Seven years of carbon dioxide enrichment, nitrogen fertilization and plant diversity influence arbuscular mycorrhizal fungi in a grassland ecosystem

• Published in: The New phytologist 2011-10, Vol.192 (1), p.200-214
• Main Authors: Antoninka, Anita, Reich, Peter B., Johnson, Nancy Collins
• Format: Article
• Language: English
• Subjects: Abundance; arbuscular mycorrhiza; Arbuscular mycorrhizas; Availability; Biodiversity; Biological fertilization; Biomass; Carbon dioxide; Carbon Dioxide - pharmacology; Carbon sequestration; CO2 enrichment; Coastal inlets; Community composition; Composition; Ecosystem; Enrichment; Environmental changes; Fertilization; Fertilizers; Functional groups; Fungal spores; Fungi; grassland; Grasslands; Herbivores; Host plants; Hyphae; Hyphae - drug effects; Minnesota; Models, Biological; Monoculture; Monoculture (aquaculture); Multivariate statistical analysis; Mycorrhizae - drug effects; Mycorrhizae - physiology; Mycorrhizal fungi; niche partitioning hypothesis; Nitrogen; Nitrogen - pharmacology; Nitrogen enrichment; nitrogen fertilization; Plant communities; Plant diversity; plant richness; Plant Shoots - drug effects; Plant Shoots - growth & development; Plant species; Plant spores; Plants; Poaceae - microbiology; Polyculture; Polyculture (aquaculture); Resource availability; Slope stability; Soil; Soil ecology; Soil fungi; Soil Microbiology; Soil stability; Spores; Spores, Fungal - drug effects; Spores, Fungal - physiology; structural equation model; Structural equation modeling
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2011.03776.x

We tested the prediction that the abundance and diversity of arbuscular mycorrhizal (AM) fungi are influenced by resource availability and plant community composition by examining the joint effects of carbon dioxide (CO ₂ ) enrichment, nitrogen (N) fertilization and plant diversity on AM fungi. We quantified AM fungal spores and extramatrical hyphae in 176 plots after 7 yr of treatment with all combinations of ambient or elevated CO ₂ (368 or 560 ppm), with or without N fertilization (0 or 4 g N mˉ² ), and one (monoculture) or 16 host plant species (polyculture) in the BioCON field experiment at Cedar Creek Ecosystem Science Reserve, Minnesota, USA. Extramatrical hyphal lengths were increased by CO ₂ enrichment, whereas AM spore abundance decreased with N fertilization. Spore abundance, morphotype richness and extramatrical hyphal lengths were all greater in monoculture plots. A structural equation model showed AM fungal biovolume was most influenced by CO ₂ enrichment, plant community composition and plant richness, whereas spore richness was most influenced by fungal biovolume, plant community composition and plant richness. Arbuscular mycorrhizal fungi responded to differences in host community and resource availability, suggesting that mycorrhizal functions, such as carbon sequestration and soil stability, will be affected by global change.