary for this article on the Journal blog.