TY - JOUR A1 - Stein, Claudia A1 - Unsicker, Sybille B. A1 - Kahmen, Ansgar A1 - Wagner, Markus A1 - Audorff, Volker A1 - Auge, Harald A1 - Prati, Daniel A1 - Weisser, Wolfgang W. T1 - Impact of invertebrate herbivory in grasslands depends on plant species diversity N2 - Invertebrate herbivores are ubiquitous in most terrestrial ecosystems, and theory predicts that their impact on plant community biomass should depend on diversity and productivity of the associated plant communities. To elucidate general patterns in the relationship between invertebrate herbivory, plant diversity, and productivity, we carried out a long-term herbivore exclusion experiment at multiple grassland sites in a mountainous landscape of central Germany. Over a period of five years, we used above-and belowground insecticides as well as a molluscicide to manipulate invertebrate herbivory at 14 grassland sites, covering a wide range of plant species diversity (13-38 species/m(2)) and aboveground plant productivity (272-1125 g.m(-2).yr(-1)), where plant species richness and productivity of the sites were not significantly correlated. Herbivore exclusion had significant effects on the plant communities: it decreased plant species richness and evenness, and it altered plant community composition. In particular, exclusion of belowground herbivores promoted grasses at the expense of herbs. In contrast to our expectation, herbivore effects on plant community biomass were not influenced by productivity. However, effect size of invertebrate herbivores was negatively correlated with plant diversity of the grasslands: the effect of herbivory on biomass tended to be negative at sites of high diversity and positive at sites of low diversity. In general, the effects of aboveground herbivores were relatively small as compared to belowground herbivores, which were important drivers of plant community composition. Our study is the first to show that variation in the effects of invertebrate herbivory on plant communities across a landscape is significantly influenced by plant species richness. Y1 - 2010 UR - http://esapubs.org/esapubs/journals/ecology.htm U6 - https://doi.org/10.1890/09-0600.1 SN - 0012-9658 ER - TY - JOUR A1 - Stein, Claudia A1 - Rißmann, Cornelia A1 - Hempel, Stefan A1 - Renker, Carsten A1 - Buscot, Francois A1 - Prati, Daniel A1 - Auge, Harald T1 - Interactive effects of mycorrhizae and a root hemiparasite on plant community productivity and diversity N2 - 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. Y1 - 2009 UR - http://www.springerlink.com/content/100458 U6 - https://doi.org/10.1007/s00442-008-1192-x SN - 0029-8549 ER - TY - THES A1 - Stein, Claudia T1 - Biodiversity and ecosystem functioning : regional and local determinants of plant diversity in montane grasslands T2 - PhD dissertation / Helmholtz Centre for Environmental Research , UFZ Y1 - 2008 VL - 2008, 11 PB - UFZ CY - Leipzig ER -