title: Interactive effects of mycorrhizae and a root hemiparasite on plant community productivity and diversity.
abstract: Plant communities can be affected both by arbuscular mycorrhizal fungi (AMF) and hemiparasitic plants. However, little is known about the interactive effects of these two biotic factors on the productivity and diversity of plant communities. To address this question, we set up a greenhouse study in which different AMF inocula and a hemiparasitic plant (Rhinanthus minor) were added to experimental grassland communities in a fully factorial design. In addition, single plants of each species in the grassland community were grown with the same treatments to distinguish direct AMF effects from indirect effects via plant competition. We found that AMF changed plant community structure by influencing the plant species differently. At the community level, AMF decreased the productivity by 15-24%, depending on the particular AMF treatment, mainly because two dominant species, Holcus lanatus and Plantago lanceolata, showed a negative mycorrhizal dependency. Concomitantly, plant diversity increased due to AMF inoculation and was highest in the treatment with a combination of two commercial AM strains. AMF had a positive effect on growth of the hemiparasite, and thereby induced a negative impact of the hemiparasite on host plant biomass which was not found in non-inoculated communities. However, the hemiparasite did not increase plant diversity. Our results highlight the importance of interactions with soil microbes for plant community structure and that these indirect effects can vary among AMF treatments. We conclude that mutualistic interactions with AMF, but not antagonistic interactions with a root hemiparasite, promote plant diversity in this grassland community.
authors.affiliation: Department of Community Ecology, UFZ, Helmholtz Centre for Environmental Research, Theodor-Lieser-Strasse 4, 06120, Halle, Germany. claudia.stein@ufz.de
authors.forename: Claudia
authors.initials: C
authors.lastname: Stein
authors.forename: Cornelia
authors.initials: C
authors.lastname: Rissmann
authors.forename: Stefan
authors.initials: S
authors.lastname: Hempel
authors.forename: Carsten
authors.initials: C
authors.lastname: Renker
authors.forename: François
authors.initials: F
authors.lastname: Buscot
authors.forename: Daniel
authors.initials: D
authors.lastname: Prati
authors.forename: Harald
authors.initials: H
authors.lastname: Auge
mesh_terms: D017753:Ecosystem; D006790:Host-Parasite Interactions; D038821:Mycorrhizae / Q000502:physiology*; D018517:Plant Roots / Q000469:parasitology*; D010944:Plants / Q000382:microbiology* / Q000469:parasitology*